I am currently researching a high hazard task, involving the use of reciprocating pneumatic tools, inside a confined space. (Essentially a small silo through which production materials transit). During maintenance, the operator has to break out build up of old material for removal with a jack hammer. I am researching the exposure of the operator to vibration and noise. Vibration is reasonably straightforward but noise exposure is harder to assess. Can anybody help me please with some pointers to research material on the effect of a confined space on noise generation? The tools generate 100dB in the open, so what happens when you use them in a confined space? What level of hearing protection will be required and what will be the effects on limits of exposure duration? Has anyone independently researched / tested this?

Or use the Cardox system and clear it from outside the silo without any risk. We use it extensively in Commercial diving for underwater demolition, but it started life as a product for clearing silos of blockages and for maintenance. PM me if you need any more details. Phil

Also meant to add: it was the thread title that attracted me. A simple "noise" title may have failed.

Thanks for the feedback everyone. We can't just measure the noise because the silo has material running through it at hunderds of degrees C and takes days to cool down. It's only accessible twice a year during a planned maintenance shutdown. So we need a riask management plan ready to go before the next shutdown in five months time, so that we don't hold up the contractors. Hence I am looking to see if there are any research papers or other test results available comparing external and internal noise levels for pneumatic tools, this way we can make an initial plan for risk management and then measure and monitor the ongoing risk during the job, and change the plan as necessary. Cheers, KJT.

Whilst I don't want to disrespect Cardox, as it has some great uses, but as an ex-user of Cardox, it is not risk free. One of the tubes we used fragmented and it was only by complete luck someone was not badly hurt. If you do use it make sure you use plenty of ignition cable so that every one is standing out of the line of fire. We never did find the ignition end of the tube, only the hole in the roof!! This was reportable to the HSE under RIDDOR "Pressure Vessels". If you are having to use a jack hammer to remove the build up from the inside, I doubt if Cardox would remove it. On the subject of Noise, use the best hearing protection you can and measure the db whilst the task is being done for a short time then change the protection if not enough. Using ear plugs inside ear defenders can reduce the noise a little more to be on the safe side. Paul