Room acoustics – sound absorbing surfaces
The reverberation time should be kept short and reflections should be reduced as much as possible. Be careful with constructions that focus the noise i.e. concave surfaces. Use screens to separate noise sources from each other.
Airborne sound insulation – double layer constructions If possible use double constructions with absorption in the cavities (best thickness >100 ... 200 mm to achieve low f0 < 50 ...100 hz). in practice 50 - 150 mm will provide the desired values. Avoid if possible sound bridges between the solid layers.
Floating floor construction
Floating floor constructions with a resilient layer of Rockwool improve the airborne sound insulation and impact noise / structure borne noise. Here the optimum for compression strength and dynamic stiffness of the products have to be adjusted to the required mechanical load maximum on the floor.
Materials with high internal damping factor
Special sandwich materials with integrated viscoelastic layers are developed for the marine and offshore sector.
Resilient connections between construction elements To reduce noise transmission via structural vibrations, resilient connections should be used as much as possible. E.g. pipes and pipe bearings, cable ducts etc. can transmit considerable vibration energy over long distances.
Resilient mounting of machinery It is strongly recommended to reduce noise problems and noise emission as close to the source as possible. All rotating and vibrating machines should be mounted resiliently.
Silencers in ventilation ducts Ventilation ducts should be equipped with all necessary silencers. This will not only remove noise from the ventilation plant itself but can also reduce noise transmitting via the duct system from other sound sources on the ship (e.g. from machine room to cabins)
Rockwool solution examples Below a list of typically solutions seen, where Rockwool Marine & Offshore products are used. Rockwool Marine & Offshore products are particularly well suited for reduction of noise problems. Some usefull applications are: - Passive Fire Protection constructions. These Class approved Rockwool solutions provide the additional benefit of noise reduction
- Marine panels, i.e. sandwich panels with Rockwool core
- Floating Floor constructions
- Marine ceiling systems
- Dedicated “open” Rockwool products installed as absorbers
- Thermal Rockwool insulation covered by glass cloth facings for a visually nice finish and offering highly improved absorption/reduction
- Dedicated noise absorbers/reduction cassettes with Rockwool core and perforated outer steel sheeting
- Encapsulation systems. Noise reduction boxes with inner lining of Rockwool Marine Slabs, to cover a noisy engine, compressor or similar completely
- Rockwool infill for penetrations in bulkhead/deck of cables, pipes, ducts, etc
- Air intake silencers for ventilation fans
- Reactive / absorbing silencers. Resonance dampers in funnels
- Specific frequency noise damping by Rockwool Slabs, mounted in calculated distance from bulkhead
- Rockwool products for absorption covered by special foils allowing the energy to pass into the Rockwool and at the same time acting as vapour barrier for oil and water
- Combination solution where the Rockwool products are absorbing/reducing the high frequencies and systems with PU-rubber with thin steel sheets, cassettes or similar is dampening the lower frequencies
- Combination solutions with Rockwool floating floor, vibration mounts, encapsulation and similar
- Fluid transmission noise from pipes and valves, insulated by Rockwool Pipe Sections / Rockwool Marine Wired Mats, and mattresses for valve covering
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