Both preceding comments are valid. The installation, as described so far, would typically fall under NFPA 54, the National Fuel Gas Code. While the Standard references the NEC as the appropriate standard for electrical installations, it does not generally require electrical area classification in most cases. A small exception is in Section 7.12.5.2 – it is not applicable here.
Philosophically, the likelihood of the electrical installation igniting a leak from the typical fired equipment instsallation is exceptionally low.