Exploring the innovative features and engineering principles of Severn’s OCT TOV Butterfly Valve that puts safety first in safety‑critical valve applications.

At Severn, safety is paramount in the design of our products. With our background in safety‑critical industries such as oil & gas, petrochemical and process plants, Severn understands the importance of safety‑first valve design for both our customers and employees.

As well as adhering to the strictest international valve safety standards, Severn have identified that shaft blowout prevention was paramount to our end users and the wider industrial valve and process industries, for improved valve performance and reduced operational downtime.

Butterfly Valve shafts are designed to connect to the disc with either dowel pins, taper pins, or keyways. The separation of the shaft and disc in service can be catastrophically dangerous in high‑pressure and safety‑critical valve applications. If any of these parts fail, the shaft may be ejected from the valve body. Shaft blowouts can occur when a coupling mechanism fails, therefore, disconnecting the shaft from the disc. With the pressures in the system, it may eject the unrestrained drive shaft through either end of the valve.

Not only is this projectile a huge safety concern but has the potential to compromise the pressure envelope of the valve allowing hazardous process media to escape into the atmosphere.

Severn has designed all their Triple Offset Butterfly Valves as standard with dual anti‑blowout protection, incorporated at both ends of the valve. This negates any chance of the shaft blowing out if the pins were to fail. The reduced shaft diameter at the drive end ensures the shaft cannot blow out through the packing follower, significantly improving operator and plant safety.

On the blank end of the valve, Severn have multiple engineered anti‑blowout features, which prevent shaft blowout. The anti‑blowout ring on the threaded shaft end ensures positive engagement without the need for additional fasteners. The blank end plate is locked in place and is designed to withstand full rated test pressures in severe service conditions.

Dual anti‑blowout devices are standard on the OCT TOV Butterfly Valve, meaning that even if the gland is removed, the secondary internal anti‑blowout device will stop ejection of the shaft under pressure, further enhancing industrial valve safety and reliability.

Severn have designed their Triple Offset Butterfly Valves to exceed the minimum wall thicknesses stated in ASME B16.34 valve design standards. Instead of using only the minimum allowance, Severn have engineered additional material to ensure improved pressure containing integrity and long‑term safety performance in the field.

Within Severn’s Triple Offset OCT TOV Butterfly Valve, there is a corrosion allowance. This means that the valve can afford to concede material to corrosion over time without affecting the pressure‑containing integrity or safety of the valve. The amount of corrosion may vary depending on the environment the valve is operating in, but due to Severn’s engineering heritage and design excellence, the OCT TOV Butterfly Valve has been designed to withstand changes in process conditions and operating environments.

High MAST (Maximum Allowable Shaft Torque) figures and safety factors are key when designing quarter‑turn butterfly valves for severe service. MAST represents the Maximum Allowable Shaft Torque a valve shaft can withstand during operation without mechanical failure. By utilising higher MAST figures, Severn helps maintain the structural integrity and mechanical safety of the valve throughout its service life.

Sizing actuators correctly is a credit to Severn’s engineering‑driven valve design approach. Actuators, gearboxes, or other valve drives must be sized correctly using accurate input and output torque values. By torque testing physical valves prior to final inspection, Severn compares real operating torques against theoretical calculations, ensuring accuracy, consistency and reliable valve automation performance across the range.

Safety has always been at the forefront of Severn’s designs, and this commitment is paramount in the 8500 OCT Triple Offset Butterfly Valve range, delivering confidence, compliance and reliability for safety‑critical applications worldwide.

Operators are under increasing focus on reducing fugitive emissions control for both onshore and offshore assets, to reduce harmful emission to achieve their core imperatives of safe operations, regulatory compliance, and minimum downtime across critical process industries.

Fugitive emissions is a hot topic that will only become more critical in today’s environmentally conscious energy and process industries. Fugitive emissions are a gas or vapour leak, normally due to poor valve maintenance, inadequate valve sealing solutions, or packing sets being utilised without a true understanding of the application. This can lead to valve performance issues, increased unplanned downtime, and a variety of costly and detrimental failures impacting operational reliability and asset integrity.

How are Severn meeting the challenges of emission control?

Severn have been investing a significant amount of research and development (R&D) in emission reduction technologies to address fugitive emissions in control valves and their specific valve application requirements. By utilising a range of materials from filled graphite through to custom PTFE‑based packing compounds, Severn have, coupled with innovative valve packing designs, been able to achieve tighter leakage rates than previously achieved with standard packing sets.

We have reduced control valve emission leaks to a minimum across our whole control valve product range, without impacting valve performance, process controllability, or long‑term valve reliability.

The performance of valves fitted with fugitive emission sealing systems is a critical consideration for operators within oil and gas, petrochemical, power generation, and process plant operations. Traditionally, compression packings were simply tightened to ensure the seals were effective. This practice increases friction, reducing valve control accuracy, limiting process efficiency, and potentially leading to premature valve failure or total valve shutdown.

Thanks to extensive valve testing and qualification programmes carried out as part of Severn’s ongoing product research and development, we now have packing sets that achieve ISO 15848‑1 fugitive emissions classes A, B & C with valve processes from ‑196°C to +425°C and at pressures up to 10,000 PSI on both linear and rotary control valves.

A critical consideration is that the operation cycles required for an isolation valve to meet ISO 15848‑1 compliance can be as few as 201 cycles, while a control valve must achieve at least 20,000 cycles. This makes the reliability of the valve sealing system a significant consideration and often necessitates a specifically engineered fugitive emission packing system.

It is essential that the correct valve specification is identified from the outset. Severn’s valve application experts are on hand to support this process, drawing upon our unrivalled bank of control valve performance data, failure analysis history, and real‑world operating insight that forms part of Severn’s Repair Intelligence™ capability.

By working closely with the client and implementing over 60 years of valve engineering excellence, control valve expertise, and sealing system knowledge, Severn ensures that true application needs are identified. This guarantees that correct valve components are utilised, avoiding packing sets that are unsuitable for the operating conditions and which could otherwise lead to significant valve performance degradation and increased emissions.

Implementing these structured procedures and collaborating closely with the client helps to achieve lower fugitive emissions across the valve population, supporting clients’ commitments to environmental compliance, emissions reduction targets, and global initiatives following COP26 climate commitments.

Severn also offers the ability to utilise its significant expertise in high‑integrity valve sealing systems to retrofit existing control valves from all major OEMs, upgrading them with advanced low‑emission packing solutions without replacing the entire valve assembly.

Meeting the challenge of fugitive emissions is just one of many ways we help our clients achieve their core operational imperatives — safe operations, process efficiency, and maximum plant uptime.

If you are experiencing valve performance issues, emission compliance challenges, or sealing failures that are affecting your production capabilities, contact our control valve specialists today via the button below.

Speak to our control valve and fugitive emissions specialists to improve compliance, extend valve life, and reduce unplanned downtime.

Mars Valve UK, a Severn company, have recently secured a 10-year agreement with Mars Taiwan to become the sole UK distributor.

Despite the agreement taking longer than initially thought to achieve, the work from Rhys Jones, Chief Commercial Officer Severn Group and Sarah Jamison, Senior Legal Counsel Severn Group, has helped greatly to get this agreement over the line and put in place a much more robustly secure agreement that will help Mars Valve UK with its continued business growth.

‘This new agreement also displays the high level of trust built up over the last 12 months between Mars Valve UK and Mars Taiwan, after what was a difficult time for the business. The level of hard work put in day in, day out from the Mars Valve UK team is second to none and the results for such a small team are outstanding. The whole team is looking forward to continuing this growth over the next 12 months and beyond‘ – Wayne Lyons, Business Manager, Mars Valve UK

This 10-year agreement strengthens Mars Valve UK’s position as the leading UK distributor of stainless steel ball valves, reinforcing long-term supply security, continuity, and confidence for customers across industrial valve supply, process engineering, and fluid control systems in the UK.

If you want to find out more about Mars Valve UK, and its UK distribution with the securing of the 10-year agreement with Mars Taiwan then get in touch below.

Speak to our team today for UK stainless steel valve distribution, technical valve support, and long-term industrial valve supply solutions tailored to your application.

Mars Valve UK Ltd is the UK master distributor for Mars Valve Taiwan.

As the exclusive UK master distributor, Mars Valve UK provides locally held stock, reliable lead times, and expert technical advice for a full range of high-performance stainless steel valves used across oil & gas, chemical processing, and water treatment industries.

Established in 1997, Mars Valve Taiwan, design and manufacture a large range of stainless steel ball valves for a range of industrial applications.

Mars Valve Taiwan is internationally recognised for its precision-engineered stainless steel ball valves, manufactured to meet global quality standards, ensuring durability, pressure integrity, and operational reliability in demanding environments.

Mars Valve UK Ltd was formed in 2000 and has grown from strength to strength, we have a excellent technical knowledge of over 28 years in the UK valve industries, we have gained a global reputation for the quality of its valves and the aftersales service provided.

With over 28 years of UK valve industry expertise, Mars Valve UK combines deep technical knowledge, responsive customer service, and after-sales support, helping customers select the right industrial valve solutions for critical applications.

Mars Valve’s channel to market is through a series on regional master distributors – who represent the product, and ensure local stock and technical support provides the service orientation.