Fires in waste storage bunkers are a frequent and well-known problem. Waste management plants therefore need an accurate and high-performance early warning system to protect both life and property.
By Pieter Claerhout
Incidents involving fire and smoke in waste management plants can have devastating effects, hence the reason why they are a continuous concern to waste management operators. Detecting a fire incident in time in such an environment is not that simple. Anyone who has been inside a waste bunker facility will know that this is not a regular environment such as an office. Waste, dust, vapor or exhaust gases from vehicles can severely hinder the performance of smoke detectors. Since traditional smoke detection systems will not work effectively in waste plants, waste management professionals are increasingly looking for an alternative that is more tailored to the industry. That alternative is video smoke detection.
Fires in waste storage bunkers are a frequent and well-known problem. Very often, fires are caused by spontaneous combustion from waste that is brought in. A hidden source of heat resulting from biological decomposition or the chemical oxidation processes generates a rise in temperature. If the waste mass cannot dissipate the heat faster than it is generated, then spontaneous combustion can occur.
The Cost of Fire
The consequences of a fire outbreak can be very serious. Not only is there the cost of lost waste material and lost energy, but waste plant owners also need to take into account the cost of the extinguishing measures and cleaning. Calling in the emergency services usually comes with a huge price tag as well and this is only the financial cost. Environmental effects and the risk of human loss are harder to calculate, but nonetheless, they are actual risks. A fire incident might also lead to reputational damage and ultimately to the withdrawal of the environmental permit.
Waste management plants therefore need an accurate and high-performance early warning system to protect both life and property. Such a system needs to prevent situations from escalating and allow operators to take the required decisions in the event of a fire incident. The problem is that traditional smoke detection systems are not efficient in waste management bunkers for at least two reasons.
Contact-Based Smoke Detection Systems
First, conventional smoke detection systems, like point, beam or aspiration-based smoke detectors, need to make contact with the smoke before they can generate an actual alarm. However, a waste bunker is typically a high building where smoke from an initiating fire will either reach the smoke detector very slowly, too late or not all, because of a process called stratification, which stops the upward movement of smoke (thermal barrier).
A second difficulty with conventional smoke detectors is that waste plants typically generate substances that can activate smoke detection systems unintentionally. Chemicals, dust, exhaust gases or vapor will cause conventional smoke detectors to generate a high volume of unwanted alarms. A conventional smoke detector will respond to dust in the same way as to smoke particles. Dust is also one of the reasons why a conventional smoke detector will degrade very fast, which has an impact on its smoke detecting performance.
Smoke detection systems that generate too many unwanted alarms are not only very annoying, but they are also quite costly. A fire outbreak will require all activities to be stopped, in spite of the fact that business interruption losses are also not always covered by insurance policies. False alarms also lead to the unavailability of emergency services in the event of real fires. In some cases, users of these detection systems might decide to deactivate the detectors altogether, just to avoid the annoyance.
The Visual Alternative
Conventional smoke detection systems have proven their worth for many years and in many environments. But in the challenging environment of the waste bunker, they are inefficient, either because they are activated too late, or they generate a high number of unwanted alarms. That is why waste management professionals today are looking into more intelligent systems that can take into account the challenging conditions of waste facilities. One of the most effective systems in place today is Video Smoke Detection (VSD).
A video smoke detection system relies on the resolution and accuracy of a standard network security camera and uses carefully developed video analytics software installed on the camera to scan the environment and continuously analyze it in real time to precisely locate the smoke/fire incident at the source. In case of an event, a VSD system will send an alarm output over to the fire control panel in order to generate an alarm.
The visual nature of VSD makes it a very effective early warning system. Video smoke detection will be able to analyze phenomena like smoke, dust or vapor in a much more intelligent way through the use of smart video analytics. This will heavily reduce the number of unwanted alarms. That is why video-based smoke detection is an appropriate technology for use in harsh environments, like waste recycling plants.
For a smooth surveillance and monitoring experience, a video detection system can be connected to a video management system in order to provide control room operators with 24/7 situational awareness and the added facility of providing visual verification.
Lower False Alarm Rate
VSD is very accurate and thus the unwanted alarm rate will be extremely low. Video smoke detection systems will efficiently analyze the video image to make a distinction between starting smoke and other irregularities, such as dust, damp, people walking in the field of view, animals, vehicles or objects.
Damp from spontaneous combustion, dust or waste flying around caused by loaders moving the waste heaps: a waste plant is the casebook example of a harsh environment. To make an accurate distinction between these phenomena and an actual smoke fume and initiating fire, there is a need for intelligent detection technology. Because of its visual nature and pattern-based analytics, VSD can accurately detect starting fires without generating unwanted alarms.
In fire safety, speed is crucial. Video smoke detection systems will see initiating smoke much faster than conventional systems. Waste storage bunkers usually have tall ceilings. Therefore, conventional point or beam type detectors installed at the ceiling would be very inefficient, because it would take way too long for the smoke to reach them. VSD on the other hand makes efficient use of CCTV, so it is able to see dangers from a very large distance, without the need to make physical contact with the smoke. It immediately ‘sees’ the danger when and where it originates.
Video smoke detection cameras can be installed high up attached to the bunker walls to ensure a good overview of the entire bunker. The distance between the camera and the waste pile is no problem, since the video image can be accurately analyzed from practically any distance.
Control room operators can monitor the CCTV video images in real time. This allows them to assess the nature and severity of the fire as well as the stage it is in. Based on pre-incident recording, they can see whether people are present at the place of the incident and they can better assess the overall situation. This way, they can also make better use of their emergency resources. After the incident, the video footage can be used for risk analysis and prevention of future incidents.
Smoke detection systems usually have the possibility to lower the detection sensitivity during specific time slots when extreme activities take place that otherwise would generate unwanted alarms. These conditions could include the start-up of the waste management process or the cleaning of the waste shredder.
Today’s self-learning video detection systems are intelligent enough to filter out unwanted events, such as exhaust gases of loaders, moving dust or waste heaps. As such, they are perfectly able to adapt their sensitivity autonomously, without actually adhering to fixed time slots. For example, in periods of heavy activity from loaders or a shredder, the detected activity will enable the smoke detection sensitivity to be decreased. Conversely, when the VSD system detects no activity, for example at night, during weekends or in the holiday season, the system will adjust to a higher degree of sensitivity.
Enabling Better Decisions
Video smoke detection seems to be a perfect fit for the waste management professional. Because of its visual nature, it can accurately detect initiating fires directly at source, practically from any distance. This is a huge speed advantage compared to smoke detection technologies that need to make physical contact with the smoke. With VSD, there is no need to wait until the smoke has reached the ceiling. This is time gained for the personnel responsible for making crucial decisions and for taking the appropriate actions to avoid further fire/smoke damage or life-threatening situations.
A detection system that generates too many unwanted alarms will become useless and ignored in the long run. Video smoke detection technology, on the other hand, can effectively filter out unwanted events that are so typical of waste bunker environments.
False alarm or not, probably the biggest advantage of video smoke detection technology is that it gives the operator room for interpretation. As it allows for super-fast detection and visual verification, VSD provides the operator with valuable time to make a well-founded decision. That decision could be calling the emergency services and avoid further damage or human suffering, it could be ignoring the alarm, or, if possible, isolating the fire event in order to prevent the entire operation from closing and running into costs.
Pieter Claerhout is CEO of Araani, a Belgian company, specializing in video analytics for people, property and process protection. Araani is also the developer of SmokeCatcher®, the company’s advanced video smoke detection solution that has been designed to guarantee business continuity and fire safety for companies that operate in critical and demanding environments. Pieter can be reached at 003256 49 93 94, via e-mail at Pieter.firstname.lastname@example.org or visit www.araani.com.