Breathing Apparatus and Air Cylinder

Firefighter BA has a fullface mask, regulator, air cylinder, cylinder pressure gauge, and a harness with adjustable shoulder straps and waist belt which lets it be worn on the back. The air cylinder usually comes in one of three standard sizes: 4 liter, 6 liter, or 6.8 liter. The duration of the cylinder can be calculated to Size of cylinder X Pressure / by 40 and then less 10 minutes because of a safety margin. so a 6 liter cylinder, of 300bar, is 6 X 300 / 40 - 10 = 35minutes working duration The relative fitness, and especially the level of exertion of the wearer, often results in variations of the actual usable time that the SCBA can provide air, often reducing the working time by 25% to 50%. Air cylinders must be hydrostatically tested every 5 years for composite cylinders, and every 5 years for metal cylinders.