Oxygen-Enriched Atmosphere

[ed_gur]

Dear Moderator,
I tried to send this question before but have no idea, if it reached you.
If yes, please discard this question.
I could not find any references in NEC that the oxygen storage tank area is considered a hazardous location. However, NFPA 53 Chapter 7 requests that electrical installation in oxygen-enriched atmosphere areas should comply with the requirements of Article 500, Class I, Division I NEC.

Would a storm drain sump pump, installed in a well next to oxygen tank (located outside) be required to meet Class I, Div. I requirements (in case of the tank leakage)?
Is there anything I am missing in NEC that would address this condition?

Thank you.
Edward Gurevich.

 

[DRGREG]

This is an interesting question. If oxygen was considered a flammable gas, your application would be, class 1, div 2. But since oxygen is not flammable, I would consider the area not classified.

 

[rbalex]

NFPA 53 is a Recommended Practice rather than a Code or Standard. In NFPA terminology this means it is '[a] document that is similar in content and structure to a code or standard but that contains only nonmandatory provisions using the word “should” to indicate recommendations in the body of the text. '(See the definition in Section 3.3.6.1 of the NFPA’s Regulations Governing Committee Projects) This doesn’t mean it isn’t authoritative, but it isn’t mandatory either.

Oxygen enrichment can obviously exacerbate the conditions in an already classified location, but it alone will not create one.

I reviewed NFPA 53, Section 7.7 and found that using Division 1 installations techniques wouldn’t make any difference especially in light of the explanatory material in Appendix A, Section A.7.7.1.

A close review of the definition of OEAs in 3.3.25, would also lead me to the conclusion that the installation you described would not require Division 1 construction[edit add:] or any other Class I constuction.

 

[augie47]

Edward,
Welcome to the forum.
I am not a moderator, but, I have been thru this previously.
After input from Forum members, engineers and the Fire Marshalls Office, I was advised that as long as it was a storage area, since NEC did not list Oxygen as hazardous, it would not be a hazardous area.
I know that the info clashes somewhat with NFPA53., but I found noone who looked at the area as "oxygen enriched"

just my experience with the "officials", nothing "official"

(Note: Bob, I was typing and posted prior to reading your far better answer..thanks)

 

[charlie b]

Take a look at FPN 2 following 500.5(B)(2). It tells me that the vicinity of an storage tank for flammable gases might be considered hazardous, and it might not, and all depends on quantities, sizes, and ventilation. It refers the reader to two other NFPA standards that do not seem to apply to gases, so I can’t suggest a next step for your investigation. Also, I cannot offer more than he others did, with regard to the treatment of oxygen as being flammable.

Welcome to the forum. Nice to hear from you, Ed.

Regards,
Charlie

 

[rbalex]

Your answer was just fine - I wouldn't have researched it but for your earlier inquiry

 

[weressl]

Dear Moderator,
I tried to send this question before but have no idea, if it reached you.
If yes, please discard this question.
I could not find any references in NEC that the oxygen storage tank area is considered a hazardous location. However, NFPA 53 Chapter 7 requests that electrical installation in oxygen-enriched atmosphere areas should comply with the requirements of Article 500, Class I, Division I NEC.

Would a storm drain sump pump, installed in a well next to oxygen tank (located outside) be required to meet Class I, Div. I requirements (in case of the tank leakage)?
Is there anything I am missing in NEC that would address this condition?

Thank you.
Edward Gurevich.

If it is oxygen storage only then you would not need to concern yourself about Cl.I, Div. 1 installation requirements. However if the area is to be considered as an OEA where elevated oxygen level is required not only your equipment needs to be approved for Cl.I, Div.1, but also should be suitable for OEA. If you read the entire standard, including the Annex, you may have a better understanding of what they trying to accomplish.

 

[rbalex]

If it is oxygen storage only then you would not need to concern yourself about Cl.I, Div. 1 installation requirements. However if the area is to be considered as an OEA where elevated oxygen level is required not only your equipment needs to be approved for Cl.I, Div.1, but also should be suitable for OEA. If you read the entire standard, including the Annex, you may have a better understanding of what they trying to accomplish.

Laszlo,

I'm an old dog but I hope I haven’t gotten beyond learning something new yet.

I did reread NFPA 53 and the Annexes. (It isn’t a particularly long document.) Nothing I read lead to “…a better understanding of what they [are] trying to accomplish” with respect to using Class I, Division 1 equipment and wiring methods.

Nothing in Appendix C, Utilization of Oxygen-Enriched Atmospheres; Appendix D, Fire Experience; or Appendix E, Fundamentals of Ignition and Combustion in of Oxygen-Enriched Atmospheres indicated how Division 1 construction would have prevented, mitigated or ameliorated the condition. In fact, Section C.1.2 specifically states, “An OEA does not, however, by definition produce an increased fire hazard.”

In addition, both the main text in Section 5.3, its explanatory material in Appendix A, and Appendix F, Materials for Use in Oxygen-Enriched Atmospheres indicated that the usual materials of construction for Division 1 equipment is not likely to be suitable for OEAs.

From what I can tell, unless the location needed to be classified Class I, Division 1 in the first place, the fact that it may be an OEA makes no difference.

I am genuinely interested in your insight though. I was a bit tired last night so I could have missed something.

 

[weressl]

Laszlo,

I'm an old dog but I hope I haven?t gotten beyond learning something new yet.

I did reread NFPA 53 and the Annexes. (It isn?t a particularly long document.) Nothing I read lead to ??a better understanding of what they [are] trying to accomplish? with respect to using Class I, Division 1 equipment and wiring methods.

Nothing in Appendix C, Utilization of Oxygen-Enriched Atmospheres; Appendix D, Fire Experience; or Appendix E, Fundamentals of Ignition and Combustion in of Oxygen-Enriched Atmospheres indicated how Division 1 construction would have prevented, mitigated or ameliorated the condition. In fact, Section C.1.2 specifically states, ?An OEA does not, however, by definition produce an increased fire hazard.?

In addition, both the main text in Section 5.3, its explanatory material in Appendix A, and Appendix F, Materials for Use in Oxygen-Enriched Atmospheres indicated that the usual materials of construction for Division 1 equipment is not likely to be suitable for OEAs.

From what I can tell, unless the location needed to be classified Class I, Division 1 in the first place, the fact that it may be an OEA makes no difference.

I am genuinely interested in your insight though. I was a bit tired last night so I could have missed something.

Bob,

I hear you barking :grin:, backatcha.....

Many of the materials behave differently when exposed to an OEA, some self ignite. It seems to me that what they suggest is to avoid the use of materials that are easily affected by OEA and avoid sources of heat and constructions that could generate heat. In some cases they talk about nitrogen inerted conduit systems and enclosures. It appears to me that the use of equipment and installation method that is approved for Class I Division 1 will help with the containment of the fire if it happens to originate within an arcing or heat producing electrical equipment, like it would contain the explosion and would not allow hot gases to escape into the outside area. Please notice that they do not say to classify the area as Cl. I, Div.1, only that the equipment and installation should comply.

This is the only logic I can find, although they do not state it so.