Whether during exploration or production, enhancing fire detection is critical to uninterrupted safe working practices and the environment. Safety design engineers and operators expect technology to increase not only the safety of a facility but to make it far easier to design, install and operate. This has lead to several new developments by fire detection equipment.
A look at flame detection
Flame detectors are a key element of any fire safety system, but unfortunately in the past many of the technologies available were also prone to give false alarms under certain circumstances. However, flame detectors are not low cost items, particularly when compared to smoke and heat detectors for example, and are vital where the risk of immediate flame in the event of ignition could spread rapidly, causing risk to life, major damage, and costly shutdowns.
Due to the cost, many plant operators tend to use detectors with a long range and wide field of view to cover vast areas with a relatively small number of devices. This has resulted in a requirement for larger and more complex extinguishing systems and release mechanisms to cover the larger areas of risk. It is important to remember however that this approach can increase the cost of the fire suppression system, as larger pumps and a higher quantity of foam agent are needed.
It is generally understood that there are two key ways of detecting flaming fires: Measuring ultraviolet (UV) or infra-red (IR). Both of these methods monitor the radiation given off by the combustion. Measuring UV was the first method to be invented, however it has a short range and tends to elicit false alarms, as UV detectors can react to sources like lightning, welding, angle grinding or similar activities. IR flame detector technology, on the other hand, does not react to these sources and is generally recognised as being the most reliable detection method. These detectors specifically identify the IR waveband of hot carbon dioxide.
Innovation in IR array technology
Combining IR technology with multi-sensor devices offers enhanced fire detection functionality to plant operators. The FLAMEVision™ FV300 detector from Tyco Fire Protection Products uses an IR array of 256 individual sensors that detect where in the field of view any build up of IR radiation is occurring. By using highly tuned image analysis, this technology distinguishes between flame and non-flame sources to identify the characteristics of a flame or a modulated black body. This discrimination is made easier by the use of the array as any IR sources within the field of view will form images on different parts of the array.
If a black body is detected the device is able to compensate for it just in that area of the field of view while maintaining optimum sensitivity for all other areas. Suspicious events can be reported to the operator and raised as events which may require further investigation, with the detector able to send the co-ordinates of the suspicious object directly to the operator. This inherent feature of the IR array together with the ability to mask an area results in a detector with an unrivalled false alarm rejection capability.
IR array detectors can provide location information of single or multiple fire events in two ways; by referencing the IR sensing array cells that register alarms and sending co-ordinates to the main control system, and secondly by superimposing a CCTV image with the fire location highlighted. Weather conditions can have an impact on a CCTV picture (fog, mist, direct sun light etc), so highlighting the location of the fire helps the operator to react as quickly as possible should manual intervention be required.
Better site operation
As IR array detectors report where in the field of view the fire is it is possible to identify the fire among a multitude of other assets and to automatically release a local extinguishing system. This avoids the need for a total plant shutdown. IR Array based flame detectors also monitor the fire size and can therefore monitor the effectiveness of any extinguishant. Using two or more array based detectors to monitor an area allows the control system to triangulate the co-ordinates and pin point the exact location of the fire.
Consistent sensitivity across the field of view
The range of the FLAMEVision™ is consistent across the field of view, unlike UV/IR detectors where the range reduces as the target moves away from the axis. This makes design of the site fire detection layout much easier and could result in fewer detectors being required.
Forensic audit of events
Typically an IR array based detector is able to track and output information on the target sources over time and consequently store information about an incident prior to any alarm. This presents the benefit of a forensic audit of what took place in infrared terms prior to the alarm. Similarly, the tracking of hot IR sources allows maintenance staff to understand any hot body changes which take place from one maintenance period to another while giving facilities operators advance warning of a potential flame situation.
It is important to integrate safety systems to enable effective emergency response. FLAMEVision detectors can be integrated into the DCS / PLC systems via a range of industrial interface standards and also to fire and gas systems that could be monitoring the whole facility, including non- production areas. Alternatively, FLAMEVision sensors can directly connect to the Tyco MZX addressable fire detection system whereby data is collated by the control panel and sent to the site safety system. Fire and gas detection, along with fire suppression systems and emergency shutdowns, can be truly integrated to provide a cost effective solution ensuring minimum disruption to operations while maximising the safety of personnel and assets.
Offshore accommodation and other non-process areas
Fire detection is not just essential for process areas but is also required across a facility. Areas such as server rooms and offshore accommodation areas are examples where smoke and heat detectors are necessary. Typically, following a risk assessment most areas offshore might be classed as a minimum of a zone two hazardous location, so an expensive intrinsically safe fire detection system is specified. Occasionally, designers try to cut costs by fitting conventional rather than addressable intrinsically safe detectors, but this gives very limited information as the emergency response team does not know the exact location of the fire.
The T2000 MZX fire and gas detection system from Tyco Fire Protection Products offers a programmable solution, not only for sensitivity, but also for device operation. For example, a combined optical smoke and heat detector situated near an incinerator can be programmed to work as a High Performance Optical (heat enhanced smoke) detector but automatically switched to heat detection mode when the incinerator is running. This ability to switch operating modes greatly reduces the possibility of false alarms and ensures all staff react as per their safety training when there really is an alarm rather than casually assuming it is a false alarm. The use of combination detectors including carbon monoxide (CO) detection gives fast reaction to true fire situations while further reducing false alarm possibilities.
The new FLAMEVision™ range of infra-red flame detectors from Tyco Fire Protection Products reliably pinpoint the source of a fire, eliminating any guesswork and enabling fast response to a fire incident. Utilising advanced patented infrared (IR) array (FV300 detector) and triple IR (FV400 detector) solar blind technologies with a CCTV camera, the FLAMEVision family of detectors provide reliable and cost effective fire detection solutions. Minimizing unwanted alarms and improving life safety through detection with less disruption and downtime, FLAMEVision™ detectors offer complete peace of mind to the customer.
About Tyco Fire Protection Products
Tyco Fire Protection Products is a division of Tyco, the world’s largest pure-play fire protection and security company. As an industry leader, Tyco Fire Protection Products uses its global scale and deep expertise to drive innovation, advance safety and solve the unique challenges of customers in more than 190 countries worldwide. Every day, Tyco Fire Protection Products manufactures and delivers an unmatched range of detection and suppression systems, extinguishing agents, sprinkler systems, valves, piping products, fittings, fire-fighting equipment and services that helps its customers save lives and protect property. Its global technology portfolio includes fire suppression, fire detection and mechanical building product offerings sold under many of the world’s best-known brands: ANSUL, CHEMGUARD, EZCARE, FIRECLASS, FLAMEVISION, GRINNELL, HYGOOD, LPG, NEURUPPIN, PYRO-CHEM, RAPID RESPONSE, SABOFOAM, SHURJOINT, SIMPLEX, SKUM, SPRINKCAD, THORN SECURITY, VIGILANT, WILLIAMS FIRE & HAZARD CONTROL, and ZETTLER.