What is a Fire-Safe Valve? API 607 vs API 6FA

In sensitive applications where fire accidents can occur easily, industrial valves must offer reliable fire protection. In the oil and gas, refinery, chemical, and petrochemical industries, valves must provide a reliable and safe shut-off in case of fire. Such industrial valves must be designed to be fire-safe. A fire-safe valve minimizes the amount of process lost (leakage) downstream or to the atmosphere after a fire test.

There is no fire hazard associated with industrial valves. The American Petroleum Institute (API) has developed fire tests for oil and gas valves. The API 607, ISO 10497, API 6FA, BS 6755, and BS 5146 are the standards for fire testing valves after years of refinement. Other standards and procedures include API RP6F, FM 6033, Exxon BP3-14-1, and OCMA FSV-1. Many organizations make their own internal fire-safe valve procedures based on these standards.

In a universally accepted firefighting strategy, if a fire cannot be beaten within one-half hour, a withdrawal and containment strategy is implemented. There will be structural failures such as flange bolt failures, pipe rack collapses, and concrete eruptions. On the basis of this concept, a fire test duration of 30 minutes has been determined.

Principle of Fire Testing of Valves

A fire-safe valve under pressurized conditions must operate after being burned at a specified high temperature for a specified period, and leakage after burning should be within specified limits. In the case of fire testing of valves or fire-safe valve testing, the principle is as follows:

Water-filled pressurized closed valves are fully immersed in flames of around 750°C to 1000°C for 30 minutes. Temperatures are monitored using thermocouples and calorimeter cubes when the valve is completely engulfed in fire, exposing the seat and sealing areas to burn temperatures. The external and internal leakage past the valve is measured during this period. As long as the leakage is within acceptable limits, it should be acceptable. Once the valve is cooled after the fire test, the same valve seats, shells, and seals are tested for their pressure-containing capability.

• There is usually a horizontal position for the stem and bore. The check valves are tested in their normal operating position.

• Two thermocouples are used to measure the temperature. On the horizontal centreline, one is located 25 mm from the upper stem packing box and the other is located 25 mm below the valve under test.

• Valves are not tested for fire if the piping to valve end connections leaks.

API 607 vs API 6FA

API 607 and API 6FA are the most widely used standards for fire testing industrial valves. Both standards are developed by the API. What are the differences between the two?

The difference between Fire Safe by Design and Fire Safe Tested

• Fire Safe by Design: A valve that is designed to be fire safe by design is referred to as a "fire safe by design" valve. There has been no testing of the valve, however.

• Fire Safe Tested: There could have been a test on a "fire safe tested" valve. A governing body has not approved the valve, however.

• Approved and Certified: "Fire safe approved and certified" valves have been tested, approved, and certified by a governing third party following common standards such as API 607, API 610 6FA, and ISO 10497.

Fire-Safe Ball Valves

The Fire safe ball valve is produced for applications in explosive or fire-risk environments. The valves are specially designed to limit the spread of fire. Fire-safe ball valves are usually tested according to API 607, API 6FA, and BS 6755-Part 2.

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