The risks associated with fire in the petrochemical industry, whether it be on production platforms at sea or on shore at oil terminals and storage facilities, have been brought into sharp focus by a number of high profile incidents, resulting in tremendous damage to infrastructure and sadly, in some extreme cases, the large-scale loss of life. This has caused the industry to look at new approaches such as Video Smoke Detection (VSD) to protect key elements of their infrastructure and to ensure the safety of workers by providing early fire detection. Jon East, Engineering Consultant at D-Tec, explains the benefits of VSD.
Back in 1988, the devastation wrought by the world's worst offshore oil disaster on the Piper Alpha platform in the North Sea was a major shock and wake-up call to the sector. In this case, a gas leak resulted in blasts on the rig and sparked a major fire, which engulfed the structure - then the largest platform in the North Sea - leading to 167 fatalities. This traumatic event demonstrated all too clearly the hazardous nature of the oil and gas environment, and the serious repercussions that occur when problems are not detected early enough and a fire is allowed to take hold.
More recently - in December 2005 - we were again reminded of the ever-present danger, this time manifested in the biggest blaze seen in the UK since World War II, at Hertfordshire Oil Storage Terminal in Buncefield, near Hemel Hempstead. Prior to the fire, the terminal was handling 2.37 million metric tonnes of oil products annually. The problem at Buncefield resulted from the overflowing of unleaded petrol being pumped into a storage tank. A rich fuel and air vapour rapidly formed and spread across the site and set off a number of major explosions - heard for miles around - and an associated fire. This unprecedented incident took in 20 storage tanks and caused extensive damage to the site and adjacent business premises, and the evacuation of a significant area around the facility.
So what measures can be taken to help minimise the fire hazards in this sort of environment and provide an early warning of fire, to protect key assets against the potential of a problem escalating into a full scale disaster, if left unchecked?
A technology based on the intelligent analysis of CCTV images is being increasingly deployed to protect such valuable assets from fire. This solution is aptly referred to as Video Smoke Detection (VSD) - a technology pioneered by D-Tec - and is a capability that is now operational in a wide range of sites worldwide.
Typical projects, across the petrochemicals industry, include for example using video smoke detection to protect the generator rooms on North Sea rigs. These assets are essential to the smooth and ongoing operation of the multi-million pound platforms and are particularly challenging installations, as they are prone to heavy vibration and atmospheric contamination. Another application is the monitoring of a huge on-shore oil terminal connected to oil-fields.
Benefits of Video Smoke Detection
The beauty of VSD is that it takes detection to the fire rather than waiting for the fire to come to the detector. This approach is ideally suited to the large, extensive nature of oil terminals and platforms where it is just not practical to cost-effectively place conventional detectors close enough to the area of risk to provide the required level of fire detection.
In extensive structures or sites covering a large geographic area, there is a high reliance - as far as traditional fire detection solutions are concerned - of smoke overcoming distance before being detected. This can mean that with conventional detectors, it can be many minutes before a fire alarm is activated - if at all - making it much more problematic to tackle a blaze, as it is likely to have reached a more advanced stage. Given the speed that fires can grow in such a combustible environment, early smoke detection is even more critical for the oil and gas industry.
Thankfully, distance is not a limitation faced by Video Smoke Detection (VSD), as this technology is able to utilise images from standard CCTV cameras and analyse these, by applying sophisticated algorithms to detect smoke. By programming the software to look for anticipated motion patterns of smoke over a specified area within the range of a CCTV camera image, and looking for pixel changes, VSD has the potential to deliver an exceptionally fast response - typically in seconds.
Crucially, once smoke has been detected, the system can alert the operator as well as deliver a visual representation of the smoke on the system's monitor.
Consequently, VSD is not reliant on the proximity of smoke to a detector; whether the camera is 10 or 100 metres away from a risk area, VSD will detect smoke in the same amount of time.
Although it is claimed that other camera-based systems are able to detect smoke, the reality is that these are really motion detectors or obscuration-change detectors which are unable to differentiate between smoke and other sources of movement and hence are prone to false smoke alarms.
In terms of practicality, the CCTV cameras associated with VSD can be fixed in conveniently accessible places, rather than being positioned well out of reach, as is the case with conventional detectors. Additionally, as CCTV can cover a much larger area, fewer cameras would be required, compared to smoke detectors, for a given size of oil platform. It may also be possible to take advantage of already installed security CCTV cameras for some of the monitoring.
IP enhances visual smoke detection capabilities
VSD's capabilities have been further enhanced by the potential for CCTV camera images and alarms to be distributed, for review, over a network to a number of viewing locations. This is being realised through solutions that readily integrate the well-recognised advantages of VSD with IP (Internet Protocol) based functionality.
In practice, this advance means that, for ease of management, it is perfectly possible for a number of geographically dispersed oil rigs to be monitored from the same control room, and more to be added should the need arise. This can also be invaluable for unmanned platforms where, should an alarm be activated; the remote operator actually has a visual indication of what is going on.
As a consequence, an operator can make an informed decision there and then as to whether a firefighting team needs to be sent to the platform. This is in contrast to more conventional smoke alarm systems, which just sound an alarm without the possibility of ascertaining the severity of an incident without automatically paying a visit - a costly process.
There is also the ability, with this flexible approach to VSD, for changes to configuration, testing and diagnosis to be carried out remotely - reducing cost and minimising delay.
Integrating Smoke and Flame Detection
Another big leap forward with VSD is the potential, for the first time, to combine smoke and flame detection. This is ideal for more hazardous situations, such as those thrown up by the petrochemical industry.
A key benefit of the application of an advanced flame detection algorithm - in addition to smoke detection - is that it is now perfectly possible to deliver a layered response, typically alarming on smoke first and then confirming again if fire appears. There is also the potential for the application of this capability in designated areas at night where flame rather than smoke is likely to be the most visible sign of an incident.
Fast Track Detection for effective fire protection
The message to fire and safety professionals concerned with the petrochemical industry is this: Now is the right time to look again at Video Smoke Detection (VSD) for key projects, whether it be an oil refinery on land or a production platform at sea.
Ultimately, the effectiveness and ease of installation of VSD, particularly in the shape of the networkable and dual smoke and flame detection capabilities, makes a compelling case for adopting this technology, where conventional approaches are simply not going to provide the early warning necessary to minimise the very real risks associated with fire.
Source : Jon East - Engineering Consultant - D-Tec (part of AD Group)