Enclosures for Emergency Generators

Q: Do emergency power generators have to be located in a room by themselves? We have a generator that is located in a mechanical room which is shared with an air-handler, condensate pumps and other equipment. This generator was installed in the 1970’s, but a consultant told us we had to relocate the generator to a 2-hour room where it can be located by itself.

A: NFPA 110 (1999 edition), section 5-2.1 says the generator must be installed in a separate room with a 2-hour fire rating, and no other equipment is permitted in the room. However, section 1-3 of the same standard says NFPA 110 only applies to new installations and existing systems are not required to conform to the standards, unless the authority having jurisdiction (AHJ) determines that nonconformity presents a distinct hazard to life. If the generator has been installed since the 1970’s and no AHJ has cited you for nonconformity, then I suggest it is safe to assume the AHJs that have inspected your facility do not have a problem with the arrangement. If an AHJ attempts to cite this situation for non-compliance with NFPA 110 (1999 edition) section 5-2.1, then I would make the case that it is not required to since this room was constructed long before NFPA 110 was in existence. NFPA 110 was first adopted in 1984 by NFPA, so it was not part of the Life Safety Code until probably the 1985 edition.  Therefore, it may be assumed it met the standards that were in existence in the 1970’s when the building was constructed.