Control rooms are utilised by large-scale refineries to monitor and control plant operations. The control room and network of control equipment enable these facilities to maintain the highest efficiency possible. If the control room malfunctions, there can be very costly unscheduled downtime. Particulate and corrosive gaseous contaminants present a serious risk for these control rooms. Contaminants can enter the control rooms in a variety of ways, including outdoor ventilation systems, adjacent interior areas, and with individuals entering and exiting the room. Maintaining a positive air pressure within the at-risk area using filtered air is good practice and in this hostile environment AAF will offer either conventional or self-cleaning air filters, often in stainless steel housings.