Air change


Also found in: Acronyms.

air change

[′er ‚chānj]
(engineering)
A measure of the movement of a given volume of air in or out of a building or room in a specified time period; usually expressed in cubic feet per minute.

Air change

The replacement of air contained within a room with an equivalent volume of fresh air.
References in periodicals archive ?
Figure 2 illustrates the effectiveness of local source control (Figure 2b), and compares the performance to an increased air change rate without controls (Figure 2c).
The coefficient of the air change performance corresponds to the air change performance in the microchamber.
Depending on the level of cleanliness (class of the cleanroom), the required airflow rates vary from a few to a few hundred air changes per hour (ach).
The levels of C[O.sub.2] in the bedrooms were measured during the winter and summer periods to assess the air change in the apartments.
"Ways to minimize the air volumes with strategies like setbacks in unoccupied times or sensors that can monitor the air to adjust the flow allows us to have higher air change rates only when needed, rather than ubiquitously as was done in the past," says Andrea Love, AIA, LEEP AP, Director of Building Science, Payette.
Through comparing this result with the result of the ventilation measurement using the PFT technique, which determines the average air change rate during the entire period, the air change rate during periods of use--i.e., teaching time--can be estimated.
This analysis indicates that mini-environment cleanrooms can be operated at lower air change rates without significantly affecting the cleanliness of the mini-environment provided that the resulting higher particle concentrations in the room are of less concern.
Because of the high initial velocity of the cough and the close distance between the doctor and the sick patient, the PCT was not dependent on the background air change rate.
The recommendations for outside air on continuous operating systems vary on the size of the home and number of occupants, with the minimum of one complete air change every two to four hours.
How many times will Gulf Air change its management?
Unitized, low-intensity gas heaters are said to be ideally suited for high air change environments commonly found in warehouses and plant facilities to help create an efficient and comfortable atmosphere for employees and customers.