ABYC is more strict that NFPA in this case
I think that Propane is in the fuel section.The last few times I bought LPG-related stuff (gas detector, solenoid, etc.) I got a copy of the regs in the package.There are few high level things to keep in mind. the tank and any connection (solenoid, tee for BBQ,etc.) must be such that it is in a sealed compartment that opens only to the outside of the boat, and is vented. There are restrictions on the size of the vent and placement relative to exhaust. Your line should run all the way to the appliance. No connecting short pieces together along the way.There are also requirements for leak detection, and suggestions for leak testing on regular basis. All good given that propane collects in the bilge and explodes.http://www.sailnet.com/collections/articles/index.cfm?articleid=woodto0070westmarine may also have some info.