Re: Question about acceptable noise/vibration

[Neil Todd <TODD@xxxxxxxxxxxxxxxxx>]

>Date:    Fri, 23 Jun 2006 04:05:43 -0700
>From:    Daniel Levitin <levitin@CCRMA.STANFORD.EDU>
>Subject: Question about acceptable noise/vibration levels in workplace
>
>Dear list,
>
>Al Bregman and I are experiencing problems with vibration and noise
>in our building at McGill.  The problems have arisen gradually, and
>appear to be the result of damaged damping and isolating systems on
>ventilation machinery that is on the floor directly above our
>workspaces.  We have been asked to supply our Facilities maintenance
>people with exact figures on what we consider acceptable levels based
>on "industry norms" and "standard practice."
>
>We took the following readings with a hand-held, relatively
>inexpensive decibel meter:
>
>Location                       A-weighting  B-weighting     C-weighting
>Bregman's office             52                62                    74
>Bregman's lab                  51                62                    70
>Levitin's office               46                57                    68
>
Robert E. Remez" wrote:
>
> Dear Dan and Al:
>
> The WHO report, Guidelines for Community Noise, can be found at:
>
>         http://www.who.int/peh/noise/noiseindex.html
>
> The report is more appropriate for your purpose (protecting the
> tranquility of  the workplace) than the OSHA Program for Hearing
> Conservation, for instance, or other standards that stem solely from
> health considerations. Basically, the levels of exposure that impair
> the auditory system are far higher than the levels that simply impair
>
> performance in the workplace, and you will want to impose the latter
> standard rather than the former. The WHO standard for an office,

Dear Dan,  Al and List

In addition to the various factors discussed above the frequency distribution
is also important in determining the annoyance of a noise. Industrial noise tends
to have a rather flat spectrum, whereas 'musical' noise tends to predominate
in low-frequencies, particularly any seismic component. This can make all the
difference between a 'pleasurable' (for some) experience and one that is extremely
unpleasant, especially at SPLs often in excess of 120 dB A-weighting. In recent
investigations of dance clubs and bars in Manchester, to recall one anecdote,
I came across a bar owner who complained bitterly about one DJ who had the PA so
loud that it was distorting (clearly underpowered, and thereby producing lots of
unpleasant high frequencies). Normally mild mannered punters were transformed into
raging beasts causing great havoc all round.

For a properly engineered club environment though,  the UK Health and Safety
Executive  guideline of  90 dB LEQ (equivalent continuous level) also seems
inappropriate.  It just isn't loud enough!

Cheers

Neil