Hello PSTC, I'm listening..... I've been asked to respond re. Annex P2 of UL 1950/CSA 22.2 No. 950.
Your read of the Standard is correct. Components listed in Annex P2 that meet either the designated UL or CSA standard are considered to meet the requirements of UL 1950/CSA 22.2 No. 950. Also note for Insulating Systems that it is indicated (by symbol) that both UL 1446 and CSA 22.2 No. 0 meet or exceed the IEC 85 reguirements. All very interesting, but I think we should get back to the issue of testing insulation systems. Both CSA 22.2 No. 0 and IEC 85 indicate that incompatibility between materials should be considered when evaluating insulation systems. IEC 85 states, "On the other hand, problems of incompatibility between materials may decrease the appropriate temperature limit of the system below that for the individual materials. Such problems should be investigated by functional tests." Note that no insulation system tests are provided for either IEC 85 or CSA 22.2 No.0. A best quess by our local materials "guru" is that we experience failure rates of around 10% when testing systems using known materials to UL 1446. The rate is much higher for "uncommon" combinations and/or materials. This would tend to discount the theory that insulation system testing is not needed and/or has no value. Both CSA 22.2 No.0 and IEC 85 indicate that an evaluation is needed. UL 1446 provides a means supported by testing to make that evaluation. This doesn't mean that a UL 1446 evaluation is the only way to determine compatibility of materials within an insulation system. I'll leave the method up to you, but I strongly suggest that somehow a determination of compatibility be made. Disclaimer: The above reflect my personal opinions and interpretations and are not to be considered the "official" UL response. _________________________________________________________________ Bob M. Miller Underwriters Laboratories Inc. Voice : (408) 985-2400 x32382 1655 Scott Blvd. Fax: (408) 296-3256 Santa Clara, CA 95050 E-mail: [email protected] _________________________________________________________________
