70 (or 72) & 50% are usually the standards for film etc. But you being in assembly I would ask your solder past supplier. I have heard that they are environmentally sensitive! ______________________________ Reply Separator _________________________________ Subject: Temp. and RH Author: [log in to unmask] at corp Date: 7/3/96 8:09 AM Our PWB assembly facility is in a controlled environment kept at 72 degrees F, and 50% R.H. The problem is, we don't remember how we decided these were the best conditions. Does anyone know of an IPC document or other source stating the best environmental conditions for PWB assembly (including SM assembly)? Any info. is appreciated. Thank you. The mail list is provided by IPC using SmartList v3.05 To unsubscribe from this list at any time, send a message to: [log in to unmask] with <subject: unsubscribe> and no text.