In the aftermath of the horrendous Grenfell Tower disaster in London last year, I would like to know why rescuing trapped individuals appears to be beyond our present capabilities. Why can鈥檛 we construct ladders that will reach people trapped in tall buildings? Why can鈥檛 all towers have nets that can be deployed around their bases to catch those willing to jump, especially if combined with occupants being provided with inflatable suits to cushion their fall? Why can鈥檛 helicopters be deployed to rescue those in windows or balconies? Why aren鈥檛 all occupants of high-rise apartments given the chance to escape by sliding down wires or slides? Why are such suggestions considered outlandish?
鈥� The reason most are considered outlandish is that few such ideas could work. Nets around towers would be vandal-prone and need a lot of maintenance to ensure they were ready for an emergency. Unskilled people falling more than a few metres into nets could break their necks, inflatable clothing or not. Nor can jumpers rapidly vacate a net 鈥� before hundreds of people could evacuate, many would die landing on each other. Fire escapes are more useful. Forget helicopters, unless an undamaged, accessible helipad is on the building, but it would still take many helicopters to evacuate a large building.
Some ideas might be worth developing. Suitable fire-escape parachutes could ease victims down cables. Individual fire-escape reels could be designed to unwind at a controlled speed to lower occupants to the ground, or something could be based on a zip line. Fire-escape slides or ladders deployable externally from the top of the building might work, but deploying them in emergencies would be a challenge. Rationally designed lifts are probably the best escape route while the building remains intact, but current design standards mean most lifts are not useful in emergencies.
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鈥淔lying helicopters next to burning buildings with falling debris would be especially dangerous鈥�
I prefer the idea of those who are trapped jumping into inflatable funnels that can rise to a few hundred metres, deployed and steered from a rescue vehicle. Controlled airflow and baffles in the funnel would avoid dangerous speeds and rescued subjects could be extracted at the bottom.
Jon Richfield, Somerset West, South Africa
鈥� The longer a ladder is, the stronger and heavier it needs to be. This would make ladders capable of high-rise rescues hard to manoeuvre in narrow city streets. The limited access to the area around the base of Grenfell Tower made it much harder for the London Fire Brigade to set up normal appliances.
As for nets, in order to slow someone鈥檚 descent gently enough to avoid fatal injuries, they would need to be suspended high off the ground. This would make it tricky to set them up quickly. They would also potentially get in the way of firefighters. Inflatable suits would need to be very bulky to make a difference and would slow down people trying to escape.
Flying helicopters next to buildings is dangerous at the best of times, especially if the building is on fire and debris is falling from it. Zip wires have some merit, but are slow, heavy and need training to set up, not to mention suitable anchor points. Along with slides, they have their uses in situations where the risk of a fire is relatively high 鈥� Boeing has them at space launch sites, for instance.
I suspect that most such ideas are thought outlandish for tower blocks because the strategy of containing a fire within a single flat is cheaper, easier and usually very effective.
Richard Miller, London, UK
鈥� There are better solutions than nets and wires and so on. By all means use cladding to make a building look prettier, but use non-flammable materials. Design the building to resist fire, avoiding cavities through which it can spread. Install sprinklers and pressurise the air in stairs and lift shafts to help keep smoke at bay, and hence provide a safe exit path where temperatures, visibility and toxicity are kept within safe limits long enough for people to escape. You could include a bridge to an adjacent tall building.
Allow for safe refuges, to give time for the fire brigade to rescue the occupants, such as installing entrance doors to flats that are able to resist a fire for longer than 15 minutes.
And finally, towers should have a means of warning the occupants of an emergency evacuation.
Terence Hollingworth, Blagnac, France
鈥� During my 32 years in the fire and rescue service I have been to numerous fires in flats, and the fire had never spread beyond the flat where it started.
This is how buildings must be designed. However, for the policy advising residents in other flats to stay put during a fire to be reliable, design and maintenance of the fire resisting components and fire doors is vital.
As for outlandish ideas, in the Victorian period there were numerous patents for self-rescue devices to use in a building fire. One I recall was a cord concealed in a gentleman鈥檚 belt, which could be used to escape down the outside of a building.
Derek Wheeler, Cheltenham, Gloucestershire, UK
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