High voltage: Fire suppression in control rooms

Fire poses a significant risk to power generation plants. As well as the obvious threat from the widespread use of fuel sources, combustible materials and rotating machinery, areas with large amounts of electrical or electronic equipment can present a substantial fire hazard. Not only can an electrical fire endanger lives, but it can also cause severe damage to power plants – leading to forced shutdowns and production downtime as a result. As demands for power continue to increase, thanks to the rapidly growing population, it is becoming even more important that the right fire suppression systems are put in place to protect all parts of power generation plants.

The threat to power plants

Whether it is a hydroelectric, nuclear or fossil fuel, the control room is a crucial part of any power generation plant. Along with communications rooms, switch rooms and cable basements, the large amount of electronic and electrical equipment on-site and subsequent high voltages can potentially cause a short-circuit – posing a significant risk to employees. Any damage to the control room could also incur loss of valuable information, potentially delaying plant production.

For example, an electrical fire started in the Sharavathi Generating Station in India in 2016, as a consequence of an electrical short circuit in the control room, trapping 20 workers in the building. A crucial power generation unit, it supplies 20-22% of the local state’s total power, with an installed capacity of 1,035 MW. The fire burned cables and damaged power distribution lines, severely compromising power generation. It was estimated that it would take over a month to restart power generation on the plant – the first incident of its kind since it opened in 1964.

Mitigating the risk

Although smaller control room fires can generally be controlled easily, soot and smoke can cause short-term damage, incurring considerable clean-up costs. Furthermore, the presence of wiring, motors and breakers means that a major fire can spread quickly throughout the plant, particularly when located close to combustibles. A fire suppression system and its associated detection system needs to be able to detect and contain the hazard as quickly and effectively as possible.

Gaseous suppression solutions are commonly used to fight fires in control rooms, as they are electrically non-conductive and cause little or no damage to critical equipment. While foam and water sprinkler systems are effective, they can damage the hardware – potentially losing valuable information and increasing costs to replace damaged equipment. When gas is deployed, it is easier to clean up following a fire, as it leaves no residue, allowing normal service to be resumed quicker, with minimal disruption. In addition, the nature of power plants means rapid deployment of extinguishing systems is crucial to lessening the impact of fires. With gas systems taking between 10 seconds (for halocarbon agents) and two minutes (for inert gases) to discharge the suppression agent, they can present a more reliable choice for plant managers looking to mitigate the risk of fire.

A reliable replacement

Historically, halon systems were commonly used in the protection of electronic equipment in power plants, thanks to their effectiveness in high value asset protection. Following restrictions on using halon due to its potential to cause environmental damage, plant managers have since sought more sustainable options.

A popular alternative in the past was hydrofluorocarbons (HFCs), a man-made compound that extinguishes fires by chemical cooling and inhibition of the flame. HFC-227ea (sold under the tradename FM200) is an example of one of the first-generation halon alternatives widely used for its fire suppression ability. However, its potential impact on global warming has raised questions across the industry. In fact, recent European legislation in 2014 will effectively cut the importation of HFCs to just 21% of average 2009-2012 levels by 2030. As such, increasing numbers of plant managers are looking to retrofit HFC and halon systems with more compliant, sustainable solutions.

Choosing the right fire suppression system

As plant managers continue to seek solutions that meet current guidelines, Johnson Controls’ SAPPHIRE^® PLUS gaseous system is particularly suited to the protection of high value assets, such as control rooms and associated hazards. With space a premium, risk assessments in control rooms need to consider fire suppression systems carefully and take up as little space as possible, which may include locating the agent containers centrally – without compromising on efficiency. In a market first, the SAPPHIRE PLUS system has an increased pressure rating of 70 bar, allowing containers to be filled up to 1.4kg/L. As such, fewer containers may be required – particularly important for older power plants retrospectively up-grading their fire suppression solutions, and for new power plants seeking to use centralised container storage rooms.

An added advantage of a fire suppression system with an increased storage pressure, such as SAPPHIRE PLUS, is that it enables extended pipe runs – above 100 metres. This allows containers to be stored further away from the protected space, as well as the option to protect multiple hazards at one time, using selector valves – saving valuable installation costs and time.

Furthermore, SAPPHIRE PLUS delivers 3M™ Novec™ 1230 Fire Protection Fluid, a clear, colorless agent that vaporizes on discharge, totally flooding the protected area, absorbing heat to suppress fire. The agent has zero ozone depleting potential and a global warming potential of just one, providing for an environmentally sustainable alternative to HFCs. The system equipment has been designed for use in temperatures up to 65°C, making it suitable for use in all regions of the world.

In addition, although the configuration of control rooms in power generation plants may differ across the globe, the SAPPHIRE PLUS range employs a common equipment platform – meaning that there is no need to switch equipment based on where it is used in the world. The system is UL listed, FM approved and EN compliant, so that plant managers can be assured of its safety credentials, wherever the system is installed.

Ensuring a safer future

A reliable fire protection system is crucial to ensuring the continued functioning of power generation plants, while safeguarding high value assets and people. Although fires in control rooms can often be much smaller and less intense than in other areas on the plant, such as turbine enclosures and emergency generators, it still presents a viable and significant threat to power generation across the site. Gaseous fire suppression systems, such as SAPPHIRE PLUS, therefore offer a reliable option for plant managers looking to mitigate the risks and ensure fires are extinguished, with minimal damage to equipment.

Innovations in fire suppression systems are not only helping to reduce footprint, installation costs and service time in control rooms, but also leading the way in improving safety standards across the entire power generation industry.

For more information, go to www.johnsoncontrols.co.uk