Brief Guide on FC and FLS Style Gate Valves

A gate valve is designed to permit or prevent liquid and gas flow. It is an integral component of many industries, including oil & gas upstream, midstream & transmission, geothermal, and power generation.

FC style and FLS style gate valves are two standard gate valves. They are precisely designed, engineered, and manufactured reliable gate valves that comply with the API 6A requirements.

What is the Difference between FC Style and FLS Style Gate Valves?

FC style gate valves are one of the oldest designs and consist of 6 sealing surfaces, including:

  • Body to Body Bushing (x2)
  • Body Bushing to Seat Ring (x2)
  • Seat Ring to Gate (x2)

On the other hand, FLS style gate valves are generally considered a replacement for FC-style gate valves. It consists of 4 sealing surfaces, including,

  • Body to Seat (x2)
  • Seat to Gate (x2)

The seat seals of the FLS gate valve were updated to non-elastomeric, pressure energized, and spring-loaded lip seal between the body and seat. It assists in low-pressure sealing and protects from damage. Moreover, it has eliminated the gate guide that permits the gate to float with fewer restrictions.

FC style gate valves are the most preferred choice due to their availability of replacement parts, price, and lead time.

What Considerations Should You Make When Purchasing FLS and FC Style Gate Valve?

When shopping for FLS, FC, or any other style gate valve, you must not compromise on the quality. A high-quality gate valve is durable and has a low maintenance cost. It reduces the lifecycle costs, as it doesn’t require early replacement when the valve fails.

Before purchasing a gate valve, ensure it meets the quality criteria for long service lifetimes. It should meet or exceed the standard requirements. You must also ensure that the manufacturing company has been in the business for a long time and is reputed for offering durable and premium-quality valves.

The surface of the gate valve must be free of irregularities from the casting process, such as groves or pores. The surface of the bonnet flange should be machined. You can check this by running a finger along it. If the bonnet flange is left as cast and is not machined, the gasket might be squeezed unevenly. It might result in premature leakage and failure.

The Bottom Line

While gate valve shopping, you will come across a wide range of gate valve choices. Make a choice as per your requirement. Ensure that it is durable and from a reputed manufacturer.


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