1、37.1CHAPTER 37ABBREVIATIONS AND SYMBOLSAbbreviations for Text, Drawings, and Computer Programs. 37.1Letter Symbols. 37.1Dimensionless Numbers 37.4Mathematical Symbols 37.4Subscripts 37.5Graphical Symbols for Drawings 37.5Piping System Identification . 37.10HIS chapter contains information about abbr
2、eviations andTsymbols for HVAC avoidtheir use in documents circulated in foreign countries.Graphical symbols in this chapter of piping, ductwork, fittings,and in-line accessories can be used on scale drawings and diagrams.Identifying piping by legend and color promotes greater safetyand lessens the
3、chance of error in emergencies. Piping identificationis now required throughout the United States by the OccupationalSafety and Health Administration (OSHA) for some industries andby many federal, state, and local codes.ABBREVIATIONS FORTEXT, DRAWINGS, AND COMPUTER PROGRAMSTable 1 gives some abbrevi
4、ations, as well as others commonlyfound on mechanical drawings and abbreviations (symbols) used incomputer programming. Abbreviations specific to a single subjectare defined in the chapters in which they appear. Additional abbre-viations used on drawings can be found in the section on GraphicalSymbo
5、ls for Drawings.Computer ProgramsThe abbreviations (symbols) used for computer programming forthe HVAC for example, (a/b)/cor a/(b/c) is correct, but not a/b/c.Subscripts and superscripts, or several of them separated by com-mas, may be attached to a single basic letter (kernel), but not to othersub
6、scripts or superscripts. A symbol that has been modified by asuperscript should be enclosed in parentheses before an exponent isadded (Xa)3. Symbols can also have alphanumeric marks such as (prime), + (plus), and * (asterisk).More detailed information on the general principles of letter sym-bol stan
7、dardization are in standards listed at the end of this chapter.The letter symbols, in general, follow these standards, which are outof print:Y10.3M Letter Symbols for Mechanics and Time-RelatedPhenomenaY10.4-82 Letter Symbols for Heat and ThermodynamicsOther symbols chosen by an author for a physica
8、l magnitude notappearing in any standard list should be ones that do not already havedifferent meanings in the field of the text.The preparation of this chapter is assigned to TC 1.6, Terminology.37.2 2013 ASHRAE HandbookFundamentalsTable 1 Abbreviations for Text, Drawings, and Computer ProgramsTerm
9、 Text Drawings Programabove finished floor AFF absolute abs ABS ABSaccumulat(e, -or) acc ACCUM ACCUMair condition(-ing, -ed) AIR COND air-conditioning unit(s) ACU ACUair-handling unit AHU AHUair horsepower ahp AHP AHPalteration altrn ALTRN alternating current ac AC ACaltitude alt ALT ALTambient amb
10、AMB AMBAmerican National Standards Institute1ANSI ANSI American wire gage AWG AWG ampere (amp, amps) amp AMP AMP, AMPSangle ANGangle of incidence ANGIapparatus dew point adp ADP ADPapproximate approx. APPROX area Aatmosphere atm ATM average avg AVG AVGazimuth az AZ AZazimuth, solar SAZazimuth, wall
11、WAZbarometer(-tric) baro BARO bill of material b/m BOM boiling point bp BP BPbrake horsepower bhp BHP BHPBrown specify type.Abbreviations and Symbols 37.7Elbow, facing away from viewerElbow, base-supportedLateralReducer, concentricReducer, eccentric, flat on bottomReducer, eccentric, flat on topTeeT
12、ee, facing toward viewerTee, facing away from viewerUnion, screwedUnion, flangedPiping SpecialtiesAir vent, automaticAir vent, manualAir separatorPipe guideAnchor, intermediateAnchor, mainBall jointExpansion jointExpansion loopFlexible connectorFlowmeter, orifice plate with flangesFlowmeter, venturi
13、Flow switchHanger rodHanger springHeat exchanger, liquidHeat transfer surface (indicate type)Pitch of pipe, rise (R) drop (D)Pressure gage and cockPressure switchPump (indicate use)Pump suction diffuserSpool piece, flangedStrainerStrainer, blow offStrainer, duplexTank (indicate use)ThermometerThermo
14、meter well, onlyThermostatTraps, steam (indicate type)Unit heater (indicate type)Air-Moving Devices and ComponentsFans (indicate use)CentrifugalPropellerRoof ventilator, intakeRoof ventilator, exhaustRoof ventilator, louveredVaneaxialDuctworka,bDirection of flowDuct size, where first dimension is vi
15、sible ductDuct section, supplyDuct section, returnDuct section, exhaustChange of elevationrise (R) drop (D)Access doors, vertical orhorizontalCowl, (gooseneck) and flashingDuct liningFlexible connectionFlexible ductSound attenuatorTerminal unit, mixingTerminal unit, variable volumea Units of measure
16、ment are not shown here, but should be shown on drawings. The firstdimension is visible duct dimension for duct size, top dimension for grilles, and hori-zontal dimension for registers.bShow volumetric flow rate at each device.37.8 2013 ASHRAE HandbookFundamentalsTransitionaTurning vanesSmoke detect
17、orsDampersBackdraft damperFire damperManual volumeSmoke damperGrilles, Register and DiffusersbSidewall inlet, (exhaust) outlet, registers, and grillesSidewall outlet, registers, and grillesRectangular four-way outlet, supplyLouver and screenTransfer grille or louverDoor grille or louverUndercut door
18、Ceiling diffuser, rectangularRound outletLinear outletLight troffer outletRefrigerationCompressorsCentrifugalaIndicate flat on bottom or top (FOB or FOT), if applicable.bShow volumetric flow rate at each device.ReciprocatingRotaryRotary screwCondensersAir cooledEvaporativeWater cooled, (specify type
19、)Condensing UnitsAir cooledaWater cooledaCondenser-Evaporator(Cascade System)Cooling TowersCooling towerSpray pondEvaporatorsbFinned coilForced convectionImmersion cooling unitPlate coilPipe coilcLiquid Chillers (Chillers only)Direct expansiondFloodeddTank, closedTank, openChilling UnitsAbsorptionaL
20、 = Liquid being cooled, RL = Refrigerant liquid, RS = Refrigerant suction.bSpecify manifolding.cFrequently used diagrammatically as evaporator and/or condenser with label indicat-ing name and type.dL = Liquid being cooled, RL = Refrigerant liquid, RS = Refrigerant suction.Abbreviations and Symbols 3
21、7.9CentrifugalReciprocatingRotary screwControlsRefrigerant ControlsCapillary tubeExpansion valve, handExpansion valve, automaticExpansion valve, thermostaticFloat valve, high side, or liquid drain valveFloat valve, low sideThermal bulbSolenoid valveConstant pressure valve, suctionEvaporator pressure
22、 regulating valve, thermostatic, throttlingEvaporator pressure regulating valve, thermostatic, snap-actionEvaporator pressure regulating valve, throttling-type, evaporator sideCompressor suction valve, pressure-limiting, throttling-type, compressor sideThermosuction valveSnap-action valveRefrigerant
23、 reversing valveTemperature or Temperature-Actuated Electrical or Flow ControlsThermostat, self-containedThermostat, remote bulbSensor, temperaturePressure-reducing regulatorPressure regulatorValve, condenser water regulatingAuxiliary EquipmentRefrigerantFilterStrainerFilter and drierScale trapDrier
24、Vibration absorberHeat exchangerOil separatorSight glassFusible plugRupture diskReceiver, high-pressure,horizontalReceiver, high-pressure, verticalReceiver, low-pressureIntercoolerIntercooler/desuperheaterEnergy Recovery EquipmentCondenser, double bundleAir to Air Energy RecoveryRotary heat wheelCoi
25、l loopHeat pipeFixed plate37.10 2013 ASHRAE HandbookFundamentalsPIPING SYSTEM IDENTIFICATIONThe material in piping systems is identified to promote greatersafety and lessen the chances of error, confusion, or inaction intimes of emergency. Primary identification should be by means of alettered legen
26、d naming the material conveyed by the piping. In addi-tion to, but not instead of, lettered identification, color can be usedto identify the hazards or use of the material.The data in this section have been extracted from ASME Stan-dard A13.1.DefinitionsPiping Systems. Piping systems include pipes o
27、f any kind, fit-tings, valves, and pipe coverings. Supports, brackets, and otheraccessories are not included. Pipes are defined as conduits for thetransport of gases, liquids, semiliquids, or fine particulate dust.Materials Inherently Hazardous to Life and Property. Thereare four categories of hazar
28、dous materials:Flammable or explosive materials that are easily ignited, includ-ing materials known as fire producers or explosivesChemically active or toxic materials that are corrosive or are inthemselves toxic or productive of poisonous gasesMaterials at extreme temperatures or pressures that, wh
29、enreleased from the piping, cause a sudden outburst with the poten-tial for inflicting injury or property damage by burns, impinge-ment, or flashing to vapor stateRadioactive materials that emit ionizing radiationMaterials of Inherently Low Hazard. These include all mate-rials that are not hazardous
30、 by nature, and are near enough to ambi-ent pressure and temperature that people working on systemscarrying these materials run little risk through their release.Fire-Quenching Materials. This classification includes sprin-kler systems and other piped firefighting or fire protection equip-ment. This
31、 includes water (for firefighting), chemical foam, CO2,Halon, and so forth.Method of IdentificationLegend. The legend is the primary and explicit identification ofcontent. Positive identification of the content of the piping system isby lettered legend giving the name of the contents, in full or abb
32、re-viated form, as shown in Table 2. Arrows should be used to indicatethe direction of flow. Use the legend to identify contents exactly andto provide temperature, pressure, and other details necessary toidentify the hazard.The legend should be brief, informative, pointed, and simple.Legends should
33、be applied close to valves and adjacent to changesin direction, branches, and where pipes pass through walls or floors,and as frequently as needed along straight runs to provide clear andpositive identification. Identification may be applied by stenciling,tape, or markers (see Figure 1). The number
34、and location of identi-fication markers on a particular piping system is based on judgment.Color. Colors listed in Table 3 are used to identify the charac-teristic properties of the contents. Color can be shown on or con-tiguous to the piping by any physical means, but it should be usedPlate fin, cr
35、ossflowPower SourcesMotor, electric (number for identification of description in specifications)Engine (indicate fuel)Gas turbineSteam turbineSteam turbine, condensingElectrical EquipmentaSymbols for electrical equipment shown on mechanical drawings are usu-ally geometric figures with an appropriate
36、 name or abbreviation, with detailsdescribed in the specifications. The following are some common examples.bMotor controlDisconnect switch, unfusedDisconnect switch, fusedTime clockAutomatic filter panelLighting panelPower panela See ARI Standard 130 for preferred symbols of common electrical parts.
37、b Number each symbol if more than one; see ASME Standard Y32.4.Table 2 Examples of LegendsHOT WATERAIR 100 PSIGH.P. RETURNSTEAM 100 PSIGTable 3 Classification of Hazardous Materials and Designation of ColorsaClassification Color FieldColors of Letters for LegendMaterials Inherently HazardousFlammabl
38、e or explosive Yellow BlackChemically active or toxic Yellow BlackExtreme temperatures or pressures Yellow BlackRadioactivebPurple YellowMaterials of Inherently Low HazardLiquid or liquid admixturecGreen BlackGas or gaseous admixture Blue WhiteFire-Quenching MaterialsWater, foam, CO2, Halon, etc. Re
39、d WhiteaWhen preceding color scheme is used, colors should be as recommended in latest revi-sion of NEMA Standard Z535.1.bPreviously specified radioactive markers using yellow or purple are acceptable ifalready installed and/or until existing supplies are depleted, subject to applicable fed-eral reg
40、ulations.cMarkers with black letters on green field are acceptable if already installed and/or untilexisting supplies are depleted.Fig. 1 Visibility of Pipe MarkingsAbbreviations and Symbols 37.11in combination with a legend. Color can be used in continuous totallength coverage or in intermittent di
41、splays.Visibility. Pipe markings should be highly visible. If pipe linesare above the normal line of vision, the lettering is placed below thehorizontal centerline of the pipe (Figure 1).Type and Size of Letters. Provide the maximum contrastbetween color field and legend (Table 3). Table 4 shows the
42、 size ofletters recommended. Use of standard size letters of 1/2 in. or largeris recommended. For identifying materials in pipes of less than 3/4 in. in diameter and for valve and fitting identification, use a per-manently legible tag.Unusual or Extreme Situations. When the piping layout occursin or
43、 creates an area of limited accessibility or is extremely complex,other identification techniques may be required. Although a certainamount of imagination may be needed, the designer should alwaysclearly identify the hazard and use the recommended color and leg-end guidelines.CODES AND STANDARDSASHR
44、AE. 2005. Graphic symbols for heating, ventilating, air-conditioning,and refrigeration systems. ANSI/ASHRAE Standard 134-2005.ASME. 2007. Scheme for the identification of piping systems. ANSI/ASMEStandard A13.1-2007. American Society of Mechanical Engineers, NewYork.ASME. 1998. Graphic symbols for h
45、eating, ventilating and air conditioning.Standard Y32.2.4-1949 (RA 1988). American Society of MechanicalEngineers, New York.IEEE. 2004. Standard letter symbols for units of measurement. Standard260.1-2004. Institute of Electrical and Electronics Engineers, Piscat-away, NJ.IEEE. 1996. Letter symbols
46、and abbreviations for quantities used in acous-tics. Standard 260.4-1996. Institute of Electrical and Electronics Engi-neers, Piscataway, NJ.NEMA. 2011. Safety colors. Standard Z535.1-2006 (RA 2011). NationalElectrical Manufacturers Association, Rosslyn, VA.NFPA. 2012. Standard for fire safety and emergency symbols, 2012 edition.Standard 170. National Fire Protection Association, Quincy, MA.Table 4 Size of Legend LettersOutside Diameterof Pipe or Covering, in.Length ofColor Field A, in.Size ofLetters B, in.3/4 to 1 1/4 8 1/21 1/2 to 2 8 3/42 1/2 to 6 12 1-1/48 to 10 24 2-1/2over 10 32 3-1/2
