New seal pouring material

[sparks 479]

Has anyone used or heard of expanding foam being used instead of Chico to pour seals?
There are several products on the market, but as yet, I have been unable to find one that is UL listed or NEC approved. Comments will be appreciated.

 

[augie47]

I've seen that (expanding foam) and duct-seal used........ each with accompanying "rejection tags".
The only place I have seen either accepted is for 300.7 applications.

 

[weressl]

Has anyone used or heard of expanding foam being used instead of Chico to pour seals?
There are several products on the market, but as yet, I have been unable to find one that is UL listed or NEC approved. Comments will be appreciated.

Sealing fittings only retain their UL/FM listing if used with the approved sealing material that is installed according to the installation instructions and restrictions listed in the fitting's installation instructions.

 

[don_resqcapt19]

Take a look at Crouse Hinds Chico SpeedSeal.
It is some type of expanding foam listed for use with Crouse Hinds sealing fittings in classified locations. You do not have to use the Chico fiber packing material for a hortizontal seal. I have not tried it yet.

 

[rbalex]

It will depend on the application. The rules that apply to the OP are found in Section 501.15(C) and its Subsections (1) & (2). I have copied the relevant text here:

501.15 (C) Class I, Divisions 1 and 2. Seals installed in Class I, Division 1 and Division 2 locations shall comply with 501.15(C)(1) through (C)(6).
Exception: Seals not required to be explosionproof by 501.15(B)(2) or 504.70.
(1) Fittings. Enclosures for connections or equipment shall be provided with an integral means for sealing, or sealing fittings listed for the location shall be used. Sealing fittings shall be listed for use with one or more specific compounds and shall be accessible.
(2) Compound. The compound shall provide a seal against passage of gas or vapors through the seal fitting, shall not be affected by the surrounding atmosphere or liquids, and shall not have a melting point of less than 93?C (200?F).
?
​

Note the location of the Exception. According to the NEC Manual of Style (MOS) the location means the Exception applies to all of Section 501.15(C) including its Subsections. My interpretation is that, if the seal isn?t required to be explosionproof, [Class I, Division 2, boundary seals (501.15(B)(2)) and Intrinsically Safe seals (504.70]) virtually anything that reasonably minimizes the passage of the volatile materials may be used the as a sealing medium ? including duct seal. Otherwise, with respect to the OP, the sealing medium must be specifically listed for the seal fitting.

 

[weressl]

It will depend on the application. The rules that apply to the OP are found in Section 501.15(C) and its Subsections (1) & (2). I have copied the relevant text here:

501.15 (C) Class I, Divisions 1 and 2. Seals installed in Class I, Division 1 and Division 2 locations shall comply with 501.15(C)(1) through (C)(6).
Exception: Seals not required to be explosionproof by 501.15(B)(2) or 504.70.
(1) Fittings. Enclosures for connections or equipment shall be provided with an integral means for sealing, or sealing fittings listed for the location shall be used. Sealing fittings shall be listed for use with one or more specific compounds and shall be accessible.
(2) Compound. The compound shall provide a seal against passage of gas or vapors through the seal fitting, shall not be affected by the surrounding atmosphere or liquids, and shall not have a melting point of less than 93?C (200?F).
?
​

Note the location of the Exception. According to the NEC Manual of Style (MOS) the location means the Exception applies to all of Section 501.15(C) including its Subsections. My interpretation is that, if the seal isn?t required to be explosionproof, [Class I, Division 2, boundary seals (501.15(B)(2)) and Intrinsically Safe seals (504.70]) virtually anything that reasonably minimizes the passage of the volatile materials may be used the as a sealing medium ? including duct seal. Otherwise, with respect to the OP, the sealing medium must be specifically listed for the seal fitting.

Bob, so how do we deal with the following highlighted wording:

501.15(B)(2) .....Such seals shall not be required to be explosionproof but shall be identified for the purpose of minimizing passage of gases under normal operating conditions and shall be accessible.

What do 'identifed for' mean and how do we meet the accessibility requirement? Is duct seal - the example you use identified as usable for the 'purpose of minimizing pasage of gases'? What do 'normal operating conditions' mean, or what is it's benefit? They don't talk about pressures, pressure differentials and corresponding elakeage rates. What if normal operating conditions is a presure difference accross the seal?

(The whole provision is just muddy in my mind and I am looking for some clarity.)

​

 

[rbalex]

Identified is a defined term in Article 100. See also Section 500.8(A).

 

[weressl]

Identified is a defined term in Article 100. See also Section 500.8(A).

Exactly. Ductseal, that you mentioned, for example does not seem to have such identification. 500.8(A) Seem to add a defintion, which it should not, because the method of acceptable identification now becomes unique to 500 and why the same method of suitability be not applicable to ANY identified equipment in ANY Article? But I guess what you are saying here is that despite ductseal having NO published factory identification that it complies with the 'minimizing passage of gases under normal operating conditions' meaning that neither thrid party, nor manufacturers self-evaluation is available, the Owner's engineering judgement if accepted by the AHJ, could still make the product suitable.

As Bill O'Reily would ask: where am I going wrong?

 

[rbalex]

Exactly. Ductseal, that you mentioned, for example does not seem to have such identification. 500.8(A) Seem to add a defintion, which it should not, because the method of acceptable identification now becomes unique to 500 and why the same method of suitability be not applicable to ANY identified equipment in ANY Article? But I guess what you are saying here is that despite ductseal having NO published factory identification that it complies with the 'minimizing passage of gases under normal operating conditions' meaning that neither thrid party, nor manufacturers self-evaluation is available, the Owner's engineering judgement if accepted by the AHJ, could still make the product suitable.

As Bill O'Reily would ask: where am I going wrong?

Sorry I didn't get back to this sooner; I've been sick the last two days.

Identified, by definition, means, “Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.” It does not require listing or labeling although both are “suitable,” of course.

Under 500.8(A)(3) a reasonable “engineering” evaluation would be to demonstrate that the “nonexplosionproof” seal would limit gas or vapor flow to the rate permitted for seal fittings [200 cm3/hr (0.007 ft3/hr) of air at a pressure of 1500 pascals (6 in. of water)].(cf (501.15(E)(2)for reference)

I was (and still am) opposed to the Proposal that permitted “non-explosionproof” seals in Section 501.15(B)(2); however, it has been permitted since the 2005 NEC. Apparently it hasn’t caused too many problems though; I suspect it is because seals (of any kind) weren’t needed in the first place. That’s what 501.15(B)(2) Ex No 4 is all about. Nevertheless, I believe if a Class I, Division 2/unclassified location boundary seal is actually necessary, it should be explosionproof – I said so in my Comment.

 

[weressl]

Sorry I didn't get back to this sooner; I've been sick the last two days.

Identified, by definition, means, ?Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.? It does not require listing or labeling although both are ?suitable,? of course.

Under 500.8(A)(3) a reasonable ?engineering? evaluation would be to demonstrate that the ?nonexplosionproof? seal would limit gas or vapor flow to the rate permitted for seal fittings [200 cm3/hr (0.007 ft3/hr) of air at a pressure of 1500 pascals (6 in. of water)].(cf (501.15(E)(2)for reference)

I was (and still am) opposed to the Proposal that permitted ?non-explosionproof? seals in Section 501.15(B)(2); however, it has been permitted since the 2005 NEC. Apparently it hasn?t caused too many problems though; I suspect it is because seals (of any kind) weren?t needed in the first place. That?s what 501.15(B)(2) Ex No 4 is all about. Nevertheless, I believe if a Class I, Division 2/unclassified location boundary seal is actually necessary, it should be explosionproof ? I said so in my Comment.

Perhaps some different wording that distinguishes seals that require to CONTAIN an explosion from devices that (only) limit the passage of gas, would resolve the issue. ( Don't censor me now but in instrumentation the device is called orifice.)