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 HandbookFundamentals (SI)Table 1 Abbreviations for Text, Drawings, and Computer Program
9、sTerm 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
10、 amb 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,
11、wall WAZbarometer(-tric) baro BARO bill of material b/m BOM boiling point bp BP BPBrown specify type.Abbreviations and Symbols 37.7Elbow, facing away from viewerElbow, base-supportedLateralReducer, concentricReducer, eccentric, flat on bottomReducer, eccentric, flat on topTeeTee, facing toward viewe
12、rTee, facing away from viewerUnion, screwedUnion, flangedPiping SpecialtiesAir vent, automaticAir vent, manualAir separatorPipe guideAnchor, intermediateAnchor, mainBall jointExpansion jointExpansion loopFlexible connectorFlowmeter, orifice plate with flangesFlowmeter, venturiFlow switchHanger rodHa
13、nger 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)ThermometerThermometer well, onlyThermos
14、tatTraps, 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 visible ductDuct section,
15、 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 measurement are not shown here
16、, 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 HandbookFundamentals (SI)TransitionaTurning vanesSmoke detectorsDampersBackdraf
17、t 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 doorCeiling diffuser,
18、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)Condensing UnitsA
19、ir cooledaWater cooledaCondenser-Evaporator(Cascade System)Cooling TowersCooling towerSpray pondEvaporatorsbFinned coilForced convectionImmersion cooling unitPlate coilPipe coilcLiquid Chillers (Chillers only)Direct expansiondFloodeddTank, closedTank, openChilling UnitsAbsorptionaL = Liquid being co
20、oled, 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 37.9CentrifugalReci
21、procatingRotary 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 regulating valve,
22、 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 reversing valveTe
23、mperature or Temperature-Actuated Electrical or Flow ControlsThermostat, self-containedThermostat, remote bulbSensor, temperaturePressure-reducing regulatorPressure regulatorValve, condenser water regulatingAuxiliary EquipmentRefrigerantFilterStrainerFilter and drierScale trapDrierVibration absorber
24、Heat exchangerOil separatorSight glassFusible plugRupture diskReceiver, high-pressure,horizontalReceiver, high-pressure, verticalReceiver, low-pressureIntercoolerIntercooler/desuperheaterEnergy Recovery EquipmentCondenser, double bundleAir to Air Energy RecoveryRotary heat wheelCoil loopHeat pipeFix
25、ed plate37.10 2013 ASHRAE HandbookFundamentals (SI)PIPING 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 legend naming the
26、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 of any kind, f
27、it-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 hazardous material
28、s: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, whenreleased fr
29、om 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 by nature, a
30、nd 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 includes wat
31、er (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 abbre-viated for
32、m, 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 be applied cl
33、ose 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 and location
34、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, crossflowPower
35、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 name or abbr
36、eviation, 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.b Number each
37、 symbol if more than one; see ASME Standard Y32.4.Table 2 Examples of LegendsHOT WATERAIR 700 kPAH.P. RETURNSTEAM 700 kPATable 3 Classification of Hazardous Materials and Designation of ColorsaClassification Color FieldColors of Letters for LegendMaterials Inherently HazardousFlammable or explosive
38、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. Red WhiteaWhen pr
39、eceding 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 regulations.cMarke
40、rs 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 displays.Visibili
41、ty. 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 size ofletters
42、 recommended. Use of standard size letters of 13 mm or largeris recommended. For identifying materials in pipes of less than20 mm in diameter and for valve and fitting identification, use a per-manently legible tag.Unusual or Extreme Situations. When the piping layout occursin or creates an area of
43、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 STANDARDSASHRAE. 2005. Graphic sy
44、mbols 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 heating, ventilating
45、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 and abbreviations fo
46、r 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, mmLength ofColor Field A,mmSize ofLetters B,mm20 to 32 200 1340 to 50 200 2065 to 150 300 32200 to 250 600 65over 250 800 90
