[ASHRAE Standard 241]:a filter test to check how well the filters and spacers are installed in a central station air handling unit. The intent is that if light is visible through cracks or openings, that the air would go through … Continue reading →

[EN 12792:2003, 181]:duct which can be manually longitudinally compressed or decompressed and flexed without permanently damaging the cross section area.

[EN 12792:2003, 183]:continuous motion of a fluid in pipes, ducts, channels or through openings.