Section 181.120 - Equipment installed but not required(a) Fire extinguishing equipment installed on a vessel in excess of the requirements of §§ 181.400 and 181.500 must be designed, constructed, installed, and maintained in accordance with a recognized industry standard acceptable to the Commandant (CG-ENG-4).(b) Use of non-approved fire detection systems may be acceptable as excess equipment provided that- (1) Components are listed by an independent, nationally recognized testing laboratory as set forth in 29 CFR 1910.7 , and are designed, installed, tested, and maintained in accordance with an appropriate industry standard and the manufacturer's specific guidance;(2) Installation conforms to the requirements of 46 CFR chapter I, subchapter J (Electrical Engineering), especially the hazardous location electrical installation regulations in 46 CFR 111.105 ; and(3) Coast Guard plan review is completed for wiring plans.USCG-2012-0196, 81 FR 48299 , July 22, 2016