We are currenty doing a remodel of an existing spray room that is classified as a class 1 division 2 hazardous location. The original build was done in the 70's. I had some questions regarding the current locations of the conduit seal off's. For the lighting there are seal off's on each side of a junction box that splits off to feed the (3) seperate switch locations. Being that the switches are less then three feet from the j box there is only the one seal off in each run. Leaving each switch there is a seal off on each conduit that goes up to it's respective row of class 1 div 2 lights in the spray room. There is not a seal off on the conduit as it enters the explosion proof light, nor are there any on the conduits between the next 6 lights in each. At these lights the conduit enters a box that is part of the fixture that has the 3/4" hubs along with another threaded access hole on the side that appears that it is there for makeup purposes. Are seal off's not required at boxes used for makeup? In some of these runs between lights that don't have seal off's there are unions. Does this change whether or not a seal off is required between makeup boxes?
We will also be adding some new fire alarm devices in this room. Currently there is a heat detector in the room that doesn't have a seal off at the device, but has one in the run after it exists the classified location. Is this a proper install? Does fire alarm need seal offs between devices inside a hazardous location?
Lastly, there are a couple added "hazmat" rooms (sounds like it may be for paint storage) that are all sharing common walls. Are seal offs required when going from one classified location into another, or are they only required when exiting/entering a hazardous location?