Passive Fire Constructions utilised as noise reduction
In case of installations of fi re protection constructions the noise reduction is almost a freebee. Please see our examples of constructions which are tested for noise reduction through the construction.
All measuring data is available on our web site www.rockwool-marine.com Here it is clear that these fire protection constructions give a high degree of noise reduction. Thoughts in the design work for, as example an offshore rig, should therefore not be split in separate designs.
It would often be an advantage to work with Rockwool passive fi re protection systems, as you gain the combination of the authority required fi re protection and at the same time the needed noise reduction, hereby avoiding other (expensive) noise reduction solutions and maybe also a deluge system. A Rockwool solution would therefore be the far most cost effective solution. Please see our complete set of easurement result at the web site and in the appendix I.
When choosing a fi re protective solution, among the many Rockwool possibilities, you should go for following when noise reduction is important.
Bulkhead A-60; 2x30/30 mm Rockwool Marine Firebatts 130 or
Deck A-60; 40/40 mm Rockwool Marine Firebatts 130
The noise reduction through the bulkhead will be improved when a steel cladding is fitted in front of the insulation. It is here important to mount the cladding system as “separate” as possible from the bulkhead/deck, in order to transfer as little sound energy as possible. Flexible hangers/brackets will do the job, and equally important is to seal all edges and joints with fl exible sealant.
A range of parameters have been set-up when i.e. fi re protective material as Rockwool Marine Firebatts 130 has been designed.
Of cause the fi bres have to have the right composition formed into the right structure to withstand the severe conditions found during a fi re, but at the same time our research engineers have been investigating the best possible way of also utilising this fi re material as noise absorption and noise reduction.
In most cases the general saying is that the higher density mineral wool the better noise reduction and noise absorption characteristics you will find. But sophisticated and clever design and manufacturing of the Rockwool material and not least the built-up of the solutions can further enhance the qualities, thus the density statement will not always be true.
Studies and design work have given the fi re protective solutions made with Rockwool Marine Firebatts 130 as the best solutions, when the improvement of noise is important.
As SOLAS requires the fire insulation in engine rooms to be covered by oil resistant foil or cladding system, this goes nicely together with the noise reduction when using thin steel plate cladding, but for the noise absorption within the engine room itself it is not the best solution.
A perfect solution for A-60 Bulkhead, where the sound absorption is important will be a solution with Rockwool Marine Firebatts 130 coverd by loose fitted thin (< 20 my) foil and then covered by perforated plate (> 25 % hole ratio) for mechanical protection.
If cabins are situated just above the engine room, it is important to have all the insulation covered and preferably in a mounting system with anti-vibration studs. It will not be sufficient just to make a good sound insulation at the deck towards the lower cabins, as the airborne noise can be transmitted into the bulkhead and then move as structure-borne noise upwards (flanking transmission path). Therefore the bulkheads should also be proper sound insulated.
 |
|
