NFPA 53 is a
Recommended Practice. According to the latest NFPA
Regulations Governing Committee Projects a
Recommended Practice is ?A document 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.? [rba note: underline added] In the interest of full disclosure virtually every document that deals with general electrical area classification practice, e.g. NFPA 497 or API RP500, is also a ?Recommended Practice.?
I was not familiar with
NFPA 53 before today. (The link is to the free online version) It isn?t particularly long so I read the material relevant to the OP.
The Scope and Purpose statements (Sections 1.1 and 1.2) are fairly general and lack the specificity that usually required; nevertheless, the ?Application? statement (Section 1.3) and the Definition of OEAs (Section 3.3.25) seem to vaguely apply to the OP.
The first question then is ?under normal operation and design conditions does the area under concern meet the definition of a OEA?? I seriously doubt it.
The Fire Marshall appears to be citing Sections 7.7.2 and 7.7.3. It appears that the NFPA 53 TC is actually unfamiliar the NEC. They cite Article 500 rather than 501 for installation practices. The do recognize in 7.7.2 that that the location should already be classified according to the ?fuel.? However, using Division 1 installation techniques will make absolutely no difference unless the location needed to be classified in the first place because of the ?fuel? involved.