Sound Insulation


Why should
I insulate the
engine
compartment?
Marine engines are usually installed in dedicated engine rooms, or boxed-in within the accommodation. These areas are like an empty room in a brand new house, noise echoes off the bare, hard walls and ceiling, until you add carpets and curtains to 'absorb' it. Anyone studying a new house will also have noticed that a heavy brick wall is better at stopping noise than a light stud partition. This is because the extra weight deals better with noise 'transmission' . A heavy brick wall will also stop a high pitched whistle better than the low pitched rumble of a passing lorry, due to the different 'frequency' involved. A good noise insulation will be soft to absorb as much noise as possible. It will have weight, to prevent noise transmission and its make-up will be tuned to suit the frequencies found with marine engines. If properly used it will remove the harsh unpleasant elements of an engine's noise and can make an engine almost silent. Twenty years ago all polyurethane foam would burn and give off poisonous fumes from halogen gasses. Even so-called non drip foams, and those meeting the old BS4735, would burn fiercely in the right conditions. Today, all our foams meet the special BS476 fire zero rated standard. We also have foams to meet the exacting requirements of the Recreational Craft Directive (RCD). Specifically this requires that materials have a non fuel absorbing facing and have an oxygen index 01 of at least 21% according to ISO 4589-3(2). Our materials were tested by the Defence and Evaluation Agency ( DERA ) in July 1998 to prove this and certificates confirming the results are held by HMI. The key is to clad as much of the engine space as possible, leaving no gaps for the noise to get out and no hard surfaces for the noise to bounce off. As a minimum, we recommend that the boards over the engine and the bulkhead between the engine compartment and the main accommodation be covered. Standard materials can be glued to dry, grease free surfaces using contact adhesives such as Evostick. In really hot climates, materials should be positively fixed to bulkheads with pins or similar, or special high temperature adhesives should be used. Only recently has it been proved to us that technology has come up with a self-adhesive backing that compares to the performance of liquid glues. The use of a self-adhesive backing makes the job of fitting out the engine room a little easier, not as messy and certainly not as smelly. It must be noted that just like using glue, the surface to which the material is to be fastened must be dry and free of oil or grease. At the moment it is only possible for us to supply self-adhesive versions of the silver re-inforced faced materials in the 12mm and 32mm thickness. A detailed brochure is available and remember our technical staff are always to hand with advice over the phone.

Does
it
Burn ?

How do I
use it ?

How do
I fix it ?