Oxygen Cylinder / Valve Burns Firefighter
Oxygen cylinders are used by professionals to help save lives and heal the injured. Oxygen is a life sustaining gas and the use of it can help heal when used properly. Oxygen cylinders are commonly seen in ambulances, hospitals, airplanes, care facilities, dive operations and persons’ private homes; places where it can be accessed quickly and easily when needed. Oxygen cylinders are pressurized and require the use of a regulator to control the flow of the gas. The regulator, with attached pressure gauge, determines the amount of oxygen remaining within a cylinder. It is common practice to periodically check the cylinder to ensure the regulator is working properly and to ensure there is an adequate supply of gas in the oxygen cylinder.
What people may not realize is that each time the oxygen valve is turned on to check the functions of the regulator, they are exposing the oxygen regulator to an immediate increase in pressure. This sudden increase in pressure can cause adiabatic compression which generates heat. If the temperature is great enough, and there is particle impingement, it can cause particles to burn. When the burning starts the oxygen within the cylinder accelerates the process causing catastrophic effects.
A firefighter was performing a daily check of the oxygen cylinder located on an ambulance. When the firefighter turned the valve to check the function of the regulator, two flames shot out 4 feet and caught his clothing on fire. Other firefighters, working nearby washing a fire truck, were able to use their hose to extinguish the flames on the victim firefighter. The cylinder continued to burn for another 30+ seconds before it was able to be extinguished. The firefighter had 1st, 2nd and 3rd degree burns over 35% of his body. He was later airlifted to a burn center.
During the investigation the inspectors realized that the oxygen regulator was manufactured with Aluminum. Aluminum ignites at a much lower temperature than the more common Brass regulators. Aluminum has been reported to ignite with as little as 35psi. Brass has an ignition rating near 5000psi. Aluminum also burns faster and hotter than brass. In the listed case there was likely particle impingement from a filter. The impingement, and sudden rush of oxygen was enough to ignite the aluminum oxygen regulator.
The investigators came up with safety protocols for oxygen regulators, both brass and aluminum:
- Replace any aluminum regulators with BRASS regulators
- Open and close the oxygen valve prior to attaching the regulator to clear the opening
- When turning on any oxygen regulator, point the opening away from the operator
- Open the valve slowly
- Train all employees in the safe operation of oxygen cylinders