How to choose the sealing material for CO2 fire extinguisher valve

In the fire protection industry, carbon dioxide (CO2) fire extinguishers are widely recognized for their rapid and efficient fire extinguishing capabilities. However, the performance of a fire extinguisher does not only rely on the carbon dioxide fire extinguishing agent filled inside it, but is also closely related to the design and manufacturing quality of key components such as valves. In particular, the selection of valve sealing materials directly affects the sealing performance and long-term reliability of the fire extinguisher.

The selection principles of sealing materials are mainly reflected in the following aspects:
Corrosion resistance: Since the inside of a CO2 fire extinguisher is filled with high-pressure carbon dioxide gas, the sealing material must have excellent corrosion resistance to resist the erosion of carbon dioxide. This feature is crucial and can effectively prevent gas leakage caused by corrosion during long-term storage and use.
High temperature resistance: In the case of emergency fire extinguishing, the fire extinguisher may be used in a high temperature environment. Therefore, the sealing material needs to have good high temperature resistance and be able to withstand a certain amount of heat without deformation or failure, thereby ensuring the normal opening and closing of the valve at critical moments.
Low temperature resistance: In cold climate conditions or winter environments, fire extinguishers also need to remain effective at low temperatures. The sealing material should maintain sufficient elasticity and toughness under low temperature conditions to avoid the risk of leakage due to embrittlement.
Sealing performance: The sealing material needs to have excellent sealing performance, be able to maintain a tight fit under various working conditions, prevent the leakage of fire extinguishing agents, and ensure the effectiveness of the fire extinguisher.
Durability: The sealing material should have a long service life and be able to maintain excellent sealing performance after multiple opening and closing operations.
When choosing sealing materials, common choices include the following materials and their characteristics:
Nitrile rubber (NBR): As a widely used sealing material, nitrile rubber exhibits good oil resistance, wear resistance and low temperature resistance. In CO2 fire extinguisher valves, nitrile rubber seals can effectively prevent gas leakage and ensure the normal function of the fire extinguisher.
Fluororubber (FKM): Fluororubber is known for its excellent high temperature resistance, chemical corrosion resistance and ozone resistance. In industrial applications of high pressure, high temperature and corrosive media, fluororubber seals can maintain long-term and stable sealing performance.
Silicone rubber (SI): Silicone rubber has excellent high temperature resistance, low temperature resistance, oxidation resistance and ozone resistance. Its good flexibility and elasticity enable it to adapt to the sealing needs under complex working conditions.
EPDM: This material has excellent weather resistance, aging resistance and chemical corrosion resistance. In CO2 fire extinguisher valves used outdoors or in harsh environments, EPDM seals can maintain long-term stable sealing effects.

In the process of selecting sealing materials, the following points should also be noted:
Consider the working environment: When selecting sealing materials, it is necessary to fully evaluate the working environment of the fire extinguisher, including factors such as temperature, pressure and medium. According to different working environments, choose appropriate sealing materials to ensure the long-term reliability of the fire extinguisher.
Consider material compatibility: There may be chemical or physical incompatibility issues between different materials. When selecting sealing materials, be sure to ensure that they are compatible with the carbon dioxide gas filled inside the fire extinguisher and the materials of other valve components to avoid chemical reactions or physical damage.