Christine, In the past the problem with silicones has been their breakdown during electrical arcing in crossbar (mechanical) switches and the formation of nonconducting silicone dioxide (sand) on switch surfaces. The other problem with silicones is that they are themselves incredibly good electrical insulators. So you do not want them on conducting mating surfaces; like inside mating connectors, inside dip switches, etc. This is further complicated by the fact that silicones have a tendency to creep and if they get on a circuit pack it is quite possible to find that the material has moved considerable distances across the circuit pack. As a result of these problems, liquid silicones and solid silicones containing a certain % of liquid silicones are not allowed for use in Nortel products. So if you are going to be putting product in an environment where these materials are prevalent it would be nice if all your connectors make gas-tight connections and that they are not going to have to be removed/reinserted once the packs are in the field, that all your dip switches are sealed and that you use a silicone impermeable conformal coating (if there is such a thing, Nortel doesn't generally have to use coatings so I can't offer much there.) Hopefully other Technetters can give you more info. regards, Bev Christian Nortel > ---------- > From: Christine Cleveland[SMTP:[log in to unmask]] > Sent: Tuesday, March 10, 1998 9:40 AM > To: [log in to unmask] > Subject: [TN] Silicone oil environments > > Hello, everyone. > > I am new to the forum and have a question; hopefully, you can help me. > My question is regarding an application where a printed circuit board > (polyamide) will be operating in a "silicone oil" environment. Are > there > any reliability standards or other information available on PCB > environments and their long term reliability? > > Any information you can provide will be greatly appreciated. > > Best regards, > Christine > > -- > Christine Cleveland > Custom Standards Services > Engineering Documents and Information Services > Phone: (800)699-9277 (734)930-9277 Fax: (734)930-9088 > e-mail: [log in to unmask] On the Web: www.cssinfo.com > > **Ask me about > --IEC Standards on CD-ROM > (http://www.cssinfo.com/iec.html) > --PERINORM - The new International Standards Database > (http://www.cssinfo.com/perinorm.html) > --The new 1998 ASME Boiler and Pressure Vessel Code > (http://www.cssinfo.com/BPV1998.html) > These are all available now at great discounts! > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV > 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC web site (http://jefry.ipc.org/forum.htm) for > additional information. > For the technical support contact Dmitriy Sklyar at [log in to unmask] or > 847-509-9700 ext.311 > ################################################################ > > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################