If compressed air was used instead of oxygen, the air inside the hood would need to be constantly replenished to maintain the oxygen content at a life-supporting level. Because the VRU uses pure, aviator's grade oxygen, the exhaled air can be rebreathed once the carbon dioxide is removed. A typical industrial escape hood that relies on compressed air contains 350 L of air at 3,000 psi pressure. The VRU contains 18 L of oxygen at 3,000 psi pressure. The typical industrial escape hood weighs over 6 pounds.
Carbon dioxide is a natural byproduct of respiration.
Because the VRU is a closed circuit system, it is necessary to remove the carbon dioxide that builds up inside the hood. This is accomplished with a unique, patented passive scrubber. Also, the size of the VRU user will affect usable life, with heavier individuals consuming oxygen more rapidly. The VRU is folded and sealed inside a multi-laminate pouch, which, in turn, can be packaged a variety of ways depending on your requirements including inside a fire resistant container. Containers are available with carabineers for carrying the VRU on web gear or belt.