Flex duct installation

[Chris Bernhardt]

I see flexible insulated ducting not installed well all of the time.

How far do you go in reporting installation issues when the typical SOP doesn't require an opinion on adequacy or efficiency of heating or cooling?

For example if kinked, crushed or collapsed duct is still delivering conditioned air isn't it functioning?

Are there other performance issues that could develope as a result of sloppy installation or does it mainly affect the efficiency of the system?

At a minimum I want to see them off of the ground and not torn up or damaged but if they are putting out heat etc. and the house warms up what is the justification to install them better. Seems that it might make the house heat up a little faster maybe but that is a question of efficiency.

Chris, Oregon

[hausdok]

http://www.acca.org/

http://www.flexibleduct.org/

http://www.ashrae.org/

http://www.aabchq.com/

http://www.hrai.ca/

http://www.hvi.org/

http://www.iaqa.com/

[Jim Morrison]

Link-boy to the rescue!! Mike, you are a bottomless well of relevant links. Every user on this site owes you and Yung dinner, and I probably owe you two by now. Thank you!

Chris,

My HVAC guru tells me never to use flex duct runs longer than 14 feet because it's too hard to overcome the friction beyond that length and efficiency goes through the floor. I see it much longer than that fairly regularly, and will usually mention it.

I also see lengths of flext duct in tatters where it is exposed to sunlight through an attic window or something. I mention that, too. My guru tells me he considers flexduct a disposable part of the system.

If it is crushed, or if the ductwork in the attic resembles an overturned plate of spaghetti, I'll also suggest that the ducts be rerouted to make the runs as short and straight as possible.

Hope this helps,

Jim

[randynavarro]

Don't have the exact issue right now, but a fairly recent article in the ASHI Reporter covers duct installation well.

I use a lot of that information in my reporting.

[Darren]

New Jersey is best known for all it's political woe's; however, we probably have the best building code educational program around.

http://www.nj.gov/dca/codes/ccc_article ... ll2005.pdf

See page 8

Darren

www.aboutthehouseinspections.com

[ozofprev]

Darren,

That's a good publication. I never thought about a duct's bouyancy actually lifting the structure. That would be one hell of a submarine.

People in New York are often amused when I tell them that swimming pools in New Orleans must contain water year round. Take the water out, and the pool can pop out of the wet ground like a boat.

New York also has a very good educational program and website. They just don't know how to license HI's so that it means anything.

Originally posted by Darren

New Jersey is best known for all it's political woe's; however, we probably have the best building code educational program around.

http://www.nj.gov/dca/codes/ccc_article ... ll2005.pdf

See page 8

Darren

www.aboutthehouseinspections.com

[Darren]

Gary,

When I was a construction Super doing office building in the Meadowlands (near Giants stadium) we used to install underground oil tanks for heating (2,000 gallons).

After several years you could actually see the outline of the area where the tanks were (by the way, there were covered with up-to 30 yds of concrete). Everyone thougth the parking lots was sinking; no, the oil tanks were floating up due to the tides.

Darren

[ozofprev]

Pretty cool, Darren. I would worry about the connections to those tanks & leaking. Perhaps they thought the 30 yds of concrete would cover that problem up.

Originally posted by Darren

Gary,

When I was a construction Super doing office building in the Meadowlands (near Giants stadium) we used to install underground oil tanks for heating (2,000 gallons).

After several years you could actually see the outline of the area where the tanks were (by the way, there were covered with up-to 30 yds of concrete). Everyone thougth the parking lots was sinking; no, the oil tanks were floating up due to the tides.

Darren

[Chris Bernhardt]

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New construction, 3750sf house, duct was probably about 25 feet long and went to the kitchen sink cab kick board register. Air flowing reasonably well.

Do you still write it up for correction? What are the detrimental consequences?

Chris, Oregon

[hausdok]

Hi,

It's certainly nothing I'd lose sleep about not mentioning. The only reason I would, is that someday they'll sell the house and you know that if you don't say anything about it the next guy will and they'll be dissing you over it. Better off to write it.

I'd say that the installer got lazy, installed a duct 2-1/2 to 3ft. too long and that it was bent practically double. At the same time, I'd point out that it was the toe warmer register, that it had a reasonable amount of air going to it and that if it's corrected the increased air is liable to cause someone to complain about the thing being too]/b] hot, so you're damned if you fix it and damned if you don't - sort of.

ONE TEAM - ONE FIGHT!!!

Mike

[Scottpat]

Overtime ( a few years) that bend will collapse. The flexduct manufacturers say that the bend can be no more that the diameter of the duct. So an 8" line could have a bend with an 8" radius.