I have a large manufacturing facility that primarily deals with aerospace products. This large building has several areas that utilizes propane, hydrogen, oxygen, etc. There are also other areas where there is what appears to be a woodshop with saws, etc. ALong with spray areas for painting some of their products. I had requested an area classification study to be submitted and basically I got a response back today that was interesting. The designers are proposing to install large mechanical equipment thruout that will ensure that the areas of concern will have adequate venitlation that includes multiple air changes per hour. They would like to use this in lieu of having the areas as part of a classification study. Is there something that dictates that this would work (maybe in the NFPA) ? Or will the classification study need to be done completely in order to ensure the right wiring methods are done? Input in appreciated!