SECTION 237000 - CENTRAL HVAC EQUIPMENT



This master should be used by designers working on Port of Portland construction projects and by designers working for PDX tenants (“Tenants”). Usage notes highlight a few specific editing choices, however the entire section should be evaluated and edited to fit specific project needs.

SECTION 237000 - CENTRAL HVAC EQUIPMENT

GENERAL

1. DESCRIPTION

A. This section describes custom factory fabricated air handling units and central station air handling units.

2. RELATED WORK SPECIFIED ELSEWHERE

A. Section 230500, Common Work Results for HVAC

B. Section 230519, Meters and Gauges for HVAC Piping

C. Section 230520, Piping Specialties for HVAC Piping

D. Section 230523, General Duty Valves for HVAC Piping

E. Section 230529, Hangers and Supports for HVAC Piping and Equipment

F. Section 230545, Seismic Restraints for HVAC Piping and Equipment

G. Section 230548, Vibration and Seismic Controls for HVAC Piping and Equipment

H. Section 230553, Identification for HVAC Piping and Equipment

I. Section 230593, Testing, Adjusting, and Balancing

J. Section 230719, HVAC Insulation

K. Section 230900, Instrumentation and Controls for HVAC

L. Section 232000, HVAC Piping

M. Section 232500, HVAC Water Treatment

N. Section 232923, Variable-Frequency Motor Controllers

O. Section 233114, Medium Pressure Ductwork

P. Section 233300, Air Duct Accessories

Q. Section 233319, Sound Attenuators

R. Section 233400, HVAC Fans

S. Section 234000, HVAC Air Cleaning Devices

T. Section 238200, Convection Heating and Cooling Units

U. Division 26, Electrical

3. REFERENCES

A. UL: Underwriters Laboratories

1. UL 181: Standard for Factory-Made Air Ducts and Air Connectors

4. SUBMITTALS

A. For systems, equipment, and components specified herein, submit product/material data; shop drawings; operation and maintenance data; as-constructed data; installation, startup, and testing manuals; operation and maintenance manuals; and as-constructed drawings.

1. Shop Drawings: Include details of construction, dimensions, arrangement of components, and isolation.

2. Product Data: Include performance data.

Use only if Commissioning Section 019100 is included in the project manual.

B. For systems, equipment, and components specified herein, submit commissioning plans and schedules; checkout, startup, operational, functional and final acceptance test plans, procedures, checklists, and reports; systems manuals; and operation and maintenance training plans.

PRODUCTS

The following is typically used for air handling units serving concourse holdrooms and Port offices.

1. CUSTOM FACTORY FABRICATED VARIABLE AIR VOLUME AIR HANDLING UNITS

A. Acceptable Manufacturers: Pace, Haakon, Huntair, or pre-bid approved equal.

B. Description: Blow-through air handling units consisting of future air cleaning equipment section, mixing sections, prefilter and final filter sections, coil sections, fan sections with motors and drives, inlet plenum sections, and discharge plenum sections, all contained in an insulated steel casing mounted on a common steel base.

C. Unit Casing:

1. Casing shall be 16-gauge steel, reinforced and braced for operation to 10 inches W.G. Caulk and seal all seams to make unit water- and airtight. Support unit on continuous steel supports with intermediate angle and channel framework. Floor shall be 3/16-inch checker plate continuously welded and internally watertight. Provide bellmouth duct fittings at unit supply discharge connection. Bellmouths shall have minimum radius/duct diameter of 0.20. Provide screen at all floor outlets. Mount screen at floor level.

2. Provide access doors as indicated on the drawings for inspection of fan and motors, coils, filters, dampers, and other components. Access doors shall be 16-gauge steel, with double wall construction and 22-gauge solid metal liner on inside and 2 inches of insulation sandwiched between outer and inner layer. Provide continuous piano hinge fastened to door frame. Door frame shall be 16-gauge steel continuously welded. Provide continuous perimeter of closed cell neoprene gasket to form an airtight seal. Provide heavy duty adjustable knurled knob door handles. Provide wired glass window for inspection of fan and motor and on access downstream of cooling coil.

3. Provide manufacturer’s standard factory finish.

4. Insulation of walls and roof shall be minimum 4-inch-thick, 3 pounds per cubic foot density rigid fiberglass. Provide internal liner of 22-gauge perforated metal throughout. Insulation of base shall be with 4-inch-thick rigid fiberglass under floor base plate, supported with 22-gauge perforated metal throughout.

The following paragraph is optional.

5. Provide two layers 5/8-inch thick gypsum wall board and R19 (6 1/2-inches thick) fiberglass batt to the underside of the air handling unit.

D. Fans: Plug fans and provide screen at fan inlet.

E. Motor and Drive:

1. Integrally mounted 1800 rpm motor, with prelubricated sealed ball bearings.

2. V-belt drive sized for 150 percent of motor horsepower, with cast iron fixed sheaves.

3. Multiple belt drives.

4. Sheaves shall be statically and dynamically balanced.

F. Vibration Isolators:

1. Provide as an integral part of each unit as indicated.

2. Coordinated weights and location of support points with the vibration isolation equipment supplier.

3. Provide vibration isolator restraints.

G. Water Coils:

1. Provide structural steel support rack so that each coil can be individually removed without disturbing other coils.

2. Provide drain pan for each level of cooling coils. Drain pans shall be welded stainless steel and double sloped.

3. Provide space between heating and cooling coils for temperature sensing station.

H. Filters: Provide suitable access doors, slide rack, and sealant strips for filters specified.

I. Future Gaseous Pollution Control Filters: Provide space in unit to house future filters.

J. Flexible Connections:

1. Constructed in accordance with UL 181, Class I airduct with flanged connections.

2. Flexible, neoprene-coated glass fabric, not lighter than 30 oz/sq. yd.

3. Ventglas by Vent-Fabrics, Inc., or equal.

K. Dampers:

1. Provide parallel blade dampers for outside and return air dampers and opposed blade dampers for relief air.

2. Provide minimum outside air damper so that damper is closed with motor shaft retracted and at minimum flow position with motor fully extended.

3. Arrange return air and minimum outside air dampers to discharge against each other for maximum mixing in the mixing box prior to the coil.

4. Provide temporary metal cap on all roof openings for added weather protection during shipping and storage on site.

L. Lights and Convenience Receptacles:

1. Mount unit light switch with pilot light on the front of each unit.

2. Provide factory-mounted lighting fixtures so that each section of the unit is illuminated. Lights shall be marine type with protective metal cage and glass seals. Install duplex receptacles on inside wall of supply and return fan sections.

3. Provide two single point power connections. Wire lighting and receptacles on separate circuits. Factory prewire lighting and convenience outlets.

The following is typically used for tunnel ventilation air handling units or bag makeup heating and ventilating units.

2. CENTRAL STATION AIR HANDLING UNITS

A. Acceptable Manufacturers: Pace SI, Trane, Carrier, McQuay, Bohn, Airfan, Thermal Corp., or pre-bid approved equal.

B. Description:

1. Single zone blow-through central station air handling units consisting of fan section, coil section with face and bypass dampers, filter section, motor and drive, all contained in an insulated steel casing and mounted on a common steel base. Arrange components as specified and as shown on the drawings.

2. Units shall be AMCA rated.

C. Unit Casing:

1. Casing shall be 16-gauge steel, properly reinforced and braced and shall be of sectionalized construction. Support entire unit on continuous steel supports.

2. Provide access doors for inspection of fan and motor.

3. Manufacturer’s standard factory finish.

4. Two-inch fiberglass type insulation securely fastened to interior of casing.

5. Arranged with motor and drive inside fan casing; isolated fan and motor assembly within unit casing.

D. Fans:

1. Double width, double inlet centrifugal fan wheels with backward inclined, air foil, or forward curved blades.

2. Statically and dynamically balanced in its own bearings with a maximum full amplitude shaft deflection at bearings not to exceed 0.001-inch at 1200 rpm.

3. Grease lubricated, self-aligning, interior-mounted pillow block or flanged bearings permanently sealed.

E. Motor and Drive:

1. Integrally mounted 1800 rpm motor, with prelubricated sealed ball bearings.

2. V-belt drive sized for 150 percent of motor horsepower, with cast iron fixed sheaves for motors over 5 horsepower, variable pitch drives for motors 5 horsepower and under.

3. Multiple belt drives on units over 2 horsepower.

4. Sheaves statically and dynamically balanced.

F. Vibration Isolators:

1. Provide as an integral part of each unit.

2. Coordinated weights and location of support points with the vibration isolation equipment supplier.

G. Water Coils:

1. Provide water coils as specified.

2. Provide space between heating and cooling coils for temperature sensing station.

H. Filters: Provide suitable access doors, slide rack, and sealant strips for filters specified.

I. Flexible Connections:

1. Constructed in accordance with UL 181, Class I airduct with flanged connections.

2. Flexible, neoprene-coated glass fabric, not lighter than 30 ounces per square yard.

3. Ventglas by Vent-Fabrics, Inc, or equal.

EXECUTION

1. INSTALLATION

A. Air Handling Unit:

1. Inspect units weekly and rotate fan wheel monthly.

2. Install with air filters in place before operating unit.

3. Mount on concrete curb.

4. Pipe drain pan to floor drain with 3-inch trap seal.

5. Remove temporary metal roof caps only after unit is protected from weather.

B. Flexible Connections:

1. Provide flexible connections between fans and the connected ducts or plenums.

2. Install with 1-inch space between the fan and connecting duct or plenum with fabric snug but not stretched tightly.

3. Provide accurate alignment between fan and duct or plenum.

4. Secure in place with flanged connections. Do not crimp into the duct construction. Ends of the screws shall not project into the duct more than 1/8 inch.

Choose from Commissioning and Testing articles. Use Commissioning if Section 019100 is included in the project manual; otherwise use Testing.

2. COMMISSIONING

A. Commission items specified herein.

3. TESTING

A. Check out, start up, and test items specified herein.

END OF SECTION 237000

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