Units of Measure 29 - Western University

Units of Measure

29 Chapter

Introduction to Units of Measure ...................................................... 29-3

Units of Measure Length, Area, Volume ....................................................................... 29-5 Mass, Mass per Length, Mass per Volume ....................................... 29-6 Pressure, Velocity ............................................................................. 29-7 Flow Rates ......................................................................................... 29-8 Electric, Power .................................................................................. 29-9 Viscosity, Angular, Other.................................................................. 29-10

Miscellaneous Useful Constants ........................................................ 29-10

Project Specifications and their Use of Units of Measure Special Units of Measure .................................................................. 29-11 Length and Area Units ...................................................................... 29-11 Volume Units .................................................................................... 29-13 Mass and Unit Mass .......................................................................... 29-14 Pressure Units ................................................................................... 29-15 Velocity and Flow Rate Units ........................................................... 29-15 Electrical Units .................................................................................. 29-17 Power Units ....................................................................................... 29-18 Viscosity Units .................................................................................. 29-18

G1 ? ICARUS Corporation, 1998.

29-2 ICARUS Reference

? ICARUS Corporation, 1998. G1

Chapter 29: Units of Measure 29-3

Introduction to Units of Measure

ICARUS systems provide a choice of two sets of units of measure: ? I-P (Inch-Pound) ? METRIC (Metric).

The user must select the desired set indirectly (by specifying the country base location) or directly. Once the appropriate set is selected, the user may wish to redefine one or more variables from the base units of measure to some other measure. The Units of Measure Data provides the means of identifying the conversion. The user should refer to units of measure later in this chapter for the basic definitions of variables and their associated units of measure for I-P and METRIC sets. Along with these definitions are conversion multipliers for relating I-P to METRIC units. Each line bearing a two-digit Type Number is a candidate for user redefinition. The type number is used to identify the specific unit of measure to be redefined. The user would then provide a new name for that unit of measure and the appropriate conversion multiplier to convert from the base unit of measure to the desired unit of measure. The following special units of measure are not characterized by a Type Number and simple conversion multiplier:

? Temperature - User may define temperature to be in DEG C, DEG F or DEG K. ? Process Pipe Size (diameter and thickness dimensions only) - User may specify process pipe to be designed

in INCH or MM units of measure, independently of other linear units of measure. ? Driver Power - User may specify drivers to be specified, sized, selected, reported in HP or KW.

Notes of Caution

All user-provided numeric values for dimensions, sizes, extents, intensities, flows, etc., are considered by the system to conform to those units of measure selected and/or defined by the user. It is the user's responsibility to be constantly aware of the units of measure so selected throughout the entire exercise of preparing project data for the system. The user is cautioned that variable redefinition from system base to a user unit of measure could have unpredictable downstream effects, for example, in selection of plates, wire, tubing, pipe, etc. Further, the user is cautioned that each base set of units, I-P and METRIC, has its own special set of default values; the pair of default values are not necessarily related to one another by usual conversion relationships; each is established by itself as a reasonable value in the base unit of measure. Once the user's set of units of measure is established, default values are evaluated as follows:

? Unit of Measure Conversion: are used to convert the base unit of measure default value by the user's numeric value to obtain the value of the revised default value in the desired units of measure.

? No Unit of Measure Conversion: the system uses the default value as tabulated.

G1 ? ICARUS Corporation, 1998.

29-4 ICARUS Reference Example

? METRIC base set selected in Project Title Data, and ? Unit of measure data used to convert pressure in KPA (METRIC) to PSIG using 0.14504 = 1/6.894757 as

conversion for Type No. 18. ? Turbine steam pressure METRIC default is 2000 KPA, which, converted to PSIG, is 290.047549 PSIG.

The PSIG value is used in sizing the turbine if the user does not enter the pressure value. ? Contrast this value with the I-P default value printed in the turbine table as 300 PSIG.

Another Example

The METRIC base user will have all length variables defined in terms of millimeters, meters, etc. As a consequence, pipe sizes (diameters) and wall thicknesses will be expected to be specified, sized, selected and reported in MM. Should the METRIC base user desire pipe to be specified, sized, selected and reported in MM. Should the METRIC base user desire pipe to be specified, sized, selected and reported as INCH values, the user must enter the designator INCH in the field labelled Pipe Size. This note of caution is tendered for temperature and driver power a well as pipe sizing.

Final Note of Caution

The User of this section should exercise extreme care and deliberation in redefining units of measure. Since, once established:

? All user input is expected in the defined units of measure. ? Default values subject to conversions will not be in rounded numbers but will be conversions from base

default values. ? Selection and design criteria may be impacted and affected by user redefinition of units of measure. ? All reporting by the system will conform to the selected units of measure. ? The trial of consequences of redefinitions of the units of measure is one expectedly difficult to backtrack,

especially if that variable affects size selection of materials in a non-standard way.

? ICARUS Corporation, 1998. G1

Units of Measure

Chapter 29: Units of Measure 29-5

Type Inch-Pound No.

Description

Symbol

Conversion

Metric Description

Symbol

Length

01 Inches 02 Feet 03 Miles (statute) 04 Mesh

INCHES FEET MILES MESH

x 25.4 x 0.3048 x 1.60934 x 1.0000

= Millimeters = Meters = Kilometers = Mesh

MM M KM MESH

Area

05 Square feet 06 Square yards

SF

x 0.092903

= Square meters

M2

SY

x 0.836127

= Square meters

M2

Volume

07 Cubic feet 08 Cubic yards 09 Gallons

(231 cubic inches) 10 Barrels (42 gallons) 11 Bags

(94 pounds) 48 Board feet

CF

x 0.028317

CY

x 0.76455

GALLONS x 0.00378541

= Cubic meters = Cubic meters = Cubic meters

BARRELS x 0.1589873

BAGS

x 0.852749

BDFT

x 0.0023597

= Cubic meters

= Bags (50 kilograms)

= Cubic meters

M3 M3 M3

M3 BAG-50KG

M3

G1 ? ICARUS Corporation, 1998.

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