EN 402 and ISO 23269-1 – Lung governed demand self-contained open-circuit compressed air breathing apparatus with full face mask or mouthpiece assembly for escape.SNM provides breathable air contained in a cylinder through a pneumatic system which adjusts quantity and pressure of air so to make all parameters suitable for breathing. The cylinder contains 600 liters, which under normal conditions of use are enough to grant about 15 minute duration. However, this value is indicative, because it can be significantly influenced by numerous parameters such as: the effort exerted during the escape, the user’s size and his own stress condition.