Fireproof Assurance: Severn’s OCT TOV Butterfly Valves Exceptional Fire Safety Design and Testing Credentials

As part of a safety‑first valve design approach, Severn incorporates into its innovative Oblique Cone Technology (OCT) Triple Offset (TOV) Butterfly Valve, fire safety is a critical part of that safety first objective. Fire testing standards state the minimum requirements the valve must achieve in order to receive fire safe certification. The standards dictate the setup & parameters required to simulate the conditions a valve may be subjected to during a hydrocarbon fire scenario, and test to ensure the valve can operate satisfactorily afterwards.

To summarise, the test consists of a valve being mounted in a fire testing rig to flow water through the valve, and measure leakage both internally past the seal as well as externally through the packings and gaskets. The valves are then pressure tested at ambient temperature, once the valve has passed this element of the test, any leakage is recorded. The valve is then subject to a simulated fire by use of gas burners, with average temperatures of between 750°C & 1000°C recorded by thermocouples for the 30‑minute fire test duration. Once complete, the flames are extinguished, and the valve is subjected to a forced cooldown using water to simulate the fire being extinguished on site.

The leakage during fire is measured and recorded. The valve is then subject to a re‑ambient temperature and post‑fire operational test, with the maximum leakage requirements being defined within the relevant API and ISO fire safety standards. The tests are carried out in both the preferred and reverse directions and are witnessed by a 3rd party approval body, giving added confidence that the fire tested butterfly valve will perform as required in either flow direction.

By investing in and developing their own on‑site fire test facility, Severn can understand and interpret the results to re‑design & develop the fire safe valve technology for the OCT TOV Butterfly Valve, to further exceed the requirements set out in the standard. By doing this, Severn have been able to achieve up to zero seat leakage, even after API 607, API 6FA and ISO 10497 fire testing, giving further confidence in safety‑critical valve applications and ensuring a safety‑first solution for the end user and their operations.

The key to Severn’s success lies in their patented Oblique Cone Technology (OCT), which received approval from the UK Intellectual Property Office in 2018. This innovative triple offset valve design uses an ‘infinite circle’ geometry that allowed the research and development team to develop the circular sealing geometry, providing the flexibility to use the valve for both control and isolation duties, with the option of interchangeable seals and control trims.

Utilising its over 60 years of valve engineering expertise, Severn have designed and developed the innovative OCT TOV Triple Offset Butterfly Valve, a valve that meets the requirements of API 6FA, API 607, and ISO 10497 fire testing standards. These bi‑directional isolation and control valves offer repeatable zero leakage performance, providing peace of mind for operators while ensuring safe operations and reduced downtime.

Severn’s fire test certification covers the OCT Laminate, Hybrid (OCT‑HS) and Seawater (OCT‑SW) seals, achieving the required leakage rates in accordance with relevant international fire safety standards. By designing, developing, and testing the hybrid polymer metallic fire safe seal, Severn have been able to deliver a graphite‑free firesafe sealing solution that continues to perform even after exposure to extreme fire conditions. The OCT‑SW seal technology, designed for seawater service, prevents graphite contact with line media, eliminating galvanic corrosion risks and extending valve service life.

By meeting stringent fire testing and certification requirements, Severn provide customers with a reliable and proven fire safe butterfly valve solution. With its patented oblique cone technology, Severn has set a new benchmark in triple offset valve design, helping end users achieve their core objective of safe operations, asset protection, and reduced downtime.