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.