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Posted By steve williamson
Our medical staff occasionally have to receive casualties from large helicopters. Whilst these handovers don't last very long I am told that they are very noisy. Can any of our military friends give an indication of what the sound level and frequencies involved are likely to be, or better still specify suitable hearing protection? Always something new in this job, isn't there! Thanks in anticipation.
Steve Williamson
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Posted By Paul Maddock
Steve, I haven't had any experience of dealing with helicopter noise, but I imaging the SPL and frequency would depend on the type of helicopter and the number of/speed of rotation of the rotors.
If you need to calculate the LEP,d in line with the Noise at Work Regulations, there's an usefull tool on the HSE website at:
http://www.hse.gov.uk/ht...ames/noise/noisecalc.xls
If you need to discuss this further please e-mail me.
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Posted By Ken Lucas
Steve
There was a thread set up recently on helicopters and landing etc - I think it might provide some useful information for you.
It is titled:
Landing requirements for helicopters, posted by Matt on Friday 9th August 2002 at 10.25.
Regards
Ken
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Posted By Bob Pedley
As an offshore worker we wore soft foam ear plugs when boarding helicopters and Peltor E7(I think)? earmuffs when in flight. Flights to the far north sea lasted from 45 mins to 1hr 30mins depending upon the weather.
For comfort I often kept the plugs in whilst wearing the muffs during the flight.
I could still hear the cabin information but reduced the noise level down to an acceptable level.
The helideck crew wore the same ear muffs during deck operations.
That was up to 1994/5. For further information try contacting Bristows or Bond helicopters at Aberdeen.
Bob
Bob
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Posted By lawrence baldwin
Steve
It depends what type of helicopters your guys are exposed to and to what the helicopter is doing at the time, If it is hovering, it is using more power and will be more noisy than if it is just sat on the ground with the rotors turning. The biggest helicopter we have for search and rescue purposes is on the military register the Seaking and on the civil register the S61. Both very identical to each other. We operate the S61 in both the civil transport role and the search and rescue role and a sound level reading for one of our S61's adjacent to the helicopter, beneath the disc, rotors engaged on the ground is 92 dB Laeq.The bigger the helicopter, does not mean that it is the noisiest.
I am assuming that this is infrequent so any hearing protection you supply that has a SNR figure (single noise reduction figure, this figure should be written on the general particulars from the manufacturer, either on separate instructions or on the packing)greater than 20 should be adequate. If the exposure is frequent throughout the day, then a noise assessment should be made to ascertain the daily noise dosage and specific hearing protection suitable for the octave bands should be identified. Please feel free to contact me if you require any further advice on this or helicopter operations in general.
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Posted By Laurie
I actually had to measure noise inside a helicopter cabin during my noise officer's course. It's nearly fifteen years ago now, but I seem to remember noise levels of around 104 - pretty hairy!
We wore the standard military hearing protection, and since this was designed to protect when stood next to a jet doing full throttle checks it was very effective. The specification/supplier should not be hard to find.
Bear in mind that at these sorts of frequencies/amplitudes noise can also be transmitted through the skull and other bony tissues and further protection may be required. Apart from simple noise, vibration may be a problem, adult females in particular may suffer severe pain in the breasts.
I'd be interested to know if this is a problem for female combat pilots/crews - this was an unknown species during my time!
Laurie
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