Valve Operability During a Fire

Abstract

Fire and explosion are a major cause of concern for refinery, gas processing, petrochemical, and gas installations. The safest way to deal with a fire is to prevent it. However, fire prevention strategies are not always successful, and fires can happen. Therefore, valves should be designed and tested to be fire-safe. This paper reviews valve design features that can help prevent fires, including secondary sealing between the ball and body in case of losing a soft seat, a graphite fire-safe ring design for stem and seat sealing, antistatic devices, and antistatic tests to ensure that the valve is fire-safe. In addition to design considerations, a fire-safe design should be validated through tests defined in standards such as API 607, API RP 6FA, and ISO 10497. The API RP 6FA tests reviewed in this paper include seven tests that check the operability of the valve from closed to open position. A case study was done to prove the operability of a fail close 38″ pipeline ball valve on an oil export pipeline in case of fire during the first 20 s from the open to the closed position. Thermal analysis on the body of the valve proved that there was no thermal expansion inside the valve after 150 s of fire. Additionally, the maximum radial displacement on the valve body after 150 s of fire was 0.34 mm which is negligible. Thus, the valve thermal expansion did not disturb the operation of the valve after 20 s.