Phil, Thanks, but I have perused those specifications and did not come up with a concrete answer. I was hoping some designers would know if there was a section that specifically covered my question and/or give me their personal design criteria. I am surprised I did not receive more feedback from all the designers that usually comment on the TechNet. Scott ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d ############################################################## 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. If you need assistance - contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################