Cover for cabin mounted surge tank?

[Hachiroku]

When you have a surge tank, pumps etc mounted inside a hatch/wagon I assume you need to make some sort of cover for it. What material does it need to be made of to pass cert / MSNZ inspection? Are there any special criteria that it needs to adhere to (externally vented etc)?

[Leon]

Flame and fume proof. Vented outside the cabin (and NOT onto the exhaust pipe).