Page 89 of 91
© Retrotec 2017
Glossary
Term
Definition
Air Current Tester
Neutrally buoyant smoke (manufactured by Retrotec Inc.) used to locate leakage locations, and
to observe the direction of air flow, or to see if pressure neutralization between two zones is
reached.
air leakage
Pertains to how leaky an enclosure may be; The movement/flow of air through the building
Envelope, which is driven by either or both positive (infiltration) or negative (exfiltration)
pressure differences or test pressures across the building Envelope.
background pressure
See “Baseline pressure”
Baseline pressure
Pressure that exists when the enclosure has been prepared for the test, but before the fan is
activated. There is always some Baseline pressure due to stack, wind, flues and active HVAC
systems. There are two components of Baseline pressure. A fixed Baseline offset (usually due
to stack or HVAC) and a fluctuating pressure (usually due to wind or elevator operation). A
method determining baseline pressure is by having a digital gauge accumulate readings over an
adjustable time period
(Note: The terms “static pressure”, “bias pressure,” and “zero Fan Pressure difference” are used
interchangeably with the term baseline pressure in other documents/standards used in the
industry.)
CFM
Cubic feet per minute, the units of volumetric flow
Control Cable
An Control Cable used to control Retrotec fans
Control port
Control port on a Retrotec fan, labeled “Control”
Depressurization
The process of creating a negative pressure in the enclosure by blowing air out of it. Air is
drawn in from outside to replace it, showing up as “geysers” when checked with an air current
tester.
digital gauge
A gauge with an electronic pressure sensor and digital display that is capable of reading in
tenths of a Pascal.
Door Fan
A test instrument that fits into an open doorway in order to pressurize or depressurize an
enclosure. It is a calibrated fan capable of measuring air-flow, and is used while mounting it
into a doorway.
A Door Fan is often called a “Blower Door” or an “Infiltrometer™”
.
Door Panel
A solid or flexible panel used to temporarily seal off a door way while allowing for the
installation of a fan for the purpose of blowing air into the building in order to measure the air
leakage rate or to provide a pressure to assist in the location of air leaks.
DucTester
Retrotec’s duct testing system is named the DucTester.
effective leakage area
A common term used to describe air flow at a pressure by equating it to an equivalent size hole
in an elliptical nozzle that would pass the same air flow at the same test pressure. It is usually
taken at 4 Pa and incorporates a 1.0 discharge coefficient. It is typically about half the size of an
equivalent leakage area that describes the same air flow rate. See ASTM E779-10, eq. (5).
enclosure
The surface bounding a volume, which is connected to outdoors directly. For example an
apartment whose only access to outdoors was through a doorway that leads directly outdoors.
Or, a building with a series of apartments or offices whose only access to the outdoors is
through a common hallway then the enclosure would be the volume that bounds all of the
apartments or offices.
