Willis, IPC has not developed a standard for "shelf life" because the storage conditions at your shop may vary from those of a shop in Singapore, or a shop in Calgary. However, there is a relatively new committee working on PC Board Storage and Handling - D35. The internet address for their committee minutes and standards dreaft is: _http://www.ipc.org/committeedetail.asp?Committee=D-35_ (http://www.ipc.org/committeedetail.asp?Committee=D-35) I see that they have now developed a "Strawman" standard as a starting point for their standard. I believe that from the storage and handling procedures that they establish, a projected shelf life will be much easier for you to project. Denny Fritz MacDermid, Inc --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------