I don't want to get into specifics, but a lot of my work is in applications that are about as critical as they come and the very definition of "COPS" in everyone's view of the term... and even the managers and officers responsible for the projects (myself included) think some of these requirements have gone overboard and are simply unreasonable. It's gone beyond minimum requirements for safety and has started mandating risk mitigation design criteria that may or may not be necessary, and should be left to the designing engineer to decide. For instance, does ALL conduit require firestop? NEC seems to say "yes". But if a piece of conduit goes up from a UPS, over 6 feet, and down into the switchgear it serves... what sort of fire would the code be protecting this cable from? And under what circumstances would RMC protect it while EMT would be a critical risk? Funds aren't unlimited, and there is always risk. The risks must always be balanced against the costs, and codes like this make that difficult.
I saw down and did a whole slew of calculations yesterday. Unfortunately, they're highly dependant on the size of the conduit and how much copper is in it, so it would have to be recomputed for every installation, but in this case, R6 (1.5") pipe lagging would allow an appx 180C rise in 1 hour. R13 insulation would reduce that to 115C, and meet Class 150 requirements. However, a 115C rise is still high enough to damage THHN insulation. Another option is ventilating the RMC- installing fans to circulate air through continuously so that if there is a fire, the heat can be dissipated. Not something we typically see in an NEC installation, and some insulation (R6, etc) would still be required, but it would be a whole lot less expensive than flameseal and should be as effective. Thoughts on this?
Also, what part of "business continuity" in 708.2 doesn't apply to Wal-Mart? Sorry, reno, you've got to comply, it's the Law!
