# UL-181 tape for ducts



## atkins (Oct 3, 2013)

Hello,

According to IRC 2009:

M1601.4.1 Joints and seams.

Joints of duct systems shall be made substantially airtight by means of tapes, mastics, liquid sealants, gasketing or other approved closure systems. Closure systems used with rigid fibrous glass ducts shall comply with UL181A and shall be marked181A-P for pressure-sensitive tape, 181A-M for mastic or 181 A-H for heat-sensitive tape. Closure systems used with flexible air ducts and flexible air connectors shall comply with UL 181B and shall be marked181B-FX for pressure-sensitive tape or 181B-M for mastic. Duct connections to flanges of air distribution system equipment or sheet metal fittings shall be mechanically fastened. Mechanical fasteners for use with flexible nonmetallic air ducts shall comply with UL 181B and shall be marked 181B-C. Crimp joints for round metal ducts shall have a contact lap of at least 11/2 inches (38 mm) and shall be mechanically fastened by means of at least three sheet-metal screws or rivets equally spaced around the joint. Closure systems used to seal metal ductwork shall be installed in accordance with the manufacturer's installation instructions.

How serious is this if the tape is not marked or worse, does not conform to the proper UL standard?  How would one respond to something like this:

"The HVAC company that did the installation has confirmed that their supply house only supplies UL rated tape and that tape is labeled on the package but not on the tape face."

Would a home inspector agree to this?

Thank you.


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## cda (Oct 3, 2013)

Show me the package


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## JPohling (Oct 3, 2013)

doubtful that any manufacturer would market a product that conforms to the standard but does not also mark it, as that is also necessary for a compliant install.


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## Glennman CBO (Oct 3, 2013)

The supply house may supply only a UL rated tape, but which UL do they have. It seems to me that I've seen UL rated tape that wasn't 181 but rather some other number, but I don't recall where I've seen it. Hopefully not on some job site somewhere. If I recall, the UL was for some other purpose than HVAC. It must have been for boat building, or for doing repairs on space craft or airplanes(?)


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## Gregg Harris (Oct 3, 2013)

atkins said:
			
		

> Hello,According to IRC 2009:
> 
> M1601.4.1 Joints and seams.
> 
> ...


UL 181 listed tapes are required for duct board and is imprinted on the tape


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## Yikes (Oct 18, 2013)

For my own home kitchen exhaust DIY project, I bought the tape at my local big box retailer.  I saved a dollar by buying tape that was UL labeled on the inner cardboard core of the roll, but not on the tape itself.  The building official made me go back and re-tape with labeled tape.  I wanted to argue with him, but it wasn't worth the battle; I re-taped and moved on.

There are components such as fire caulk, etc. where you can't tell by the final application, other than it looks red; but that's no guarantee - - who's to say I didn't just color up some nonrated caulk?  In those instances, the inspector just looks at the caulk, or looks for empty tubes of fire caulk laying around the site.

I suppose a smart***** installer could retroactively take a Sharpie marker and handwrite "UL 181AP" on the already installed tape, and the inspector would technically have to accept it.

At this point, I just with the home improvement store woudl stop sellign the unlabeled tape.


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## Gregg Harris (Oct 18, 2013)

Yikes said:
			
		

> For my own home kitchen exhaust DIY project, I bought the tape at my local big box retailer.  I saved a dollar by buying tape that was UL labeled on the inner cardboard core of the roll, but not on the tape itself.  The building official made me go back and re-tape with labeled tape.  I wanted to argue with him, but it wasn't worth the battle; I re-taped and moved on.There are components such as fire caulk, etc. where you can't tell by the final application, other than it looks red; but that's no guarantee - - who's to say I didn't just color up some nonrated caulk?  In those instances, the inspector just looks at the caulk, or looks for empty tubes of fire caulk laying around the site.
> 
> I suppose a smart***** installer could retroactively take a Sharpie marker and handwrite "UL 181AP" on the already installed tape, and the inspector would technically have to accept it.
> 
> At this point, I just with the home improvement store woudl stop sellign the unlabeled tape.


Unless you ran your kitchen exhaust in rigid fiberglass duct board or UL listed factory made air duct there would not be a requirement for the use of UL 181A or B labeling on the metal tape.


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## Gregg Harris (Oct 18, 2013)

603.9 Joints, seams and connections.

All longitudinal and transverse joints, seams and connections in metallic and nonmetallic 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 duct work shall be installed in accordance with the manufacturer’s installation instructions. Unlisted duct tape is not permitted as a sealant on any duct.



This was added to the 2012 IMC requiring the duct tape to be "listed" but is not construed to mean that it must be labeled on the face of the tape as is required UL 181A or B as used on UL listed  factory flexable duct or UL listed factory rigid Fiberglas duct board.


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