Sorry to send you two of these Ed but after getting excited about
remembering the actual Name of B & K I nodded off for a minute.
Yes, I think you're going to have trouble verifying the noise
level because of the background stuff. Including the rumbling of trucks,
forklifts and the like. I would put even money that the only way you
would be able to do so is to actually take the fan into its own acoustic
chamber which is obviously isolated from the outside world and to run
the test. Other than that measure in the middle of the night. You still
won't know what noise is coming from the fan and what is coming from
around the area but if the sound level is 53dBA you can reasonable say
that the fan noise is at least that quiet.
I've been wrong before and I suspect somebody out there is about
to tell me it has happened again, but I have more free advice if you
need it.
Gary
-----Original Message-----
From: Gary McInturff
Sent: Friday, August 28, 1998 7:19 AM
To: '[email protected]'; EMC-PSTC
Subject: RE: Acoustic Emissions
Ed,
I think our European friends may be able to direct us to
a standard, but I can't remember it right now. Having not made those
measurements in some time if forget which standards discuss them. When I
was making those measurements the levels were standards for office noise
of 55dBA for office environments and 70 dBA (I think) for other areas.
Bruel & Kjaer makes many sound measuring devices. There home page pretty
much sucks but here it is http://www.bkhome.com/btg_hp1.html
<http://www.bkhome.com/btg_hp1.html> There equipment is better than
their web presentation. They may also be able to point you at the
correct standards.
Gary McInturff
-----Original Message-----
From: [email protected] [SMTP:[email protected]]
Sent: Thursday, August 27, 1998 4:52 PM
To: EMC-PSTC
Subject: Acoustic Emissions
My plant facilities engineer just asked me if I knew
anything about acoustic noise testing. (The answer is; very little.)
He said that he was thinking about buying some
clean-room air cleaners. These are self-powered particulate filters
which mount into a drop ceiling. He said that the salesman told him that
the filters had a "53dBA sound level", measured 30" from the fan grill,
at 90 FPM flow rate. He wanted to know if I could verify that level
after installation.
First, can anyone point me to any applicable light
industrial sound level spec? Maybe OSHA or Cal/OSHA. Or is there some
voluntary industry standard? Does what I described above sound familiar?
Second, 53dBA sounds (oops) really quiet to me. A few
years ago, I measured the sound level in an RF anechoic room. IIRC, I
found about 55dBA. So 53dBA (from a filter/blower) must be REALLY quiet.
Maybe it wouldn't be possible to prove this low a level because of
ambient noise (other air handlers, transformer hum, outside traffic and
fluorescent lights). Any comments?
TIA,
Ed
--------------------------
Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
619-505-2780
Date: 08/27/1998
Time: 15:51:51
--------------------------
---------
This message is coming from the emc-pstc discussion
list.
To cancel your subscription, send mail to
[email protected]
with the single line: "unsubscribe emc-pstc" (without
the
quotes). For help, send mail to [email protected],
[email protected], or [email protected] (the list
administrators).
---------
This message is coming from the emc-pstc discussion list.
To cancel your subscription, send mail to [email protected]
with the single line: "unsubscribe emc-pstc" (without the
quotes). For help, send mail to [email protected],
[email protected], or [email protected] (the list
administrators).
