The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: carykong on March 13, 2017, 09:41:36 PM

Title: Decibels for electric woodmizer
Post by: carykong on March 13, 2017, 09:41:36 PM
Hi Forum
Attempting to get zoning approval with the county for an electric Woodmizer.
Anyone know the decibel level while cutting?
Title: Re: Decibels for electric woodmizer
Post by: paul case on March 13, 2017, 11:01:26 PM
My  2 HP 220V sawdust blower is much louder than the mill.

Decibels I do not know.

PC
Title: Re: Decibels for electric woodmizer
Post by: thecfarm on March 14, 2017, 06:28:16 AM
I have no idea.
But for someone to give a guess,what size?
Can't be much. I betcha a riding lawn mower is louder.
Title: Re: Decibels for electric woodmizer
Post by: bandmiller2 on March 14, 2017, 07:25:09 AM
Kong, I would just call WM I'am sure they would have a good idea as their mills are used indoors in industrial setting. Frank C.
Title: Re: Decibels for electric woodmizer
Post by: MartyParsons on March 14, 2017, 08:28:38 AM
Hello,
There is nothing listed for the electric 25 hp motor. The diesel is around 89.
I have one E25 at our location but have no way to measure it for you. You are welcome to come and do a test.
Marty
Title: Re: Decibels for electric woodmizer
Post by: Raider Bill on March 14, 2017, 09:54:03 AM
You can get a free app for your smart phone that will measure it.
Title: Re: Decibels for electric woodmizer
Post by: carykong on March 14, 2017, 10:40:54 AM
Good suggestions
Just followed your lead and download the free decibel meter app
Have a colleague close by that has an electric wm
Will advise on results
Title: Re: Decibels for electric woodmizer
Post by: ScottCC on March 14, 2017, 06:23:23 PM
My neighbor was concerned across the field what noise level would be when I started using it, he was two weeks late.  So the next Sunday morning I gave it another test.  Still nothing!  I wish he would keep his dog quiet.🙊
Title: Re: Decibels for electric woodmizer
Post by: Brucer on March 15, 2017, 12:20:10 AM
When you're collecting sound information (and before you pass it on to anyone else) be sure you understand what you're dealing with. A decibel isn't a unit of measure, it's a ratio.

Manufacturers will nearly always give you the Sound Power level measured in decibels (relative to 10-12 Watts if you want to get technical). It's the amount of power that is converted to sound by their product, (but it's not what you hear).

Regulations usually deal with what people actually hear, which is the pressure wave created by the equipment. This is the Sound Pressure level measured in decibels (relative to 20 microPascals if you want to get technical).

So how do you convert one to the other? It's not simple. Sound pressure depends on how much of the sound gets to your ears.

This is complicated even further because sound occurs over a wide range of frequencies and the human ear damps out some frequencies better than others. There are different weighting scales that compensate for this and you need to know which one is being used (A, B, or C).

If the manufacturer actually gives you a sound pressure level, you have to know under what conditions it's measured (open field, enclosed), at what distance, and what scale is being used. Then you have to figure out what the sound pressure at your property line will actually be.

Whew. Generally speaking electric motors are pretty quiet -- way quieter than diesel engines. Usually the saw in the wood makes more noise.

Sometimes the best thing to do is measure an existing unit under similar conditions to what you will be using yours.
Title: Re: Decibels for electric woodmizer
Post by: Magicman on March 15, 2017, 08:44:13 AM
And to add to what Bruce stated above, Decibel (dB) readings are not linear ie, twice the noise level doesn't double the dB reading:

On the decibel scale, the smallest audible sound (near total silence) is 0 dB. A sound 10 times more powerful is 10 dB. A sound 100 times more powerful than near total silence is 20 dB. A sound 1,000 times more powerful than near total silence is 30 dB. Here are some common sounds and their decibel ratings:

Near total silence - 0 dB
A whisper - 15 dB
Normal conversation - 60 dB
A lawnmower - 90 dB
A car horn - 110 dB
A rock concert or a jet engine - 120 dB
A gunshot or firecracker - 140 dB

Also all dB reading require a reference point.  The dB level is the amount of noise (sound) above that know reference point.  As Bruce stated above, db is not a unit of measure, but a ratio.

In a former life (telephone industry) taking dB readings was a vital part of my job.  100 mw (C) was our "0" reference.



Title: Re: Decibels for electric woodmizer
Post by: fat olde elf on March 15, 2017, 02:36:15 PM
The Magicman knows a lot about magic........
Title: Re: Decibels for electric woodmizer
Post by: GDinMaine on March 15, 2017, 09:31:31 PM
Be aware that the sound level metering app on a smartphone may not be accurate at all. I once saw the comparison of phone app decibel reading next to an official decibel meter used in OSHA applications. They were quite different. I was looking at the two devices side-by-side and the phone showed 20db higher. You need to ask what kind of device they will measure the noise level with, if they will come out to do so.
Title: Re: Decibels for electric woodmizer
Post by: Magicman on March 15, 2017, 10:17:21 PM
And also whoever takes the readings with whatever they do it with will have no earthly idea what they are doing.  It will probably be the "permit man".  Whoopee!
Title: Re: Decibels for electric woodmizer
Post by: Brucer on March 16, 2017, 09:49:35 PM
My experience was in the fan industry. We used a meter that would measure sound in 8 different octave bands; you had to take readings in all 8 bands, record them and do the math to combine them into one number.

We measured the noise levels produced by the various fans in our research facility, then converted them to sound power levels to put in our specification sheets.

We also made a great many field calls to show customers that our fans were, in fact, generating exactly the amount of sound we said they were. (Note to customers: you can't put 4 fans in one fully enclosed concrete building and expect them to produce the same noise level that a single fan would produce in an open field.  :D)

Sometimes we'd have to ask the customer to turn off other machinery in the room so we could take our readings. Funny thing, the room got a whole lot quieter. "Oh, maybe it wasn't the fan after all."  ::)

As far as consistent readings go, we sent our meter out once a year to be checked and recalibrated if necessary.
Title: Re: Decibels for electric woodmizer
Post by: wesdor on March 22, 2017, 04:29:43 PM
Decibel Meter is FREE today if you have an Apple Device.  Not sure about other platforms but you should check.

I just downloaded but haven't had a chance to try it out. At least the price is right.