I am currently adding insulation to my icebox. I am doing this in place,
because it is difficult to remove existing cabinetwork without wrecking it.

Basically, I will use sheet foam where I can get at surface - probably
polyisocyanurate with foil on it. Elsewhere, I will pour in urethane foam.

I am concerned about the flammability of these products. Are there
regulations for boats as there are for homes that require the foam to be
covered with a fire barrier? What is recommended?

My box will end up with 1/2" plywood as sheath on two sides. The back is a
large cavity with hull as outside. The front and bottom are exposed and
should probably be covered. The insulation has an aluminum foil, but I doubt
that provides any flame resistance. Thinking about just using 1/2" plywood -
Would this be acceptable to a surveyor?

GM