Glossary
apparent power
A value of power for AC circuits that is calculated as the product of RMS current times RMS voltage, without taking the power factor into account.
ASHRAE Standard 52-76
Industry standard for air filtration efficiency set forth by the American Society of Heating, Refrigerating, and
average floor load
The load computed by dividing total equipment weight by the area of its footprint. This value is expressed in kg/m2 (lb/ft2).
BTU/h
The abbreviation for British thermal units per hour. The amount of heat required to raise one pound of water one degree Fahrenheit per hour, a common measure of heat transfer rate.
CFM
The abbreviation for cubic feet per minute, commonly used to measure the rate of air flow in an air conditioning system.
CMM
The abbreviation for cubic meters per minute, commonly used to measure the rate of air flow in an air conditioning system.
concentrated load
The load that a floor panel can support on a 6.45 cm2 (1 in2) area at the panel's weakest point (typically the center of the panel), without the surface of the panel deflecting more than a predetermined amount.
dead load
The weight of the raised floor panel system, including the understructure. Expressed in lb/ft2 (kg/m2).
derate
To lower the rated capability of an electrical or mechanical apparatus.
downflow
A type of air conditioning system that discharges air downward, directly beneath a raised floor, commonly found in computer rooms and modern office spaces.
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