The age old question "What tests can be run in the short term under stress conditions on materials/products that will correlate to long term under normal conditlions?" Bell Laboratories (now Bellcore) has been wrestling with this problem for a long time because of their need to assure the reliability of their products in an ambient, field envoronment (i. e. the telephone switching boxes that are located all over the countryside). The standard "stress" conditions that have been used in the printed wiring board and assembly industries have consisted of: 1. High temperature - 85+ deg C 2. High humidity - 85+% R. H. 3. Thermal cycling or thermal shock - -55 deg C to +125 deg C (or even greater range). 4. High pressure - such as a pressure cooker 5. Low pressure - such as a vacuum chamber 6. Varying degrees of voltage applied to the PWB or assembly 7. Chemical corrosive environment - High acid, high alkaline, salt spray, etc. 8. All of the above I would say that one document that covers a wide spectrum of both PWB's and assemblies would be the Bellcore #TSY-000078 specification. In this document there are lots of "stress" tests for many different areas. This is a very long document; however, I can make a copy and send it to you if you request it off line. Hope this helps Larry Fisher Dexter Electronic Materials [log in to unmask] ############################################################## TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################