THE issue of fire safety is brought into sharp review with alarming regularity. In November 2012, the prestigious 34-storey Tamweel Building in Jumeirah Lakes Towers (JLT), Dubai, UAE, suffered a horrendous fire that took several hours to extinguish.
The frequency of fires that endanger life as well as assets has remained very high since the Tamweel fire. Some 18 major fires were recorded in the UAE alone from January 2012 to May 2013 – a rate of one a month. Three people died as a result.
A recent garment factory fire in Dubai’s Al Quoz 3 in September 2013 and another at a tower block near the junction of Shaikh Mohammad Bin Zayed and Al Khail roads in November reminds residents, business people and fire prevention professionals of the life-threatening dangers.
The authorities have recognised the situation cannot be tolerated. Legislation has been enacted and practical measures will make such occurrences a rarity rather than a shocking, albeit not entirely unexpected, part of life in the Gulf.
It was recently announced, for instance, that mandatory fire alert systems will soon be installed at all new villas and apartments in Dubai as the Dubai Civil Defence overhauls fire safety in homes.
Needless to say, the success of the Gulf region is reflected in some fantastic construction projects that reflect the incredible development of the region’s economies and in turn cities and sophisticated infrastructure, such as state-of-the-art aircraft installations.
The Gulf’s high-rise creativity, in particular, has presented a range of fire detection scenarios that are as challenging as any metropolis.
Conventional fire detection will generally not pick up smoke above 20 ft. Smoke stratifies, meaning that it might not trigger fire surveillance equipment above this height. This scenario can apply to infrastructure as well. Yet, many sites are signed off as safe using conventional systems when they are not necessarily adequate to protect life and property. In addition, the voluminous nature of many internal spaces such as hotel lobbies are an extra challenge to be addressed.
Time is also of the essence. Effective fire detection cannot wait for a fire to develop before an alert is triggered. Monitoring has to pick up potential danger signals early to prevent disasters. Monitoring should focus on potential danger areas (as well as the general scene, if required) before a fire can develop.
There are three advanced fire detection technologies to consider:
• Video smoke detection (VSD): This is a mature and tested technology in terms of what it can deliver. Essentially, it detects danger by looking for smoke patterns, often at points that might be particularly vulnerable to fire risk.
Rather than waiting for a signal to trigger specific sensors, VSD can offer early warnings by cameras pointing at the subject space and looking for changes in variables such as brightness, contrast, shape, motion, colour matching, content and loss of detail.
If a complex has areas that could trigger alerts from signals that might resemble smoke, such as steam in a turbine or dirt from recycling plants, then such areas can be isolated. This allows safety staff to concentrate on the key danger areas.
Safety operators can work on site or remotely. With high quality video, they can determine if an alert is a real fire risk and take appropriate action or if it was a false alarm. Alerts can be studied after the event to improve safety. It is not a cheap system though, but it is effective.
• Aspirating smoke detector (ASD): This works by assessing the presence of smoke particles suspended in air that have been drawn through sample holes in a pipe network into a detection chamber.
ASD is highly sensitive, often detecting smoke before it is visible to the human eye, which is particularly valuable in slow growth fires. However, the sensitivity to distinguish between smoke and dust in early stage smouldering fires can be compromised, as the size of dust and smoke particles can be similar.
Industrial environments such as manufacturing, power generation and large cities often also have high levels of background ambient smoke or dust.
There are technological approaches to reduce nuisance alarms, but compensatory technology may impact the sensitivity of a smoke detector and early warning reliability.
Future integration of ASD with intelligent detection systems, including remote monitoring and verification will improve its effectiveness.
• Infrared (IR) detection: An infrared detector is simply a transducer of radiant energy, converting radiant energy in the IR into a measurable form. Like VSD and ASD, IR detectors can be used in a range of environments.
Detecting IR energy emitted by objects takes away reliance on visible light and so obscured conditions should not affect its effectiveness although thick smoke, and oil and grease on the kit can.
Most IR detectors are designed to ignore constant background IR radiation, which is present in all environments, focusing on the modulated part of the radiation. When exposed to modulated non-flame IR radiation, IR detectors become more prone to false alarms. Operator verification, as with VSD, ensures optimum actions are taken.
Going forward
The political will and the professional expertise are in place to significantly reduce the current litany of major fires. Regulations are taking the initiative to tackle construction issues – particularly banning the further use of aluminium composite panels that are often a contributing factor in fires taking hold, although it will be years before it is phased out.
The current fire detection technology is sophisticated enough to minimise risk in the most challenging of environments. There is still a long way to go before an acceptable level of risk and incidents are established, hopefully that day is not too far away.
*FireVu (www.firevu.co.uk) has an established presence in the Gulf and has completed projects for the Royal Airwing Hangar, Palm Jumeirah, which are both in Dubai and King Khaled airport in Riyadh, Saudi Arabia.
