Repairing Old Transite HVAC System

[BrentStru]

So I'm not a mechanical engineer, but I've tasked to come up with a sketch for the repair of a transite HVAC system. The transite is very old and has deteriorated significantly. We are suggesting to cut out sections of damaged duct and basically replace the sections with sheet metal couplings. I'm trying to determine how many (and what size) screws to use for the transition and how to keep the repair from leaking at the seam. Anyone have any insight on this? Our in-house mechanical engineers basically told me to just figure it out, because they don't know either.

Thanks.

 

[cdxx139]

Had to look up "transite"

The transite that is produced today is made without asbestos. Transite HT, and Transite 1000 are currently available fiber cement boards that contain no asbestos. Instead they contain crystalline silica, which the International Agency for Research on Cancer has classified as being carcinogenic to humans (Class 1). Crystalline silica is also known to cause silicosis, a non-cancerous lung disease.

Is the system so big, you wouldnt replace it in whole? New ductwork is installed per SMACNA guidelines

knowledge is power

 

[BrentStru]

Yes, the system is several miles long. We are recommending replacing the whole system, but the owner wants the option to replace only the deficient areas.

 

[urgross]

I would suggest having an IH take PLM samples for determining if this is asbestos containing material, as it is stated to be very old. If it is deteriorated ACM, it would indicate a friable source providing respirable air. You may think it is unlikely, but I have found transite ACM on heat wheels from the 1980's.