cln wrote:
My concern with Tyvek tape is, would it be a fire hazard?

I know I can put my hand on ducts and not burn myself, but, would you
like to explain to the insurace company that, because you were too
cheap to spend an extra quarter on a roll of tape that is designed for
the purpose of heat ducts vs combustable tape.

I can guarantee that duct tape does dry out and break down.

Mike Holmes on Homes (canadian show) talked about tape too. They were
repairing an issue with the heat not getting to the third floor.

10% of the heat was lost in joints alone!! do the monthly math...
worth the trip to the store and back.

Busting the drywalls reveiled that a pipe was disconnected and was
just blowing in the ceiling and walls.
Since i'm on it, they also added insulation around the ducts, which I
would love to do since my basement is not finished ... yet.
cln

Dicko;

Use UL-181 approved tape only. The rubber backed duct tape of yesteryear is
no longer approved for flexible ducting. The UL-181 is a newer standard
that uses acceptable adhesives and is used by the manufacturer of flexible
ducting to connect collars. It is also advisable to use a "mechanical
restraint" on duct connections. A 48" zip tie is used today by the trades
to provide the mechanical restratint requirment. When ever you join two
pieces of flexible ducting, you must use a metal collar or sleeve to connect
them. Duct sealing mastic is also approved for flexibe ducting but it too
must have the UL-181 approval. Duct sealing mastic is designed to stay
flexible and expand as the ducts are warmed. Approved tapes also have a
none permeable [breathing] backing so the adhesives have a longer life than
those in rubber backed duct tape [cloth tapes.]

Through recent testing it is know that most residential air duct systems
have a leakage rate as high as 30%. By providing superior sealing you can
cut that to 6%.

I hope this is helpful.

--
Zyp