# Duct tape



## Wirenuting (Sep 12, 2010)

There are different grades of foil tape. I like the fiber reinforced one for exhaust. The pure foil tape is better for AC supply duct work. 
Fiberglass trunk gets zip tied. 

Old fashioned duct tape never lasted long on bathroom exhaust. Especially in attics.


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## backstay (Feb 3, 2011)

Electek inc said:


> One job I was on the inspector failed the bathroom fans because we used... duct tape? Said we needed to use foil tape. A first for me. A/C mechanic said the foil tape if for fiberglass ducting.


Ok, I can't resist. Code section please? Because I really can't believe 1. An electrical inspector said that. 2. An electrician would listen to one that did.


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## bobbarker (Aug 6, 2015)

As an Electrician-Duct tape is only good for labeling mc, a temporary patch when you have a backside blow-out, sealing stubbed up pipes(and being sure to back wrap them first righttttt!!!!!) and tying up hostages, I mean customers who do not pay :laughing:


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## wildleg (Apr 12, 2009)

heat/cool + condensation makes duct tape a fail. sounds like a combo inspection to me. in my experience, mechanical inspectors usually require at least one screw for exhausts and 3 for supplies, but I don't know jack about mechanical code, that's just from failing stuff I shouldn't have been doing in the first place . :laughing:


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## chicken steve (Mar 22, 2011)

~C:jester:S~


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## Jarp Habib (May 18, 2014)

Duct tape only exists to hack things together. For any specific task there's a specific kind of tape that's ideal for that project...and then ALSO duct tape. But nobody wants to carry 30 kinds of tape around, so DT it is! [emoji1] 

Sent from my SM-G900T using Tapatalk


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## Signal1 (Feb 10, 2016)

I don't know "duct codes", but although duct tape has a million uses, it actually sucks for duct work. It wont last very long.

The foil stuff is really much better and durable.


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## chicken steve (Mar 22, 2011)

~C:jester:S~


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## telsa (May 22, 2015)

chicken steve said:


> ~C:jester:S~


Where did you find this gag photo ?

:laughing::laughing::laughing::laughing::laughing:


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## telsa (May 22, 2015)

IIRC duct tape was originally intended for WWI biplanes.

To repair bullet holes.

Since the life span of such craft was pitiful...

The rest follows. :whistling2:


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## sbrn33 (Mar 15, 2007)

You can vent your own fans? I have done it but only when there was no permit. Most of the new construction around here they are insulated flexible duct.


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## MikeFL (Apr 16, 2016)

The standing joke in the industry is "You can seal a duct with anything but duct tape"

Here's the Florida Building Code on the subject:

603.9 Joints, seams and connections. 
All longitudinal and transverse joints, seams and connections in metallic and non-metallic ducts shall be constructed as specified in SMACNA HVAC Duct Construction Standards—Metal and Flexible and NAIMA Fibrous Glass Duct Construction Standards. All joints, longitudinal and transverse seams and connections in ductwork shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastic-plus-embedded-fabric systems, liquid sealants or tapes. Closure systems used to seal ductwork listed and labeled in accordance with UL 181A shall be marked “181A-P” for pressure-sensitive tape, “181 A-M” for mastic or “181 A-H” for heat-sensitive tape. Closure systems used to seal flexible air ducts and flexible air connectors shall comply with UL 181B and shall be marked “181B-FX” for pressure-sensitive tape or “181B-M” for mastic. Duct connections to flanges of air distribution system equipment shall be sealed and mechanically fastened. Mechanical fasteners for use with flexible nonmetallic air ducts shall comply with UL 181B and shall be marked “181B-C.” Closure systems used to seal metal ductwork shall be installed in accordance with the manufacturer’s installation instructions. Unlisted duct tape is not permitted as a sealant on any duct.

Exception: Continuously welded and locking-type longitudinal joints and seams in ducts operating at static pressures less than 2 inches of water column (500 Pa) pressure classification shall not require additional closure systems.

I've never heard of SMACNA approved cloth duct tape.


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