CADR: Clean Air Delivery Rate.

Carbon Dioxide (CO2): A gas consisting of one atom of carbon and two of oxygen. It is a product of oxidation of organic compounds. It is the principal metabolic product contained in the air we exhale.

Carbon Filter: Air purifier using activated carbon as the air cleansing agent for the removal of gaseous contaminants.

Carbon Tetrachloride Activity: The maximum percentage increase in weight of a bed of activated carbon after air saturated with carbon tetrachloride is passed through at a given temperature.

Catalyst: A material which promotes the rate of a chemical reaction and which may be involved in the reaction itself. However, at the end of the reaction it is essentally unchanged.

Central Fan System: A mechanical system for heating, ventilating or air conditioning in which air is treated or handled by equipment outside the space served and is conveyed to and from the space by means of a fan and distributing ductwork.

CFM: Cubic feet per minute.

CFU: Colony forming unit. A single microorganism or a cluster of microorganisms which when cultured on a suitable nutrient will form a single visible colony with a impregnant on the surface of or distributed throughout the adsorbent or carrier.

Cleanroom: A space in which the concentration and size of airborne dust particles is carefully controlled.

Coil: Any heating or cooling element made of finned pipe or tubing. The pipe or tubing may be connected in series or it may be installed in parallel between two headers.

Condensation: Liquid or droplets which form when a gas or vapor is cooled below its dew point.

Contaminent An unwanted airborne constituent that may reduce acceptability of the air.

Convection: Transfer of heat by means of movement or flow of liquid or gas.

Cooling Coil: A heat transfer device wwhich absorbs heat.

Cooling Tower: A device which cools water by evaporating a portion of it in the air. Water is cooled to the wet bulb temperature of the air.

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