forwarded for Steve Williams. -------- Original Message -------- Subject: Re: RTI on Plastics List-Post: emc-pstc@listserv.ieee.org Date: Tue, 2 Oct 2001 10:56:00 -0400 From: steve.willi...@apcc.com To: tony.reyno...@pb.com CC: emc-p...@ieee.org, owner-emc-p...@majordomo.ieee.org
Tony, some background UL sets the world standards on plastic and they look at alot more than just flammability. So, the RTI issue is a UL 1950 issue. Now, I took a two day seminar to learn all of UL's crazy plastic requirements (very boring but useful). Here is how RTI ratings work. The actual temperature of the plastic part in question has to be measured. The RTI has to be greater than or equal to the temp measured during test. Now, here is the tough thing. Your plastic has an RTI of 60. What this means is that it has never been tested (UL assigns a generic rating of 60C to ABS and my guess is that you are using an ABS). What you need to do is ask the lab if you can do an end product test. In this case mold stress relief at 85C for 7 hours would be appropriate (Max Temp plus 10). Now, in terms of Ball pressure that only applies if you are using this plastic piece for direct support of live parts. If you are then the test needs to be done. I didn't think that UL1950 looked at things like RTI (I build products to UL 1950, 1778, 1449 etc. and I deal with RTI daily but I have never had to for UL 1950). My guess is that the test lab will have a hard time understanding your arguments and you may need to call UL's plastic division in Melville, NY USA. Good Luck Steve tony.reyno...@pb.com Sent by: To: emc-p...@ieee.org owner-emc-pstc@majordom cc: o.ieee.org Subject: RTI on Plastics 10/02/2001 08:45 AM Please respond to Tony.Reynolds All, I am having some fun with a lab over RTI ratings on plastics. Basically we have a plastic moulding with a component mounted directly on it. The RTI of the plastic is 60C and the component is getting to around 75C actual. I have always looked at the flammability of plastics 5V, V-0, V-1, etc but never the RTI. Is this a just a UL1950 requirement or is it in EN60950 as well. We have done the thermal stress at 70C and all is OK. They are suggesting doing the ball pressure test at 125C, however, I have only used this for qualifying mains transformer bobbins, etc. Regards Tony Reynolds Pitney Bowes +44 (0) 1279 449479 +44 (0) 1279 449118 tony.reyno...@pb.com ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.