Final leak test of HVAC system 1

[LJthien]

We are going to do the final leak test of HVAC system after installing and connecting all portions together.
I only know I can do it using a blower or a fan and measuring airflow and pressure differentials.
Can someone advises me if there are tools for testing portions of the duct separately since we are looking other options instead of testing the entire duct line.
Thanks for your advice.

 

[LittleInch]

What you describe isn't a "leak" test, but a performance test or are you doing this against a closed end.

Or do you mean leakage of air to the outside?

IT's not clear what you mean to me so probably not to others as well.

Try to be a bit more precise.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[HVAC-Novice]

I think SMACNA has a procedure. Are you doing it per their guideline?

If you do partial system testing, you need to block off airtight, which in itself is hard to do.

Make sure you don't exceed the pressure class of the duct (positive AND negative pressure). Like if this is a 1"duct, don't do a -4" vacuum test or so. I heard of ducts that collapsed during testing (I assume there are not sealed anymore?

 

[LJthien]

Thanks HVAC-Novice,
That is what I am talking about: Block off to split duct line into several portions.
Can you advise some tools which can go inside and block off ducts?

 

[HVAC-Novice]

I've seen partial tests like that before all duct was installed. Or they just left a segment out and installed that later. So they just tested the completed part and blocked that off with some tarp cover or similar. If all duct is already installed, they use some sort of inflatable bladder to seal off portions of the duct.

Obviously you want to make sure yo get a tight seal.

I'm personally not a friend of partial tests. IMHO, the entire duct system leakage is relevant. When duct is in unconditioned or outdoor spaces, that specific section is more important to be sealed. But for a typical system where all ductwork is inside, I fail to see why a leak in the main trunk matters, but we don't care about leaks elsewhere.

 

[LJthien]

@HVAC-Novice,
Very professional and helpful.
Thanks a lot.