AIRBORNE SOUND INSULATION
Permacrib Environmental Noise Barrier Systems are designed to provide adequate sound insulation so sound transmitted directly through the wall is not significant compared with the sound diffracted over the wall.
*2 According to pr EN 1793-2 and extrapolated based on laboratory results which indicate that compaction due to seismic activity and natural settling and accumulation of dust particles will cause the acoustic insulation properties of the wall to increase with time, (reference Marshall Day and Associates 1993)
Permacrib Environmental Noise Barrier Systems are designed to be effective as sound absorbing devices on the traffic side (noisy side of the wall) to reduce additional noise nuisance caused by reflected sound (NRC=0.8 dB). Circumstances in which this treatment may be needed include;
- noise barriers, rocks, or retaining walls that can reflect sound rays toward the unprotected areas;
- vertical cuttings or where reflective surfaces face each other;
- Tunnels and their approaches;
- Traffic passing close to a barrier where reflection between vehicles & the barrier may reduce effectiveness.