COMMON NOISE & VIBRATION APPLICATIONS
Generators are usually cooled by moving a large volume of air. Typically propeller fans, which have extremely low static capabilities, are used. Proper selection of silencer solution is needed to ensure that the silencers, once installed, have a minimal pressure drop and do not affect air distribution for generator cooling.
Most generators are extremely loud (120 dBA), making environmental noise a major concern. Noise traveling through air intake and discharge paths, used for generator cooling, is the most common occurrence of environmental noise complaints and lawsuits.
Depending on where the generator is located, there are different solutions:
Intake and discharge silencers with an extremely low pressure drop coupled with intake and discharge plenums.
Full Enclosures can be built around the generator to prevent noise from reaching the property line.
Shaft silencers are very common if the generator is located underground.
Acoustic Louvers are a possibility in addition to intake and discharge silencers.
OCCUPIED SPACE NOISE
If a generator is located in the main building, there is always a concern of the generator noise reaching the occupied space. This problem can occur by noise radiating through the walls, ceiling or floor as well as noise breaking in to the ducts from the generator room.
Floating floors, ceilings and walls, which create an air barrier that reduces low frequency noise offer a great solution if generators are neighboring sound-sensitive spaces.
HTL (High Transmission Loss) silencers and sometimes HTL ductwork is recommended in mechanical rooms where break-in is possible. Placing a silencer at the wall between the mechanical room and the occupied space will reduce break-in before and prevent breakout noise from reaching the occupied space.
Generators are a major source of vibration. If this vibration is transferred to the structure, it can create serious noise problems in different areas of the building. Vibration problems are difficult to diagnose post design. Thermal expansion of the mufflers is also a concern when designing vibration isolation for generators.
Specialized isolators are typically used for generators. Thermal expansion and contraction of the engine muffler can be addressed by installing a support system with rollers.