# Duct seal for 504.70



## hardworkingstiff (Jan 22, 2007)

I remember a discussion of using duct seal for the purpose of 504.70, but I do not remember if we had a consensus. (I've used it and it's passed inspection)

Anyone care to comment please?


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## thegoldenboy (Aug 15, 2010)

Is duct seal listed for such use? I don't have any directly in front of me.

*504.70 Sealing.​*​​​​Conduits and cables that are required to be
sealed by 501.15, 502.15, 505.16, and 506.16 shall be
sealed to minimize the passage of gases, vapors, or dusts.
Such seals shall not be required to be explosionproof or
flameproof but shall be identified for the purpose of minimizing
passage of gases, vapors, or dusts under normal​
operating conditions and shall be accessible.


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## hardworkingstiff (Jan 22, 2007)

thegoldenboy said:


> Is duct seal listed for such use? I don't have any directly in front of me.
> 
> *504.70 Sealing.​*​​​​Conduits and cables that are required to be
> sealed by 501.15, 502.15, 505.16, and 506.16 shall be
> ...


Listed or identified?


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## thegoldenboy (Aug 15, 2010)

hardworkingstiff said:


> Listed or identified?


Shouldn't it be identified in the listing?


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## hardworkingstiff (Jan 22, 2007)

> Use as a fire stop around conduit and cable runs; Seals around junction boxes, flashings and service entrances; Permanently soft, non-toxic compound can be painted immediately after application; would not adversely affect other plastic materials or corrode metals


http://www.goodmart.com/products/ideal-31-605-duct-seal-5-lb-block.htm

If it's a fire stop, well, that's seems good enough for me.

A friend of mine in VA just completed a continuing education class and the instructor said duct seal was compliant for this particular application. 

Just looking for any other opinions. You have asked a question, but not stated an opinion.


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## hardworkingstiff (Jan 22, 2007)

thegoldenboy said:


> Shouldn't it be identified in the listing?


Maybe you can locate the listing.


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## thegoldenboy (Aug 15, 2010)

hardworkingstiff said:


> http://www.goodmart.com/products/ideal-31-605-duct-seal-5-lb-block.htm
> 
> If it's a fire stop, well, that's seems good enough for me.
> 
> ...


I am yet to form an opinion. I don't have the UL White Book at my disposal and I missed the prior discussion, if you could be kind enough to supply a link so I can read through what was already said on the subject.


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## thegoldenboy (Aug 15, 2010)

hardworkingstiff said:


> Maybe you can locate the listing.


Well I'm not home, but I do have a brick of ductseal at home, I'll see what it says and get back to you at a later time.


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## thegoldenboy (Aug 15, 2010)

It reads:


```
Arlington 
Industries, Inc.

Duct Seal Compound.

Has greater adhesion properties for 
sealing around service entries, junction
boxes, flashings and service mast
conduit.

Use indoor or outdoor where a per-
manently soft non-staining sealer is
required to seal out weather, moisture, 
dust and atmospheric conditions.

ARLINGTON INDUSTRIES, INC.
Stauffer Industrial Park
Scranton, PA 18517
1 - 800 - 233 - 4717

DSC1 1lb. pkg.
```
The UL info:


```
UNDERWRITERS LABORATORIES, INC
R15211      CLASSIFIED
          GENERAL USE TAPES
SURFACE BURNING CHARACTERISTICS
             Flame Spread: 5
          Smoke Developed: 10
                   23N3
```
I'm going to say that the Code requires the following criteria:

"*Such seals shall not be required to be explosionproof or flameproof but shall be identified for the purpose of minimizing passage of gases, vapors, or dusts under normal** operating conditions and shall be accessible*."

More importantly the Code uses the word "or" in that list meaning it has to meet only one of those specified. Had it been "and", the sealing compound would have to meet all of the criteria.

The Duct Seal compound from Arlington is listed to seal against dust in normal operating conditons, therefore it meets but does not exceed the requirements of Article 504.70 and is a compliant install in accordance with 110.3 (B).


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## thegoldenboy (Aug 15, 2010)

I've been thinking about this one a little longer and I've come to the following conclusions:

Art. 504.70


*504.70 Sealing. *
​Conduits and cables that are required to be
sealed by *501.15, 502.15, 505.16, *and* 506.16* shall be
sealed to minimize the passage of gases, vapors, or dusts.

Such seals shall not be required to be explosionproof or
flameproof but shall be identified for the purpose of minimizing
passage of gases, vapors, or dusts under normal​​
operating conditions and shall be accessible.​

Duct seal is listed for sealing against dust and not gases or vapors as previously established. Therefore duct seal is a compliant sealing method in the instances of Art. 502.15 and Art. 506.16:​
I'm going to say that duct seal is not a compliant install in accordance with Art. 501.15 and Art. 505.16 because of the presence of gases or vapors.​ 
So when the Code uses the word "or" in this instance, it means that the sealing compound used has to be listed or identified for the location it's being installed in. This Article covers multiple locations but does not supersede each listed Articles specific requirements.​ 
If you look at Art. 502.15 FPN it says "Electrical sealing putty is a method of sealing." That right there tells me that it accepts duct seal without question.​ 
My conclusion and revised opinion is that duct seal is a recognized method of sealing by Art. 504.70 in Class II Div. 1 and Div. 2 locations as well as Zone 20, 21, and 22 locations, but does not meet the requirements of Class I Div. 1 and Div. 2 or Class I Zone 0, 1 and 2 locations.​


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## dvx216 (Feb 24, 2011)

rainbow tech.net makes a duct seal that comes in a brick that is flame rated and is listed for such applications


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## thegoldenboy (Aug 15, 2010)

dvx216 said:


> rainbow tech.net makes a duct seal that comes in a brick that is flame rated and is listed for such applications


This stuff? 

http://www.rainbowtech.net/products/view.php?cn=2537

That link mentions gases but the .pdf fails to do so. 

http://www.rainbowtech.net/products/docs/45c48cce2954b319d21/79508 Firestop Kit.pdf.pdf

It would have to be listed directly on the package for that application or else the company can make any claim they want. I also don't see a UL listing referenced anywhere on that site.


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## Journeymanjoe (Aug 19, 2011)

*Duct Seal not to be used in seal offs!*

UL White Book states "Conduit fittings for sealing are intended for use only with sealing compounds specified by the manufacturer in instructions furnished with the fitting."

Cooper Crouse-Hinds catalog states "Sealing Fittings are approved for use in hazardous locations only when Chico®
X fiber and Chico A sealing compound or
Chico SpeedSeal are used to make the seal.
§See Certifications and Compliances for classification of each product."

http://www.cooperindustries.com/con...tings/EYD_EZD Sealing Fittings with Drain.pdf

Duct Seal has not been "identified" (NEC wording) or "specified" (UL wording) as a sealing compound by the manufacturer of the sealing fittings!


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## hardworkingstiff (Jan 22, 2007)

Journeymanjoe said:


> UL White Book states "Conduit fittings for sealing are intended for use only with sealing compounds specified by the manufacturer in instructions furnished with the fitting."
> 
> Cooper Crouse-Hinds catalog states "Sealing Fittings are approved for use in hazardous locations only when Chico®
> X fiber and Chico A sealing compound or
> ...


OK, I won't use a conduit seal fitting.


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## IBEW191 (Apr 4, 2011)

Why not buy the right stuff, thats just stupid. Save a buck?


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## AFOREMA1 (Nov 23, 2009)

IBEW191 said:


> Why not buy the right stuff, thats just stupid. Save a buck?


WHY? I bet it's the same crap as duct seal, they just want you to buy their product. And I have never had an inspector ask for the package of sealing putty to check manufacturer.


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## IBEW191 (Apr 4, 2011)

AFOREMA1 said:


> WHY? I bet it's the same crap as duct seal, they just want you to buy their product. And I have never had an inspector ask for the package of sealing putty to check manufacturer.


 I dont think it is the same stuff, not even close really, Duct Seal is soft and stays soft, sealoff compound gets hard and makes more of and airtight seal. If somone messes with the wires on the other end im sure it chould make a spot for gas or vepore to sneak through. but then agin, AHJ is the judge right? Was it stated to him that it was duct seal or did he just see somthing was thare?


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## AFOREMA1 (Nov 23, 2009)

IBEW191 said:


> I dont think it is the same stuff, not even close really, Duct Seal is soft and stays soft, sealoff compound gets hard and makes more of and airtight seal. If somone messes with the wires on the other end im sure it chould make a spot for gas or vepore to sneak through. but then agin, AHJ is the judge right? Was it stated to him that it was duct seal or did he just see somthing was thare?


Most the sealing putties I see and have used stay mostly soft. Never used a sealing Putty that got hard. Fire stop and such but that is not what he is asking about.


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## hardworkingstiff (Jan 22, 2007)

IBEW191 said:


> Why not buy the right stuff, thats just stupid. Save a buck?


Who say's it's not the right stuff?

NEC says the seals do not need to be x-proof nor flameproof. I'm not convinced that duct seal does not meet the application requirements.

What do you use to seal a conduit entering a walk in cooler/freezer?

And, why would you not "save a buck" if you can?


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## IBEW191 (Apr 4, 2011)

hardworkingstiff said:


> Who say's it's not the right stuff?
> 
> NEC says the seals do not need to be x-proof nor flameproof. I'm not convinced that duct seal does not meet the application requirements.
> 
> ...


 Its not listed for such use, you find a package that says its is, well thats the right stuff... gas and vapor...... really guys?


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## hardworkingstiff (Jan 22, 2007)

IBEW191 said:


> Its not listed for such use, you find a package that says its is, well thats the right stuff... gas and vapor...... really guys?


What do you use to seal a conduit going into a refer?


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## IBEW191 (Apr 4, 2011)

hardworkingstiff said:


> What do you use to seal a conduit going into a refer?


 Duct seal...


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