Be careful when choosing your "Seismic Rated Rack". I had the
misfortune of purchasing such a rack for a test and had the thing come apart
at the seams. My product held up great, but watching this thing increase in
displacement as we got further into the testing was a scary sight. I
eventually changed to another vendor as recommended by my lab and
experienced a world of difference. I sent photos of the results to the
vendor and they refunded my money, but that's a small portion of the costs
incurred.
Thx,
Joe
-----Original Message-----
From: randolph.j.iv...@us.ul.com [mailto:randolph.j.iv...@us.ul.com]
Sent: Wednesday, February 13, 2002 1:32 PM
To: nebs@world.std.com
Subject: RE: GR-63 Seismic
I agree with Dave. The test of a shelf level unit is only intended to be
representative of a typical installation. Unless you can test the actual
configuration of the entire rack there are too many variables, the rack
itself being only one of them. The weights used (flat plate, round,etc.),
the weight distribution (top to bottom, side to side and back to front) and
the weight mounting (stiff multipoint mounting of weight plates will
stiffen the whole rack while center point mounting of gym weights on a
shelf could add to the movement) all contribute a lot to the test
variations and rack movement during the test. Add to this the fact that the
weight distribution and the weight itself is unlikely to match the final
installation and you can see why the specific rack used is not so critical
as long as it is designed to withstand seismic forces itself (a "seismic
rated rack").
Here at UL we test shelf units in a seismic rated rack, weigh it down as
Dave describes and specify the test configuration in our NEBS reports. We
have never had a problem with the tests/test reports being accepted by the
RBOC community.
Randy Ivans
Global Program Manager -Telecommunications
Underwriters Laboratories Inc.
1285 Walt Whitman Rd.
Melville, NY 11747
TEL: 631-271-6200; Ext. 22269
Department FAX: 631-439-6096
Direct FAX: 631-439-6131
email: randolph.j.iv...@us.ul.com
David Spencer
<dspencer@oresis. To: "'nebs@world.std.com'"
com> <nebs@world.std.com>
Sent by: cc:
nebs-approval@wor Subject: RE: GR-63 Seismic
ld.std.com
02/13/02 12:38 PM
Please respond to
nebs
Hi Scott,
It is not necessary to quantify the use data for self-level equipment. The
racks on hand in CO's are purchased because they meet the requirements of
that installation and the test data for those racks is reviewed just as
rigorously as the data on the equipment that goes into them. Your mandate
is to ensure that the tests your unit are subjected meet the test criteria.
For your self-level unit, the intent of the test is to assertion the
operational performance under seismic stress in the worst possible
'typical'
installation. Consequently, your unit should be placed at the top of an
unequal-flange seismic rack where the deflection is greatest. The rack,
per
GR63 section 5.4.1.3, should be fully loaded with dummy weights to ensure
it
duplicates the mass and stiffness of a fully loaded rack. Additional
weights are place on top of the rack to simulate cable weight.
The test plan should be approved by an RBOC SME, such as Larry Wong or one
of his designates at SBC, prior to running the test. CA has the biggest
threat and they know what "representative" means to them. The test report
will show that the unit has been tested with an approved zone 4 rack and
load configuration.
If your test lab doesn't have test plans approved prior to testing, get
another lab. The going rate for repeating a seismic test is too high to
have to do it twice because someone didn't have a plan approved.
The contact information I have for Larry Wong is a little dated, e.g. no
guarantees:
lxwo...@msg.pacbell.com
925 823-4544
Have a Great Day!
Dave Spencer
Oresis Communications
-----Original Message-----
From: Scott Lemon [mailto:sle...@caspiannetworks.com]
Sent: Wednesday, February 13, 2002 8:35 AM
To: nebs@world.std.com
Subject: Re: GR-63 Seismic
This has been my experience too in talking with test labs. Maybe this is
the generally accepted way?.?.? Are you guys addressing this in any way in
your user/customer docs (e.g. only tested for compliance in Hendry, model
xyz, etc.)??
Naftali Shani wrote:
> Sounds like the CE + CE = CE?
>
> In my limited experience with the 1 product tested so far NOT in its
> normally installed rack, the lab did just that (generic Hendry).
>
> Regards,
> Naftali Shani, Catena Networks (www.catena.com)
> 307 Legget Drive, Kanata, Ontario, Canada K2K 3C8
> 613.599.6430/866.2CATENA (X.8277); C 295.7042; F 599.0445
> E-mail: nsh...@catena.com
>
> -----Original Message-----
> From: Scott Lemon [mailto:sle...@caspiannetworks.com]
> Sent: Wednesday, February 13, 2002 10:19 AM
> To: Nebs (E-mail)
> Subject: GR-63 Seismic
>
> Greetings Nebs group,
>
> I am interested in the general consensus with respect to one aspect of
> seismic testing of rack mounted equipment....
>
> If a shelf-based system, which is designed to be installed in any
> seismic approved rack assembly (e.g. 19"), is seismic tested in a
> particular rack (e.g. Newton), is the performance normally extrapolated
> to be representative of installation in any generally "seismic approved"
> 19" rack (e.g. Hendry, tested by rack manuf with dummy loads, etc.)??
> In other words, is GR-63 seismic compliance for the shelf system linked
> only to the rack in which it was tested, or will any generally tested
> GR-63 "seismic approved" rack suffice?
>
> Any and all opinions welcome.
>
> Thanks,
> Scott
>
> --
> Regards,
>
> Scott Lemon
> CASPIAN NETWORKS
> sle...@caspiannetworks.com
> www.caspiannetworks.com
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