The Grenfell tragedy and other high level fires have raised public debate as to whether firefighting should go airborne for roof-top rescues and high-level fires.
The most famous such rescue was during Al-Qaeda’s first terror attack on the World Trade Centre in 1993. They exploded a van packed with explosives in the underground garage of the North Tower, hoping to topple the building. That failed but it sent a column of thick black smoke up through the building – 28 people climbed onto the roof.
A NYPD helicopter, rushing to the scene after the report of the explosion, lowered two officers onto the roof, cutting down obstacles and antennae to make a landing area, and people were airlifted to safety.
However, there was not universal approval of the tactic, particularly from the New York Fire Department, who argued there were many dangers attempting air rescue in built up areas, while the owners of the World Trade Centre – the Port Authority of New York and New Jersey – rejected a NYPD request for a heli-pad on the North Tower, and reinstated the much-needed communications antennae.
When the Twin Towers were attacked again on 9/11, two NYPD helicopters were immediately on the scene, one of them a Bell 412 equipped with a 250 foot hoist, and capable of carrying 10 passengers. However, this time there was no-one on the roof as the access doors had been kept locked for security reasons.
So is helicopter rescue an option? Firefighters think not. Safety Advisor to the Fire Brigades Union Dave Sibert said that the general consensus about such an option was that the negatives outweigh the positives, adding that such rescues from high rise buildings were “…something that happens in Hollywood, not real life.”
The reasons cited are manifold:
- It would be rare in a high-rise fire for the conditions to be suitable to execute a safe landing. Escaping smoke and flames tend to cling to the sides of the building in what is known as the ‘Coanda Effect’ – the rule of physics where a jet stream stays attached to a convex surface – thus obscuring visibility of any obstacles in and around the building. Certainly, the dense smoke during the Grenfell fire made such a rescue impossible.
- Updrafts from an intense fire creates turbulence, again making landings difficult.
- The downdraft from a helicopter’s rotas could exacerbate the fire.
- A pilot cannot be sure the building is stable or that the roof has not been compromised by the fire.
- The numbers that the small type of helicopter capable of landing on a rooftop could carry is very limited, of between 8 – 10 people.
- Airborne hoists of the type used in air-sea rescue are very limited, being able – if possible in dense smoke – to rescue one survivor at a time, a slow process in what would be a very fast-moving incident.
- It would involve upward evacuation up-stairs, with people more prone to mobility issues and fatigue, compared to downward evacuation.
- Manoeuvring an aircraft into a high density, urban area would create more risks to the public than perhaps the actual fire. The crash by a police helicopter into a pub in Glasgow in 2013 killed 10 people and injured scores more.
So with such a risk assessment, it can be seen why there is reluctance to invest in this type of rescue. That said, the drones being developed by the military world-wide may raise such possibilities in the future, with drones doing the dangerous work.
The other possibility is whether fire-fighting capabilities can be delivered from the sky, but this too is limited. The vast quantities of water dropped by aircraft in forest fires (called ‘waterbombing’) does not need pinpoint accuracy and is in unpopulated areas. By comparison, a burning tower block is a miniscule target – if the pilot missed there would be damage to surrounding buildings not to mention danger for the firefighters, emergency services and local public on the ground: the average weight of water dropped in a waterbomb is around three tons.
Also, as firefighters understand, it is the base of the fire that needs to be attacked rather than a scattergun burst from above.
Airborne firefighting may be a factor in the near future; all around the world, buildings are getting higher, particularly in areas of the world where land for urban development is at a premium.
The Russians have developed the new Ka-32A 11BC helicopter which can include a water cannon. However, the limitation is the amount of water an aircraft can carry. For example, a typical water cannon ground vehicle used for riot control only has four minutes’ worth of water.
In Dubai, they have developed a ‘strap-on’ drone that can take a (very brave) firefighter up to a thousand feet with 60 litres of water. And hopefully a parachute too.
However, given the hit or miss nature of airborne rescue – although still always an option – the solution must be in building in fire safety measures from the start.
One example to follow may be Los Angeles. The Fire Department there recently relaxed ‘LAFD Requirement No 10’, first introduced in 1958, which demanded the city’s tallest buildings must include heli-pads for the Fire Department’s helicopters. In response however, the buildings’ owners must include ‘compensatory measures’ including more stairways, elevators, sprinkler systems and safety cameras.
- This is an extract of a full feature in Resilience magazine, the quarterly journal of the EPS. Free subscription to the magazine is one of the benefits of joining the EPS – to join,