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#1 Posted : 08 February 2007 20:22:00(UTC)
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Posted By Tony Gladman
Hi

Can anybody expand in plain english on the requirements / specification of
'Type 2 Integrating Sound Level Meter'.
Been looking to buy but can't see to find what the specification actually is, other than suppliers quoting 'Type 2' or 'Intergrating'

TG
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#2 Posted : 09 February 2007 07:55:00(UTC)
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Posted By Booney
Morning Tony,

I'm no expert but, as I recall:

when you are measuring, a long term average is required so integrating is done by the meter to 'average' the sound it is measuring - this is because sound can and does fluctuate a lot.

Class 2 meters are slightly less accurate than class 1, usually due to the type of microphone the meter has.

Also, most meter suppliers are happy to demo their products and of course, their reps are very knowledgeable and you can glean a lot of information from them.

If you are going down the workplace noise route, I would recommend attending an approved course such as the Institute of Acoustics Certificate in Workplace Noise Assessment

Hope this helps

Kind Regards
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#3 Posted : 09 February 2007 08:09:00(UTC)
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Posted By John Cook
Tony

I am also looking to buy a meter at the moment. As the previous respondent stated you do need one which will give you the Leq reading. However I have also been advised that if you are looking to use it for a noise abatement programme and also to inform in relation to hearing protection then you will need the capability to carry out a frequency band analysis.

Occupational hygienist did state that for our purposes a type 2 meter would be sufficiently accurate.

John
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#4 Posted : 09 February 2007 10:53:00(UTC)
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Posted By Richie
Hello Tony,

In answer to your question, there are four types of Sound Level Meter, graded 0,1,2 & 3.

The Type 0 integrating sound level meter is normally used in laboratories as a reference standard (for instance to calibrate other SLMs).

Type 1 meters are rarely found as they would be used in laboratories and in the field where the acoustical environment can be closely specified / controlled, which is incredibly rare.

Type 2 Integrated Meters are the type most commonly used in the workplace. These are very versatile instruments hence their popularity. Measurement of industrial noise, community noise and average SPL from a noisy product (or other sound source) are able to be undertaken using a type 2 Integrated SLM, it's key aspects being it's ability to average noise over a given period, along with it's ability to emulate the human ear by way of weighting the sound received (designated A-Weighting). There are other optional weightings commonly found on these instruments but the important functions are Linear and A-Weighted.

Type 3 meters are used invariably for initial surveys, commonly fire & safety advisers carry these on their person to provide an indication of noise level, in the case of fire advisers this is really handy for ensuring minimum decibel levels, whilst in the case of safety advisers they are handy as an indicator when it is possible an in-depth survey is required.

Hope this helps.

Richie.
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#5 Posted : 12 February 2007 13:21:00(UTC)
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Posted By andrew morris
Just to disagree with the previous, Type 1 meters are the meter of choice and it is becoming increasingly rare for people who need to rely on their work for legal reasons to use a type 2. The spec doesn't matter as long as it gives you the functions you want and it states Type 1 or 2...
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#6 Posted : 13 February 2007 08:24:00(UTC)
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Posted By Adrian Watson
I agree with the above; whilst it is often stated that a type 2 SLM is adequate, I don't know of any occupational hygienists who don't use a type 1 meter. A type 1 meter has an error of approximately 1 dB and a type 2 meter an error of approximately 2 dB.

Regards Adrian Watson
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#7 Posted : 13 February 2007 13:19:00(UTC)
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Posted By Alan Hoskins
Hi Tony,

It really depends on what type of survey you are undertaking.

I understand why an occupational hygienist would use a type 1 meter, but for giving a general indication of noise levels a type 2 might well be sufficient and is cheaper.

The difference in accuracy does not initially appear to be great - +/- 1dBA or +/-2 dBA, but when you consider that 3dBA is a doubling of sound pressure it does have some significance.

Having the meter calculate the 8 hour time weighted average (Lepd) is a definite bonus.

You will need both A and C weighted scales. A is weighted to reflect the ear's response to the frequency spectrum and C (virtually linear) is used for measuring peak levels.

Octave band or third-octave band filters can also determine dominant frequencies, which is important information for designing any engineering control measures.

Alan
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#8 Posted : 13 February 2007 16:14:00(UTC)
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Posted By Bill Parkinson
Tony

Would suggest you make contact with Castle Group and tell them what you are trying to measure and why. They will then tell you whether you can achieve this with either a class 1 or class 2 meter.

They also speak plainly and you can hire the meters if required.

Would also suggest that if you are not aware of differences between the classes then you need some training (which Castle do as well).

By the way I do not work for them but have used a wide range of meters from a number of companies and they are good and easy to use.

Regards

Bill

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#9 Posted : 13 February 2007 16:18:00(UTC)
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Posted By Peter Leese
Happy to support that Bill. We're intending using them again. Lots of good advice given.
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#10 Posted : 13 February 2007 21:06:00(UTC)
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Posted By Tony Gladman
Thanks everyone who responded.
TG
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#11 Posted : 14 February 2007 08:47:00(UTC)
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Posted By Phil Brunton
Hi Tony,

I would suggest contacting Chris Gilbert at Acoustic Associates rather than Castle who after all are trying to sell their product.
Chris runs the courses for Castle group and would more likely give you impartial advice.

Also if you ever go to court a class 1 meter will have more grounds than a class 2.

Hope this helps.

Phil
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