ES Glossary
Here are some common abbreviations and terms found in the pages of Engineered Systems.

A

A/C – air conditioning
ach – air changes per hour
AE – architectural and engineering
AFD – adjustable-frequency drive
AHU– air-handling unit
ASD – adjustable-speed drive
ASHRAE – American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.


B
BAS – building automation system
Bhp – boiler horsepower; also, brake horsepower
BMS – building management system


C
CAD – computer-aided design
cfm – cubic feet per minute
chw – chilled water
CMMS – computerized maintenance management system


D
D-B – design-build
db – drybulb
DDC – direct digital controls
DOAS – dedicated outdoor air system
DOE – The U.S. Department of Energy
DX – direct expansion

E
EMS – energy management system
EPA – U.S. Environmental Protection Agency


F
fpm – feet per minute

G
gpm – gallons per minute


H
HEPA – high-efficiency particulate air


I
IAQ – indoor air quality
IS – information systems


L
LEED® – Leadership in Energy and Environmental Design, a designation by the U.S. Green Building Council


M
MEP – mechanical, electrical, plumbing


O
O&M – operations and maintenance
OEM – original equipment manufacturer


R
rh – relative humidity
RFP – request for proposal
RFS – request for submittal
ROI – return on investment
RO – reverse osmosis
RTD – resistance temperature detector


S
scfm – standard cubic feet per minute


T
TES – thermal energy storage


V
VAV – variable-air volume
VFD – variable-frequency drive
VSD – variable-speed drive


W
WAN – wide area network
wb – wetbulb
wc – water column