HVAC Abbreviations

The list of HVAC abbreviations used in a set of engineering drawings varies from office to office.  Be sure to check the front section of the construction drawing set for the abbreviations used within.

A	Air or Compressed Air
AC	Air Conditioning
ACD	Automatic Control Damper
AD	Access Door
AF	Air Foil
AHU	Air Handling Unit
AMP	Ampere
AP	Access Panel
APD	Air Pressure Drop
AS	Air Stream
ATC	Automatic Temperature Control
ATM	Atmosphere
BDD	Back-Draft Damper
BHP	Brake Horsepower
BI	Backwards Inclined
BOD	Bottom of Duct
BTU	British Thermal Unit
BTUH	BTU per Hour
CENT	Center or Centrifugal
CF	Cubic Feet
CFM	Cubic Feet per Minute
CH	Chilled or Chiller
CHW	Chilled Water
CHWR	Chilled Water Return
CHWS	Chilled Water Supply
CO	Carbon Monoxide
CONN	Connection
CPT	Compressor Protector Terminal
CT	Cooling Tower
CTBD	Cooling Tower Blow Down
CUH	Cabinet Unit Heater
CWR	Condenser Water Return
CWS	Condenser Water Supply
D	Drain
DB	Dry Bulb (Temperature)
DEG	Degree
DDC	Direct Digital Control
DIA	Diameter
DIM	Dimension
DP	Differential Pressure
EA	Each or Exhaust Air
EAHU	Exhaust Air Handling Unit
EAT	Entering Air Temperature
EF	Exhaust Fan
EMER	Emergency
EMS	Energy Management System
ESP	External Static Pressure
ET	Expansion Tank
EUH	Electrical Unit Heater
EWT	Entering Water Temperature
EXH or EX	Exhaust
EXT	External
EXP	Expansion
F	Fahrenheit
FA	Free Area or Fire Alarm
FC	Flexible Connection
FCU	Fan Coil Unit
FD	Floor Drain, Fire Damper, or Fire Department
FLA	Full Load Amps
FLEX	Flexible
FLRDR	Floor Drain
FPM	Feet per Minute
FPS	Feet per Second
FRP	Fiberglass Reinforced Plastic
FS	Flow Switch
FT	Feet
FTR	Fin Tube Radiation
G	Gas
GA	Gauge
GAL	Gallons
GALV	Galvanized
GFU	Glycol Feed Unit
GPH	Gallons per Hour
GPM	Gallons per Minute
GR	Grade
HB	Hose Bib (Connection)
HD	Head
HP	Horsepower or High Point
HR	Hour
HRU	Heat Recovery Unit
HTG	Heating
HWR	Hot Water Return
HWS	Hot Water Supply
HZ	Hertz (Cycles per Second)
ID	Inside Diameter
IN	Inches
KW	Kilowatt
LAT	Leaving Air Temperature
LB	Pound
LF	Linear Feet
LD	Linear Diffuser
LP	Low Point
LPS	Low Pressure Steam
LRA	Locked Rotor Amps
LUVR or LVR	Louver
LVDR	Louvered Door
LVG	Leaving
LWT	Leaving Water Temperature
MAX	Maximum
MBH	1000 BTUH
MCA	Minimum Circuit Amps
MD	Motorized Damper
MECH	Mechanical
MIN	Minimum
MU	Make-Up Water
MUA	Make-Up Air
NC	Noise Criteria or Normally Closed
NO	Normally Open
NOM	Nominal
OA	Outside Air
OAI	Outside Air Intake
OC	On Center
OD	Outside Diameter
ODP	Open Drip Proof
OV	Outlet Velocity
PCF	Pounds per Cubic Foot
PD	Pressure Drop
PH	Phase
PRV	Pressure Reducing Valve
PSI	Pounds per Square Inch
PSIA	Pounds per Square Inch - Absolute
PSID	Pounds per Square Inch - Differential
PSIG	Pounds per Square Inch - Gauge
PVC	Polyvinyl Chloride
R	Radius
RA	Return Air
RET	Return
RH	Relative Humidity
RLA	Running Load Amps
RLF	Relief
RPM	Revolutions per Minute
RTU	Roof-Top Unit
SA	Supply Air
SCR	Screen
SCT	Saturated Condensing Temperature
SD	Smoke Detector or Smoke Damper
SE	Smoke Exhaust
SEN	Sensible
SFD	Combination Smoke / Fire Damper
SHC	Sensible Heat Capacity
SP	Static Pressure
SF	Square Feet
SS	Stainless Steel
SUP	Supply
T	Temperature or Thermostat
TEFC	Totally Enclosed Fan Cooled
TEMP	Temperature
TON	12,000 BTUH (Cooling Capacity)
TSP	Total Static Pressure
TSTAT	Thermostat
TYP	Typical
UC	Undercut (Door)
V	Volts
VAV	Variable Air Volume
VD	Volume Damper
VEL	Velocity
VFD	Variable Frequency Drive
WB	Wet Bulb Temperature
WC	Water Column
WG	Water Gauge
WPD	Water Pressure Drop
WTD	Water Temperature Difference

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