What type of pipe do I need for 6″ duct in a 4″ concrete slabe over crushed stone? My inspector only offered the standard and it needed to adhere to AFEMD 2412.
Would 6″ schedule 40 pvc work and what type of boot do I need for the vent?
Thanks, any help will be a great.
Engineered-stone shower panels are waterproof, but proper installation relies on tight seams and silicone sealing.
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Replies
Well, the ducts in our slab are Transite, but I suspect that's fallen out of favor. (Nothing better than having your furance blowing through an asbestos factory.)
In our case the registers are fed from sheet-metal saddles on the pipe, set over matching rectangular holes in the pipe.
Look into a material called SpunStrand. You would probably need a mechanical contractor to furnish and install. Commercial guys are used to stuff like this, residential guys not as much. Galv ductwork will rust out and/or fill with water under a slab.
Any ductwork will fill with water under a slab, if the groundwater level gets high enough. One should be sure that there's an accessible sump at the low point in the system.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
From what I've been told, the Spunstrand material is fiberglass and is sealed at the joints so that water won't get in. I had to research it a bit for a job but we ended up with something else so I haven't had the hands on it.
Maybe less water will get in than with other options, but water will get in if it wants to.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
I dunno, man... out here we got all these boats... made of fiberglass... they all seem pretty waterproof to me, except when someone hits a rock. IIRC from the SpunStrand website their piping is used to convey more than air... process gases, etc., in underground and aboveground installs.
Hopefully it doesn't sound like I sell the stuff.
Unless the saddle connections are glassed, they'll leak. And any water that gets to floor level can run down the register openings.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
http://www.akduct.com/
Why use ducts in a slab when you can have zonal heating/cooling without ductwork at all with something like this:
http://us.lge.com/products/model/detail/home%20appliances_air%20conditioners_multi-zone_LM360HE.jhtml
Troy Sprout
"Don't forget the screws"
In commercial applications the standard is PCD, polyvinyl coated galvanized steel duct, in what is called a 4x2 configuration, 4mils on the outside, 2mils on the inside. All the fittings, plenums, boots etc, are of the same material. Joints are made with stainless sm screws, and taped with polyvinyl tape. Some manufacturers are Foremost, Sheet Metal Connectors and Air Duct Inc., and most commercial sheet metal fabrication shops will make it to order, as well.
For new construction, pvc duct is commonly used for underlsab supply, though this is pvc pipe specifically for air distribution and not schedule 40 or dwv. BlackMax by General Plastics is a brand of fittings, register boots, etc. In N. IL this is very common in tract house construction and all of the HVAC supply houses have it in stock.
Take a look at http://www.general-plastics.com/products.asp