Sure, why not? It sounds like the gas meter room was misclassified in the first place.
Originally Posted by gadfly56
Classifying a location isn't rocket science but it isn't trivial either.
Whenever an enclosed space has a potential internal source, without sufficient additional information disclosed, it can only be Division 1. Division 2 isn't an option unless the space is properly purged or adequately ventilated. It may even be unclassified without purging or ventilation if the piping is totally closed with no intended openings to atmosphere such as pressure relief ports or spigots. However, possible valve leaks, without adequate ventilation would render the space Division 1 as I originally mentioned.
If the meter room were properly classified, it is possible, depending on other piping geometry and process conditions, that the adjacent room, or part of it, could also be classified. Without full installation details I couldn't say.
Robert B. Alexander, P.E.
Answers based on 2014 NEC unless otherwise noted.