2 min read
01 Nov

Designed to reduce downstream leakages and fugitive emissions in the event of a high-temperature fire, fire-safe ball valves reduce downstream leakages and fugitive emissions. Due to the non-alloy materials used for sealing, most of the valves have to function even at high temperatures or fail in a predictable manner, which makes fire-safe ball valves different from other types of valves. Fire-safe ball valves must meet certain design and testing standards. Manufacturers of fire-safe ball valves follow these standards to ensure the valve works properly. Ball valves are operated manually by a hand lever or by an actuator. Electric or pneumatic actuators can be used with fire-safe ball valves. During and after fire exposure, a fire-safe ball valve must maintain its ability to contain pressure. Fire-safe ball valves are used because flammable or hazardous liquids may leak from valves in the event of a fire. Fire will cause fluid leakage from the valve stem if a non-fire-safe ball valve is used. The leakage of fluid will support the fire and make it grow bigger. Therefore, a fire-safe ball valve is needed to prevent fluid leakage when exposed to fire. In refineries and chemical processing plants, fire-safe ball valves are used to handle flammable fluids. Ball valve manufacturers are responsible for ensuring a tight shut-off of the valve during and after fire outbreaks. 

How does a fire-safe ball valve work? 

The use of a fire-safe ball valve before and after the fire prevents two types of fluid leakages. There is a possibility that the leak is caused by the stem or the seat. For the design of a fire-safe ball valve, two methods are employed. The first method involves using a fire-proof component and the second involves using a non-fireproof component with a special design that prevents leakage after the material melts. To create a fire-proof component, metallic seats, graphite inserts, and graphite packing are used. The graphite remains in a fire-safe ball valve that has a stem packing and seat insert. A thermoplastic stem packing and thermoplastic seat material like PTFE are used in the other method. During high temperatures, the thermoplastic melts and a secondary seal is obtained by using a machined body designed to serve as a secondary seal. To support the thermoplastic seal material in case of fire, graphite seals are used as secondary packing. 

A fire-safe ball valve maintains normal operation when opening and closing fluid flow. The flow of fluid through a fire-safe ball valve is controlled by a ball with a bore at its center. To open a fire-safe ball valve, the handle must be rotated 90 degrees. The handle, which is connected to the ball via a valve stem, rotates the ball. As the ball rotates 90 degrees, it becomes in line with the pipeline, allowing fluid to flow. Close the fire-safe ball valve by turning the handle in the opposite direction as you opened it. Fluid flow is blocked as the ball bore rotates and becomes perpendicular to the pipeline. 

Types of fire-safe ball valve

Forged fire-safe ball valves 

The forging method is used to manufacture this fire-safe ball valve. Fire-safe ball valves are made by forging metallic materials while they are solid. By using industrial tools and heat, compressive force is delivered to the metallic material to bend it. To create a fire-safe ball valve, dies are used to shape and cut the materials. High-temperature and high-pressure applications are suitable for forged ball valves due to their strength. Manufacturing a forged fire-safe ball valve refines the grain structure, increasing its overall impact strength. Furthermore, forging reduces the thickness of fire-safe ball valves, which minimizes thermal fatigue while the valve is in operation. 

Casted fire-safe ball valves

This is a fire-safe ball valve that has been cast using the casting method. Ball valves are formed using molten metal in the casting process. High temperatures are used to melt metallic materials. Molds are filled with molten material. After cooling and solidifying, the molten material is ejected from the mold. Using the casting method, it is possible to create fire-safe ball valves with complex patterns, shapes, and sizes. Unlike forging, cast fire-safe ball valves are more cost-effective and make the valves cheaper by reducing machining costs.

Aira Euro Automation is the leading fire-safe ball valve manufacturers in India. We offer various types of industrial valves like ball valves, butterfly valves, control valves, and many more. 

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