Specifying the Right Valve in Firewater Systems

In offshore oil and gas operations, firewater systems are mission-critical safety assets. These systems, often exposed to corrosive seawater, must perform flawlessly in the rare but high-stakes event of a fire. Yet, many installations still rely on non-fire-safe or rubber-lined butterfly valves—decisions that could have catastrophic consequences.

The Fire Safety Imperative

Isolation Butterfly valves are central to firewater system integrity. Under fire conditions, Rubber lined or non-firesafe Double Offset valves can fail due to the extreme heat caused by a fire, leading to external leakage, through seat leakage, or complete operability loss. Therefore, it is crucial for the end user to specify the correct valve. Fire-safe certified valves, particularly Triple Offset designs, offer metal-to-metal sealing that withstands extreme heat and ensures continued operation during emergencies. In most cases graphite is used a s sealing mechanism to enable the valve to perform at extreme temperatures.

The Hidden Threat: Galvanic Corrosion

While fire events are rare, corrosion is a persistent and costly challenge. Galvanic corrosion occurs when dissimilar metals—such as graphite and stainless steel for example—are electrically connected in seawater. Graphite, though excellent for sealing, acts as a cathode and accelerates the degradation of adjacent metal components. This can lead to premature valve failure, compromised seal integrity, and unplanned downtime.

OCT-SW: Engineering Out the Risk

Severn Glocon’s OCT-SW valve offers a robust solution. This patented Triple Offset Butterfly valve uses Oblique Cone Technology and is specifically designed for seawater firewater systems. It isolates graphite components from the line media, eliminating galvanic corrosion risk while maintaining fire-safe performance.

The OCT-SW features:

• Primary metal-to-metal torque-seated seal for fire resilience
• Graphite isolation to prevent corrosion
• Dual anti-blowout protection and fugitive emission-certified packing
• Extended service life and reduced maintenance costs

Conclusion: Safety by Specification

Specifying the correct valve is not a matter of preference—it’s a matter of safety, compliance, and operational continuity. The OCT-SW valve exemplifies how advanced engineering can mitigate both fire and corrosion risks, ensuring that firewater systems remain reliable when they’re needed most.

The cost of getting it wrong? Potentially catastrophic.

Find out more about Severn Glocon’s OCT-SW range or contact us at www.severnvalve.com

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