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ER noise level

Posted: Fri Aug 02, 2019 4:04 pm
by The Dieselduck
Anyone have any research or documentation on engine room noise. What is the decibel level for the average medium speed (800 rpm) engine room for something like a large coast guard patrol boat - i estimate around 120 decibels, anyone have any better numbers?

Re: ER noise level

Posted: Sat Aug 03, 2019 2:31 am
by Merlyn
Depends where you are standing and if your ear defenders are working 100%
But don't worry, get enough hours in down below and you'll be like me losing it a bit in one ear.
Has its good points when on leave taking a bollocking from the wife and you develop that knack of hearing only the good news.
Or forgetting something and blaming it on all those hours spent not in the control room but out on the job in the ER,
This of course proves beyond all doubt that you are a proper marine engineer and not a control room dweller.
( i.e. A bus conductor type character as I have mentioned before )
Just thought I would mention it so you have something to look forward to in life.

Re: ER noise level

Posted: Sat Aug 03, 2019 9:36 pm
by Merlyn
Way back when I measured engine noise levels by downloading an android app.from the net on my mobile phone. measured ER noise levels no probs.
Brain just remembered

Re: ER noise level

Posted: Sat Aug 03, 2019 11:37 pm
by Big Pete
A lot of noise can be eliminated by good design, it is always too high, I don't think that there is an acceptably high level of noise, it all causes long term damage to your hearing.
Reducing structural transmission of noise/vibration helps, such as with Diesel Electric ships where the generator sets are mounted resiliently. Acoustic enclosures for high noise machinery such as air compressors helps. Proper maintenance of the rubber seals on doors around the machinery spaces stops noise leaking into the Control Room, workshop and accommodation. Use of Soft sound absorbent material would help, I am not suggesting scatter cushions and curtains everywhere, but in a house they make a huge difference, as anyone who has been round an empty house and come back when it is furnished can tell you. Years ago a system was developed that had microphones all round noisy spaces that picked up the noise, shifted it out of phase and re broadcast it, so that the Broadcast sound waves cancelled out the natural ones, worked very well on trials but was never adopted, probably too expensive and if it went wrong it could have doubled the noise level!

BP.

Re: ER noise level

Posted: Tue Aug 06, 2019 6:19 am
by JK
Ha, noise levels, we went all through that with one of our older ships.
It depends on :
propeller noise
auxiliaries
turbos,
silencers,
exhaust gas system spring hangers
ventilation, supply and exhaust
hydraulics
reduction gears
insulation,
piping and pipe supports
resilient mounts and isolation

Those patrol vessels with go fast engines seem to be the noisiest ones.

Does it translate to a noisy accommodations or messrooms? If it is over MOSH requirements, then something is required to be done.

Re: ER noise level

Posted: Wed Aug 07, 2019 12:46 am
by Merlyn
And RPM
I reckon those squirters are the worst.
Up on the top end of the governors for most of their lives.
Screamers all day X 4 of 'em performing ( well down to 3 a lot of times )

Re: ER noise level

Posted: Tue Aug 20, 2019 10:07 pm
by camshaft
Martin, I'm thinking that by average engine room level you don't mean the average of a bunch of different locations in an engine room but the expected noise level for a given engine installation? I only have figures from memory and engineers who are working should have real numbers because these are supposed to be regularly measured and the readings supplied to the worksite.
What I recall is standing close between two 900 RPM two stroke engines was about 118 decibels. Between a couple of 500 or 900 RPM four strokes is more like 110 - 115 decibels. This was where the highest levels were (I think that's right where Merlyn is standing in his avatar? - with no ear protection). I think your 120 decibel guess is pretty good but maybe a bit high as I don't recall ever seeing anything that high, although screaming kilowatts in a small engine room could be there.
Speaking of which, everyone called them "Screaming Jimmies" but I never thought they were that bad.

Re: ER noise level

Posted: Wed Aug 28, 2019 5:10 pm
by JollyJack
GM 58 and 71 series engines were called screaming Jimmies, the blowers really didn't have any noise suppression.

The Halifax class frigates has extensive noise suppression. On sound trials, the hydrophone people had to reset lower limits several times, because ships passing off Halifax were drowning out the frigate's noise! On exercise with the yanks, the Halifax was completely invisible, no sonar, no IR signature, radar returns showed as clutter. We built a goodun in St John. 6 ships, contract came in under budget and before time. Then Irving shut the yard down to break the Union.

Re: ER noise level

Posted: Thu Aug 29, 2019 8:22 pm
by The Dieselduck
One of my first work experiences was working at the Victoria Fire Dept, and we had to go and get al old detroit powered ladder truck from Vancouver. Man, I was grinning ear to ear, driving down the street, setting off every car alarm there was. That thing was really loud. The Chief mechanic said the engine had no restrictions and was made to get the truck to the fire asap, damn any noise or whatever else restrictions. I have worked with many detroits since, but none seemed louder than that one, certainly earned the "screaming jimmy" moniker in my view.

Re: ER noise level

Posted: Wed Sep 04, 2019 5:12 am
by JK
As a project manager, I sure gained some respect for the detroits. We would disassemble them and they would be running with cracked bottom ends and worn right out. If you could get them started, they kept going. I've also spend many a cold morning cursing them on barges as they needed a fire to get them going. lol

Re: ER noise level

Posted: Sat Nov 16, 2019 7:03 am
by D Winsor
It's not only the enginerooms are noisy I've been on Self Unloading Bulk Carriers that when the Unloading Gear was running the Noise level was higher in the cabins than the Engineroom. So for some crew there was no escaping noise in excess of 90 DB