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HVAC abbreviations

  • A - compressed air line or area
  • ABC - above ceiling
  • AC - air chamber, alternating current
  • A/C - air conditioning
  • AFF - above finished door
  • AFG - above finished grade
  • AL - aluminium
  • AMB - ambient
  • AMP - amphere
  • ARR - arrangement
  • ATC - automatic temperature control, at ceiling
  • ATM - atmosphere
  • AUTO - automatic
  • AUX - auxiliary
  • AVG - average
  • BBD - boiler blowdown
  • BF - boiler feed
  • BHP - boiler horsepower, brake horsepower
  • BOD - bottom of duct
  • BOP - bottom of pipe
  • BOT - bottom
  • BP - back pressure
  • B & S - bell-and-spigot
  • BSMT - basement
  • BTU - british thermal unit
  • BV - butterfly valve
  • oC - degrees celcius
  • C - condensate line
  • C to C - center to center
  • CA - compressed air
  • CAL - calorie
  • CAP - capacity
  • CD - condensate drain
  • CF - chemical feed, cubic foot
  • CFH - cubic feet per hour
  • CFM - cubic feet per minute
  • CI - cast iron
  • CIRC - circular
  • CL - center line
  • CM - centimeter
  • CM2 - square centimeter
  • CO - clean out
  • COL - column
  • CONC - concrete, concentric
  • CONN - connect, connection
  • CONT - continuation
  • CPVC - chlorinated polyvinyl chloride
  • CR - condenser return
  • CRW - chemical resistant waste
  • CS - condenser supply
  • CTR - center
  • CU - cubic
  • CU FT. - cubic feet
  • CU IN. - cubic inches
  • CV - check valve
  • CW - cold water
  • CWR - cold water riser
  • D - drain, deep
  • DB - dry bulb
  • DDC - direct digital control
  • DEG - degree
  • DELTAT - temperature difference
  • DET - detail
  • DIA - diameter
  • DISC - disconnect
  • DN - down
  • DP - dew point temperature
  • DR - drain
  • DWG - drawing
  • EA - exhaust air, each
  • EAT - entering temperature
  • E to C - end to center
  • EER - energy efficient ratio
  • EFF - efficiency
  • EJ - expansion joint
  • EL - elevation
  • ELB - elbow
  • ELEC - electrical
  • ENT - entering
  • ESP - external static pressure
  • ET - expansion tank
  • EVAP - evaporator
  • EWT - entering water temperature
  • EXH - exhaust
  • EXP - expansion
  • EXST - existing
  • EXT - external
  • oF - degrees fahrenheit
  • F - fahrenheit
  • FC - flexible connector, flexible connection
  • FCO - floor cleanout
  • FD - floor drain
  • FDW - feed water
  • FEC - fire extinguisher cabinet
  • FF - finish floor
  • FG - finish grade
  • FHC - fire hose cabinet
  • FLA - full load amps
  • FLR - floor
  • FM - flow meter
  • FO - fuel oil
  • FOV - flush out valve
  • FPM - feet per minute
  • FPS - feet per second
  • FS - flow switch, federal specs
  • FT - foot, feet
  • FTG - fitting
  • FU - fixture unit
  • FV - flush valve
  • G - gram, gas line
  • GA - gauge
  • GAL - gallons
  • GALV - galvanized
  • GL.V - globe valve
  • GND - ground
  • GPD - gallons per day
  • GPH - gallons per hour
  • GPM - gallons per minute
  • GPS - gallons per second
  • GR - grain
  • GV - gate valve
  • GWH - gas water heater
  • H2O - water
  • HB - hose bibb
  • HD - head
  • Hg - mercury
  • HGT - heigth
  • HMD - humidity
  • HORIZ - horizontal
  • HP - horsepower
  • HR - hour
  • HTD - heated
  • HTR - heater
  • HW - hot water
  • HWH - hot water heater
  • HWR - hot water return, hot water riser
  • HWS - hot water supply
  • HWT - hot water tank
  • HZ - herts
  • ID - inside diameter
  • IN. - inch
  • INHg - inches of mercury
  • INSUL - insulation
  • INT - international
  • INTL - internal
  • IPS - iron pipe size
  • IV - indirect vent
  • IW - indirect waste
  • J - joule
  • K - kelvin
  • KG - kilogram
  • KM - kilometer
  • KM2 - square kilometer
  • KPA - kilopascal
  • KS - kitchen sink
  • KW - kilowatt
  • L - length, liter
  • LAT - leaving air temperature
  • LB. - pound
  • LBF - pound-force
  • LIQ - liquid
  • LP - low pressure
  • LRA - locked rotor amps
  • LVL - level
  • LVR - louver
  • LWT - leaving water temperature
  • M - meter
  • M2 - square meter
  • M TYPE - lightest type of rigid copper pipe
  • MAN - manual
  • MAT - mixed air temperature
  • MAX - maximum
  • MBH - thousand british thermal units per hour
  • MFR - manufacturer
  • MG - milligram
  • MGD - millions gallons per day
  • MIN - minimum or minute
  • ML - milliliter
  • MM - millimeter
  • MM3 - cubic millimeter
  • MPT - male pipe thread
  • MTD - mounted
  • MU - make up
  • NA - not applicable
  • NC - normally closed
  • NEG - negative
  • NIC - not in contact
  • NO - normally open
  • NPHP - name plate horsepower
  • NPS - nominal pipe size
  • NPSH - net positive suction head
  • NTS - not to scale
  • O - oxygen
  • OA - outside air
  • OAT - outside temperature
  • OC - on center
  • OD - outside diameter
  • OED - open end duct
  • OF - overflow
  • OV - outlet velocity
  • OZ. - ounce
  • PA - pascal
  • PC - plumbing contractor
  • PCR - pumped condensate return
  • PD - pressure drop
  • PF - power factor
  • PG - pressure gauge
  • PL - plate
  • PNEU - pneumatic
  • PRESS - pressure
  • PROP - propeller
  • PRV - pressure reducing valve
  • PSI - pounds per square inch
  • PSIA - pound per suare inch absolute
  • PSIG - pound per square inch gauge
  • PV - plug valve
  • QTY - quantity
  • RA - return air
  • RAD - radius
  • RAT - return air temperature
  • RD - roof drain
  • R/E - return and exhaust
  • RECOV - recovery
  • RED - reducer
  • REF - reference
  • RH - relative humidity
  • REQD - required
  • REV - revision
  • RL - refrigerant liquid
  • RM - room
  • RS - refrigerant suction
  • RTN - return
  • RV - relief valve
  • S - switch
  • SA - shock absorber, supply air
  • SAT - supply air temperature
  • SCH - schedule
  • SDT - saturated discharge temperature
  • SEC - seconds, secondary
  • SENS - sensible
  • SEP - separate
  • SEQ - sequence
  • SER - series
  • SERV - service
  • SF - service factor
  • SHT - sheet
  • SI - international systems of units
  • SOL - solenoid
  • SP - static pressure
  • SPEC - specification
  • SQ. - square
  • SQ.FT. - square feet
  • SS - stainless steel
  • SSH - static suction head
  • SST - saturated suction temperature
  • STD - standard
  • STH - static total head
  • STL - steel
  • SUCT - suction
  • SPLY - supply
  • SV - service
  • SVH - static velocity head
  • SW - service weight
  • SWS - service water
  • TD - temperature difference
  • TDH - total dynamic head
  • TEMP - temperature
  • TH - termometer
  • THK - thick
  • TP - total pressure
  • TSP - total static pressure
  • UF - under floor
  • UH - unit heater
  • V - vent, volt, volume
  • VAC - vacuum
  • VAV - variable air volume
  • VB - vacuum breaker
  • VCI - vacuum cleaning inlet
  • VCL - vacuum cleaning line
  • VEL - velocity
  • VERT - vertical
  • VIB - vibration
  • VOL - volume
  • VSD - variable speed drive
  • VP - velocity pressure
  • VTR - vent thru roof
  • W - watt, wudth, wide
  • WB - wet bulb
  • WCO - wall cleanout
  • WG - water gauge
  • WH - water heater