Building Construction (2nd Edition)-ALL CHAPTERS
Building Construction (2nd Edition)
Chapter 1-Building Construction & the Fire Service
Test Review
▪ Construction methods and materials are driven by economics, changing technology, and needs of society.
▪ During the design process, full consideration is given to heights, area, exits, interior finish materials, structural assemblies, occupancy factors, sprinklers, access, exposures, building codes, alarms, and smoke management systems.
▪ The laws of physics and chemistry that govern fire behavior never change.
▪ Building variables firefighters must consider include: building age, fire protection systems, occupancy, fire loads, construction type, configuration, access, and exposures.
▪ The age of the building in itself is NOT a hazard, but rather an indication of potential hazards.
▪ Older buildings may offer advantages over newer computer-generated designs because many were built with greater structural mass than was necessary.
▪ An automatic fire protection system is the first line of defense in a building.
▪ Highly flammable materials found in body shops include: gas/diesel, plastic, tires, flammable liquids, paint, and torches.
▪ When the amount of fuel in a building is limited, fire duration and temperatures are less.
▪ Fire load is the weight of the combustible material per square foot (lbs./ft2).
▪ Fire load can be used as an estimate of the total potential heat release to which a building may be subjected if full involvement occurred.
▪ Fire load does NOT necessarily result in an equivalent structural load (ie-cast iron radiator=light fire load, very high structural load)
▪ Combinations of construction types are likely when an older structure has been enlarged or renovated.
▪ The configuration of a building refers to its general shape or layout.
▪ Building designers rarely consider fire fighting a principle design criterion.
▪ Churches, auto dealerships, and bowling alleys require large floor areas with clear spans.
▪ Vertical openings create the appearance of openness and create a means for fire communication.
▪ Access can be affected by steep slopes and narrow roads.
▪ Exposure is the heat effect from an external fire that may cause ignition of or damage to an exposed building.
▪ Exposure also means a structure or separate part of the fireground to which fire could spread.
▪ The earliest provisions of building codes were directed at the danger of conflagrations (large disastrous fire).
▪ Communication of fire from building to building occurs by means of convection or radiation.
▪ Convection is the transfer of heat by the movement of fluids or gases, usually in an upward direction.
▪ Horizontal communication of fire from building to building is mainly due to radiation.
▪ Radiation is the transfer of heat energy through light by electromagnetic waves.
▪ All bodies emit radiation at a rate dependent on their absolute temperature.
▪ An atrium is a vertical opening favored by designers for the openness it creates.
▪ Factors that affect the communication of fire include: temperature, area of exposing flame, and distance between buildings.
▪ Methods to reduce communication of fire between buildings include: building spacing, sprinkler protection, non-combustible exterior walls, parapets, free-standing barrier walls, outside water curtains, elimination of openings, glass block in wall openings, and approved roofing materials.
▪ Communicating fires can grow, resulting in a conflagration.
▪ In engineering, failure occurs when a part is "no longer capable of performing its required function satisfactorily".
▪ Building failure can mean excessive vibration, deflection, noise, or wear.
▪ To firefighters, building failure usually means structural collapse.
▪ Sources of building failure include: structural integrity, building systems, and design deficiencies.
▪ Structural integrity is related to the fire resistance and combustibility of construction materials.
▪ Building systems include: HVAC, electrical, communications, plumbing, and transportation (elevators).
▪ A very basic aspect of building safety is an adequate number of exits.
▪ An example of a design deficiency in a sprinkler system would be failure to provide an adequate water supply.
▪ Building codes only provide a "reasonable" level of protection for "common" situations, NOT special designs.
Building Construction (2nd Edition)
Chapter 2-Design Principles
Test Review
▪ Chicago architect Louis A. Sullivan's design philosophy was "form follows function".
▪ Some construction is undertaken as real estate speculation (AKA Spec Buildings).
▪ When buildings become unmarketable, they become targets for arson.
▪ In pioneer days, the appearance of a building was secondary to its structural design.
▪ The desired appearance of a building indicates the material used.
▪ Factors affecting building design include: cost, building use, aesthetics, codes, safety, accessibility, infrastructure, climate, soil, physical laws of engineering, and owner's needs/desires.
▪ Buildings whose fundamental design is determined by their use include: grain silos, aircraft hangars, fire stations, and movie theaters.
▪ To construct a building, a unit of local government such as City, County, or State, requires a building permit to be obtained.
▪ Proposed building designs must meet provisions of the local building code before a building permit can be obtained.
▪ A building code is a body of law that determines the minimum standards to which buildings must meet in the interest of community safety and health.
|Model Building Codes |
|Model |Published By |Includes |
|Uniform Building Code (UBC) |International Council of Building Officials (ICBO) |Uniform Fire Code (UFC) |
|Standard Building Code |Southern Building Code Congress International |Standard Fire Prevention Code |
|National Building Code |Building Officials & Code Administration (BOCA) International |National Fire Prevention Code |
▪ Fire safety provisions in building codes include: fire resistance, interior finish flammability, means of egress, vertical opening enclosures, fire/exposure protection, and occupancy separation.
▪ Occupant safety factors include: stair/walking surfaces, balcony railings, overhead obstacles, wiring, and elevators.
▪ Building elements affected by ADA include: entrances, loading zones, elevators, drinking fountains, toilets, alarms, phones, ATMs, and egress.
▪ Wheelchair ramps are required by the ADA.
▪ An area of refuge is a protected area in which persons who cannot use stairs may remain temporarily until they receive assistance or instructions.
▪ Area of refuge examples include: stairway landing in a smoke-proof enclosure, balcony adjacent to an exterior stair, or a protected vestibule adjacent to an exit enclosure.
▪ In area with large annual rainfall, buildings may be designed with overhangs or enclosed walkways for pedestrians.
▪ Soil strength, strain resistance, and stability are important to foundation design.
▪ Soil properties are affected by frost action, water content, seismic shock, organic decomposition, and disturbance during construction.
▪ The design and construction process consist of a concept, modeling, financing, documentation/permitting, construction, and inspection/testing.
▪ The design and construction process begins when the developer perceives a need.
▪ The owner may contract with a single firm to undertake both the design and construction of a building (AKA Design-Build Project).
▪ Design-build projects usually consist of a general contractor with its own architects and engineers on staff.
▪ Requirements of financing may include a market analysis to evaluate economic feasibility of a building project.
▪ Lending institutions may require engineering documents such as land surveys and soil test reports before financing a building project.
▪ Local building officials may or may not review the life safety and fire aspects of a facility plan submitted during the permit process.
▪ In some jurisdictions, the fire authorities have statutory authority to review building plans.
▪ "Fast Tracking" is when the design and construction phases overlap.
▪ Inspections are done by architects during construction to ensure work is completed in accordance with drawings and specifications.
▪ Testing is performed on certain materials, systems, and components such as concrete, fire pumps, and emergency generators.
▪ The usual role of fire inspectors during inspection and testing is to ensure proper installation of fire protection systems.
▪ The architect usually functions as the prime designer and chooses major aspects of the building and eliminates alternatives.
▪ Local zoning codes may require a specific type or amount of landscaping to be done in the interest of community beautification.
Building Construction (2nd Edition)
Chapter 3-Building Classifications
Test Review
▪ To firefighters, the most significant building characteristic is how a building will behave under fire conditions.
▪ The strength of wood is determined by its species and grade.
▪ Fire resistance is a collective property of materials and assemblies, and is defined as the ability to maintain load-bearing ability under fire conditions or to act as a fire barrier.
▪ Properties of materials include: combustibility, thermal conductivity, chemical composition, density, and dimensions.
▪ The fire resistance rating of an assembly is determined by test procedures simulating fire conditions and is expressed in hours.
▪ Fire resistance ratings are obtained for structural elements such as beams, columns, walls, partitions, floors, roofs, and ceilings.
▪ The primary means used to determine fire resistance ratings is to subject the component to the heat of a fire in a test furnace.
▪ Furnace temperatures for fire tests are regulated to conform to an established time-temperature curve.
▪ Fire resistance tests are used in fire protection to establish performance standards for building codes.
▪ Fire resistance tests do NOT provide information for materials other than those tested, the extent to which an assembly may generate smoke/toxic gases, passage of smoke through an assembly, fire behavior of joints between building elements, measurement of flame spread, or effect of fire endurance of openings in an assembly.
▪ Organizations that perform fire resistance testing include: Underwriters Laboratories, National Institute of Standards and Technology, Factory Mutual Research Corporation, Forest Products Laboratory, Portland Cement Association, Armstrong Cork Company, and National Gypsum Company.
▪ Underwriters Laboratories publishes the Fire Resistance Directory annually.
▪ The expansion or end rotation of an assembly will affect its ability to support a load.
▪ Computer models used to calculate fire resistance can deal with more realistic fire behavior of materials other than the traditional standard time and temperature "furnace" test procedure.
▪ Fundamentally, a non-combustible material is one that "in the form in which it is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat."
▪ Building classifications are based on the materials used in the construction and the hourly fire resistance rating of structural components.
▪ Steel is a non-combustible material but is not fire resistant and must be protected to attain fire resistance.
▪ Concrete is an inherently non-combustible material with good thermal insulating properties.
▪ Unprotected steel has NO fire resistance.
▪ The point at which unprotected members fail depends on ceiling height, dimensions of members, and intensity/duration of exposure.
Building Construction (2nd Edition)
Chapter 4-The Way Buildings Are Built - Structural Principles
Test Review
▪ To design an adequate structure, the engineer must determine the type and magnitude of forces involved.
▪ The magnitude of forces acting on a building is the most critical aspect of engineering design.
▪ A load is defined as any effect which a structure must be designed to resist.
▪ Sources of loads include: gravity, wind, earthquakes, and water/snow on the roof.
▪ Gravity exerts a force on a building through the weight of the building, all of its contents, and snow, ice and water on the roof.
|Wind Effects |
|[pic] |The impact of the wind on a surface |[pic] |Due to variations in wind |
|DIRECT PRESSURE | |ROCKING or BUFFETING |velocity |
|[pic] |The fluid effect of the wind as it |[pic] |Due to the harmonics of the |
|AERODYNAMIC DRAG |moves along a surface |VIBRATION |building |
|[pic] |A suction effect produced on the |[pic] |The tendency of moving air to |
|SUCTION (Negative Pressure) |downwind side of the building |CLEAN-OFF EFFECT |blow objects off buildings |
▪ Subterranean faults cause earthquakes.
▪ Earthquakes occur most frequently in parts of the world called Zones of High Probability (coasts of California & Alaska, Southern Illinois, & Central Utah).
▪ The forces developed by earthquakes are known as seismic forces.
▪ Lateral shaking forces created by earthquakes are usually the most damaging.
▪ Weight/height of buildings, ground condition, seismic zone, and structural system are all factors for building susceptible to earthquakes.
▪ Building codes contain engineering equations and procedures for designing buildings to withstand earthquakes.
▪ Buildings particularly essential to recovery after an earthquake, such as hospitals, emergency preparedness centers, and fire/police stations, must be designed for greater anticipated loads.
▪ Forces associated with soils may only be estimated.
▪ Soil exerts horizontal pressure against a foundation (AKA active soil pressure).
▪ The force of the foundation against the soil is called passive soil pressure.
▪ The magnitude of soil pressure depends on type of soil (clay, sand, rock), degree of cohesion, and moisture content.
▪ In determining forces created by active soil pressure, soil is assumed to behave like a fluid with zero pressure at the top of a foundation and maximum pressure at the base of the foundation.
▪ If soil supported by a foundation is not horizontal, the soil pressure will change.
▪ A dead load is the weight of any permanent part of the building.
▪ A live load is any load that is not fixed or permanent.
▪ The term live load could include seismic and wind loads but is usually applied to building contents, occupants, and the weight of snow or rain on a roof.
▪ A uniformly distributed load is applied over a large area, while a concentrated load is applied at one point over a small area.
▪ Concentrated loads produce high localized forces.
▪ The amount of snow that can accumulate on a roof depends on the slope or shape of the roof and effect of adjacent structures.
▪ Static loads are loads that are steady or applied gradually such as dead loads, snow loads, and many live loads.
▪ Dynamic loads are loads that involve motion such as wind, moving vehicles, earthquakes, vibration, and falling objects.
▪ Unlike static loads, dynamic loads are capable of delivering weight to the structure that is in excess of the object's weight.
▪ Dynamic loads have the ability to cause failure after repeated cycles such as heavy vehicle movement over time on a garage floor.
▪ When support provided by a structural system is the same as the applied loads, the structure is said to be in equilibrium.
▪ Equilibrium is lost during a collapse but is re-established after a building collapse when the building becomes a pile of debris.
▪ The forces that resist applied loads are known as reactions.
▪ The loads and forces applied to a structural member create internal forces within the member.
▪ Internal forces of structural members must be evaluated to prevent failure from cracking, crumbling, bending, or breaking.
▪ A beam that is supported at one end is a cantilever beam.
▪ The support for a cantilevered beam must resist a force called the bending moment and is equal to the force multiplied by the distance at which the bending moment is applied.
▪ Interior forces of materials, which are tension, compression, and shear, are classified according to the direction in which they occur in the material.
▪ Tension tends to pull the material apart.
▪ Compression tends to squeeze the material.
▪ Shear tends to slide one plane of the material past and adjacent plane.
▪ The strength of materials varies with the direction of internal forces.
▪ Concrete has good compressive strength, but little tensile strength.
▪ Stress is a measurement of force intensity and is expressed as force units divided by the area over which the force is applied (force / area = pounds per square inch).
▪ Exterior loads can be further classified into axial, eccentric, or torsional.
|An axial load is a load applied to the center of the cross section of a member and perpendicular to that cross |[pic] |
|section. | |
|Can be tensile or compressive and creates uniform stresses across the cross section of the material. | |
|Force is applied across a members axis. | |
|An eccentric load is a load which is perpendicular to the cross section of the structural member but does not pass |[pic] |
|through the center of the cross section. | |
|Creates stresses that vary across the cross section and may be both tensile and compressive. | |
|Bending Tendency | |
|A torsional load is offset from the center of the cross section of the member and at an angle to or in the same plane|[pic] |
|as the cross section. | |
|Produces a twisting effect that create shear stresses in the material. | |
|Twisting Tendency | |
▪ Loads that were originally axial before a fire can become eccentric or torsional during a fire.
▪ Structural components consist of beams, columns, arches, cables, trusses, and space frames.
▪ A beam is a structural member that can carry loads perpendicular to its longitudinal dimension.
▪ A simply supported beam is supported at each end and is free to rotate at the ends.
▪ Beams can be made of wood, steel, or reinforced concrete.
▪ The primary design consideration for beams is the ability to resist bending force.
▪ When a beam bends, it creates compression in the top of the beam and tension on bottom.
▪ The most efficient type of beam is the I-beam.
▪ In an I-beam, the major stresses occur in the top and bottom flanges.
▪ Columns are structural members designed to support an axial compressive load.
▪ Columns are not primarily designed to withstand stresses because of bending.
▪ Columns can be made of wood, steel, cast iron, concrete, or masonry.
▪ An arch is a curved structural member in which the interior stresses are primarily compressive.
▪ Arches develop inclined reactions at their supports.
▪ If an arch's supports shift, bending stresses may result.
▪ Arches are sometimes designed with hinges to provide minor adjustments.
▪ Arches can be constructed of masonry, steel, concrete, or laminated wood.
▪ Cables are flexible structural members used to support roofs, brace tents, and to restrain pneumatic structures.
▪ Cables used to support a load over a distance assume the shape of a parbola.
▪ Cables have tension force on them.
▪ Cables are usually made of steel strands, however, aluminum can be used where weight is of concern.
|Trusses are framed structural units made of a series of triangles in one plane. |[pic] |
|If loads are only applied at the intersection of a truss, only compression or |[pic] |
|tensile forces will be present in the members. | |
|A true truss is only made of straight members. | |
|The top members of a truss are called the top chords, and bottom members, the | |
|bottom chords. | |
|Diagonal members of a truss are called diagonals or web members. | |
|Joints in trusses are formed with either pin connections, welding, gusset plates, | |
|or strap connectors. | |
|Trusses may be made of wood, steel, or a combination of wood and steel. | |
|Trusses have the potential for early failure because any damage to top or bottom | |
|chords results in total failure of the truss. | |
|[pic] [pic] |
|[pic] |
▪ Bearing wall structures use the walls of the building for support of spanning members.
▪ Bearing walls are usually the exterior walls with the interior support system consisting of columns and beams.
▪ The walls of bearing wall structures are subjected to compressive loads.
▪ Materials used for bearing walls includes concrete masonry units, bricks, stone, and concrete panels.
▪ Bearing walls provide lateral support to the structure and mutual support where the walls intersect.
▪ The "skin" of a structural frame may provide lateral stiffness but provides no structural support, only the frame itself provides support.
▪ Types of structural frame construction include: steel stud wall framing, post & beam, rigid frame, truss frames, and slab & column.
▪ Post & Beam construction uses a series of vertical elements (posts) to support horizontal elements (beams) that are subjected to transverse loads.
▪ Post & Beam is commonly associated with wood beams and columns.
▪ Studs in Post & Beam construction may be spaced several feet apart.
▪ A rigid frame is when joints between a column and a beam are reinforced so that bending stresses can be transmitted through the joints.
▪ The most easily-recognized rigid frame structure is the single-story, gabled roof.
▪ The peak of a rigid frame roof is usually hinged to allow for slight movement of the two halves of the frame.
▪ Rigid frame can be constructed of steel, laminated wood, or reinforced concrete.
▪ The joints of rigid frame construction are typically the last portion of the structure to fail in a fire.
▪ Slab and column frames are frequently encountered in concrete structures,
▪ The intersection between the slab and column of slab & column frames is a region of high stress and is usually reinforced by additional material in the form of a capital or drop panel.
▪ Concrete slabs, wood decks, and metal decks can be used to support floor loads.
▪ Surface systems consist primarily of an enclosing surface in which the stresses resulting from the applied loads occur within the surface.
▪ Membrane structures can be supported by cable, interior framework, or by air pressure.
▪ Shell structures lend themselves to geometric shapes such as cones, domes, barrel vaults, and folded plates.
▪ Shell structures are most commonly constructed of concrete but may be of plywood or fiberglass.
Building Construction (2nd Edition)
Chapter 5-Building Materials
Test Review
▪ Materials most commonly used for construction are: wood, masonry, concrete, steel, aluminum, glass, gypsum board, plastics, and fabrics.
▪ Properties of building materials include: strength, density, appearance, durability, thermal conductivity, and resistance to corrosion and insects.
▪ Shared properties of ALL building materials include: combustibility, thermal conductivity, rate of thermal expansion, and variation of strength with temperature.
▪ Wood is never dimensionally true.
▪ Wood does not swell or shrink uniformly.
▪ The strength of wood varies significantly with species, grade, and direction of load with respect to grain.
▪ The strength of wood is affected by moisture content.
▪ Lumber can be defined as lengths of squared lumber used for construction.
▪ Laminated members are produced by joining small, flat strips of wood with glue (AKA glulam).
▪ Laminated members can be formed into curves.
|With laminated members, scarf joints permit the glue to transmit tensile and compressive forces |[pic]SCARF JOINT |
|along the length of the member. | |
|Laminating permits higher quality control than solid members. | |
▪ Plywood is made from several thin veneer layers that are sliced from logs and glued together.
▪ Composite panels are produced with parallel external face veneers bonded to a core of reconstituted fibers.
▪ Wafer board and particle board are both produced from particles of wood that are compressed and bonded together.
▪ Greater distances exist between structural supports in roofs than in floors.
▪ Manufactured members are prefabricated from components, such as dimension lumber, panels, adhesives, and metal fasteners, and shipped to the construction site for erection.
▪ Manufactured members include trusses, box beams, I-beams, and panel components.
▪ Trusses for floors and roofs can be produced from pre-engineered designs or by computer program.
|Box beams and I-beams can be manufactured from plywood or dimension lumber. |[pic] |
▪ A common use of manufactured panels is in mobile homes and modular housing.
▪ The relative hazards posed by combustible materials are ignition temperature, heat of combustion, and ratio of surface area to mass.
▪ Ignition temperature of wood is affected by density, size and form, moisture, rate of preheating, nature of ignition source, and air supply.
▪ The process of the chemical decomposition of wood is caused by heat (AKA pyrolysis).
▪ The heat of combustion of a fuel is the total amount of thermal energy that could be released if the fuel were completely burned (measured in Btu's or calories per gram).
▪ The rate at which a fuel is consumed and the rate at which energy is released determines fire growth rate and severity.
▪ Flaming combustion of wood takes place at the surface where the gaseous products of pyrolysis can combine with the surrounding air.
▪ A greater surface area for a given mass of wood permits a more rapid combining of fuel vapors and air for combustion and an overall greater rate of burning.
▪ Building codes permit the use of fire-retardant-treated wood for certain fire-resistive and non-combustible construction.
▪ Pressure impregnation involves pulling air out of wood with a vacuum and introducing fire retardant with pressure to replace the air.
▪ Pressure impregnation is permanent when performed under the right conditions.
▪ The most commonly used fire retardant treatments are inorganic and organic salts such as ammonium phosphate, ammonium sulfate, ammonium polyphosphate, boric acid, zinc chloride, and sodium dichromate.
▪ Some fire retardant chemicals can affect strength of wood under conditions of elevated temperature and humidity.
▪ Most fire retardant chemicals work by accelerating the formation of charring when wood is exposed to heat which decreases the formation of volatile gases to retard flaming combustion.
▪ Masonry is one of the oldest and simplest building techniques.
▪ The drawback of masonry is that it is labor intensive to use.
▪ Masonry units can be made of brick, stone, concrete block, clay tile block, or gypsum block.
▪ Bricks are produced from clays and shales.
▪ Concrete blocks are also known as concrete masonry units (CMU).
▪ The most commonly used concrete block is hollow concrete block.
▪ Concrete masonry units can be produced as hollow block, bricks, or solid block.
▪ Stone masonry consists of pieces of rock removed from a quarry and cut to desired shape and size.
▪ Principle types of stone include granite, limestone, sandstone, slate, and marble.
▪ Brownstone is a form of sandstone.
▪ Stone can be laid similar to brick to form a solid wall or as a veneer attached to structural frame.
▪ Clay tile and gypsum blocks were once used for interior partitions.
▪ Structural glazed tile is commonly used in shower rooms for its smooth surface.
▪ Masonry units have no significant tensile strength and are used to support compressive loads.
▪ The primary function of mortar is to bond the individual masonry units into a solid mass.
▪ The mortar joints in masonry can be the weakest points in the wall.
▪ Most mortar is produced with a mixture of Portland cement (bonding agent), hydrated lime, sand, and water.
▪ An admixture is when ingredients are varied or chemicals are added to a concrete mixture.
▪ Superplasticizer is an admixture that flows more easily.
▪ Types of concrete include ordinary stone, lightweight structural or insulating, gypsum, high early strength, and expansive.
▪ To resist tensile forces, concrete can be reinforced with steel bars which have high tensile strength and expands at the same rate as concrete.
▪ The overall fire resistance of reinforced concrete depends on the depth of concrete covering the steel bars and the quality of the concrete.
▪ A formwork for concrete can be made of wood, metal, or plastic.
▪ A danger of collapse with wood formwork is heaters used to dry the concrete may ignite the wood.
▪ Precast concrete is poured and cured away from the jobsite.
▪ The primary advantage to precasting concrete is quality control.
▪ The primary disadvantage of precast concrete is transportation costs.
▪ Cast-in-place concrete permits casting in a wider variety of shapes.
▪ The presence of excess moisture in concrete can cause spalling under freezing or fire conditions.
▪ Spalling causes expansion and tensile forces in concrete which results in pieces of concrete breaking off.
▪ New concrete that has not yet cured is subject to more severe spalling.
▪ Concrete tends to absorb heat and release it slowly (AKA Heat Sink effect).
▪ Steel is the strongest of structural materials.
▪ Steel is non-rotting, resistant to aging, and dimensionally stable.
▪ Steel is basically an alloy of iron and carbon.
▪ Molybdenum can be added to steel to increase strength.
▪ Vandium can be added to steel to increase strength and toughness.
▪ Manganese increases steel's resistance to abrasion.
▪ The lower carbon content in steel compared to cast iron, the more ductile and less brittle the steel.
▪ Ductility of steel permits the steel to be rolled (heated or cold) into a variety of structural shapes.
▪ Maximum allowable stress for steel must be kept below the yield point.
▪ Steels with higher yield points have less ductility.
▪ Disadvantages of steel are tendency to rust and loss of strength in a fire.
▪ Painting or coating with zinc or aluminum can prevent rust on steel.
▪ Factors affecting failure of unprotected steel include mass, fire intensity, load supported, and structural connections.
▪ Unprotected steel members with less mass take less time to fail.
▪ Bar joists or slender trusses are expected to fail early in a fire.
▪ When lower stresses (loads) occur in steel members, they are less likely to fail.
▪ When steel members are rigidly welded or bolted to the structural assembly, they resist failure to a better degree.
▪ Linear coefficient of thermal expansion deals with the expansion of steel members under conditions of heat.
▪ Both yielding and thermal expansion of steel members take place simultaneously, causing bending or buckling in most fire situations.
▪ Cast iron is a brittle material and tends to fail by fracturing instead of yielding in a fire like steel.
▪ The most common method of protecting steel members is with an insulating material.
▪ Materials used to fire protect steel include metal lath & plaster, multiple layers of gypsum board, sprayed-on cementitios coating, and mineral & fiberboards.
▪ Intumescent coatings are insulating materials for steel members that expand when exposed to heat and create an insulating barrier to fire.
▪ Steel floor support systems are frequently protected by suspended insulating ceiling tiles called membrane ceilings.
▪ When penetrations in membrane ceilings occur, such as lighting fixtures, special provisions such as increased insulation or fire dampers, may be required.
▪ Aluminum is sometimes used as a structural material but its limited strength, higher thermal expansion, and greater cost limits its use.
▪ Aluminum is used for roof panels, siding, door/window frames, and hardware.
▪ Aluminum is an electrical conductor.
▪ Copper is used for decorative purposes such as sheet metal roofing and gutters.
▪ Copper and zinc are not as strong as steel.
▪ Glass is frequently used as exterior curtain walls.
▪ Ordinary glass (AKA single-strength annealed), is produced by slowly cooling hot glass during production.
▪ Tempered glass is produced by cooling the exterior glass surfaces while letting the core cool more slowly, to create compressive stresses in the edges of the glass.
▪ Tempered glass shatters into small granules rather than large sharp-edged chunks.
▪ Heat-strengthened glass is not as strong as tempered glass but is produced with similar compressive stresses.
▪ Laminated glass adheres to the center vinyl section when broken.
▪ Laminated glass is found in security and bank-teller windows and also acts as a good sound barrier.
▪ Glass block is produced in either solid or hollow units with variations in surfaces to create different light patterns.
▪ Glass block is NOT load bearing.
▪ Glass block is assembled into panels with mortar or silicone sealant and secured to the surrounding wall with steel channels or special anchors.
▪ Glass is NON-combustible but is NOT fire-resistive.
▪ Wired glass and fire-rated glass are acceptable where fire resistance is required.
▪ Wired glass is made by rolling a wire mesh into a sheet of hot glass.
▪ When wired glass breaks, the wires hold the glass in place, allowing it to act as a barrier to fire.
▪ Wired glass is used in fire doors, areas adjacent to fire escapes, and in corridor separations.
▪ Fire-rated glass panels are made from a combination of glass and plastic and contain NO internal wires.
▪ Fire-rated glass block cannot be substituted for a fire-rated wall.
▪ Interior applications which use sprinkler protected glass panels must be sprinklered on both sides of the glass.
▪ Gypsum board is also known as gypsum wall board, plasterboard, and drywall.
▪ The inner core of gypsum board is produced as a slurry and passed through rollers to obtain desired thickness.
▪ Regular gypsum board is used in most applications.
▪ Water-resistant gypsum board has water-repellent paper for use in areas with moisture.
▪ Type X gypsum board is used in fire rated assemblies.
▪ Foil-backed gypsum board is used to eliminate the vapor barrier in outside walls.
▪ Gypsum backing board is used as a backing layer in multiple layer assemblies.
▪ Coreboard (gypsum board) is used for shaftwalls and solid partitions.
▪ Type X gypsum board is produced with glass fibers that provide tensile strength and hold the board together under fire.
▪ Gypsum board is used in fire-resistive assemblies such as corridor partitions, stair enclosures, shaft walls, column protection, membrane ceilings, and protection of individual beams and girders.
▪ The paper on gypsum board has very low surface flammability (heat is transferred to the core).
▪ Plastics can be formed by pressure, heat, extrusion, and other methods.
▪ Plastics are usually made from resins, polymers, cellulose derivatives, caseins, and proteins.
▪ Thermosetting plastics are hardened into a permanent shape during manufacturing and are NOT subject to softening when heated.
▪ Thermoplastics soften and melt under heat and can reach a flowable state.
▪ Plastics are used for siding, floor covering, insulation, tub and shower enclosures, vapor barriers, pipe and pipe fittings, lighting fixtures, skylights and roof domes, and sprinkler piping.
▪ The molecules of plastic are long polymers with repeating groups of atoms.
▪ Glass fiber reinforced plastic may have a strength close to steel.
▪ Plastics have low rates of thermal conductivity.
▪ Cellular plastics are widely used for thermal insulating purposes.
▪ Groups of plastics within the vinyl group of plastics include vinyl acetate, vinyl alcohol, vinyl butyral, vinyl chloride, and vinyl fluoride.
|PLASTIC GROUPS & USES |
|Plastic Group |Construction Uses |
|Acrylonitrile-Butadiene Styrene (ABS) |Water & gas supply lines, drain & waste systems |
|Acrylics |Skylights, translucentceiling panels, light diffusion, & glazing |
|Cellulosics |Piping & pipe fitings, outdoor lighting fixtures |
|Epoxies |Adhesive for sandwich panels, floor tiles, & patching concrete |
|Fluorocarbons |Chemical piping |
|Nylons |Carpeting, fabric in air-supported structures |
|Phenolics |Electrical parts, foamed insulation, & sandwich panels |
|Polycarbonates |Safety glazing, lighting fixtures, & lighted signs |
|Polyesters |Translucent sheeting, molded bathtubs, shower stalls, & sinks |
|Polyethylene |Vapor barrier in wall assemblies, wire & cable insulation |
|Polystyrene (foamed) |Duct & pipe insulation, insulation in freezers, refrigerators, walls, & ceilings |
|Polyurethanes |Wall & ceiling insulation, pipe & duct insulation, upholstery |
|Vinyls |Tile flooring, gutters, molding, window frames, siding, & exterior finish |
▪ Some plastics such as cellulose nitrate burn so rapidly that they present a unique fire hazard.
▪ Nylon usually melts and drips when it burns.
▪ Combustion of vinyl chloride produces hydrogen chloride which is the gaseous form of hydrochloric acid.
▪ When large amounts of plastic are used in a structure, such as foam plastic in wall insulation, the fire hazard is greatly increased and would require a non-combustible coating of the insulation surface or sprinkler protection.
▪ An exterior veneer of plastic on building walls is called an Exterior Insulation & Finish System (EIFS) and can consist of fiberglass, gypsum board, and expanded polystyrene OR extruded foam with a hand-troweled finish coat OR simple foam plastic panels.
▪ Structures with fabric as part of their exterior enclosing surfaces are called membrane structures.
▪ Materials used for membrane structures include nylon and Teflon-coated fiberglass.
▪ Fabrics can NOT support compressive forces and must be supported by cables and masts or tubular framework.
▪ The materials used in membrane structures must be non-combustible.
▪ Membrane structures can be used in fire-resistive construction when building code only requires a non-combustible roof.
▪ In membrane structures, lighting/heating equipment and sprinklers must be supported by the framework, NOT the membrane structure.
Building Construction (2nd Edition)
Chapter 6-Foundations
Test Review
▪ Movement of foundations may be downward (AKA settling), upward (AKA heaving), or outward (AKA lateral displacement).
▪ Settlement of foundations is the most frequent building movement.
▪ Foundations resting on clay can have an alarming amount of settlement, while on bedrock, it is minimal.
▪ Uniform Settlement is when all parts of a foundation settle at the same rate, and structural member misalignment is minimal.
▪ Differential Settlement takes place when different parts of a foundations settle different amounts, and significant structural member misalignment can occur.
▪ Differential settlement can result from non-uniform soil conditions, footings of different sizes or at different elevations, and unequal loads on footings.
▪ High-rise structures require foundations that extend 100 feet or more.
▪ Foundations must support live, dead, and wind loads, seismic forces, soil pressure, uplifting forces from groundwater, and thrusts resulting from the support of arches, domes, or vaults.
▪ Foundations are divided into 2 types: Shallow and Deep.
▪ Shallow foundations transfers the weight of the building to the soil and can be used when soil conditions are adequate to support the weight.
▪ Deep foundations penetrate the layers of soild directly under the building to reach soil at a greater depth that is adequte to support the weight of the building.
▪ Shallow foundations use footings to transmit the weight of the building to the soil.
▪ A footing is a widened base at the bottom of a column or foundation wall which reduces the compressive stress on the soil.
▪ A wall footing is a continuous strip of concrete that supports a wall.
|Types of wall footings include: an increased floor slab thickness on its edges, a |[pic] |
|widened strip of concrete under a wall that supports a raised floor with crawlspace,| |
|or a widened strip of concrete under full-story high walls that create a full or | |
|partial basement. | |
▪ A column footing is a square pad of concrete that supports a column.
▪ Most column footings are reinforced concrete, but some may have a grillage footing if a large load is supported.
▪ A grillage footing consists of layers of beams placed at right angles to each other and are usually encased in concrete.
▪ A mat foundation is a thick slab under the entire area of the building and is used when load-bearing capacity of the soil is low.
▪ Mat foundations may be several feet thick and heavily reinforced, while slab foundations may not be more than 1 foot thick.
▪ The amount of earth excavated for a floating foundation will approximately equal the weight of the building, minimizing settlement.
▪ Deep foundations use either piles or piers.
▪ Piles, which are either timber, steel, or concrete, are driven into the ground and develop their load carrying capability through friction with the surrounding soil or by contacting rock or load-bearing soil layer.
▪ Use of timbers for piles is limited by factors such as decay and available tree lengths.
|Piers (AKA caissons) are constructed by drilling a shaft in the soil and |[pic] |
|filling it with concrete. | |
|Piers can be a straight shaft or have a conical footing. | |
|A pier with a footing is known as a belled pier. | |
|A caisson is defined as the protective sleeve that keeps water out of the | |
|excavation for a pier. | |
▪ Concrete is the material most commonly used for foundation walls.
| |
|[pic] |
|Foundation Wall Types |
▪ Concrete block is a contemporary material for basement walls.
▪ Stone basement walls are found only in older buildings.
▪ Stone foundations were often constructed without mortar.
▪ Where cost is a factor, wood may be used for foundation walls if treated with preservatives to prevent decay.
▪ Wood foundation walls have a pea gravel base below the frost line.
▪ The process of strengthening an existing foundation is called underpinning.
▪ Reasons for underpinning include: excessive settlement, increased foundation load, erosion of soil, excavation on adjacent property.
▪ Shoring refers to temporary support, while underpinning refers to permanent support.
▪ Shoring is frequently necessary to support structures until underpinning can be put into place.
▪ Shoring and underpinning frequently involves excavation by hand due to limited space.
Building Construction (2nd Edition)
Chapter 7-Structural Systems
Test Review
▪ Reinforced concrete of protected steel framing are found in Type I fire-resistive buildings.
▪ Use of unprotected steel results in a Type II building classification (non-combustible).
▪ Wood an masonry together are found in ordinary construction Type II and mill construction Type IV.
▪ 3 methods are used to reinforce concrete: ordinary, PRE-tensioned, and POST-tensioned.
▪ With ordinary reinforcing, wet concrete is poured around steel bars within a framework.
▪ Design engineers determine the number of reinforcing bars, diameter of bars, and depth of concrete around bars.
▪ Standard size reinforcing bars vary from 0.375" to 2.257".
▪ Vertical steel reinforcing bars are known as stirrups, which resist diagonal tension.
▪ Concrete beams are frequently cast in the shape of a tee (more efficient/lightweight).
▪ The primary function of reinforcing steel is to resist tensile forces but they can support some compressive forces.
▪ With prestressing, a compressive force is applied to the concrete BEFORE a load is applied by tightening or preloading the reinforced steel.
▪ Preloading of reinforcing steel creates compressive stresses in concrete to counteract tensile stresses from applied loads.
▪ Initial prestressed forces applied to reinforcing bars are slightly higher than what is needed to support the concrete and applied loads.
|2 methods of prestressing concrete are PRE-tensioning and POST-tensioning. |[pic] |
|In PRE-tensioned concrete, steel strands are stretched between anchors creating a tensile | |
|force in the steel BEFORE applying concrete. | |
|PRE-tensioned concrete usually has a slight upward deflection. | |
|With POST-tensioning, reinforcing bars are NOT tensioned until AFTER the concrete is | |
|hardened. | |
|A general rule is that reinforcing steel should only be cut to rescue trapped victims. | |
|Reinforcing bars in POST-tensioned concrete is NOT bonded to the concrete and are likely to | |
|spring out of the concrete if cut. | |
▪ Cast-in-place concrete (AKA site-cast concrete) is poured into forms at the building site.
▪ Most cast-in-place concrete is proportioned at a central bulk plant and mixed in mixing trucks enroute to the work site.
▪ Power-driven mixers may be used on work sites for small cast-in-place jobs.
▪ When cast-in-place concrete arrives at the work site, a slump test is performed to check the quality of the concrete.
▪ A slump test checks moisture content by measuring the amount that a small cone shaped concrete settles after it is removed from the standard test mold.
▪ Concrete may be subjected to compression testing to determine quality (requires hardening).
▪ Reinforcing steel overlaps construction joints which occur between successive pourings of cast-in-place concrete.
▪ Common cast-in-place structural systems include flat slab, slab & beam, and waffle construction.
▪ Flat slab concrete frames are simple systems consisting of a slab supported by concrete columns.
▪ Flat slab concrete varies from 6 to 12 inches thick.
▪ Shear stresses exist where columns intersect with flat concrete slabs.
▪ In flat slab concrete frame buildings with heavy live loads, supporting columns are reinforced with additional concrete in the form of drop panels or mushroom capitals.
▪ Flat plate concrete systems can be found when buildings will support light loads as in residential or small commercial buildings.
▪ Slab & beam frame consists of concrete slab supported by beams or beams & girders.
▪ Waffle construction concrete uses square forms to produce a thicker slab but eliminates the weight of unnecessary concrete on the bottom half of the slab.
▪ Reinforcing steel is placed in the bottom of waffle construction formwork to provide reinforcement in 2 directions (AKA 2-way slabs).
▪ Precasting plants produce precast parts (most common) and whole modular units PRIOR to delivery to work site.
▪ From a construction standpoint, precast concrete structures have more in common with steel frame buildings than cast-in-place buildings.
▪ Precast concrete was not common until after World War II.
▪ Precast concrete is produced as slabs, beams, columns, and wall panels.
▪ Precast slab types include solid, hollow-core, single-tee, and double-tee.
▪ Precast solid slabs are used for short spans up to 30 feet.
▪ Precast tee-slabs are used for spans up to 120 feet.
▪ Precast slabs can be supported by girders & columns, wall panels, or both.
▪ Precast exterior wall panels are commonly used with a steel framework.
▪ Precast elements are usually lighter than similar cast-in-place elements.
▪ Precast elements can be connected by bolting, welding, and POST-tensioning.
▪ A corbel is a ledge that projects out from a column and supports a precast beam.
▪ Precast beams can be secured to columns with steel angles, cast into a column, or with POST-tensioned steel cables.
▪ Precast units may have a cement topping up to 1 1/2 inch thick.
▪ Buildings supported by concrete frame are usually enclosed by NON-bearing curtain wall.
▪ NON-bearing exterior curtain walls can be made of aluminum, glass, steel panels, and masonry.
▪ Curtain walls make it difficult to identify the structural system by observation alone.
▪ Stucco and exterior insulation finish systems (EIFS) may appear visually to be concrete.
▪ Concrete structural systems can have fire-resistance ratings from 1 to 4 hours.
▪ Fire resistance of concrete is affected by concrete density, thickness, quality, and load supported.
▪ Structural lightweight concrete has lower density and lower thermal conductivity which results in better insulation against fire and heat than standard concrete.
▪ Cast-in-place concrete is inherently more fire resistant than precast due to continuity of the concrete.
▪ Concrete which is supported by NON-fire-resistive members or that has openings not enclosed by rated fire doors or shutters, is considered NON-fire-resistive.
▪ Concrete cannot withstand an explosion.
▪ Because steel is a very dense material, it is not efficient to use a solid slabs or panels.
▪ Sheets of steel may be used as floor decking or in exterior curtain walls.
▪ Connection of the beam to a column transfers the load between members and determines structural rigidity.
▪ Beam & girder steel frames are classified as rigid, simple, or semi-rigid.
▪ Rigid steel frames resist bending forces.
▪ Simple steel frames primarily support a vertical force.
▪ Semi-rigid steel frames provide some diagonal support by using diagonal bracing or shear panels.
▪ Shear panels are reinforced wall located between columns and beams that provide lateral support and should be continuous from foundation to the highest story needed.
▪ Steel trusses are more economical than beams for carrying loads across greater spans.
▪ Steel trusses are frequently used in 3 dimensional space frames.
|2 common basic steel trusses are the open-web joint and joist girder. |[pic] |
|Open-web steel joists are made with depths up to 6 feet and spans up to| |
|144 feet (2 foot or less depth and 40 foot span is most common). | |
|Top and bottom chords of open-web steel joists can be made from 2 | |
|angles, 2 bars, or a tee-shaped member with diagonal members being flat| |
|bars continuous round bar (AKA bar joint) welded to top and bottom | |
|chords. | |
|Bar joists often support floors and roof decks. | |
|Joist girders can take the place of steel beams for the primary | |
|structural frame. | |
▪ Steel rigid frames with inclined roof members are widely used for 1 story industrial buildings and farm buildings.
▪ Steel rigid frames usually span 40 to 200 feet.
▪ The top of a rigid steel frame is the "crown" and the points where inclined members intersect vertical members are the "knees".
▪ Vertical members of steel rigid frames may or may not be rigidly connected to foundations depending on anticipated wind loads.
▪ 1 story rigid frame structures must be braced diagonally to prevent lateral deflection.
▪ Steel arches support roofs where large unobstructed floors are needed.
▪ Steel arches can span in excess of 300 feet.
▪ Steel arches may be girder arches (solid arch), or trussed arch (using truss shapes).
▪ Steel wire strengths can be as high as 300,000 psi.
▪ Suspension roof systems can use steel rods or cables to provide large unobstructed areas without obstruction of side vertical clearances (unlike arches).
▪ Steel suspension systems may be used with cantilever roofs.
▪ The cross section of steel columns can be very small compared to their length due to the high compressive strength of steel.
▪ An unprotected slender steel column can buckle easily from the heat of a fire.
▪ The most common steel column cross sections are hollow cylinder, rectangular tube, and wide flange.
▪ Factors which affect buckling of steel columns include length, cross section, and top/bottom support.
▪ With steel columns, the slenderness ratio is a comparison of the unbraced length to the shape and area of its cross section.
▪ Steel columns used for structural support should not have a slenderness ratio less than 120.
▪ Rigid connections at the ends of steel columns resist rotation and are more resistant to buckling.
▪ Cross sectional shape of a steel column affects buckling potential.
▪ Square steel columns have less tendency to buckle than tubular shapes.
▪ Mass of steel and structural connection is determined by structural design used.
▪ Rigid connections in beam & girder frames have greater mass at the point of connection.
▪ Steel beam & girder and steel trusses frequently use steel web gussett and plates for rigid connections.
▪ Steel gussett plates strengthen connections and increase steel mass at the connection.
▪ Large beam & girder frames with repeating sections tend to be mutually supporting (redundancy).
▪ The main interest in masonry for firefighters is its use in wall construction.
▪ The most commonly encountered load-bearing masonry walls are brick, concrete block, and combinations of both.
▪ Gypsum block and lightweight concrete block are limited to NON-load-bearing partition walls.
▪ Masonry walls can be found in fire-resistive and NON-fire-resistive buildings.
▪ The most basic masonry structure consist of exterior load bearing walls which support the floor and roof.
▪ Interior floors and roofs made of wood joists and rafters, along with exterior masonry walls, is termed "ordinary construction".
▪ Interior masonry walls provide lateral and vertical load support.
▪ Wood and steel trusses commonly support roofs of masonry wall buildings.
▪ Cast iron was frequently used for interior columns in the 19th Century.
▪ Thickness of masonry walls varies from a minimum 6 inches, up to several feet.
▪ Lower partitions of multi-story walls must be thicker to carry the increased dead load from upper portions.
▪ NON-reinforced masonry walls are usually limited to 6 stories in height.
▪ Steel or concrete structural frame is more economical than masonry bearing walls when the building is more than 2 to 3 stories in height.
▪ Reinforced masonry bearing walls can be as high as 20 stories and only 10 inches thick.
|Masonry units laid side-by-side in a horizontal layer is called a "course". |[pic] |
|Horizontal courses of brick laid on top of each other is called a "wythe". | |
|The simplest brick wall consists of 1 wythe. | |
|A brick wythe is commonly used with a concrete block wythe (AKA Concrete Block Brick | |
|Faced-CCBF). | |
|When bricks are placed horizontally, end-to-end, they create a "stretcher course". | |
|When bricks are placed vertically, on end, they create a "soldier course". | |
|Parallel wythes of bricks can be bonded together using a "header course" every 6th course, or| |
|by using corrosion-resistant metal ties to bond wythes together. | |
|Horizontal bonding of brick and block is usually done with metal ties. | |
|Exterior brick walls usually have a vertical cavity between exterior and interior wythes to | |
|prevent water seepage through mortar joints. | |
▪ Masonry walls are reinforced to permit taller buildings or to provide lateral stability.
▪ Grout is a mixture of cement, aggregate, and water.
▪ Grout can be used to fill cavities between 2 adjacent wythes of a brick wall or within the openings of concrete block for reinforcement.
▪ Buttresses and pilasters can be used to reinforce masonry walls.
|Support of masonry over an opening requires the use of a lintel, arch, or corbelling. |[pic] |
|Lintels are beams (usually steel angles) over an opening in a masonry wall. | |
|When the height of a masonry wall above an opening is shorter than a triangular section | |
|above the opening, a lintel must provide support for the entire weight of masonry above | |
|the opening. | |
|Lintels (most common), and arches are common methods of supporting loads over masonry | |
|openings. | |
|Corbelling is used only for architectural styling. | |
|[pic] | |
▪ A parapet is an extension of a masonry wall that projects above the roof.
▪ Parapets are found on exterior masonry walls and fire walls when buildings have combustible roofs, but may also be used for architectural styling.
▪ Parapets project 1 to 3 feet or more above the roof and usually have NO lateral support.
▪ Live loads of a building are transferred to bearing walls and columns by joists, beams, or trusses.
▪ Masonry buildings with wood interior framing are classified as "ordinary" or "heavy timber".
▪ In many residential and small commercial buildings, wood joists or beams rest on an indentation in the masonry wall, called a beam pocket.
▪ A "fire cut" is a cut made with a slight angle at the end of a wood joist or beam to allow the member to fall freely away from the wall in the case of structural collapse.
▪ Wood roof trusses are frequently supported by pilasters.
▪ Fire resistance of masonry depends on type of masonry and thickness.
▪ Walls made of fire-rated concrete masonry units or bricks can have 2 to 4 hours of fire resistance.
▪ Well-constructed masonry walls are usually last to fail in a wood-joisted building.
▪ Masonry wall failure is usually due to deterioration of the wall and/or structural members.
▪ Cracks in masonry walls are often due to foundation shift.
▪ One method of reinforcing masonry walls is by using tension rods extending through the walls and then attached to "thrust plates" on the outside.
▪ Masonry walls usually collapse as a result of interior framing collapse.
▪ Collapsing interior framing produces horizontal forces against a masonry wall, resulting in tensile forces which the mortar cannot resist.
▪ It should be assumed that a collapsing wall will fall out from a building a distance at least equal to the height of the wall.
▪ Building codes require less clearance between buildings with masonry or fire-resistive exterior walls.
▪ Wood is almost always used in a frame structural system.
▪ Use of solid logs for log cabins is perhaps the only use of wood for solid wall construction.
▪ The 2 types of wood framing systems most frequently encountered are timber framing and light wood framing.
▪ Wood timber framing is NOT the same as a building with exterior masonry walls and heavy timber framing.
▪ Other types of wood construction include pole, log, and prefabricated panel construction.
▪ Due to basic strength limitations of wood, it is usually not economical to use wood frames in buildings over 3 stories in height.
▪ Until water-powered saws were developed 2 centuries ago, producing individual wood boards was slow and laborious.
▪ In heavy timber designs, basic structural support is provided by beams and columns made of heavy timber.
▪ In heavy timber designs, columns are NOT less than 8 x 8 inches, and beams (except roof beams) are NOT less than 6 x 10 inches.
|Integrity of wood frame structures is affected by methods used to join joists, beams, and columns. |
|Factors affecting the design of connections for timber construction include specific gravity of wood, wood shrinkage, position of fasteners, and|
|size of wood and fasteners. |
|Components of wood member connections include bearing blocks, steel straps/brackets, and mortise & tenon joints (older construction). |
|[pic] |
▪ Heavy timbers cut from a single log are usually NOT available in lengths greater than 20 feet.
▪ Glulams or timber trusses are used for greater spans of timber framing.
▪ Post & beam construction uses columns (AKA posts), and beams with dimensions less than heavy timber but greater than light frame construction.
▪ Posts in post & beam construction are usually 4 x 4 or 6 x 6 inches and space 4 to 12 foot apart.
▪ Post & beam framing is square or rectangular and must be braced for diagonal stability.
▪ Post & beam construction is usually more labor intensive than light frame construction.
▪ Interior wood surfaces of post & beam and heavy timber construction is left exposed and thus eliminates combustible voids and avenues for fire spread.
▪ The most popular form of wood framing is light wood frame construction.
▪ Light wood framing uses 2 inch nominal lumber such as 2 x 4 or 2 x 8 inch members.
▪ Vertical members of light wood framing are supported by joists or trusses, and inclined roofs are supported by rafters or light trusses.
|[pic] |
|The 2 basic types of light wood framing are balloon frame and platform frame. |
|Balloon framing can have open channels, due to continuous exterior wall studs, which permit fire spread from foundation to attic. |
|In platform framing (AKA western framing), exterior wall studs are NOT continuous from floor to floor. |
|Platform framing has double 2 x 4 inch members (AKA plates) laid horizontally along the top of the studs on each floor which act as fire stops. |
|Light wood framing is usually covered with plaster or drywall. |
|Fire in a balloon frame building is more difficult to control than in a platform frame building. |
|Platform frame buildings are easier to erect than balloon frame. |
|Wood shrinkage is greater in a direction perpendicular to the wood grain. |
|Platform framing has more horizontal members than balloon frame, which results in greater wood shrinkage (causes cracks/misalignment). |
▪ Exterior wall materials include sheathing, siding, building paper, and insulation.
▪ Sheathing provides structural stability, insulation, and an under layer for siding, and may be made of plywood, or particle board.
▪ Siding can be made of wood boards, aluminum, or of wood, asphalt, or asbestos cement shingles.
▪ Foam insulation promotes rapid fire spread over its surface and may require facing with a thermal barrier such as gypsum, by code.
▪ Fire spread due to combustion of foam insulation within a wall space is dependent on the amount of air within the space.
▪ Loose fill insulation types include granulated rock wool, granulated cork, mineral wool, glass wool, cellulose fiber, and shredded wood.
▪ Loose fill insulation can be treated with water-soluble salts to reduce combustibility, but will still smolder if involved in a fire.
|Brick veneers must be tied to a wall at intervals of 16 inches. |[pic] |
|Weep holes in brick veneers are 2 feet on center. | |
|An air space of approximately 1 inch exists between a brick veneer and its | |
|supporting wall. | |
|There is little difference between a brick veneer building and ordinary wood | |
|frame building in terms of fire behavior. | |
|A rule of thumb to determine whether a brick wall is load-bearing is a bearing | |
|wall will have a header course every 6th course. | |
|Concealed spaces must be opened to check for fire extension. | |
Building Construction (2nd Edition)
Chapter 8 - Floors & Ceilings
Test Review
▪ In multistory buildings, floors and ceilings act as the primary barrier to vertical fire spread.
▪ Concrete floors can be cast-in-place or precast.
▪ Concrete floors are often structurally self-supporting.
▪ Fire resistance of a concrete floor supported by steel beams or trusses depends on fire-proofing of the steel.
▪ The thickness of a concrete floor depends on the live load it supports and the span between supports.
|SPAN BETWEEN SUPPORTS FOR HOLLOW-CORE SLABS |
|Slab Thickness |Span Range |
|6" |14-22 feet |
|8" |20-32 feet |
|10" |24-40 feet |
|12" |30-44 feet |
|Independent factors of a concrete floor include slab thickness, unsupported span, |[pic] |
|and design load. |[pic] |
|It is common for the underside of a concrete floor (ceiling for floor below) to be | |
|left exposed. | |
|Masonry is NOT used in modern floor supporting systems. | |
|Tile arch floors should NOT be penetrated for firefighting purposes due to collapse | |
|potential. | |
|3 methods in which steel members can support floors include open web joists (bar | |
|joists) or trusses, steel beams, and light gauge steel joists. | |
|A common floor design is lightweight concrete with minimum thickness of 2 inches, | |
|supported by corrugated steel decking on open web joists. | |
|3 categories of open web joists are Standard, Long Span, and Deep Long Span. | |
|Standard open web joists are 8 to 30 inches deep and span up to 60 feet. | |
▪ Light gauge steel joists are produced from cold rolled steel.
▪ Steel joists have depths of 6 to 12 inches and are spaced 16 to 48 inches apart (depending on span and load supported).
▪ Wood flooring is often covered by concrete, terrazzo, and quarry tile.
▪ Standard concrete weighs about 150 pounds per cubic foot, while lightweight concrete weighs about 90 pounds per cubic foot.
▪ Floor decking in Type IV construction is a minimum 3 inch thick plank (tongue & groove cut) with 1 inch finish flooring and is supported by 6 x 10 inch beams.
▪ Concealed spaces are NOT permitted in the framing of heavy timber buildings, so the underside of floor decks are usually left exposed.
▪ Floor decking in ordinary masonry and wood frame construction is plywood or nominal 1 inch board subfloor covered by 2 x 6 inch to 2 x 14 inch joists, spaced 12 to 24 inches on center.
|Bridging is wood or metal diagonal bracing or solid blocking placed between joists to distribute concentrated |[pic] |
|loads. | |
▪ Modern floor construction uses plywood or particle board for subflooring and lightweight built-up wooden I-beams instead of solid joists, resulting in rapid failure in a fire.
▪ Prefabricated floor trusses, in modern wood floor construction, provide the same strength as solid joists with less material.
▪ Laminated beams usually react to fire similar to solid lumber.
|With wood flooring, it is more advantageous to have intersecting members that bear |[pic] |
|directly upon one another than to use toenailing. | |
|Joist hangars make strong connections when members meet at right angles. | |
|Joist hangers can be made of sheet metal for light wood framing, or folded metal plate | |
|for heavy timber construction. | |
|NFPA 253, Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Source, |[pic] |
|covers flammability limits of floor coverings. | |
|The floor covering sample used in critical radiant flux testing is 10 x 42 inches. | |
|Thermal energy in a critical radiant flux test is measure by a pyrometer. | |
|The critical radiant flux of floor coverings is the level of radiant heat required for | |
|ignition of the floor covering (measured in Btu per ft2 per second). | |
▪ NFPA 101, Life Safety Code, uses 2 classifications for floor coverings: Class I - minimum flux of 0.43, and Class II - minimum flux of 0.19.
▪ The higher the critical radiant flux, the higher the fire resistance.
▪ Floor coverings in stairways, exit passageways, and exit corridors in institutional occupancies are limited to Class I coverings by BOCA national building code.
▪ Raised access flooring is common in computer rooms.
▪ Raised flooring consists of a framework of adjustable steel stanchions that support a tile floor in which individual tiles can be removed for access.
▪ Ceilings can be designed to control diffusion of light and distribution of air in a room.
▪ Ceiling materials, such as plaster, gypsum board, or mineral tiles, may be required by code for fire resistance.
▪ Plaster is a cementitious material applied in several coats over lathing.
▪ Lathing can be wire mesh or gypsum board faced with a fibrous paper (wood lathing in older buildings).
|Plaster and gypsum can both be attached directly to the underside of a floor OR suspended below it.|[pic] |
|Mineral tiles are commonly used in suspended ceilings. | |
|Mineral tiles are supported by a suspension system of interlocking steel cross members supported by| |
|steel wires. | |
|A "membrane ceiling" is a ceiling suspended a designated distance below floor supports. | |
▪ An interstitial ceiling space (IS) is an area above a suspended ceiling and may be large enough for a person to walk upright through.
▪ In fire-resistive buildings, automatic sprinklers are usually NOT provided in an interstitial space.
▪ Floor assemblies may be required to have fire resistance ratings of 1, 2, or 3 hours.
▪ Ceiling materials are always rated as part of the floor and ceiling assembly, never independently.
▪ Removal or penetration of any part of a ceiling assembly may reduce or eliminate the fire resistance of the entire assembly.
▪ When penetrations occur in a rated membrane ceiling, penetrations must also be present when testing the assembly.
▪ Fire resistance of floor assemblies plays a primary role in preventing vertical fire spread.
▪ Vertical penetrations of floors (ie-elevators, stairwells, service shafts), must be provided with a fire-resistive enclosure.
▪ To allow vertical openings between floors, architects may utilize fire rated glazings or doors held open by automatic devices.
▪ Building codes require automatic sprinklers and smoke management systems for large open vertical spaces, such as atriums.
▪ An "unprotected opening" is an opening without any provision to stop the passage of fire and products of combustion.
▪ Unprotected openings are most likely encountered in older multistory industrial and warehouse buildings.
Building Construction (2nd Edition)
Chapter 9 - Walls
Test Review
▪ Most interior wall are NOT load-bearing.
▪ Shear walls provide lateral stability in multistory buildings.
▪ Types of walls of interest to firefighters include fire, party, curtain, and enclosure/shaft walls, and fire/movable partitions.
▪ Fire walls (AKA area separation walls) limit maximum fire spread.
▪ Fire walls act as an absolute barrier to fire even when total burnout occurs on either side of the wall.
▪ Building code may allow elimination of fire walls if automatic sprinklers are provided.
▪ A fire wall is a natural line along which to establish a defense in firefighting, and an opening in a fire wall can be used as a protected attack position.
▪ Fire doors may be opened to attack a fire, but must be closed if firefighters withdraw.
▪ Fire walls can be constructed as "free-standing" or "tied" walls.
▪ Free-standing fire walls are self-supporting and independent of the building frame.
▪ Fire-standing fire walls are found in wood frame and masonry construction, but may also be present in non-combustible buildings.
▪ Free-standing fire walls must be able to resist lateral loads of at least 5 pounds per square foot per NFPA 221.
▪ Tied fire walls are erected at a column line in a building of steel frame or concrete frame construction.
▪ Steel members incorporated into a tied fire wall must have the same fire resistance as the wall and the structural framework must resist the lateral pull of a collapse.
▪ Fire walls are typically made of masonry, but other fire-resistive materials, such as concrete, may be used.
▪ Fire walls are usually required to have a fire resistance of 4 hours.
▪ No combustible structural members may pass through a fire wall.
▪ Combustible members framed into a fire wall must be designed to fall way freely from the wall during a fire.
▪ Parapets are continuations of fire walls, up and above combustible roofs, usually 18 to 36 inches.
▪ All doors in fire walls must be automatic or self-closing type.
▪ Fire walls with 4 hour fire resistance frequently have 3 hour fire doors on each side of the wall.
▪ If HVAC ducts penetrate a fire wall with a fire resistance of 2 hours or greater, the ducts must have fire dampers (on 4 hour fire walls, two 3 hour dampers are required).
|Conveyors which pass through a fire wall may have fire resistive enclosures and/or water |[pic] |
|spray for protection of the opening. | |
▪ A party wall is a wall that lies on a lot line between buildings and is common to both buildings.
▪ Party walls are almost ALWAYS load-bearing.
▪ Party walls are frequently fire walls which extend from basement to roof, with a parapet.
▪ Openings in party walls are often made by building owners for many purposes.
▪ Fire partitions are interior walls used to subdivide a floor or area of a building.
▪ Fire partitions do not qualify as fire "walls".
▪ Fire partitions usually span only from a floor to the underside of the floor above.
▪ Fire partitions have varying fire resistance ratings depending on use (ie-corridor walls, occupancy separations, areas of refuge).
▪ Buildings subdivided by fire partitions are said to be "compartmentalized".
▪ Compartmentalization with fire partitions only provides "passive" fire protection.
▪ Fire partitions can be made of plaster & lath, gypsum wall board, concrete block, and combinations of materials.
▪ A 1 hour fire resistant fire partition, used for separating adjacent apartment units, can be made of 5/8 inch fire-rated gypsum applied to both sides of 2 1/2 inch steel studs.
▪ Steel-studded fire partitions may NOT be load-bearing, but wood-studded fire partitions CAN be load-bearing.
▪ A wood stud fire partition could NOT be used in a fire-resistive building due to being combustible.
▪ Fire-rated glazing is used in fire partitions when visibility and fire resistance is desired.
▪ Wall board partitions are easily penetrated with forcible entry tools.
▪ Enclosure wall are used to enclose vertical openings, such as stairwells, elevator shafts, and pipe chases, that extend floor-to-floor.
▪ Enclosure walls block vertical fire spread and/or protect a means of egress.
▪ Enclosure walls have 1 or 2 hours fire resistance, depending on building height, and are usually NON-load-bearing.
▪ Load-bearing masonry stair enclosures are found in older "mill" buildings.
▪ Most common construction materials may be used to construct enclosure walls.
|An exterior wall that ONLY functions to enclose a building is called a "curtain wall". |[pic] |
|The function of a curtain wall is to separate the interior environment from the outside environment. | |
|Curtain walls must resist wind, rain, and snow, and control heat loss, noise, and solar radiation. | |
|Curtain walls are NOT limited to buildings with steel frames. | |
|Curtain walls are frequently constructed of glass & steel, stainless steel, or aluminum. | |
|Other materials used to construct curtain walls include lightweight concrete, plastic, fiberglass, | |
|expanded paper honeycombs, and compressed glass fiber. | |
|The extent a curtain wall permits vertical fire spread, and the wall's fire resistance, is important to | |
|firefighters. | |
|Aluminum and glass curtain walls have NO fire resistance. | |
|Office buildings and high-rise apartments commonly have NON-combustible curtain walls with NO fire | |
|resistance. | |
|Curtain walls are usually supported by the building frame at the edge of the floor assembly. | |
|The gap between a curtain wall and structural frame can create a vertical pathway for fire spread if not | |
|firestopped. | |
▪ Movable partitions are NEVER load-bearing.
▪ Movable partitions may be constructed from several materials, such as wood, vinyl, and metal.
▪ Movable partitions are usually mounted on an overhead track and may be power- or hand-operated.
▪ Movable partitions are usually NOT fire-resistive, however, partitions with 1 to 2 hours fire resistance are available.
Building Construction (2nd Edition)
Chapter 10 - Roofs
Test Review
▪ Firefighters should be familiar with all aspects of roof construction, including material, means of support, architectural styles, and functional aspects such as support ventilation equipment.
▪ Roofs are usually weaker than floors because of smaller load designs.
▪ Many roof types have concealed spaces.
|Roofs are broadly categorized into 3 categories: flat, pitched, and curved. |[pic] |
|Flat roofs are found on all building types and are typical on large industrial buildings. | |
|Many flat roofs are slightly pitched from front-to-rear for drainage. | |
|Flat roofs are the easiest roofs for firefighters to work on. | |
|Hazards of flat roofs include stepping off roof edge, falling through roof openings, and stumbling| |
|over low parapets into light wells. | |
|Pitched roofs have inclined surfaces. | |
|Pitched roof design is determined by climate, function, and aesthetics. | |
|Common pitched roofs include the gable, hip, gambrel, mansard, butterfly, monitor, and sawtooth. | |
|The simplest pitched roof is the shed roof which only slopes in 1 direction. | |
|Gable roofs have 2 inclined surfaces that meet at their high side to form a "ridge". | |
|Hip roofs slope in 4 directions and have a degree of slope similar to gable roofs. | |
▪ Gambrel roofs slope in 2 directions but with a break in the slope on each side.
▪ Mansard roofs have a break in the slope on all 4 sides.
▪ Mansard roofs constructed with a flat deck are called "modern mansard" or "deck roofs".
▪ Mansard roofs for a projection beyond the building wall that creates a concealed space.
▪ A false mansard fascia may be added to a flat roof to give the appearance of a mansard roof.
▪ Mansard overhangs can collapse in large sections.
▪ Butterfly roofs slope in 2 directions and resemble 2 shed roofs that meet at their low eaves.
▪ Monitor roofs provide better light and ventilation.
▪ The vertical side of a monitor roof (normally glass), is called a "clerestory".
▪ Sawtooth roofs maximize natural light and ventilation and are found on industrial buildings.
▪ Ideally, the inclined faces of sawtooth roofs should face North for maximum constant Northern light and to avoid glare of the sun.
▪ Pitched roofs are designed to shed water and snow.
|Curved roofs take the shape of the structural system used to support them. |[pic] |
|Curved roofs are frequently supported by arches and bowstring trusses. | |
|When the area to be enclosed by a roof is circular, a done roof can be used (ie-an arch| |
|rotated 360 degrees). | |
|Like arches, dome roofs have horizontal thrusts at the base, and compressive force at | |
|the top. | |
|Lamella arches are special arched roofs constructed of short pieces of wood (AKA |[pic] |
|lamellas), varying from 2 x 6 to 3 x 16 inches and 8 to 14 feet in length. | |
|Lamellas are bolted together in a diagonal pattern with a special plate called a | |
|"lamella washer" with the curvature being formed by beveling the individual ends of the| |
|lamellas. | |
▪ Geodesic domes are created using spherical triangulation (triangles arranged in 3 dimensions).
▪ Geodesic domes may be made of wood, steel, and concrete, or plywood, bamboo, and aluminum.
|Dormers are frequently added to pitched roofs to increase light, ventilation, and usability of |[pic] |
|attic spaces. | |
|DORMER TYPES >>>>>>>>>>>>>>>> | |
▪ The simplest system to support a flat roof uses ordinary wood joists, supported at either end by a masonry wall.
▪ Wood-plank roof decks with solid wood joists tend to lose strength gradually under fire conditions and will become soft or "spongy" prior to failure.
▪ Flat roofs with plywood box beams, wooden I-beams, or unprotected open-web steel joists are susceptible to early failure in a fire.
▪ When walking on a roof, deflection and vibration is an indication of lightweight roof construction.
▪ Main roof joists for inverted roofs are located at the level of the ceiling, and a framework is constructed above the main joists to support the roof deck (creates concealed space several feet high).
▪ Main roof joists for a conventional flat roof are located at the level of the roof, and directly support the roof.
▪ Rafters are inclined joists used for some pitched roofs (shed, gable, hip, gambrel, and mansard).
|Raftered roofs create an outward thrust against building walls, similar |[pic][pic] |
|to an arch. | |
|Outward thrust of rafters is resisted by ceiling or attic floor joists, | |
|or by collar beams, which are in "tension". | |
|Rafters are ALMOST ALWAYS wood (may be steel). | |
|Wood rafters vary from 2 x 4 to 2 x 12 inches, and are spaced 12 to 24 | |
|inches, depending on span and live loads. | |
|Ceilings are often suspended from a roof truss, creating an attic |[pic] |
|concealed space. | |
|Fink truss systems are common to residential construction. | |
|Typically, lightweight trusses use "monoplane" trusses in which all | |
|chords and diagonal members lie in the same plane. | |
|In trusses that use gang nail type gusset plates, individual members are| |
|wood 2 x 4s or 2 x 6s, spaces 2 to 4 feet apart. | |
|Multiple member wood trusses use "splice plates" to produce heavier wood|[pic] |
|trusses, and may be up to 5 members thick and spaced 8 feet apart. | |
|Multiple member wood trusses use bolts or timber connectors instead of | |
|gusset plates. | |
|Ring-shaped connectors are used with heavy wood trusses to prevent |[pic][pic] |
|sliding of members (embedded in wood). | |
|Bowstring trusses use a curved top chord with split-ring connectors and | |
|bolts at all joints except the heel plates at the ends of the truss. | |
▪ Fink and Pratt style trusses are most common when steel trusses are used in pitched roofs.
▪ Behavior of arches is determined by the material used in the arch (masonry, concrete, laminated wood, or steel).
▪ Use of unprotected steel tie rods in arched roofs can result in catastrophic failure in a fire.
▪ Rigid frames are frequently encountered in 1 story buildings.
▪ Rigid frames can be constructed of concrete, laminated wood, or steel.
▪ Components of roof decks include sheathing, roof planks or slabs, corrugated steel, precast gypsum or concrete planks, poured gypsum or concrete, and cement planks containing wood fiber.
▪ 1/2 inch plywood roof decking can be placed on supports spaced 24 inches on center.
▪ Wood plank roof decking has a minimum 1 inch nominal thickness.
▪ Corrugated steel roof decking is usually 22 gauge minimum thickness, with depths from 1 1/2 to 7 inches.
▪ Corrugated steel used with concrete for roof decks is called "composite decking".
▪ Gypsum, and concrete, with the appropriate aggregate, are "nailable", unlike cast-in-place concrete.
▪ Wood nailing strips may be placed at 3 foot intervals in cast-in-place concrete for securing to the structural frame.
▪ In multistory buildings, the roof construction is typically the same as the floor system.
▪ The type of roof covering depends on roof structure & slope, climate, appearance, maintenance, durability, and wind/fire resistance.
▪ Fog, salt air, smoke, and other pollutants can corrode metal roofing.
▪ Roof coverings are typically several layers of materials, but may be a single layer such as corrugated steel.
▪ Corrugated roof decking is supported by either I- or channel-shaped purlins.
|Material component layers in a typical flat roof include (top-to-bottom): Wear course, Drainage |[pic] |
|layer, Roofing membrane, Thermal insulation, and Vapor barrier. | |
|Vapor barriers are needed when outdoor temperature is below 40oF, and indoor humidity is 45% or | |
|greater at 68oF. | |
|Vapor barriers may be made of continuous sheets of plastic, aluminum foil, kraft paper, | |
|asphalt-saturated roofing felt, or other water vapor resistant material. | |
▪ Thermal insulation in roofs should resist flow of heat, mechanical damage, moisture decay, and fire.
▪ Poured roof insulation can be portland cement or gypsum-based.
|TYPES OF RIGID ROOF INSULATION |
|Cellulose Fiberboard |Low-density board of wood or sugar cane fibers with a binder |
|Glass Fiberboard |Low-density board of glass fibers with a binder |
|Polystyrene Foam Board |Flammable foam of polystyrene plastic |
|Polyurethane Foam Board |Flammable foam of polyurethane sometimes faced with felt |
|Polyisocyanurate Foam Board |Foam of polyisocyanurate sometimes with glass fiber (best when combined with fire resistance |
| |materials) |
|Cellular Glass Board |Fire-resistant foam of glass |
|Perlite Board |Fire-resistant granules of expanded volcanic glass |
|Lightweight Fill with Asphaltic Binder |Mineral aggregate with asphaltic binder |
|Composite Insulating Boards |Layers of foam plastic & other materials such as perlite board and glass fiberboard |
▪ Roof membranes keep rain and snow out.
▪ The 3 categories of flat roof membranes include built-up, elastomeric-plastomeric, and fluid-applied.
▪ Built-up roof membranes have several layers (usually 4) of roofing felt saturated with a bituminous material such as tar or asphalt.
▪ Rolls of roofing felt are usually 3 feet wide.
▪ Built-up roofs usually last 20 years.
▪ Elastomeric-plastomeric membranes are thin sheets (0.032 to 0.120 inches) applied with adhesives, gravel ballasts, or fasteners, in a single layer, and can be extremely flammable.
▪ Materials used in elastomeric-plastomeric membranes include neoprene, synthetic rubber (ethylene propylene diene monomer), polyvinyl chloride (PVC), chlorinated polyethylene, and polymer-modified bitumens.
▪ A propane torch may be used to heat the underside of an eleastomeric-plastomeric membrane to achieve adhesion to the roof (common cause of fires).
▪ Fluid-applied membranes are useful with curved roof surfaces.
▪ Materials used in fluid-applied membranes include neoprene, silicone, polyurethane, and butyl rubber.
▪ The water-proof nature of a fluid-applied membrane tends to limit penetration of fire streams on the roof.
▪ The drainage layer of a roof can be a ballast later (for single-ply roofs), or drainage fabric or aggregate (for built-up roofs).
▪ The wear course in built-up roofs consists of a gravel ballast or aggregate.
▪ A built-up roof with gravel wear course is called a "tar & gravel" roof.
▪ For pedestrian traffic on roofs, deck pavers may be used for the wear course.
▪ Roof coverings on pitched roofs are either shingle, tile, or metal.
▪ "Rolled roofing" is used on low-cost pitched roofs and consists of a single layer of felt.
▪ "Thatch" roofs consist of bundles of reeds, grasses, or leaves.
▪ Shingles and tiles are small overlapping units that allow movement for thermal expansion and shifting of the structural system.
▪ Shingles and tiles may be wood shingles or shakes, asphalt shingles, or slate, clay, or concrete tiles.
▪ Wood shingles are thin, tapered slabs sawn from pieces of a tree trunk, while shakes, are thicker, and are split from wood by hand or machine.
▪ Wood shingles and shakes may be made from red cedar, white cedar, or redwood (to resist decay).
▪ Asphalt shingles are produced from heavy sheets of asphalt-impregnated felt made of rag, paper, or wool fiber, and topped with a mineral aggregate.
▪ The most common size of asphalt shingle is 12 x 36 inches.
▪ Slate is produced from hard rock and has a tendency to split along one plane.
▪ Slate may be produced in sheets as thin as 1/16 inch, up to 1 1/2 inch thick.
▪ Clay tile is a dense, hard, and non-absorbent, flat or round material, produced by shaping clay in molds and firing in kilns.
▪ Round clay tiles (AKA "mission" tiles) are used for Spanish-style architecture.
▪ Concrete tiles are made from Portland cement, aggregate, and water.
▪ The advantage of concrete tiles over wood is longevity.
▪ Porcelainized aluminum and mineralized materials may also be used for roof coverings.
▪ Corrosion-resistant nails are usually used to attach shingles and tiles to roofs.
|Only 1/3 of the length of wood shingles are exposed to weather once in place. |[pic] |
|Wood shingles may be attached to a conventional solid deck or to wood strips attached to roof | |
|rafters (strips cause early failure). | |
▪ Asphalt shingles are usually installed over roofing felt.
▪ Slate tiles have pre-punched nail holes from which the tile hangs from the nail (not tight).
▪ Wood shakes/shingles can be pressure-impregnated with a fire-retardant material.
▪ Asphalt shingles are combustible and tend to drip and run under fire conditions.
▪ Clay, slate, and cement tiles are NON-combustible and produce fire-resistant coverings.
▪ Wood and asphalt shingles may be used for siding as well.
▪ Metal roofs may be made of galvanized iron or steel, copper, zinc, aluminum, and lead, and may be flat or corrugated.
▪ Corrugated metal roofs may be installed without decking.
▪ Roofing felt under a metal roof increases the fire resistance of the roof.
▪ Material used for nails to secure metal roofing are the same material as the roof to prevent galvanic action.
▪ Testing procedures for fire hazards of roof coverings are contained in NFPA 256, Standard Methods of Fire Tests for Roof Coverings, and in ASTM E-108.
▪ NFPA 256 fire tests for roof coverings ONLY simulates fire originating OUTSIDE a building.
▪ Test samples for roof coverings are attached to a wooden deck measuring 3 feet 4 inches x 4 feet x 4 inches.
▪ NFPA 256 contains 6 test procedures: Intermittent flame exposure, Flame spread, Burning brand, Flying brand, Rain, and Weathering tests, with individual tests repeated 2 to 15 times.
▪ Roof coverings that pass fire resistance test procedures are classified as Class A, B or C (severe, moderate, and light fire resistance, respectively).
▪ Underwriters laboratory tests roof coverings and published results annually.
▪ A 2nd roof called a "rain roof" can be installed over a deteriorated roof.
▪ Rain roofs are difficult to penetrate and create a concealed space between the roofs.
▪ Penthouses (AKA bulkheads), are small structures erected on the main roof to house stairways, elevator machinery, mechanical equipment, or a living space.
▪ Access to some penthouses is made ONLY from the roof (common with elevator/mechanical equipment penthouses).
▪ In NON-fire-resistive buildings, do NOT use interior stairs to access a roof above a fire.
▪ Roof hatches provide access to the roof from inside a building (usually secured by padlock).
▪ Skylights, which provide natural light, are made of wired glass, tempered glass, or plastic domes.
▪ Skylights usually have no provision for automatic venting.
▪ Rooftop smoke vents are typically found in industrial and warehouse buildings.
▪ Unit type smoke and heat vents are small area hatchways (4 feet minimum in either direction is typical) with single- or double-leaf metal lids.
▪ Unit type smoke and heat vents with metal lids may be automatic (operated by fusible link) or manually operated (by hand release).
▪ Smoke and heat vents may have plastic domes that melt out, or be operated by smoke detectors.
▪ Curtain boards are used in conjunction with smoke and heat vents to increase the speed of operation and effectiveness of the vents.
▪ NFPA 204M, Guide for Smoke & Heat Venting, determines the size and spacing of smoke and heat vents based on rate-of-heat release, ceiling height, and spacing of curtain boards.
▪ Roof vents in sprinklered buildings are NOT as effective as in NON-sprinklered buildings.
Building Construction (2nd Edition)
Chapter 11 - Door & Window Assemblies
Test Review
▪ A door is basically a movable barrier use for security, privacy, and environmental control.
▪ Architecturally, the type, size, and location of doors are determined by access requirements, traffic volume & frequency, weather resistance, privacy, code requirements for fire resistance & egress, appearance, and security.
▪ Swinging doors rotate around a vertical axis by means of hinges secured to the side jambs of the doorway or on pivots at top and bottom.
▪ Swinging doors can be single- or double-leaf, and single- or double-acting.
▪ Sliding doors are suspended on overhead tracks and may use steel or nylon rollers.
▪ Floor guides prevent lateral movement of sliding doors.
|Sliding door types include surface sliding, pocket sliding, and bypass sliding. |[pic] |
▪ An advantage of sliding doors is elimination of door swing which uses valuable space.
▪ Pocket sliding doors are frequently used in residential units.
▪ Sliding doors may be used on elevators, power-operated doors, and fire doors.
▪ Folding doors are hung on overhead tracks and can either be bi-folding or multi-folding.
▪ Folding doors may be used in residences as space separations, and in one type of horizontal fire door.
▪ A door that opens in a vertical plane is called an "overhead door".
▪ Overhead doors can consist of a single leaf, or 2 or more sections.
▪ Factories and warehouses commonly have vertically rolling doors with interlocking metal slats.
▪ Vertically-operated doors usually have a counterbalance (weights or springs).
▪ Vertical doors can be raised manually, mechanically (chain hoist), or by power.
▪ Revolving doors have 3 or 4 sections, or wings, that rotate in a circular frame.
▪ Revolving doors reduce heating and cooling losses by minimizing air flow through the door opening.
▪ Normally-functioning revolving doors do NOT allow hose and equipment into a building.
▪ Revolving door wings must be collapsed for an unobstructed opening.
|Older revolving doors use simple chain keepers (catch & chain) or stretcher bars (break & catch) to hold |[pic] |
|wings in position. | |
|Newer revolving doors use spring-loaded cam-in-groove or bullet-detent hardware to hold wings in position. | |
|Most revolving doors use a collapsing mechanism to allow wings to "book-fold" when wings are pushed in | |
|opposite directions. | |
|By code, revolving door wings must collapse with 130 pounds of force. | |
▪ Doors can be classified by style and construction.
|Common styles of swinging doors include ledge & brace, flush, 2 panel, louvered, and |[pic] |
|French. | |
▪ Doors are constructed of wood, metal, and glass.
▪ Aluminum and carbon steel are the most common metals used in doors, but stainless steel, bronze, and copper are also used.
▪ Doors may have veneers of hardwood, fiberglass, or plastic.
▪ Panel doors consist of vertical and horizontal members which frame rectangular areas of thin panels consisting of wood, glass, or louvers.
▪ Flush (AKA slab) doors consist of flat-faced panels which are the full height and width of the door.
▪ Today's flush doors simulate a solid piece of wood.
|Solid-core doors have an interior core of laminated blocks (wood, |[pic] |
|particle board or mineral composition), and are covered with 2 or 3 | |
|layers of surface materials (usually plywood). | |
|A layer of sheet metal may be added to a solid-core door for security. | |
|Standard solid-core doors are 1 3/4 or 1 3/8 inch thick. | |
|Hollow-core doors have interior spacers of wood, plastic, or fiberboard,|[pic] |
|which create a grid or honeycomb. | |
|Solid-core doors are better fire barriers than panel or hollow-core | |
|doors. | |
▪ Glass doors can be framed or frameless.
▪ Codes require glass doors to have tempered glass.
▪ Lexan and Plexiglas are used in framed doors for security.
▪ Hollow-metal doors made from steel or aluminum are common metal doors.
▪ Hollow-metal doors can be panel or flush-type and are normally 1 3/4 inch thick.
▪ Face panels of steel doors are separated by internal vertical sheet metal ribs spaced 6 to 8 inches apart.
▪ Aluminum flush doors usually have a core of hardboard and honeycomb pattern paper.
▪ Heavy corrugated steel doors have 1 or 2 corrugated sheets supported by a steel frame.
▪ Heavy corrugated steel doors may have styrofoam or asbestos cores (older doors).
▪ Fire doors protect openings in fire-rated walls.
▪ Fire doors are rated in hours (4, 3, 1 1/2, 1, 3/4, 1/2, & 1/3 hours).
▪ Fire door classifications are known as "fire protection ratings", expressed in hours, by letter, or both.
▪ Letter designations for fire doors are actually meant to apply to the type of opening, NOT the door, and are no longer used.
|FIRE DOOR OPENING CLASSIFICATIONS |
|Classification |Opening Type |
|A |Fire walls |
|B |Vertical shafts or 2 hour rated partitions |
|C |Between rooms & corridors with 1 hour fire resistance or less |
|D |Exterior walls subject to severe fire exposure from outside the building |
|E |Exterior walls subject to moderate to light fire exposure from outside the building |
▪ Class B fire doors may be called Class B (1 1/2) doors (old designation).
▪ 1/2 and 1/3 hour fire doors are primarily used in smoke barriers and corridor openings.
▪ Codes may permit a 1 1/2 hour fire door in a 2 hour stairwell.
▪ Codes may require two 3 hour fire doors to protect a 4 hour fire wall opening.
▪ Fire doors are tested in accordance with NFPA 252, Standard Methods of Fire Tests of Door Assemblies, and by ASTM E-152.
▪ Fire door tests use the same time and temperature curve as for structural assembly tests, but is not as rigid as tests for fire-rated walls.
▪ The primary criteria for passing a fire door test is that the door still remains after the test (some warping permitted).
▪ Intermittent passage of flame is permitted during a fire door test after the first 30 minutes of the test.
▪ Fire doors (except 1/3 hour rated doors) are subjected to a hose stream following a fire door test and must remain in place to pass.
▪ Underwriters laboratories published fire door ratings annually.
▪ Rated fire doors are identified with a label indicating door type, hourly rating, and a logo of the testing lab.
▪ Labels for swinging fire doors are placed on the door edge.
▪ Testing of fire doors also includes testing of frames and hardware.
|Hardware on fire doors is either called Builder's|[pic] |[pic] |
|Hardware (for swinging doors) or Fire Door | | |
|Hardware (for sliding & swinging doors). | | |
|Builder's Hardware includes hinges, locks, | | |
|latches, bolts, and closers. | | |
|Fire doors have hinges for every 30 inches of | | |
|height of the door. | | |
|Builder's Hardware can be shipped to the job site| | |
|separate of the door, while Fire Door Hardware is| | |
|usually shipped WITH the door. | | |
▪ Overhead-rolling fire doors are commonly used in industrial occupancies on 1 or both sides of a wall.
▪ Overhead-rolling fire doors are made with interlocking steel slats and with operating components such as releasing devices, governors, counterbalance mechanisms, and wall guides.
▪ Overhead-rolling doors usually close under gravity when a fusible link melts, however, some are motor-driven.
▪ Care should be taken when passing through overhead-rolling fire doors to ensure the door does not trap firefighters.
|Horizontal-sliding fire doors are often found in older|[pic] |
|industrial buildings. | |
|Horizontal-sliding fire doors are usually held back by| |
|fusible link and slide closed along a track by gravity| |
|or by force of a counterweight. | |
|Horizontal-folding fire doors are motor-driven and | |
|operate on a signal from smoke detector or alarm | |
|system. | |
|Horizontal-folding fire doors are frequently used | |
|where a fire-rated partition is required, such as a | |
|corridor separation. | |
▪ A common type of sliding fire door is a metal-covered, wood-core door.
▪ Wood-core fire doors have a 4 inch vent hole to vent gases of the thermal decomposition of the wood inside the door.
▪ Metals used to cover wood-core sliding fire doors include steel, galvanized sheet metal, and terneplate.
▪ Terneplate is a metal composed of tin and lead, and doors with this covering are known as "tin-clad doors".
▪ Smooth galvanized sheet metal used on a wood-core door is called a "kalamein door".
|To allow swinging fire doors attached to both sides of a wall to swing in the SAME direction, |[pic] |
|a fire-resistive vestibule is used. | |
|Swinging fire doors are common in stairwells and corridors. |[pic] |
|The disadvantage of swinging fire doors is the requirement of clear space around the | |
|enclosure. | |
|Swinging fire doors have ratings from 3 hours to 20 minutes. | |
|Swinging fire doors may be metal-clad wood. | |
|GLASS PANEL REQUIREMENTS FOR FIRE DOORS |
|Hourly Rating |Panel Size |
|Over 3 hours |NO glass panels |
|1, 1 1/2, & 3 hours |Up to 100 square inches |
|3/4 hour |NOT to exceed 1,296 square inches |
|1/2 & 1/3 hour |Up to maximum area tested |
▪ Louvers may be used in fire doors rated up to 1 1/2 hours, but louvers must close automatically (usually by fusible link).
▪ Fire doors can either be automatic (closes when closer device is activated), or self-closing (closes after opened & released).
▪ Devices that operate fire doors include door closers, holders, and operators.
▪ Fire door "closers" are used on sliding and swinging fire doors, and can incorporate a hold-open device or be self-closing.
▪ Self-closing fire door closers are common on stairwell and hotel room doors.
▪ A common self-closing door closer uses a spring-hinge to close the door when opened and released.
|Fire door "holders" may be used with swinging, sliding, or rolling fire doors, and are intended to be used|[pic] |
|WITH a door closer. | |
|Electromagnetic door holders are operated by smoke detectors or alarm systems. | |
▪ Fire door "operators" are used with sliding fire doors which are mounted on a level or inclined track.
▪ With sliding fire doors, a fusible link disconnects the door from the operator under fire conditions, and allows the door to close by means of a spring-powered door closer or system of suspended weights.
▪ Fusible links are slower-acting then devices that react to smoke or rate of temperature rise.
▪ Interior light shafts provide a patch for fire.
|A complete window consists of a frame, 1 or more sashes, and necessary hardware. |[pic] |
|Window frames consist of a sill, side jamb, and head jamb. | |
|A window sill is the lowest horizontal member of a window frame. | |
|A sash is the framed unit that may be included within a window frame, and may be fixed or movable. | |
▪ Windows are broadly categorized as fixed (NON-operable) or movable (operable), or combination of both.
▪ Fixed windows have only a frame and a stationary sash.
|Windows that have 2 sashes that can move past each other are |[pic] |
|called "double-hung" windows (common in residences). | |
|Windows that have only the lower sash operable are called | |
|"single-hung" windows. | |
|Sashes may be held open with counterweights, springs (spiral |[pic] |
|spring), or spring-loaded coiled tape. | |
|Counterweights on windows are usually found in older | |
|buildings, and are made of cast iron. | |
▪ Types of movable windows include casement, horizontal-sliding, awning, jalousie, projecting, and pivoting.
|Casement windows have a side-hinged sash which usually swings OUTward, |[pic][pic] |
|and may contain 1 or 2 openable sashes (full ventilation possible). | |
|Horizontal-sliding windows have 2 or more sashes with at least 1 movable| |
|sash. | |
|In a 3 sash horizontal-sliding window, the middle sash is usually fixed.| |
|Awning windows have 1 or more TOP-hinged, OUTward-swinging sashes. |[pic][pic] |
|Hopper windows are similar to awning windows, but are BOTTOM-hinged. | |
|Jalousie windows have a large number of narrow overlapping, | |
|OUTward-swinging, glass sections (each about 4 inches wide). | |
|Projecting windows swing OUTward at TOP or BOTTOM, and slide UP or DOWN |[pic][pic] |
|in grooves. | |
|Projecting windows are usually operated by push bar notched to hold the | |
|window in place. | |
|Pivoting windows has a sash that pivots horizontally or vertically on a | |
|central axis. | |
|When opened, a pivoting window swings INward and OUTward, allowing full | |
|ventilation. | |
▪ Exterior metal bars or screens are commonly used for window security.
▪ Metal bars used for window security are either embedded in masonry or mounted on hinges and locked with padlocks or other locking device.
▪ Access panels are breachable points in windowless walls.
▪ Fire windows are used when windows face walls of closely-spaced buildings and near fire escapes or exit stairs.
▪ Wired glass is required in windows close to exterior stairs.
▪ Exterior sprinkler systems or fire shutters may be used in place of "fire windows".
▪ Fire windows have steel frames and must have fire-rated glazing (wired glass most common).
▪ Fire-rated glazing with interior gel is NOT suitable for cold exposure (not for exterior windows).
Building Construction (2nd Edition)
Chapter 12 - Interior Finish
Test Review
▪ The 4 ways interior finish combustibility affects fire behavior include flame spread over surfaces, rate of fire growth to flashover, fire intensity, and smoke & toxic gases produced.
▪ Interior finish applies to materials sed for exposed surfaces of walls and ceilings, such as gypsum, plaster, wood paneling, ceiling tiles, plastic, fiberboard, etc.
▪ Paint and wallpaper which is NOT thicker than 1/28 inch is NOT considered an "interior finish" by codes.
▪ "Surface Burning Characteristics" is the term which describes the degree to which fire spreads over the surface of a material.
▪ Speed of flame spread over an interior finish is influenced by material composition, ventilation, shape of the space around the material, and whether the material is applied to a ceiling or wall.
|[pic] |
▪ The Steiner Tunnel Test, identified in ASTM E-84, UL 753, and NFPA 255, is the most common method for evaluating surface burning characteristics of interior finishes.
▪ The Steiner Tunnel Test produces a numerical value known as the "flame spread rating".
▪ The Steiner Tunnel horizontal furnace is 25 feet long, 17 5/8 inches wide, and 12 inches high.
▪ Materials tested in the Steiner Tunnel are applied to the top "ceiling" of the tunnel.
▪ The gas burner in the Steiner Tunnel produces a 4 1/2 foot flame at about 5,000 Btus per minute and is ran for 10 minutes during the test.
▪ The Steiner Tunnel has 19 windows.
▪ Flame travel of a material in the Steiner Tunnel is compared to asbestos cement (flame spread of 0) and to red oak (flame spread of 100).
▪ The higher the flame spread rating, the more dangerous the material.
|FLAME SPREAD RATINGS |
|Material |Rating |
|Asbestos Cement |0 |
|Gypsum Wallboard |10-15 |
|Mineral Acoustical Tile |15-25 |
|Treated Douglas Fir Plywood |15-60 |
|Red Oak |100 |
|Walnut-faced Plywood |260-515 |
|Veneered Woods |515 |
▪ Building codes use 3 classifications for interior finishes, based on flame spread rating
A - 0 to 25
B - 26 to 75
C - 76 to 200
▪ Maximum flame spread rating for interior finishes, by building code, is 200.
▪ Class A interior finish materials are used for vertical exits.
▪ Class B interior finish materials are used for corridors that provide exit access.
▪ Codes may allow an increase of flame spread ratings if interior finishes if automatic sprinklers are provided.
▪ The Steiner Tunnel Test also tests the "smoke developed rating", which is the relative obscurity created by the tested material (measured by photoelectric cell & light source).
▪ Smoke developed ratings are based on red oak, which is given a smoke developed rating of 100.
▪ Building codes limit the maximum smoke developed rating to 450oF.
▪ Smoke developed ratings are NOT an indication of toxicity.
▪ The flame spread rating is NOT an absolute measure of the spread of fire travel, due to variations in the field.
▪ The material to which interior finish material is attached will affect the rate of burning.
▪ Flame spread ratings developed with the Steiner Tunnel Test do NOT apply to floor coverings, unless covering is used on walls or ceilings.
▪ Only relative suface burning of SOME materials can be determined in the field, NOT flame spread ratings.
▪ Types of fire retardant coatings include intumescent paints, mastics, gas-forming paints, and cementitious & mineral-fiber coatings.
▪ Intumescent paints expand when heated to form a thick, puffy coating which insulates the material.
▪ Mastic coatings form a thick, NON-combustible membrane over the surface of the wood.
▪ The effect of fire retardant coatings on Douglas fir can be found in the NFPA Fire Protection Handbook.
▪ Fire retardant coatings must be applied at a specified rate (square feet per gallon), and may require more than 1 coat.
▪ Fire retardant coatings do NOT affect the fire resistance of a structural component unless it has been tested with the coating applied.
▪ Flame spread is generally different over a vertical surface than across a horizontal surface.
|"Corner Tests" consist of a ceiling and 2 intersecting side walls in which the ceiling and |[pic] |
|walls are covered with the test material to simulate more realistic field conditions. |[pic] |
|NFPA 265, Standard Methods of Fire Tests for Evaluating Room Fire Growth Contribution of | |
|Textile Wall Coverings, uses room-size enclosures to test textile wall coverings. | |
|Textile wall covering tests (NFPA 265), consist of test material applied to upper portions of| |
|2 enclosing walls, and is subjected to 2 different size gas flames. | |
|NFPA 265 textile wall covering tests are either "satisfactory" or "NON-satisfactory", and are| |
|NOT given a numerical rating. | |
|Acceptability of NFPA 265 textile wall covering tests is based on whether flame travels to | |
|the edges of the test sample, whether flame droplets fall to the test chamber floor, whether | |
|flashover occurs, and whether the heat release rate reaches 300 kW. | |
Building Construction (2nd Edition)
Chapter 13 - Building Services & Subsystems
Test Review
▪ All building services and subsytems may affect fire safety.
▪ Important fire and life safety features include compartmentalization and fire resistance.
▪ Elevators are one of the safest and most reliable modes of transportation.
▪ Most elevator regulations are based on ASME and ANSI A17.1, Safety Code for Elevators, published by ASME.
▪ The Americans with Disabilities Act (ADA) mandates that nearly all public buildings are accessible to disabled individuals.
▪ Under the ADA, elevators (most common) or ramps are required in multistory buildings.
▪ Elevators consist of a car or platform that moves in guide rails, and serves 2 or more landings.
▪ Elevators can be classified by use: Passenger or Freight.
▪ "Service Elevator" is a term used to describe a passenger elevator which is used to carry freight.
▪ The 2 most common power sources for elevators are hydraulic and electric.
▪ Hydraulic elevators work by forcing fluid, under pressure, into a cylinder containing a piston or ram.
▪ Hydraulic elevators are slowed/stopped by controlling fluid flow back into the hydraulic reservoir.
▪ The practical upper limit of hydraulic elevators is about 6 stories.
▪ The machine room for most hydraulic elevators is located near the elevator pit (area from lowest landing to bottom of hoistway).
▪ Some hydraulic elevator machine rooms are located some distance from the shaft (requires extra piping).
▪ Electric elevators use either drum or traction devices.
▪ Older elevators use drums, located directly over the hoistway, on which hoistway cable is wound.
▪ Drum-type elevators are usually connected to counterweights.
▪ Drum-type elevators have practical height limitations, while traction-type (most common in buildings over 6 stories) do NOT.
▪ Traction elevators have hoistway cables attached to the car that run up and over the drive pulley, then down the back wall of the hoistway to connect to movable counterweights.
▪ Friction of traction elevators is produced by the weight of the car and counterweights.
▪ In traction elevators, counterweights offset the weight of the car so that the drive motor only has to lift the weight of the passengers.
▪ Drive equipment for traction elevators is contained in the machine room which is usually directly over the hoistway.
▪ Traction elevators can have up to a 500 volt power supply, with drive motors being either AC or DC current.
▪ The brake drum for traction elevators is located on the shaft of the drive motor.
▪ With traction elevators, under normal conditions, the spring-operated brake shoes are held from the drum by electromagnets (power outage releases shoes against drum).
▪ Brakes on elevators with AC motors directly aid in stopping the car, while DC motor elevators are stopped by the motor (then held in place by brakes).
|ELEVATOR SAFETY DEVICES |
|Terminal Switches |Electric switches which stop cars by removing power, before car reaches upper or lower hoistway limits |
|Buffers |Large springs or hydraulic cylinders & pistons at the bottom of the pit which act as "shock absorbers" |
| |(can NOT stop a free-falling car) |
|Speed-reducing Switches |Slows drive motor when elevator exceeds a safe speed (AKA Speed Governor) |
|Overspeed Switches |Switches connected to speed governor, and activates if speed-reducing switch fails to slow car |
| |sufficiently |
|Car Safeties |Tapered sets of steel jaws which wedge against guide rails to stop a car (CAN stop a free-falling car) |
▪ Elevator cars consist of a platform on top of a safety plank, a crosshead, and uprights to connect structural members together.
▪ Elevators are generally built of NON-combustible materials.
▪ Hoistways are vertical shafts in which an elevator car travels, and includes the "pit".
▪ Hoistways are made of fire-resistive materials and usually have fire-rated doors with 1 or 2 hour ratings.
▪ Today, practically every hoistway must be top-vented by code.
▪ Stack effect refers to a strong draft moving from ground level to the roof.
▪ The strength of the stack effect involves factors such as building height, air leakage, and air temperature/density differences.
▪ In low-rises, the entire hoistway may consist of gypsum, cement block, or other easily penetrable material.
▪ In high-rises, hoistways may be enclosed on 3 sides with poured concrete, and block on side of the wall that faces the elevator door.
▪ The 2 common types of hoistways are single, multiple, and blind.
▪ Single hoistways contain only 1 elevator.
▪ Multiple hoistways contain more than 1 elevator in a COMMON shaft.
▪ Multiple hoistways are limited to 4 cars per shaft by code.
▪ Blind hoistways can be single or multiple, and are used for express elevators that only serve upper floors of tall buildings.
▪ In SINGLE blind hoistways, access doors are provided for rescue (every 3 floors).
▪ Car doors and hoistway doors generally open together, in the same direction.
▪ Passenger car doors are powered by electric motor mounted on top of the car, and have NO locks (may be pushed open).
▪ Electric interlocks prevent elevators from moving while car doors are open.
▪ Hoistway doors are opened by a driving vane attached to the car door (strikes roller to release hoistway door lock).
▪ The 3 types of passenger car doors are single-slide, 2-speed, and center-opening.
▪ Single-slide elevator doors are slow and are NOT found in high-speed elevators.
▪ 2-speed elevator doors consist of 2 panels with 1 panel located behind the other.
▪ 2-speed elevator door panels move horizontally in the same direction and reach the open position simultaneously.
▪ Center-opening elevator doors are most common, and consist of 2 panels meeting in the center of the opening.
▪ 2-speed and center-opening elevator doors have a "relating cable" connecting the 2 panels.
▪ Vertical b-part doors are used on freight elevators and consist of 2 panels which close from top and bottom and meet in the center.
▪ Vertical bi-part doors may be opened manually (self-counterweight), or by motor at each landing.
▪ Access panels are etiher hinged access hatches through the top of the elevator car or removable panels on the sides of the car.
▪ Top exits are provided on ALL electric traction elevators and on hydraulic elevators WITHOUT manual lowering valves.
▪ Some top exit panels open from inside the elevator, but ALL may be opened from the outside.
▪ With top exit panels removed, some elevators will not move due to electrical interlocks (not required).
▪ Most elevator cars in multiple hoistways have side exits.
▪ Side exits are required to have electrical interlocks to prevent elevator car movement when opened.
▪ Hydraulic elevators WITH manual lowering valves may NOT have side exits.
▪ Hoistway doors depend on elevator car doors for their power (except freight elevators).
▪ Swinging hoistway doors swing OUTward from the hoistway, and are NOT powered (like regular doors).
▪ Hoistway doors cannot completely prevent the passage of smoke from hoistway to building, but codes typically require additional rated doors separating the lobby from the building.
▪ Hoistway doors and hardware will be listed and labeled for fire resistance (most common - 1 1/2 hours).
▪ In addition to mechanical locks, hoistway doors have electrical interlocks that must be CLOSED for the car to operate.
▪ Phase I operation is a mandatory provision which recalls all elevators in the event of a fire.
▪ Phase I recall of elevators (non-stop) to the terminal floor can be actuated manually by keyed switch or by automatically by signals from smoke detector, water flow, or fire alarm devices.
▪ If an alarm originates in the lobby, Phase I may bring elevators to a designated level (usually 2 floors ABOVE the lobby).
▪ Phase I opens doors and keeps them open upon stopping at the "recall" floor.
▪ Phase I DISABLES emergency stop and floor selection buttons.
|Phase II, equipped on ALL new elevators, allows overriding of the Phase I recall feature. |[pic] |
|Typically, Phase II requires inserting a key into a 3-position switch within the elevator car. | |
|Under Phase II operation, floor select buttons are OPERABLE (call buttons on floors INoperable), doors are OPERABLE | |
|(only from within car), electric eyes are INoperable, and emergency stop button is OPERABLE. | |
▪ Do NOT use elevators to travel to or above the fire floor.
▪ Firefighters should know the visual signals on an elevator control panel that indicate impending elevator problems.
▪ Never use elevators with fire/heat damage, or that have been exposed to water.
▪ Moving stairs (AKA escalators) are stairways with electrically-powered steps which move continuously in 1 direction (usually 90 or 120 feet per minute).
▪ Each step of an escalator rides on a track and are linked together by a "step chain".
▪ Driving machinery for escalators is under an access plate at the upper landing.
|Vertical openings created by escalators can be protected as with normal vertical openings, or |[pic] |
|alternatively with sprinklers, draft curtains, or rolling shutters. | |
|Sprinkler draft curtains for escalators consist of an 18 inch draft stop and row of automatic | |
|sprinklers outside of the draft stop. | |
|A partial enclosure for escalators uses a separate fire-rated enclosure for both the UP and | |
|DOWN escalators. | |
|[pic] |[pic] |
▪ Building codes specify egress and fire protection requirements for stairs.
▪ Stairs used for egress that meet fire protection requirements are called "protected" or "enclosed" stairs.
▪ Stairs which are NOT a means of egress typically connect no more than 2 levels, and are called "access" or "convenience" stairs.
|Components of stairs may include riser, tread (run), nosing, stringer (carriage), newel post, baluster,|[pic] |
|and handrail. | |
|Building codes specify exact dimensions of tread and riser (AKA rise & run) measurements for stairs. | |
|Straight-run stairs extend in a straight line for their entire length. | |
|Return stairs have 1 or more intermediate landings between floors and reverse direction at the landing | |
|(common in modern construction). | |
|Scissor stairs are 2 separate sets of stairs constructed in a common shaft. |[pic] |
|Older scissor stair designs were straight-run stairs that returned to every other floor. | |
|Newer scissor stair designs offer ingress and egress from each stair at each landing with egress of one| |
|stairway on ODD numbered floors and the other on EVEN floors. | |
|When 2 sets of scissor stairs in a common shaft are separated by a fire-rated barrier, they meet | |
|requirements for 2 "separate" exits. | |
|Scissor stairs in combination with return stairs is common in airports, malls, cinemas, and convention | |
|centers. | |
|Circular stairs are often found as "grand" or "convenience" stairs serving only 2 levels. |[pic] |
|The minimum width of the "run" for circular stairs is usually 10 inches. | |
|The radius of circular stairs can NOT be less than twice the width of the stairway. | |
▪ The differential of both riser heights and tread widths is often limited to 3/8 inch.
▪ Folding (AKA "disappearing") stairs are typically used to provide attic space access when permanent access stairs are not provided.
▪ Folding stairs are usually made of wood and consist of a main section that hinges from the frame, and 2 articulating sections.
▪ Folding stairs are held in place by counterbalances or springs.
▪ A light plywood is usually attached to the main section of a folding stair to conceal it.
▪ Each tread of a spiral staircase is tapered, and connects to a single column at the tread's narrow end.
▪ Stairs serve as a lifeline to safety for occupants NOT on grade level.
▪ Protected stairs are enclosed with fire-rated construction, usually 1 or 2 hour rating, depending on building code, building height, and construction type.
▪ Protected stairs generally serve more than 2 stories.
▪ Protected stair enclosures are made of NON-combustible materials, and are usually isolated from the rest of the building.
▪ Penetrations permitted in protected stair enclosures include those for light, fire protection, and environmental control.
▪ Self- or automatic-closing fire doors are required for protected stair enclosures.
▪ Exterior stairs may be open or enclosed.
▪ Open exterior stairs typically have at least 2 adjacent sides open to natural ventilation.
▪ Even open exterior stairs are protected by limiting openings in walls near the stairs.
▪ Enclosed exterior stairs are sometimes constructed to replace old fire escapes.
▪ Fire escapes are open metal stairs and landings attached to the outside of a building.
▪ The lowest flight of fire escapes may consist of a swinging stair section.
▪ Fire escapes have NOT been permitted by codes in new construction for many decades.
▪ Exterior stairs supported only from the building side should be used with caution.
▪ Stair tread failure is common with fire escapes.
▪ Fire escapes are usually anchored to the building and are NOT supported at ground level.
|Building codes require smokeproof stair enclosures for some stairs, such as high rise stairs. |[pic] |
|Smokeproof stair enclosures use either active or passive smoke control. | |
|Mechanical ventilation systems keep smoke out of smokeproof enclosures by pressurizing the shaft (activated by | |
|detection equipment). | |
|A mechanical ventilation system can keep smoke out of a stair enclosure even with a door open to the fire floor. | |
|Maximum allowable pressures in smokeproof stair enclosures is specified by building codes to allow reasonable | |
|opening of doors. | |
|Smokeproof enclosures that use natural ventilation have an opening to the outside air by using a vestibule, | |
|balcony, or smoke shaft. | |
|Smoke shafts can be used for internal stairs NOT located on an outside wall. | |
|[pic] |
▪ Use of "UNprotected stairs" is typically allowed by codes when stairs connect only 2 adjacent floors above basement level (AKA "access" or "convenience" stairs).
▪ Access ("convenience") stairs can be used as part of an exit system in 2 story buildings.
▪ Utility chases are vertical pathways that contains building services (plumbing, electrical, communications, HVAC ductwork).
▪ Vertical shafts may contain refuse/linen chutes, light shafts, and material lifts.
▪ Vertical shaft enclosures are built with fire-rated construction, but usually have NO fire barriers along the length of the shaft.
▪ Pipe chases are a type of utility chase containing piping for building services (water, drains, heating, sprinklers).
▪ Vertical shaft enclosure protection typically requires NON-combustible or fire-resistive construction, and rated access openings.
▪ Some buildings have mechanical equipment rooms instead of pipe chases, and rooms may or may not have fire-rated horizontal separation.
▪ Plumbing pipes in wood-frame construction typically form lateral and vertical fire spread pathways.
▪ Refuse/linen chutes have openings on each floor, and terminate at grade level or basement.
▪ Refuse/linen chutes are required to be made of NON-combustible material with rated fire doors.
▪ Refuse/linen chutes may be required to have sprinklers at the top of the chute, and at the termination room.
▪ Linen chutes are typically separated from corridors.
▪ Grease ducts vent grease vapors to the outside as part of commercial appliance venting systems (ie-deep fat fryers & grills).
▪ Grease ducts should have no areas where grease may become trapped.
▪ A single grease exhaust duct serves only 1 exhaust "hood", while "manifold" exhaust ducts serve more than 1 hood.
▪ Single grease exhausts typically have 1 fire suppression system for the entire system, while manifold exhausts use a system for EACH hood.
▪ Extractors are grease removal devices found in the ducts of an exhaust system, and are located in false ceiling spaces, mezzanines, or on the roof.
▪ Grease extractors may contain filters, electrostatic precipitators, catalysts, odor absorbers, and gas-fired afterburners.
▪ Grease ducts are made of NON-combustible material with solid connections and must be a minimum distance from combustibles.
▪ Fires involving cooking greases and oils are considered a Class B fire.
▪ Outside air intakes for HVAC should be located to minimize drawing in of contaminants.
▪ HVAC fans move air, smoke, and heat.
▪ HVAC air can be cleaned with filters, electrostatic equipment, or both.
▪ HVAC filters, using liquid adhesives, may present a combustible liquid hazard.
▪ Heating equipment can be fuel-fired (natural gas or oil burner), or produced with electricity or steam.
▪ Natural gas is LIGHTER-than-air, while LPG (propane) is HEAVIER-than-air.
▪ Cooling equipment hazards are mainly limited to refrigerants and electrical.
▪ Halogenated refrigerants (carcinogens) have been replaced by flammables such as butane and propane.
▪ Air ducts provide a pathway for air, fire, heat, and smoke, and commonly penetrate fire-rated assemblies.
▪ Interstitial spaces may be used for an HVAC system's return air plenum.
▪ Codes now prohibit installation of transoms above doors in corridors because they pull in smoke.
▪ Use of corridors as HVAC plenums is prohibited by codes.
▪ Smoke dampers, used to protect duct penetrations through fire-rated assemblies, are usually actuated by smoke detector (may also be by alarm system).
▪ Smoke dampers close by active mechanical action, usually spring-loaded shutter held open by fusible link.
▪ Combination smoke & fire dampers close in response to heat or smoke.
▪ Most codes require HVAC systems over a certain capacity (usually 2,000 CFM), to have internal duct smoke detection to automatically shut down the system.
▪ Duct smoke detection is NOT a substitution for area smoke detection.
▪ Certain furnace sizes (usually expressed in Btus) require fire-rated enclosures by code (does NOT apply to residential).
▪ Use of LPG in below grade fire-rated heating systems is prohibited by some codes (LPG collects in low areas).
▪ Conveyor systems are typical in manufacturing or storage occupancies.
▪ The most common type of conveyor is the "horizontal" conveyor.
▪ Types of conveyors include belt, roller, chain, and bucket systems.
▪ Conveyor penetrations are usually protected by fire door or water spray.
▪ The primary concern for conveyor penetrations in a fire is INcomplete door closure, which may be prevented by automatic stop controls, breaks in the conveyor, or multiple layers of doors.
▪ Electrical switch gears, transformers, and electrical panels may require fire-rated separation from the rest of the building by code.
▪ HIGH voltage is 600 volts or MORE, while LOW voltage is LESS than 600 volts.
▪ Transformers convert high voltage to appropriate voltage use, and may be of high- or low-voltage type.
▪ The 2 most common methods of cooling transformers is with air and oil.
▪ Air-cooled (AKA dry) transformers have fins and heat sinks which are cooled by surrounding air.
▪ Oil-cooled (AKA oil-filled) transformers contain oil to conduct heat away from the core, and also to insulate internal components from arcing.
▪ Dry-type (AKA air-cooled) transformers are designed for indoor use.
▪ The combustible oil used in transformers has dielectric properties to provide electrical insulation.
▪ Older transformers contain oil with PCBs, while newer oils are less toxic/flammable.
▪ Rooms or caults containing electrical gear or transformers should be protected by sprinklers.
▪ Fires involving electrical equipment usually de-energize the equipment early in the fire.
▪ Transformer rooms may be located on upper levels of multistory buildings.
▪ Oil containing PCBs can be retrofilled with silicone.
▪ Back-up power supplies may consist of generators, batteries, or both.
▪ Buildings with smoke management systems must have emergency back-up generator systems.
▪ Emergency power supplies that require batteries, commonly use lead-acid storage batteries.
▪ Lead-acid batteries contain sufuric acid which can cause fire through chemical reaction or on contact with some metals.
▪ A battery fire is an electrochemical reaction called "thermal runaway".
▪ Lead used in batteries is a toxic heavy metal.
▪ Typical firefighting PPE is NOT designed for acid exposure.
▪ Lead-acid battery names include: Wet cell, Gel cell, Starved electrolyte cell, Sealed cell, Maintenance-free cell, and Flooded cell.
▪ Areas with lead-acid batteries are usually NOT dikes to contain an acid spill.
▪ Small UPS power supplies, containing lead-acid batteries, can be found near alarm panels, under desks, and near computers.
Building Construction (2nd Edition)
Chapter 14 - Underground Facilities & Other Considerations
Test Review
|"Underground" usually describes below grade installations which are deeper than basements. |[pic] |
|Underground buildings are defined as by some codes as one in which the lowest level is 30 feet below the main| |
|exit that serves that level. | |
|Underground locations may include parking/storage facilities and subways. | |
|Advantages of underground facilities are security and relatively constant temperature. | |
|Difficulty in venting heat and smoke is probably the greatest single problem with underground buildings. | |
|Occupants require greater physical exertion to evacuate an underground facility (going up stairs) than in a | |
|high-rise (going down stairs). | |
|Underground structures MUST be excavated. | |
|Structural systems of underground facilities are massive compared to above-ground buildings. | |
▪ Fires exceeding 4 hours, which is the typical maximum available fire protection, are a serious threat in underground structures.
▪ Underground buildings may be grouped with windowless buildings, by codes.
▪ ALL underground buildings more than 30 feet underground require sprinklers, by code.
▪ Smoke exhaust systems are required for ventilation of some underground buildings, depending on depth.
|Atriums are vertical openings, usually extending through several floors of a building. |[pic] |
|Atrium can mean "a covered vertical opening". | |
|Atriums are usually large enough to create an interior court rather than a simple penetration (ie-pipe | |
|shafts, stairs) of floor slabs. | |
|Atriums can provide light and ventilation. | |
|Atriums CAN be enclosed to prevent spread of products of combustion. | |
|The floor level of an atrium frequently has combustible furnishings and contents. | |
|An atrium can extend 30 stories or more through a building. | |
|Buildings with atriums typically have sprinklers by code, but they may only be required on the floors which| |
|connect to the atrium. | |
▪ Basic code requirements for atriums include 1 hour fire-rated enclosure OR glass along with sprinklers.
▪ The requirement of 1 hour fire-rated enclosure for an atrium is sometimes eliminated for atriums up to 3 stories in height, if certain conditions are met (ie-smoke exhaust).
▪ Previously, smoke exhaust size for atriums was determined by size of atrium and size of unenclosed floors connected to the atrium, but today, height of atrium above the top balcony serving the exit system and fire magnitude are the determining factors.
▪ Shopping malls can be defined as "covered pedestrian ways".
▪ The advantage of a shopping mall is a comfortable and protected environment.
▪ Codes usually require malls to be a minimum 20 to 30 feet in width.
▪ Malls may be several hundred thousand square feet.
▪ Malls can be described as a business district of a medium-sized city under one roof.
▪ When malls have more than 1 level, multiple openings between levels are typical.
▪ In malls, an "anchor store" is a large well-known nationally-operated chain, and may be separated from smaller stores by a fire wall with fire doors.
▪ Many malls are NON-combustible or wood-joisted construction.
▪ Today, codes require sprinklers in malls, but older malls may be partial- or non-sprinklered.
▪ In older malls, anchor stores may be the only portion sprinklered.
▪ Individual stores in malls are usually required to have 1 hour fire-resistive partitions (does NOT apply to store "fronts").
▪ Today, codes require FD hose outlets at mall entrances, and entrances from mall to corridors and passageways.
▪ Renovation of mall occupancies presents hazards of construction such as sprinkler system being shut off.
▪ An ordinary 8 inch thick masonry wall 10 feet high normally can NOT resist internal pressure more than 0.5 psig.
▪ It is possible to design a building to withstand or minimize the destructive effects of an explosion.
▪ Structures housing flammable liquids processing or where combustible dusts are produced should be designed to reduce structural damage from an explosion.
▪ An explosion is defined as an event which produces a rapid release of high-pressure gas.
▪ Explosions can be physical (ie-boiler explosion) or chemical (ie-ignition of air & flammable vapor).
▪ Variables of an explosion include fuel-to-air ratio, chemical nature of materials, and ignition source.
▪ Explosions can take place in a few milliseconds.
▪ Damage from an explosion depends on maximum pressure developed, rate of pressure rise, duration of peak pressure, and strength of confining structure.
▪ DETONATions (more damaging) are explosions at GREATER than the speed of sound, while DEFLAGRATions are LESS than the speed of sound.
▪ Buildings can be designed to minimize damage from DEFLAGRATions, but for DETONATions, it is usually not practical.
▪ Containment and venting are the 2 general methods of reducing structural damage from a DEFLAGRATion.
▪ The "Containment" method (usually expensive) protects buildings by containing the pressure of a DEFLAGRATion, which may be as high as 10 times atmospheric pressure.
|The "Venting" method uses louvers, hangar-type doors, wall panels, windows, or roof vents, which |[pic] |
|operate at low INTERNAL pressure to relieve DEFLAGRATion pressure. | |
|Explosion vent panels should NOT weight more than 3 pounds per square foot, so they can operate at| |
|a speed faster than the internal pressure rise. | |
|Explosion vent panels can be attached with reduced-diameter bolts or be hinged on one side and | |
|fastened on the other, to swing open. | |
|A larger explosion vent area develops a lower pressure. | |
|The size of an explosion vent is a function of structure size & strength, fuel type, and vent type| |
|(requires engineering analysis). | |
|Explosion venting does NOT protect personnel in a building. | |
|Buildings may be supported by a relatively|[pic] |
|small internal pressure (air-supported). | |
|Buildings may be supported by a relatively| |
|small internal pressure (air-supported). | |
▪ INTERIOR pressure of 0.15 psi will exert a force of 21.6 pounds per square foot.
▪ Air-supported structures are supported by interior air pressure created by fans.
▪ Interior pressure for air-supported structures can only be slightly above outside pressure.
▪ Fabric used to cover air-supported structures weighs only a few ounces per square foot, and is NON-combustible.
▪ Entrances and exits for air-supported structures normally utilize air locks.
▪ Internal pressure of an air-supported structure can be increased to counteract high winds by using an "anemometer" on fan controls.
▪ Storage racks can vary from 2 or 3 tiers with a total height of 12 to 80 feet.
▪ Rack storage is highly efficient, but results in a very high density of storage contents (high fire load).
▪ Rack storage aisles are frequently narrow, and cause access problems for firefighters.
▪ Storage racks are usually arranged back-to-back in several horizontal tiers, which obstructs water penetration from sprinklers, and may create flue spaces for vertical fire spread through the racks.
▪ Rack storage uses specialized "High Rack" or "In Rack" sprinklers based on height & style of racks, commodity stored, and type of containers or palletizing.
▪ Storage racks are constructed of UNprotected steel, and are normally structurally independent of the building.
Building Construction (2nd Edition)
Chapter 15 - Building Fire Protection Systems
Test Review
▪ Fire protection systems may include automatic suppression, standpipe, fire alarm, special hazard mitigation, emergency communication, and smoke control systems.
▪ Fire protection systems affect the overall fire behavior of a building.
▪ Reasons for installing fire protection systems include code/insurance requirements, general fire protection, and marketability.
▪ Codes typically require fire protection systems for schools, hospitals, nursing homes, high rises, malls, and in buildings with atriums.
▪ Automatic sprinklers, standpipes, and fire alarms are REQUIRED in high-rise hospitals.
▪ If a building is sprinklered when it is NOT required, codes usually reduce or eliminate some construction feature requirements, such as greater areas without fire walls or an increase in a material's flame spread rating.
▪ Some large occupancies will require 2,500 gpm fire pumps with diesel engines, and on-site water storage.
▪ Engineering of fire protection systems can include electric or diesel power for pumps, structural support for piping, foundations & floor space for pumps, excavation for water mains, on-site water storage, emergency generators, and conduit runs for alarm/communication systems.
▪ The tallest building in the US, the Sears Tower, has 10 fire pumps ranging from 750 to 1,500 gpm, 2 to 4 standpipe risers at various floors, and a fire protection system divided into 7 zones.
▪ Fire protection systems are designed to fit specific applications (building-specific).
▪ The cause of death for the majority of fire victims is smoke inhalation.
▪ It is possible to produce smoke without flaming combustion.
▪ If HVAC systems are appropriately designed, they can be used to lessen circulation of smoke throughout a building.
▪ "Smoke Management" refers to all methods used to lessen the impact of smoke on firefighters and occupants.
▪ Smoke management can include barriers, smoke vents, compartmentation, pressurization, and smoke shafts.
▪ "Smoke Control" refers to systems that use mechanical fans to direct the flow of smoke.
▪ Roof vents and smoke shafts use the natural buoyancy of smoke to exhaust smoke.
▪ Mechanical fans increase efficiency of roof vents and smoke shafts in exhausting smoke.
▪ A smoke exhaust fan at the top of an atrium is an example of a "simple" smoke control system.
|Smoke control systems may use an entire HVAC system or fans in stairwells (for pressurization). |[pic] |
|HVAC systems can be as simple as a single roof top unit, or can involve hundreds of feet of distribution and | |
|return ducts. | |
|Control dampers on HVAC systems are used to vary the airflow to the building's needs. | |
|In large buildings, HVAC systems can be controlled by temperature sensors connected to computers, which can | |
|adjust dampers, blowers, and heating units. | |
|HVAC systems in "Recirculation Mode" can spread products of combustion throughout a building. | |
|HVAC systems in "Fire Mode" can be used manually or automatically to exhaust smoke. | |
|HVAC systems use smoke detectors, water flow switches, or heat detectors, to signal the system to enter "Fire | |
|Mode". | |
|HVAC dampers in "Fire Mode" can be opened or closed, depending on fire location. | |
|When an HVAC system is in "Fire Mode" and continues to supply air to NON-fire floors, it creates a "pressure | |
|sandwich" which reduces smoke in those areas. | |
|Coordination of fire alarm, sprinklers, and HVAC zones is critical to maximize the benefits of a smoke control | |
|system. | |
|Automatic initiation of an HVAC system's fire operation must ALWAYS take priority over NORMAL system functions.| |
|Manual control of HVAC fire operation should take priority over automatic control. | |
|Advantages of "Manual" HVAC system "Fire Mode" control is elimination of false alarms and more specific system | |
|control. | |
|Manual HVAC smoke control systems can be controlled from a dedicated panel, the building's main control room, | |
|or a Firefighter Smoke Control Station (FSCS). | |
|A disadvantage of manual HVAC smoke control is that it is slower than automatic operation. | |
| |[pic] |
| |[pic] |
▪ Activation of smoke control systems should NEVER be by means of pull station.
▪ Codes now require an FSCS to have status indicators and switches for all fans and dampers serving the smoke control functions, and also a diagram with system components.
▪ The FSCS has highest priority over the smoke control system, and can override controls located elsewhere in the building.
▪ The FSCS should only be used at the direction of the Incident Commander.
▪ Buildings can be designed with smoke control zones, which may include more than 1 floor, or divisions of a single floor.
▪ A "Dedicated" smoke control system is used only for smoke control, while a "NON-Dedicated" system is a portion of the normal HVAC system used for smoke control.
▪ Dedicated smoke control systems are relatively simple and are less likely to be improperly modified if the HVAC system is renovated.
▪ Advantages of NON-dedicated smoke control systems include greater reliability and lower additional cost than dedicated systems.
▪ Controls on NON-dedicated smoke control systems are likely to be more complicated than on dedicated systems.
▪ Smoke control systems must maintain adequate pressures across barriers, such as partition walls, to prevent migration of smoke.
▪ Smoke control systems can NOT be substituted for suppression systems and can NOT maintain tenable conditions in the fire area.
Building Construction (2nd Edition)
Chapter 16 - Buildings Under Construction
Test Review
▪ A 1 story mercantile building of several thousand square feet can be completed in a few weeks, while a high-rise can take as long as 3 years.
▪ Frequent construction site visits by 1st-due fire companies are necessary for construction project familiarity.
▪ Due to fences, barricades, excavations, and absence of paved drives, construction site access can be difficult for firefighters.
▪ Fire frequently occur in the upper floors of high-rise construction projects.
▪ Construction elevators are usually on the outside of a building, and are manually operated.
▪ Construction site watchmen are commonly NOT familiar with construction elevator operation.
▪ Power to construction elevators is commonly disconnected during NON-construction hours.
▪ Material hoists are for material ONLY, not people.
▪ Firefighters must often use temporary construction stairs or ladders to access fires on upper floors of construction buildings.
▪ Temporary electrical wiring on construction sites can become a source of ignition.
▪ Temporary heaters on construction sites may use natural gas, kerosene, or propane, and can cause fires if left unattended.
▪ 100 pound propane cylinders are common on construction sites (BLEVE hazard).
▪ Kerosene storage tanks are susceptible to sparks from welding (common hazard), and fire exposure.
▪ Welding is used for erection of steel frame buildings, and on reinforced concrete to weld reinforcing bars.
▪ Codes require a "fire watch" during and after welding or cutting with torches.
▪ Torches are used for soldering pipe joints.
▪ On high-rise projects, a trash chute is used to dump trash from upper floors (same hazards as other chutes).
▪ Fire resistance of concrete can NOT be ensured until the concrete has cured.
▪ Wood formwork destroyed by fire can cause freshly placed concrete to collapse onto floors below.
▪ Temporary fire protection is critical during high-rise construction projects.
▪ Temporary fire protection commonly includes standpipes & outlets, and may include sprinklers.
▪ The most efficient fire protection during construction is to have the permanent fire protection system installed.
▪ Standpipe risers should be extended upward as the building is constructed upward.
▪ Top standpipe hose & outlets on high-rise construction should be within a few stories of the structural supports.
▪ 2 standpipe risers may be required during high-rise construction so that 1 may remain in place while the other is extended.
▪ Dry standpipes supplied through FD connections must be used in cold weather, and must be drained after use.
▪ Barrels of water, with buckets, may be used on construction sites in place of extinguishers.
▪ Remodeling can be more hazardous than new construction due to building being occupied, exits obstructed by construction barricades, and by the need to shut down the sprinkler system.
▪ Propane torches may be used to remove floor covering adhesive during remodeling.
▪ If sprinklers are shut off in a remodeling construction area, first aid, hose, and extinguishers must be provided.
▪ Sectional sprinkler control valves are sometimes located in obscure corners of old warehouse and factory buildings, and can be inadvertently left off after a remodeling project.
▪ Fires on demolition sites are very common.
▪ Many building components and contents are salvaged (AKA scrapped) prior to demolition of a building.
▪ Cutting torches, used to remove scrap metal from demolition buildings, is a very common cause of fires.
▪ Exterior fire tactics, from a safe distance, are best for buildings being demolished.
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