Can a bridge crane be installed over a classified area? The area is classified because of fuel dispensing, use of a fuel day tank with venting and some auto fuel system testing (testing levels not to exceed 35% LEL). The fuel is gasoline and classified boundaries are class1, div1 10'-0 and below and class 1, div 2 between 10'-0 & 13'-0. The room is 30'-0(W) x 65'-0(L) x 22'0(H) and the crane is mounted at 16'-0AFF with the electrified rails at 18'-0AFF. The room ventilation rate is 2.5 cfm/sf and 6.2 air changes per hour with 100% outside air and floor sweeps. At this point all equipment in the room is rated class 1, div1(except the crane) as an added precaution. The crane is interlocked with the ventilation system and gas detectors(set point of 35% LEL). The crane is used for one test that does not involve flammable liquids. Except for articles 511 and 514 I do not know of any place the NEC addresses equipment installations above classified areas. Article 511 requires non-classified arcing / sparking equipment be installed a minimum 12'-0 above the floor but I do not know the reasoning behind this particular height (why not 10'-0 or 14'-0) or how it might relate to this installation. I appreciate any insight on this matter.
Thanks, Dave
Thanks, Dave
