DUCT INTEGRITY TESTING 1

[Zeroman]

Are you aware of any testing that is completed to ensure zero/minimal air loss in duct work? Is this standard practise or a requirement? Thanks for your help.

Thanks

 

[ChasBean1]

dnmb, standard practice for testing is using a blower discharging through an orifice meter into a blanked-off portion of duct to measure leakage. The DP across the orifice correlates with a known flow, which is the leak rate from the duct.

To find every last microscopic leak humanly possible, we've injected sulfur hexafluoride (SF6) into a Powercat blower that discharges into the tested portion of duct. We scan the duct top-to-bottom, all surfaces, with an ITI/Qualitek Leakmeter 200 to find any leakage. Tin knocker follows us with a bucket of duct sealant (that gray gooey stuff) and seals until the Leakmeter smells no more SF6. Is this a standard? This is much better than the "standard" standard's I've seen from SMACNA, ASHRAE, etc... It's ridiculous to go to this level for normal applications. This is for Biosafety Level 3+ type installation.

 

[quark]

CB made very good points. Even for normal application with dehumidifiation it becomes very critical that, I literally spent 3 sleepless nights sealing the ducts with silicon sealant (and I was sealing and engineering the system as well) The only leak testing device I had was a candle.
Still I was able to reduce the humidity by 20 grains.

Here is a paper from SMACNA on duct leakage.

http://www.smacna.org/products/publications/download.cfm?download_file=ductleakage.pdf

Just check this case study.

http://www.fsec.ucf.edu/bldg/pubs/fl_home_impacts/

Regards,