abbrev |
define |
A |
Air or Compressed Air |
AC |
Air Conditioning or Alternating Current |
ACCA |
Air Conditioning Contractors Associations |
ACD |
Automatic Control Damper |
ACH |
Air Changes per Hour |
ACM |
Asbestos Containing Material |
AD |
Access Door |
AEE |
Association of Energy Engineers |
AF |
Air Foil |
AFD |
Adjustable Frequency Drive |
AFUE |
Annual Fuel Utilization Efficiency |
AHU |
Air Handling Unit |
AI |
Analog Input |
AMCA |
Air Movement and Control Association |
AMP |
Ampere |
AO |
Analog Output |
AP |
Access Panel |
APD |
Air Pressure Drop |
AQS |
Air Quality Systems |
AS |
Air Stream |
ASHRAE |
American Society of Heating, Refrigerating and Air Conditioning Engineers |
ATC |
Automatic Temperature Control |
ATM |
Atmosphere |
AV |
Automatic Air Vent |
AWG |
American Wire Gage |
B |
Boiler |
BACnet |
A Data Communication Protocol for Building Automation and Control Networks |
BAS |
Building Automation System |
BCA |
Building Commissioning Association |
BDD |
Back-Draft Damper |
BHP |
Brake Horsepower |
BI |
Backward Incline or Binary Input |
BMS |
Building Management System |
BO |
Binary Output |
BOD |
Bottom of Duct |
BP |
Backflow Preventer |
BSLN |
Baseline |
BTU |
British Thermal Unit |
BTUH |
Brtish Thermal Units / Hour |
BY |
Base Year |
CAV |
Constant Air Volume |
CD |
Cold Deck (also Condensation Drain) |
CDD |
Cooling Degree Days |
CEM |
Certified Energy Manager |
CENT |
Center or Centrifugal |
CF |
Cubic Feet |
CFC |
ChloroFluoroCarbon |
CFM |
Cubic Feet per Minute |
CH |
Chilled or Chiller |
CHR |
Chilled Water Return |
CHS |
Chilled Water Supply |
CHW |
Chilled Water |
CHWP |
Chilled Water Pump |
CHWR |
Chilled Water Return |
CHWRT |
Chilled Water Return Temperature |
CHWS |
Chilled Water Supply |
CHWST |
Chilled Water Supply Temperature |
CLF |
Cooling Load Factor |
CLTD |
Cooling Load Temperature Difference |
CO |
Carbon Monoxide or Clean Out |
CONN |
Connection |
COP |
Coefficient Of Performance |
CRAC |
Computer Room Air Conditioner |
CRAH |
Computer Room Air Handler |
CSR |
Capacitor Start Capacitor Run |
CT |
Cooling Tower |
CTBD |
Cooling Tower Blow Down |
CUH |
Cabinet Unit Heater |
CV |
Constant Volume |
CVRMSE |
Coefficient of Variation of the Root Mean Square of the Error |
CWP |
Condenser Water Pump |
CWR |
Condenser Water Return |
CWRT |
Condenser Water Return Temperature |
CWS |
Condenser Water Supply |
CWST |
Condenser Water Supply Temperature |
CY |
Current Year |
D |
Drain |
DA |
Discharge Air or Direct Acting |
DAT |
Discharge Air Temperature |
DB |
Dry Bulb (Temperature) or Dead Band |
DC |
Direct Current |
DCBP |
Double Check Backflow Preventer |
DCV |
Demand Controlled Ventilation |
DD |
Degree Day |
DI |
Digital Input |
DIA |
Diameter |
DIM |
Dimension |
DO |
Digital Output |
DP |
Dew Point or Differential Pressure |
DPDT |
Double Pole Double Throw |
DPST |
Double Pole Single Throw |
DSI |
Direct Spark ignition |
DX |
Direct Expansion |
EA |
Each or Exhaust Air |
EAHU |
Exhaust Air Handling Unit |
EAT |
Entering Air Temperature |
ECM |
Electronically Commutated Motor or Energy Conservation Measure |
ECO |
Energy Conservation Opportunity |
EDH |
Electric Duct Heater |
EDR |
Equivalent Direct Radiation |
EEM |
Energy Efficiency Measure |
EER |
Energy Efficiency Ratio |
EF |
Exhaust Fan |
EH |
Electric Heater |
EMCS |
Energy Management Control System |
EMER |
Emergency |
EMF |
Electromotive Force |
EMS |
Energy Management System |
EP |
Electric to Pneumatic |
ERV |
Energy Recovery Ventilator |
ESCO |
Energy Service Company |
ESP |
External Static Pressure |
ET |
Expansion Tank |
EUH |
Electrical Unit Heater |
EWT |
Entering Water Temperature |
EXH or EX |
Exhaust |
EXP |
Expansion |
EXT |
External |
EXV |
Electronic Expansion Valve |
F |
Fahrenheit |
F & T |
Float & Thermostatic |
FA |
Free Area or Fire Alarm |
FAI |
Fresh Air Intake |
FC |
Forward Curve or Flexible Connection |
FCU |
Fan Coil Unit |
FD |
Floor Drain, Fire Damper, or Fire Department |
FIM |
Facility Improvement Measure |
FLA |
Full Load Amps |
FLEX |
Flexible |
FLRDR |
Floor Drain |
FMS |
Facility Management System |
FPM |
Feet Per Minute |
FPS |
Feet per Second |
FPVAV |
Fan Powered Variable Air Volume Box |
FRP |
Fiberglass Reinforced Plastic |
FS |
Flow Switch |
FT |
Feet |
FTR |
Fin Tube Radiation |
FW |
Feed Water |
G |
Gas |
GA |
Gauge |
GAL |
Gallons |
GALV |
Galvanized |
GFU |
Glycol Feed Unit |
GPH |
Gallons per Hour |
GPM |
Gallons Per Minute |
GR |
Grade |
GUI |
Graphical User Interface |
GWP |
Global Warming Potential |
HB |
Hose Bib (Connection) |
HCFC |
HydroChloroFluoroCarbon |
HD |
Head or Hot Deck |
HDD |
Heating Degree Days |
HEPA |
High Efficiency Particulate Arresting |
HFC |
HydroFluoroCarbon |
HHV |
Higher Heating Value |
HHWP |
Heating Hot Water Pump |
HHWR |
Heating Hot Water Return |
HHWS |
Heating Hot Water Supply |
HL |
High Limit |
HOA |
Hand Off Auto |
HP |
High Pressure or Horse Power or High Point |
HPS |
High Pressure Steam |
HR |
Heat Recovery or Hour |
HRU |
Heat Recovery Unit |
HRV |
Heat Recovery Ventilator |
HSI |
Hot Surface Ignition |
HSPF |
Heating Seasonal Performance Factor |
HSTAT |
Humidistat |
HTG |
Heating |
HVAC |
Heating, Ventilation & Air Conditioning |
HVAC&R |
Heating, Ventilation, Air Conditioning & Refrigeration |
HWP |
Hot Water Pump |
HWR |
Hot Water Return |
HWRT |
Hot Water Return Temperature |
HWS |
Hot Water Supply |
HWST |
Hot Water Supply Temperature |
HWUH |
Hot Water Unit Heater |
HX |
Heat Exchanger |
HZ |
Hertz (Cycles per Second) |
I/O |
Input Output |
IAQ |
Indoor Air Quality |
ID |
Inside Diameter |
IMC |
International Mechanical Code |
IN |
Inches |
in. Hg |
inches of mercury vacuum |
in. WC |
inches of Water Column |
IPMVP |
International Performance Measurement and Verification Protocol |
IR |
Infra-Red |
IRH |
InfraRed Heater |
JB |
Junction Box |
KO |
Knock Out |
KW |
Kilowatt |
LAT |
Leaving Air Temperature |
LB |
Pound |
LD |
Linear Diffuser |
LF |
Linear Feet |
LHV |
Lower Heating Value |
LL |
Low Limit |
LON |
Local Operating Network |
LP |
Low Pressure or Liquified Petroleum |
LPS |
Low-Pressure Steam |
LRA |
Locked Rotor Amps |
LUVR or LVR |
Louver |
LVDR |
Louvered Door |
LVG |
Leaving |
LWBT |
Leaving Wet Bulb Temperature |
LWCO |
Low Water Cut Off |
LWT |
Leaving Water Temperature |
M&V |
Measurement and Verification |
MA |
Mixed Air |
MAT |
Mixed Air Temperature |
MAU |
Makeup Air Unit |
MAX |
Maximum |
MBH |
1000 BTUH |
MCA |
Minimum Circuit Amps |
MCC |
Motor Control Center |
MECH |
Mechanical |
MFD |
Micro-Farad |
MIN |
Minimum |
MP |
Motor Protector |
MPT |
Male Pipe Thread |
MU |
Make-Up Water |
MUA |
Make-Up Air |
MUW |
Make-up Water |
MV |
Manual Air Vent |
MX |
Metrix Utility Accounting System |
MZ |
Multi-Zone |
NC |
Noise Criteria or Normally Closed |
NEC |
National Electric Code |
NEMA |
National Electrical Manufacturers Association |
NFPA |
National Fire Protection Association |
NO |
Normally Open |
NOM |
Nominal |
NPSH |
Net Positive Suction Head |
NPT |
National Pipe Thread |
NTC |
Negative Temperature Coefficient |
OA |
Outside Air |
OAI |
Outside Air Intake |
OAP |
Outside Air Percentage |
OAT |
Outside Air Temperature |
OC |
On Center |
OD |
Outside Diameter |
OP |
Oil Pressure |
OV |
Outlet Velocity |
OWS |
Operator Work Station |
PC |
Performance Contracting |
PCB |
Printed Circuit Board |
PCF |
Pounds per Cubic Foot |
PD |
Pressure Drop |
PE |
Professional Engineer or Pneumatic to Electric |
PH |
Pre-Heat or Phase |
PID |
Proportional, Integral & Derivative |
PRV |
Pressure Relief Valve or Pressure Reducing Valve |
PSC |
Permanent Split Capacitor |
PSI |
Pounds per Square Inch |
PSIA |
Pounds per Square Inch – Absolute |
PSID |
Pounds per Square Inch – Differential |
PSIG |
Pounds per Square Inch – Gauge |
PT |
Pressure Temperature |
PTAC |
Packaged Terminal Air Conditioner |
PTC |
Positive Temperature Coefficient |
PVC |
Polyvinyl Chloride |
PWM |
Pulse Width Modulation |
R |
Radius |
RA |
Return Air or Reverse Acting |
RAT |
Return Air Temperature |
RET |
Return |
RF |
Return Fan |
RH |
Relative Humidity or Reheat |
RLA |
Running Load Amps |
RLF |
Relief |
RPBP |
Reduced Pressure Backflow Preventer (sometimes also seen as RPZ) |
RPM |
Revolutions Per Minute |
RTD |
Resistance Temperature Detector |
RTU |
Roof Top Unit |
RV |
Reversing Valve |
SA |
Supply Air |
SAT |
Supply Air Temperature |
SC |
Shading Coefficient |
SCADA |
Supervisory Control and Data Acquisition |
sCHR |
Secondary Chilled Water Return |
sCHS |
Secondary Chilled Water Supply |
sCHWP |
Secondary Chilled Water Pump |
sCHWR |
Secondary Chilled Water Return |
sCHWS |
Secondary Chilled Water Supply |
SCR |
Screen |
SCT |
Saturated Condensing Temperature |
SD |
Smoke Detector or Smoke Damper |
SE |
Smoke Exhaust |
SEER |
Seasonal Energy Efficiency Ratio |
SEN |
Sensible |
SF |
Service Factor or Supply Fan |
SFD |
Combination Smoke / Fire Damper |
SH |
Super Heat |
SHC |
Sensible Heat Capacity |
SHFG |
Solar Heat Gain Factor |
SHR |
Sensible Heat Ratio |
sHWR |
Secondary Hot Water Return |
sHWS |
Secondary Hot Water Supply |
SMACNA |
Sheet Metal and Air Conditioning Contractors National Association |
SP |
Static Pressure or Set Point |
SPDT |
Single Pole Double Throw |
SPST |
Single Pole Single Throw |
SS |
Stainless Steel |
SUP |
Supply |
SV |
Solenoid Valve |
SWP |
Steam Working Pressure |
T |
Temperature or Thermostat |
TD |
Temperature Difference or Time Delay |
TDS |
Total Dissolved Solids |
TEFC |
Totally Enclosed Fan Cooled |
TEMP |
Temperature |
TEV |
Thermostatic Expansion Valve (sometimes also seen as TXV) |
TH |
Thermometer in a Thermowell |
TOD |
Time Of Day |
TON |
12,000 BTUH (Cooling Capacity) or ton of refrigeration effect |
TORR |
Millimeter of Mercury (mmHg) |
TSP |
Total Static Pressure |
TSTAT |
Thermostat |
TXV |
Thermostatic Expansion Valve |
TYP |
Typical |
UC |
Undercut (Door) |
UH |
Unit Heater |
UMC |
Uniform Mechanical Code |
UV |
Ultra-Violet or Unit Ventilator |
V |
Volts |
VAV |
Variable Air Volume |
VD |
Volume Damper |
VEL |
Velocity |
VFD |
Variable Frequency Drive |
VSD |
Variable Speed Drive |
VSP |
Variable Speed Pump(ing) |
VVT |
Variable Volume/Temperature |
W |
Watt |
WB |
Wet Bulb Temperature |
WC |
Water Column |
WG |
Water Gauge |
WPD |
Water Pressure Drop |
WTD |
Water Temperature Difference |
XFMR |
Transformer |
YTD |
Year To Date |
ZD |
Zone Damper |