Dave, As others have mentioned, there are different classes based on particle quantity and particle size. They typically range from (cleanest) Class 1 or 10 for Semiconductor manufacturing to Class 10,000 for hi rel microelectronic assembly to Class 100,000 (dirtiest, less than 100,000 particles .5 micron or larger and less than 700 particles 5 micron and larger per cubic foot) for general high rel electronics as a general guideline. A typical air conditioned office area would run about 200,000-400,000 particles .5 micron and larger per cubic foot. All Clean Rooms require positive air pressure and Class 100,000 can be accomplished with a good air handler with primary and secondary filters, proper uniflow air flow design and some makeup air (about 20% pulled from else where in the building) to maintain positive pressure. Class 10,000 would also require HEPA filter supplies. Class 1,000 or better requires specialized professional Clean Room design. Humidity control are end use driven. See also FED-STD-209. Contact me off line if you have more specific questions. Bruce Misner > ---------- > From: Dave Blevins[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;Dave Blevins > Sent: Wednesday, September 27, 2000 4:44 PM > To: [log in to unmask] > Subject: [TN] Clean Room > > Hi Everybody > I have a question, in the real world, when constructing a clean room what > type of air handling system is used? > > 1. A regular air conditioning unit with a 90% dust spot filter? > -or- > 2. Something like a Liebert Environmental Control System that maintains > temperature as well as humidity with positive > pressure? > > ############################################################## > 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 > ############################################################## > ############################################################## 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 ##############################################################