Generating Sets - Permissible Sound Levels

70Db at one Meter from Enclosure or sound proofed DG Room is the requirement of CPCB notification and depending on your locations 40Db at silent zones covering Hospitals,schools and residential zones.

CRM

The permissible exposure level (PEL) of noise is regulated by government authority and it depends from country to country. Some company may have its own policy for the noise level control. As per OSHA (Occupational Safety & Health Administration, USA, www.osha.gov), the PEL is 90 db for 8 hours. This means an employee is not permitted to stay more than 8 hours in an environment of noise level 90 db. This noise level can be counted as time-weighted average (TWA). This PEL time is decreased to half (or increase to double) for the increase (decrease) of every 5 db (called doubling factor), i.e., 95 db for 4 hours, 100 db for 2 hours, 85 db for 16 hours, 80 db for 32 hours etc. The noise is generally measured at 3 feet (1 meter) from its source. The 85 db PEL and 3 db doubling factor are in consideration in OSHA, however, it is implemented in many places. So, in case an employee needs to work continuously 8 hours in the generator area, the noise level can be set 85 db (or the highest 90 db) but check with the environmental guideline of your country or area.

As the other person (Guest) indicated the link of Indian Center Pollution Control Board, where it is indicated the maximum sound level is 75 db at 1 meter for the generator (DG) sets with rated capacity up to 1000 KVA.

These links also help:

http://www.gcaudio.com/resources/howtos/loudness.html

https://cr4.globalspec.com/thread/62079/Inverter-Noise-Level

- MS