Eric, Underwriters Laboratories has a thermal index (10 and 56 day accelerated tests) that provides a maximum continuous operating temperature rating for flex materials. The majority of rated materials on the market are limited to 105C. There are a few choices rated in the 150-160C range, so you do have the option of specifying something like 125C performance. As I've mention here recently, elevated temperature completely changes the mechanical properties of flex adhesive so be careful if the flex needs to be dynamic. Additionally, as others have already pointed out, you may run into other systems problems beyond just the flex survivability. Andy Magee Flex Guru [log in to unmask] (937) 435-3629 Eric wrote, We are designing a new product which will contain a flex PWB. This is a medical application where the product may be sterilized by Autoclave (121 deg C for 30 minutes). Is this likely to cause any problems? Eric Christison Mechanical Engineer VLSI Vision Ltd Aviation House 31 Pinkhill Edinburgh EH12 7BF Tel: +44 (0) 131 539 8165 Fax: +44 (0) 131 539 7141 ################################################################ 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's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################