Underwater noise question

Underwater noise question

Post by Steve » Mon, 30 Apr 2012 01:14:12


I am dealing with an unusual underwater question.  I am building some
underwater gold equipment.  This will have a large *** on it, that
weighs approximately 30#.  It generates 950# impact.  It is rated at
approximately 95 db noise when operated on the surface in air.  There is a
model available that has slightly less impact, and 20-25% less noise that I
could use, but it is 30% more in cost.

I have dove for a very long time, both scuba and commercially, but I am at a
loss to know what the effect will be underwater.  The operator will be
within six feet of the underwater unit while in use, and for the most part
cannot distance himself from it.  The use will be intermittent, operated by
a hand valve, meaning on/off, on/off, and sometimes on for a couple of
minutes at a time.

I have used underwater scalers, water blasters, air chisels, jetting
nozzles, and other devices, and can't recall ever being uncomfortable
underwater with the noise levels.  But then, I am about as deaf as a lemur
right now, and wear hearing aids, but that has to do with huge overexposure
to industrial noise over the years, and improper safety equipment.

Do you think that this will be uncomfortable for the underwater operator?
Will the noise amplify or deaden?   Will the water absorb enough of the
decibels to bring it under the 85db OSHA limits?  I do not know if it would
be possible because of equalization issues for a person to even wear the big
ear muff type hearing protectors underwater if the noise were to be too
much.  Probably enough water and air could go around the edges to make
equalization not to be an issue.

What do you think?  Use the noisy one, or get the quieter one and pay the
money?  Or will the noise be an issue at all?

Thanks.

Steve

 
 
 

Underwater noise question

Post by Steve » Mon, 30 Apr 2012 01:26:42


Quote:
>I am dealing with an unusual underwater question.  I am building some
>underwater gold equipment.  This will have a large *** on it, that
>weighs approximately 30#.  It generates 950# impact.  It is rated at
>approximately 95 db noise when operated on the surface in air.  There is a
>model available that has slightly less impact, and 20-25% less noise that I
>could use, but it is 30% more in cost.

> I have dove for a very long time, both scuba and commercially, but I am at
> a loss to know what the effect will be underwater.  The operator will be
> within six feet of the underwater unit while in use, and for the most part
> cannot distance himself from it.  The use will be intermittent, operated
> by a hand valve, meaning on/off, on/off, and sometimes on for a couple of
> minutes at a time.

> I have used underwater scalers, water blasters, air chisels, jetting
> nozzles, and other devices, and can't recall ever being uncomfortable
> underwater with the noise levels.  But then, I am about as deaf as a lemur
> right now, and wear hearing aids, but that has to do with huge
> overexposure to industrial noise over the years, and improper safety
> equipment.

> Do you think that this will be uncomfortable for the underwater operator?
> Will the noise amplify or deaden?   Will the water absorb enough of the
> decibels to bring it under the 85db OSHA limits?  I do not know if it
> would be possible because of equalization issues for a person to even wear
> the big ear muff type hearing protectors underwater if the noise were to
> be too much.  Probably enough water and air could go around the edges to
> make equalization not to be an issue.

> What do you think?  Use the noisy one, or get the quieter one and pay the
> money?  Or will the noise be an issue at all?

> Thanks.

> Steve

Duh, I forgot to add ......... the diver would be fully hooded all the time.
This will be in the 37 F. degree water of Nome, Alaska.  In some cases, the
diver would be wearing a hard hat.  But in all cases, at least a hood, and a
spider to hold the mask in place.  For me, I don't think the sound will be
an issue at all, but wanted to ask.

BTW, the sound will be made in an enclosed chamber, and there will be no
membrane to transfer any movement of a shock wave into the adjoining water.
It will just be the mechanical clanking of the vibrating piston inside, and
only the vibrations of that reach the water.

Steve

 
 
 

Underwater noise question

Post by dechuck » Mon, 30 Apr 2012 07:19:32


Quote:



>>I am dealing with an unusual underwater question.  I am building some
>>underwater gold equipment.  This will have a large *** on it, that
>>weighs approximately 30#.  It generates 950# impact.  It is rated at
>>approximately 95 db noise when operated on the surface in air.  There is a
>>model available that has slightly less impact, and 20-25% less noise that
>>I could use, but it is 30% more in cost.

>> I have dove for a very long time, both scuba and commercially, but I am
>> at a loss to know what the effect will be underwater.  The operator will
>> be within six feet of the underwater unit while in use, and for the most
>> part cannot distance himself from it.  The use will be intermittent,
>> operated by a hand valve, meaning on/off, on/off, and sometimes on for a
>> couple of minutes at a time.

>> I have used underwater scalers, water blasters, air chisels, jetting
>> nozzles, and other devices, and can't recall ever being uncomfortable
>> underwater with the noise levels.  But then, I am about as deaf as a
>> lemur right now, and wear hearing aids, but that has to do with huge
>> overexposure to industrial noise over the years, and improper safety
>> equipment.

>> Do you think that this will be uncomfortable for the underwater operator?
>> Will the noise amplify or deaden?   Will the water absorb enough of the
>> decibels to bring it under the 85db OSHA limits?  I do not know if it
>> would be possible because of equalization issues for a person to even
>> wear the big ear muff type hearing protectors underwater if the noise
>> were to be too much.  Probably enough water and air could go around the
>> edges to make equalization not to be an issue.

>> What do you think?  Use the noisy one, or get the quieter one and pay the
>> money?  Or will the noise be an issue at all?

>> Thanks.

>> Steve

> Duh, I forgot to add ......... the diver would be fully hooded all the
> time. This will be in the 37 F. degree water of Nome, Alaska.  In some
> cases, the diver would be wearing a hard hat.  But in all cases, at least
> a hood, and a spider to hold the mask in place.  For me, I don't think the
> sound will be an issue at all, but wanted to ask.

> BTW, the sound will be made in an enclosed chamber, and there will be no
> membrane to transfer any movement of a shock wave into the adjoining
> water. It will just be the mechanical clanking of the vibrating piston
> inside, and only the vibrations of that reach the water.

ears will be fine but their organs will vibrate till they are jelly :-) .

 
 
 

Underwater noise question

Post by Steve » Mon, 30 Apr 2012 08:58:51


Quote:
> ears will be fine but their organs will vibrate till they are jelly :-) .

I found a British study on specifically occupational diver noise in the
water.  They describe the phenomenon of "wet ear" where anyone who is
underwater has water most likely obstructing their ear c***or at least
partially.  Then there's the hood.  It said that a 35-40 db reduction in
sound can be expected.

The operational range of this tool is 106 db, higher than the 85 db topside
OSHA threshold, so with the dampening, it would be very acceptable.

This device is sealed.  It transfers energy by impact, and is attached to
hoppers, etc, to get product moving through the chutes.  There is no
concussion transferred to surrounding water, just noise.

I had to Google a good bit, but I found it.  In case you might like to see
it, it is quite interesting as it applies to diving.

http://SportToday.org/

Steve

 
 
 

Underwater noise question

Post by Steve » Mon, 30 Apr 2012 09:01:04

Sorry, page 8 of the British study.

Steve

 
 
 

Underwater noise question

Post by JRE » Mon, 30 Apr 2012 21:45:56

<snip>

Quote:

> I had to Google a good bit, but I found it.  In case you might like to see
> it, it is quite interesting as it applies to diving.

> http://www.hse.gov.uk/research/rrpdf/rr735.pdf

Wow, thanks for posting!

--
John

 
 
 

Underwater noise question

Post by Grumman-58 » Sun, 06 May 2012 02:37:50

If you are hard hat diving, the foam ear plugs will work... They still let
air through, so equalization should not be a problem...