ASHRAE Terminology

A Comprehensive Glossary of Terms for the Built Environment

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qualification test

a procedure employed for verifying the accuracy of the measuring techniques (temperature, airflow rates, duct heat calibration) employed in determination of the room heating effect. This qualification procedure is periodically employed in determining the room heating effect.


a monitored condition used to establish active or inactive status for a measured parameter.

quality-based sampling

a process for evaluating a subset (sample) of the total population. The sample is based upon a known or estimated probability distribution of expected values, an assumed statistical distribution based upon data from a similar product, assembly, or system, or a random sampling that has scientific statistical basis.

quiet air

condition in which the sound power level introduced in the frequency band of interest by the air supply alone is at least 10 dB lower than the measured sound power level generated by the air supply and the air terminal under test.