| A | B |
|---|
| Air handler | The device that moves the air across the heat exchanger in a forced-air system. In a split system, it normally contains the blower fan, cooling coil, metering device, air filter, and related housing. |
| Angle bracket | An L-shaped metal supporting member used to support vertical risers. Also called angle iron. |
| ASHRAE | American Society of Heating, Refrigeration, and Air Conditioning Engineers. |
| Atmospheric pressure | The pressure exerted on all things on Earth’s surface as the result of the weight of our atmosphere. |
| Channel | A U-shaped piece of structural steel used as a supporting device. |
| Cubic feet per minute (cfm) | A measure of the amount or volume of air in cubic feet flowing past a point in one minute. Cubic feet per minute can be calculated by multiplying the velocity of air, in feet per minute (fpm), times the area it is moving through, in square feet (cfm = fpm × area). |
| Dew point | The temperature is measured using a standard thermometer. It represents a measure of the sensible heat of the air or surface being tested. |
| Free air delivery | The condition that exists when there are no effective restrictions to airflow (no static pressure) at the inlet or outlet of an air-moving device. |
| National Fire Protection Association (NFPA) | An association that develops and publishes standards about fire prevention. |
| Plenum | A sealed chamber at the inlet or outlet of an air handler. The duct attaches to the plenum. |
