engine room sound proofing material and practices

Hi,

I was wondering what the current "norms" are for engine room sound proofing. Ideally we are looking for a material that will provide a B15 fire rating.

We have insulated the interior of our steel boat with Armacell AF and I was wondering if Armacell NF would be the most suitable material.

We have enough space for about 2-3" of material.

Thanks,
Mark

 

Armacel seems to be just a thermal insulation. It has low sound propagation and low flame spread. Therefore it can not be considered as acoustic insulation, while reducing the noise level, or as fire insulation.
Category B-15 refers to the fire barriers. It requires a material with no flame propagation and very low temperature spread, coated on the outside with steel.
In the engine compartment must guard the fire barrier, which should go inside the e.r. and that eventually reduces noise propagation. Another very important point to prevent noise, often more effective than an insulating material, is to eliminate the most vibrations that are transmitted through the hull structure.