Retrotec Blower Door User Manual
Page 87
Page 87 of 87
©Retrotec Inc. 2015
Term
Definition
Reading
A set of simultaneous Induced (Room) Pressure and Fan Pressure readings. Sometimes referred to as a data set
or test point because it is plotted as one point on a graph.
Reference Pressure
The pressure at which a result is calculated. This is usually at the test pressure. For example EqLA is typically
referenced to 10 Pa. EqLA is also taken at 25 Pa for some purposes because it tends to be more repeatable.
Forced Air Changes per Hour (ACH) are usually referenced to 50 Pa, which is why it is common to see ACH50 for
air changes at 50 Pa. CFM50 would be the airflow at 50 Pa. In all cases the test may be taken at a pressure
close to the reference pressure and then, using a computer, can be extrapolated to calculate the result that
would have been observed, had the target reference pressure been achieved.
Room Pressure
The pressure difference created by the Door Fan between inside and outside of the enclosure. (see also
“induced pressure”). This pressure is commonly measured by Channel A on the gauge.