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Zip Ties On Flex Ducts

G

globe trekker

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Oct 19, 2009
Messages
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I have seen a lot of the plastic type zip ties [ cable ties ] used to secure the flexible UL-181

ducting to the HVAC unit housings. Are they an approved means of fastening the ducting

to the housings , or is the UL-181-B-FX type tape the ' ONLY ' approved means of securing

the ducting to the housings? What are ya'll seeing / allowing? :) Also, code sections

please!

http://www.builderdepot.com/browse.ihtm ... oreid=9957

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Re: Zip Ties On Flex Ducts

I appove Zip-ties for the flex ducting when taped with the right duct tape.

Rick
 
Re: Zip Ties On Flex Ducts

What about ' JUST ' the zip ties and no tape? :o

Isn't the UL-181-B-FX tape ' required ' ? Again, please cite applicable code sections. We are on the

2006 I-codes.

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Re: Zip Ties On Flex Ducts

globe trekker said:
What about ' JUST ' the zip ties and no tape? :o

Isn't the UL-181-B-FX tape ' required ' ? Again, please cite applicable code sections. We are on the

2006 I-codes.

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Click to expand...
The tape is to stop air leaks and I know Washington State Energy Code is going in that direction with leaks in heat ducts.

Rick
 
Re: Zip Ties On Flex Ducts

See Section 603.9 of the 2006 IMC. "Duct connections to flanges of air distribution system equipment shall be sealed and mechanically fastened."

GPE
 
Re: Zip Ties On Flex Ducts

Thanks to you all for your input!

Please forgive me for not clarifying my question a little more... My OP was in regard to residential

applications. Most commercial projects around here DO seal with the approved ' foil

backed ' type of tape or other approved fastening materials. Its the residentail that I have

questions about. If I am going to fail an inspection because the type of tape is not applied,

then I need to be able to cite code chapter and verse, or in the SMACNA manual or other.

gpe,

Since my question revolves around the residential side, is there something in the IRC that you

can reference?

JayHawkInspector,

Excellent reference! ;)

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Re: Zip Ties On Flex Ducts

JayHawk,

If I am understanding you correctly the question is if tape is used on flex duct does it have to be marked "181B-FX" and according to IRC 2006 edition section M1601.3.1 yes it would for pressure-sensitive tape or "181B-M" for mastic.
 
Re: Zip Ties On Flex Ducts

gpe ( and others ),

In delving in to this conudrum further... Section N1103.2.2 Sealing. " ...shall comply with Section 1601.3.1".

Section M1601.3.1 Joints and Seams. "Joints of duct systems shall be made substantially airtight by means

of tapes, mastics, gasketing or other approved closure systems. Closure systems used with rigid fibrous glass

ducts shall comply with UL 181A and 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 with 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 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 1½ inches

(38 mm) and shall be mechanically fastened by means of at least three sheet-metal screws or rivets equally

spaced around the joint.

Ch. 11 - The Energy Chapter did not specify any type of energy retention requirements.

I recently did an inspection on a residential HVAC system and noticed that the plastic zip ties were used

to fasten the flexible Return Air ducting to the Return Air register. It was one zip tie, with 2 sheet metal

screws in it, ...but no UL-181-B-FX tape.

Should there have been the UL181-B-FX pressure sensitive tape over those zip ties and not just the zip

ties themselves? M1601.3.1 seems to indicate this, ...yes? :?:

.
 
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