During the demolition phase of our Westerly project, Jeff Sweenor set up a system to minimize the amount of airborne dust present as his crew removed drywall. The system revolves around a device known as a negative air machine. The machine, which consists of a powerful fan, filters, and an exhaust hose, filters air at a rate of either 600 cubic feet per minute (CFM) or 1000 CFM. Sweenor notes that for the area in which they are working the unit will exchange the air about once every minute when set at 1000 CFM. A crew seals off all of the openings in the room except for one door leading to it. This allows air to be pulled from a cleaner part of the house as the machine draws in the dust and exhausts it to the outside.