Smoke and fire detection solutions are an integral part of power plants. However, it is important to know the unique requirements that this vertical demands in order to ensure the fire safety measures are adequate.Power plants, by their very nature of operation and function, could be considered critical infrastructure that warrants special attention when it comes to protection from fire. Apart from the security threats a fire at a power plant would cause, interruptions to the power supply could affect other operations and cause further damage.
What’s happening in the field
When it comes to technology, there are quite a few ways to go about to ensure fire protection in power plants. Major among them are visual smoke detection solutions, infrared and aspirating smoke detection solutions. Needless to say, each of these come with its own pros and cons.
“The large spaces present challenges to any technology deployed to detect smoke and fire,” Pauline Norstrom, MD at NetVu/Dedicated Micros, said. “In power plants, other unique conditions prevail: few appropriate fixing points which enable detection to occur before the smoke stratifies. Also, dust/dirty environments render some systems such as aspirating either inoperable or subject to very high cleaning and maintenance costs.”
Kelvin Miller, Sales Director at Patol, said that his company recommends aspirating systems for certain areas within a power plant, while other technologies are more suited to different fire protection challenges. This is highly sensitive technology that can potentially detect fire smoke early and can be effective in spaces where visual access is not easy.
“The company does advocate and supply aspirating smoke detection systems for areas characterized by large open spaces, such as turbine halls, where smoke stratification can prove problematic for conventional point detectors,” Miller said. “However, Patol has products within its portfolio which are more widely employed in addressing the specific challenges of power plant fire detection.”
Frederick Koons, Director of Customer Marketing for Honeywell Advanced Detection Fire Solutions at Xtralis, which is now a part of Honeywell Security and
Fire, spoke about his company’s aspirating smoke detection solution as well, which delivers fully monitored and supervised intelligent air sample filtration, secondary filtration, modular design, all in an IP66 enclosure.
“This solution delivers very early warning of a smoke or fire threat allowing ample time for local response before lives, assets, or business continuity are compromised,” Koons said.
Pros and cons of solutions in place
Miller pointed out that many goods carried on conveyors — biomass, black and brown coal, industrial confetti (for energy from waste plants), recycling products, sulfur — are highly combustible and have the potential to self-ignite. If they should combust upon an unprotected belt, the likelihood is that the system will enable the fire to spread into the holding hoppers, blending, crushing or other processing areas of the plant.
“As part of the operators’ risk management policies, the installation of early warning protection along a conveyor susceptible to conditions of excessive heat can avoid catastrophic fire damage and substantial consequential losses,” he said. “Patol products include a range of early warning infrared transit heat sensors designed to monitor and detect, in the presence of ambient light, ‘hot spots’ and embers from combustible materials being transported on conveyor systems.”
The range of 5000 series sensors features a continuous air purging system to maintain an automatic cleaning system that prevents dust from settling on the lens of the sensor, he added. Perfectly suited to hazardous and dusty environments, the sensors are typically mounted at 1 to 1.5 meters above the conveyors at an angle of approximately 30 degrees. Initially sited five meters after the loading end of each conveyor system and thereafter roughly every 100 meters, sensors should also be located at transfer points and other inlets. The sensors are aligned such that the monitored potential hazard passes through their field of view.
Speaking of the advantages of his company’s aspirating smoke detection solutions, Koons listed, detecting smoldering/incipient and low energy flaming fires, rejection of nuisance alarms due to high airborne particulate levels and fog, reliable smoke detection in dust-laden atmosphere, reliable operation (maintain detection performance, low maintenance), flexible pipe network design which allows the detector to be placed outside harsh conditions, and particulate and chemical filtration to remove contaminants from sampled airstream.
Challenges in this vertical
Given the nature of power plants, there are certain challenges that are unique to this vertical. Among other things, combustible materials, dust and debris, and
the voluminous areas of plants make fire detection for power stations challenging. What is then required is that fire detection solutions have to be extremely sensitive to danger, alerting the people concerned at the earliest moment without making false alarms.
“Explosive atmospheres within power plants can be caused by combustible dust,” Miller said. “If there are sufficient quantities of the substance mixed with air, then it simply requires a source of ignition to cause an explosion, possibly resulting in significant damage, serious injury and even loss of life. The move from coal to biomass fuels in the generation of electricity, for instance, has resulted in the increased possibility of dust explosions in power plants.”
Overcoming the dusty, dirty environment is also a challenge in power plants. According to Norstrom, her company’s visual smoke and fire detection solution are extremely tolerant to such environments because it does not rely on a sampling of the air, therefore expensive filters do not have to be changed regularly. However, the surface of the detectors will require cleaning from time to time.