Retrotec Blower Door - Manual (Page 77)

Page 77 of 87
©Retrotec Inc. 2015
Appendix D: Optional Door Fan system components
Flex Duct to measure air flow or neutralize pressure drops
Flex Duct is available in two sizes. A 12-foot long, 24-inch diameter Flex Duct is compatible with all Retrotec Door Fans,
and can be used to neutralize the pressure difference across a dropped ceiling, below a raised floor, or to measure the
air flow through large registers and vents. When using the Flex Duct, it's important to extend it out to its full length in a
straight line.
Figure 36: Flex Duct for Door Fans (mainly used for enclosure integrity testing).
A smaller, 10-inch diameter Flex Duct is included with all Retrotec duct testing systems, and makes it easy to direct the
fan airflow into the duct system.
Flex Duct can also be used to check the calibration of a Door Fan system, if a panel with a
plate with a hole of a known size is attached to the opposite end. For more information,
see
Field Verification .