Thread: Another return air question

This was a very large town home complex, maybe 60 units in 6 buildings. These are pics of the return air. Not sure if this is acceptable. If you need additional info let me know. HVAC is forced air via air handler.

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That's a return air plenum, and there are a lot of things in there which should not be in there.

Jerry,
Besides the insulation and debris, are the plumbing and refrigerant lines the offenders.

Focus on what is missing, Sealed separated trunk and return duct/chases/lines. If these were going to be enhanced with fresh air exchanger/hrv, etc. who knows.

You can draw combustion air from such a mixed purpose open source area (assuming sufficient infiltration) but not ventillation air which will be recirculated. Think Fire and smoke suppression and/or spread.

Mat,

You stated "townhouses", as in no unit is over or under another unit, that each unit is vertical from the ground up, right? Makes a big difference on the plenum, what is above/in it, and how it is constructed.

While I don't recall a code prohibiting fiberglass insulation to be exposed in a plenum, I sure would not want those fiberglass fibers being blown around in a plenum and throughout the house.

The paper facing on that insulation is not to be left exposed. Did the insulation fall from above?

All electrical wiring methods need to be plenum rated.

I am sure that insulation on the refrigerant line is not plenum rated.

There is copper piping laying on steel hat channels - dissimilar metals need to be isolated from each other.

Looks like concrete chunks in there, and metal from something, is that a concrete floor above? If so, where did the concrete come from? Also think about all that dust and dirt blowing around in the return air flow.

How do you get to that air filter over there, is there another hatch or opening there?

I doubt that ABS DWV line is plenum rated.

Looks like copper piping on steel hanger support channels.

Is that sprinkler PVC piping plenum rated - I've forgotten, that would need to be looked up.

Looks like improperly supported DWV pipe, but I cannot tell for sure about the spacing but that perforated plumbers strap is doing nothing, and is wrong anyway.

Other things in there I can't make out what they are, but they look questionable, especially that reddish sagging pipe looking thing???

Looks like the sprinkler piping may not be supported with properly spaced supports.

Nothing but questions here, no answers.

The town home was misleading. The top units are towns home, the rest are condos. This unit was on the third floor with one unit above it.

Maybe this will help. There is a town home above this unit. This is a condo, sorry for the misinformation. Floors are concrete and the air handler simply sits in the space between each floor. There is an access panel for th air handler. It's in the ceilng and I could not remove the panel. I was about 2X 4.5 feet and weighed a ton. The space where the air handler is located I would guess is about 900 sq ft.

Using the plenum above ceiling has been approved for ages, Jerry is right you need rated materials in the space. 25-50 if i rembeber correctly. The freon Insulation most likley is rated correctly and the fiberglass is ok but not the facing. all low voltege and high need correct rating also.

You I would write it up as a have contractors evalute and verify correct installation of materials for plenum use.

Oh i forgot the ABS does need pipi insulation to meet 25-50

Thanks

Originally Posted by mathew stouffer

The town home was misleading. The top units are towns home, the rest are condos. This unit was on the third floor with one unit above it.

"The top units are towns home, the rest are condos."

You mean they are all "condos" but some are two story instead of one story, right?

By definition you cannot have a townhouse above or below another property as the townhouse goes from the bottom to the sky above.

With townhouses there are VERTICAL separation firewalls to VERTICALLY separate the separate STRUCTURES as even though the separate structures are attached, the firewalls separating them makes them into separate structures, one can burn down and the ones on either side will remain.

With condos, whether one story or more, the condo is simply "the space" with a common structure and are therefore individual "dwelling units" separated from other individual "dwelling units" and separated from common areas by fire partitions, which are not rated the same as fire walls, and there is but one structure with condos. Condos can be separated from each other and from common areas by either or both vertical or horizontal fire separation wall assemblies or floor-ceiling assemblies.