Mel Pedersen wrote:
>
> Forgot to forward this to newsgroup. - Mel
>
> ----------
> From: Mel Pedersen[SMTP:mpeder...@midcom.anza.com]
> Sent: Thursday, March 19, 1998 9:18 AM
> To: 'Peter E. Perkins'
> Subject: RE: more Recognized Plastics Directory
>
> Hello Peter,
>
> Your point is well taken, however, I am not interested in flammability data.
> I am curious about differences in the Thermal Index ratings given by European
> agencies versus UL.
>
>
>
> Also, when a manufacturer advertises a temperature rating in their catalog,
> they often don't specify at what thickness that rating is for, or other
> relevant information. That is why I am looking for a "European" recognized
> component directory.
>
> Thanks Peter. Any other thoughts would be appreciated.
>
> Mel Pedersen Midcom, Inc.
> Homologations Engineer Phone: (605) 882-8535
> mpeder...@midcom.anza.com Fax: (605) 886-6752
>
> ----------
> From: Peter E. Perkins[SMTP:peperk...@compuserve.com]
> Sent: Thursday, March 19, 1998 12:44 AM
> To: PSNetwork
> Subject: more Recognized Plastics Directory
>
> PSNet - including Mel Pedersen...
>
> Why would you, Mel, look any other place then to UL for a Plastics
> Recognized Component Directory? From the beginning of their history UL has
> focused on fire prevention in electrical installations and equipment. This
> focus has been reinforced because of the North American use of lower
> voltage for commercial and residential systems than those used in Europe
> and much of the rest of the world. This lower voltage (V/2) draws a higher
> current (2xI) which leads to 4x the heating effect (remember I**2 x R) and,
> historically, more fires in equipment and installations. This UL focus
> joined with the other forces at work within UL to develop methods for
> pre-qualification of plastic materials for use in installation components
> (wiring, switches, outlets etc) and equipment. Thus, the world's largest
> public database - the UL Plastics Recognized Component Directory.
>
> The European approach (until more recently) was not to qualify
> materials, but qualify parts and pieces of construction using tests such as
> the Oxygen Index test on finished pieces. This methodology meant that the
> same material used in another configuration would be tested again and
> again. So there is plenty of European data, but it doesn't seem to be
> published in any useable form available to worldwide users.
>
> With the ongoing harmonization of standards on a worldwide basis,
> even the Europeans recognize the benefit of pre-qualification of materials
> and have been accepting this approach in many standards... IEC 950 and IEC
> 1010 make heavy use of these prequalified materials to demonstrate adequacy
> in any application... Moreover, over the last 20 or more years, UL has
> been quietly moving their requirements into IEC (e.g. IEC 60674 -1, 2,
> 3-2,3-3, 3-4 to 6, 3-7 (and European standards)) so that the UL database is
> now more important than ever in showing compliance to the requirements
> stated in the standards... Further, plastics manufacturers worldwide
> submit their materials to UL for evaluation enlarging the usefulness of
> this database.
>
> There is some competition, CSA publishes a directory...
> CAN/CSA-C22.2 No. 0.17-92 (R1997) evaluation of Properties of Polymeric
> Materials. The Canadian requirements shadow the UL requirements. They
> have been accepting materials for evaluation for the last 10 years or so.
> The last CSA directory I used was quite a bit thinner than the UL
> directory...
>
> Well, I didn't intend for this to be a UL sales pitch, but do
> believe that their large database will be the basis of choice for selection
> of plastics materials for use in equipment meeting worldwide requirements.
>
> - - - - -
>
> Peter E Perkins
> Principal Product Safety Consultant
> Tigard, ORe 97281-3427
>
> +1/503/452-1201 phone/fax
>
> p.perk...@ieee.org email
>
> visit our website:
>
> http://ourworld.compuserve.com/homepages/peperkins
>
> - - - - -
Mel,
You are on the right track... UL's RTIs are determined by many factors,
including thickness, where the material will be used, how the material
will be used, and how the material matches up to similar material used
in a similar fashion (the control). These are just the basic factors.
This is how the same material can get many different RTIs at different
thicknesses, or even the same thickness.
A manufacturer's temperature claim could be anything, possibly just the
temperature where the material starts to physically degrade (whatever
that means,ie starts to melt, flow, discolor, get brittle????).
I don't know personally of any European directories, but perhaps you may
wish to email Larry Bruno or Steve Giannoni at UL's Plastics Group in
NY. They have/had a hand in their plastics seminars and the development
of UL's RTI program. Their emails are bru...@ul.com and
gianno...@ul.com.
If you write them, say "hello" for me. I haven't talked to them for
awhile...
Regards,
Bob Tims
Compliance Engineer
Ericsson Messaging Systems Inc.
