I have been asked by the Ops Director at work to advise on combined noise noise levels for 4 piling rigs working at the same time on a project. He needs the levels for an area of approx 70mx70m. Help!

Noise levels for one piling rig is max 92dB directly and drops to 82dB 12m away.

Identical sound wave can combine to create a larger wave and hence louder noise. However it is unlikely to occur with piling rigs due to the number of variances like ground conditions, machines, wind, obstacles etc. The peak noise level from four rigs is unlikely to be greater than that one rig. The duration and therefore exposer will change.

I do not believe you will find an answer to your question as noise is a very complex issue. The manufactures may have some data that may be useful but you may be better carrying out a survey.

Good responses so far.

I presume this information is needed either by the client or a part of the s61 application. The only way to get an exact noise reading is by engaging a noise consultant. There are several who specialise in construction related industries. As someone has mentioned, noise monitoring is a complicated business.

ps you don't mention what type of piling, so I presume it is percussion piling.