Pressure test for ductwork

[aungkyawtun]

Could you pls kindly advise me for the pressure test for offshore duct work for AC spaces.
Our duct system is low pressure ductwork referred to the SMACNA.
Now our client ask us to do the pressure test for duct work.
We have experience for the smoke test but not for pressure test.
I would like to know it is necessary to do the pressure test, and if so how is the procedure and the testing pressure.
Thanks Alot

 

[quark]

I can't say necessary but it can be good. However, the pressure test is done at a certain pressure that may not be equal to the actual system pressure when it is running. If the pressure is more than the test pressure, there will be more leakage from the openings nearer to the fan.

In any case, you have to trace the leaks once you roughly quantified the leakrate.

Two links, for example,

http://homeenergy.org/archive/hem.dis.anl.gov/eehem/93/930911.html

http://www.energyconservatory.com/articles/articles1.htm

 

[RossABQ]

In my experience, when either the engineer or the client calls for a duct pressure test, it's because they have observed sloppy workmanship in the field. On the other hand, the times I've seen the test conducted, I am amazed at the amount of leakage found.

 

[imok2]

The theory is that if a duct system is tight, all the BTUs generated by perfectly performing equipment will be delivered into the building envelope. So the current practice exists of verifying the tight duct system to assure clients are getting maximum energy efficiency. But in reality, the odds are slim that all the other factors that determine an efficient system are automatically functioning as they should. Duct pressurization testing is the first of many tests required to verify the actual performance of the installed system. It’s understood that duct pressurization is a “dead” test, because at this point, the equipment including the fan, heating, and refrigeration systems are not yet operable. So alone, this test portrays only one small piece of the system performance picture.
Once the system has been completed, then the real testing begins. Airflow is the primary performance that must be completed before all others can begin. Since air is the fluid that carries the heating or cooling throughout the building, its flow, temperatures, velocities, losses, gains, and enthalpy must be verified at many points throughout the system so it can be effectively diagnosed and performance rated.

 

[KiwiMace]

Smacna put out a 1985 duct leakage test manual, not sure if it's been updated. Referred to in this paper, which also describes the usefulness of results.

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

 

[aungkyawtun]

Thanks alot guys for ur suggestions