Identifing Duct Material (Transite?)

Supply ducts in slab. Close view shows scratched area, certainly does not look like metal.

I know that only sampling can positively ID this material, but does this appear to be Transite or similar? (All the Transite I’ve seen has been white or cream colored vent pipe wit a “weave” pattern, or gray sheet material, but I know Transite ducts were used in slabs in my area around time this was built.)

Also, does anyone have a god link (other than the OSHA/EPA material) for info on this application?



Try this if it helps.

Marcel :slight_smile:


This pic from that site pretty much nails it in my own mind (thought not, of course, for the report).

This house had Transite, Zonolite, AFT and mold - I wonder if I should have been looking for the pin-hole camera!

The “Zonolite like” material was really odd… it looked like someone had randomly tipped out a bag at various locations in the attic - looked around, no bag, though.




Wow…appears to be ACM’s everywhere.

You can’t positively identify asbestos on-site. If I find what appears to be Asbestos, I simply note it in the report and recommend testing if they plan on moving the stuff around.

Not all Zonolite has asbestos, but you will never know until it’s tested. I had a client call me and tell me that the Zonolite that I found in their attic was tested by a local lab and came back** negative** for asbestos containing materials.

I found a bunch of bags of Zonlite (piled high) in someone’s attic…
“Click To Enlarge”

Dave, that is the type I used to fill Masonry exterior walls with years ago.

Hopefully, that was the good kind, ha. ha.

Marcel :slight_smile: :slight_smile:

For the sake of your health, I also hope it wasn’t AC materials.

Like I said

A bit of follow up on the duct material above:

First picture is the duct seen from above through the floor vent.

Second picture is the same, but from a detail of a picture of a different duct identified as “Transite” at:

Pretty similar, eh?

On that basis I reported it as possible asbestos containing material.

Went out there today and met the clients HVAC contractor WRT other issues.

Also, brought along my wife’s tiny Kodak camera, which was small enough to get past the narrow register opening and operate once I got it there.

That’s the next three pictures.

HVAC guy says: "Only way to know for sure is to have it tested, but that’s NOT Transite, that’s clay tile. Almost never see that, everything around here is either Transite or formed concrete concrete. But you can see the brown glaze color, the sections are only 2’ long (Transite came in 10’ lengths, and is gray), and you can see the clay tile in cross-section in the pictures.

Client will get it tested to be sure, but of course is happy.

I of course am somewhat chagrined.

Duct - Slab - Clay Tile B Very Close Small.jpg