I have separate electric utility service for fire pump still backup source would be required if normal source is found not reliable. However, normal source reliable guidelines are in NFPA 20 2013 A.9.3.2 and also handbook blue commentary in NEC 2014 Section 695.3 there are 4 but only list 2 below:
1. The source power plant has not experienced any shutdowns longer than 4 continuous hours in the year prior to plan submittal. If the normal source power plant has been intentionally shut down for longer than 4 hours in the past, it is reasonable to require backup generator.
2. Power outages have not routinely been experienced in the area of the protected facility caused by failures in generation or transmission.
We are the AHJ their is no one we who has done this sort of research in electrical department nor they know where to look for to find data and was wondering how all you have verified or other AHJs verified the above two conditions reliable normal source: letter from utility, letter from engineer of record, websites research if so which ones or other means?