The tall-building trinity: protection, detection and evacuation

Said Ray: “Essentially, you have two domains – the public sector and the private sector. The differences lie in degrees of access and the thought processes. In terms of the public sector, there were, of course, measures taken in the wake of the Grenfell disaster last year, but then you had cases like the one in Aberdeen, in February this year, where the residents of tower blocks refused access to workers to make fire-safety improvements.

“In the private sector, it’s all about gathering information on the measures that are in place. But the difficulty here is the lack of response from private property-owners and, again, access – how to get in to prevent fires from happening in the first place.”

One solution, Ray continued, is to use wireless fire-detection systems. Around now for a number of years, there are also myriad standards and legislation governing them. “They offer the same levels of protection as wired systems but deployment is so much faster,” Ray explained. “They are also more palatable to residents, as there is less inconvenience involved, no damage to décor, etc. They are cost-neutral to install and take about 30 per cent of the time you’d take to install a wired system in tall buildings.”

Above all, he went on, they must be reliable. EN54-25 talks about reliability, Ray pointed out, with the bottom line being that wireless systems must be at least as or more reliable than wired systems. Battery life must be minimum three years.

“You can also add wireless to existing systems,” Ray concluded.

Next to speak was Evac+Chair’s Garry Hicks, who outlined a quick, no-nonsense approach to evacuating people safely from tall buildings. Citing such causes of evacuation as ageing structures, mixed-use buildings and mobility-impaired populations Garry emphasised that the key reason can often be attributed to human behaviour (amusingly – and possibly seriously! – he displayed a fire-safety sign that entreated people to “please exit before tweeting about it”).

He said: “Building management is critical. A building might have all the best systems, but no evacuation system will work without human-behaviour procedures built in and tested to these systems.”

Garry explained that the World Trade Center remains the only real-time, real-event analysis base. He said: “The evacuation of the Twin Towers was a success, in that nearly everyone that could have got out did get out. Based on this, and what happened in the case of the Royal Marsden Hospital fire in 2008, a big lesson learnt was that you can evacuate people so much quicker if you have the right equipment. As long as you have a strategy and the right procedures in place for your tall buildings, it will be fine, but you have to factor in human behaviour and understanding as well.”

The session was brought to a close by Mark Rivers, of Detectortesters, who spoke about the increase in popularity of multi-sensor detectors. While they have many advantages – including better false-alarm management – a key challenge is that having more detector-heads to test means a longer test process.

He went on to explain the change to BS 5839-1, 45.4(j), sub-clause 2, which states that “multi-sensor fire detectors should be physically tested by a method that confirms that products of combustion in the vicinity of the detector can reach the sensors and that the appropriate response is confirmed at the CIE”. This, said Mark, means testing of each head takes two or three times longer.

He wrapped up his brief overview with a list of recommended test methods: smoke/heat/CO all-in-one method; heating up to 100°C; no aerosols; and clearing mode.