An airflow control valve (20) for use in a breathmg apparatus (10) to control a flow of air fiom a pressurised air supply to a respirator. The valve comprises an inlet port (31) for connection to a pressurised air supply, and first (32) and second (33) outlets. The valve is configurable between a first position in which the inlet port is in iestricted fluid communication with the first outlet to allow a restricted flow of air from the inlet port to the first outlet and in which the second outlet is sealed from the inlet port and, a second position in which the inlet port is in substantially unrestricted fluid communication with the second outlet to allow an unrestricted flow of air from the inlet port to the second outlet.