Generators, compressors, dewatering pumps and cooling units often run around the clock – including at night, when the rest of the construction site is quiet. These stationary noise sources are the most common cause of complaints from neighbours. With an enclosure made of noise barrier mats on a construction fence frame, or with a mobile acoustic barrier wall, you can reduce the level by 10 to 20 dB(A).
How the enclosure works
- Surround the unit on three or four sides with temporary fence panels to which noise barrier mats are attached.
- Keep the clearance to the unit specified by the manufacturer for intake air, exhaust air, waste heat and exhaust routing (guide value: at least 1 m, more for large generators); leave the opening facing the non-critical side (e.g. towards the site). Keep maintenance access and escape routes clear.
- For units running permanently: add a second layer of mats on the critical side. A top cover or a fully closed enclosure only with the explicit approval of the equipment manufacturer (cooling, exhaust, fire safety clearances).
- Close to exhaust systems: use Premium mats with a flame-retardant finish.
What noise reduction is achievable?
A three-sided enclosure with Premium mats (sound reduction index 23 dB) typically delivers 12 to 18 dB(A) on the shielded side; a closed enclosure with a top cover up to 20 dB(A). The following refers to regulations in Germany; other countries apply their own limit values. For permanent commercial sources, the guide values of the TA Lärm (German technical instructions on noise) apply; for construction sites, the AVV Baulärm (German construction noise regulation). Which machines may be operated in residential areas at all is governed by the 32. BImSchV (German equipment and machinery noise ordinance).
Frequently asked questions about noise control for generators
How far away from the generator may the mat be placed?
The equipment manufacturer’s specifications for minimum clearances for intake air, exhaust air and exhaust gases are decisive; as a guide value, allow at least 1 m, and 1.5 m or more for large generators.
Are the mats heat-resistant?
The mats are designed for outdoor use but must not be in direct contact with exhaust systems or hot surfaces. For critical areas we recommend the flame-retardant Premium version.
How many dB does an enclosure achieve?
Three-sided 12 to 18 dB(A), closed with a top cover up to 20 dB(A) – depending on the mat variant, the tightness of the joints and the clearance.
Do I need a top cover?
Only if higher receptor points (windows on upper floors) are affected – and only with the equipment manufacturer’s approval regarding cooling, exhaust routing and fire safety clearances.
Does the mat have to be flame-retardant?
On construction sites this is not generally mandatory, but it is strongly recommended near exhaust systems, fuel storage and on industrial sites.