Can we save people from tops of burning buildings? Ideas please?

[Fat Controller]

 

 

 

Good points. Especially: "positive pressurisation of escape routes to keep smoke out"

What an idea. I've not heard of that before? If it could be done at almost any cite by something brought along it would mean buildings wouldn't need costly changes. Has such a process actually been used or tested ever?

 

'Positive pressurisation of escape routes' has been used in the Channel Tunnel since its opening. The Service Tunnel is at an appreciably higher pressure than the running tunnels, and airflow from the Service Tunnel can be used, via the cross-passage doors, to create a 'bubble effect' around the Amenity Car, should it have to be evacuated.

[How about a Dictator Loco Class?]

 

More representative are the (two) fires in the Dubai skyscaper ironically named "The Torch". I don't believe there were any fatalities. You might find this interesting from the Wikipedia page on that building.

 

The jet packs mentioned in the wiki link are Dubai money though. Far too expensive and not massively practical. But at least they're trying to think out of the box and solve things. That's good.

[How about a Dictator Loco Class?]

I'm afraid I can only echo the above two posts. I very, very much doubt there was a case of "we know it'll go up in smoke but we don't care." Never explain by conspiracy that which can be explained by cock-up. As for saving people, AIUI the building as built would've been OK, it would've never got beyond a minor fire in one flat, so it sounds like we probably already know how to build so the question of rescue is academic.

 

 

Actually that's a quite reassuring point. 99.9% of the time our current building knowledge and rules save us from tragedy. We're already sorted as long as our rules are followed.

[62613]

Fireproof lifts.

All evacuation instructions I've ever seen have said "Do Not Use The Lifts"

[Nearholmer]

Fire protected lifts, with precautions such as pressurised shafts, protected lobbies etc are used for escape in some very specialised circumstances.

[Vecchio]

All evacuation instructions I've ever seen have said "Do Not Use The Lifts"

 

These are special lifts for the fire brigade. Powered by special fire resistant cables which will work for a minimum period of 120 min in the fire - even if things are falling on them or they are hit by the water of the fire fighters. 

[Titan]

Yes if it can work it would be great. We just couldn't have it stop at a burning floor though. Or a hugely smokey floor when people are coming down and it keeps stopping at smokey floors it could prolong the problems. If doors open sometimes the air draft from the lift shaft can feed the fire I've heard. If fireproof lifts could be controlled by the fire fighters manually so it can stop at a floor and look to see if it's ok to open the doors or not it would help. And an instantaneous instead of delayed door shut feature for fire fighters maybe.

 

I think the main advantage of fireproof lifts would be to get the firemen to the top floors without using up all their air climbing stairs, this was a big problem at Grenfell, as well as the fireman having to fight past all the people coming down stairs. If the firemen had control of the lifts from within then with radio contact they could stop only at the floors where there was a need - for example evacuating someone who was incapacitated quickly.

 

All evacuation instructions I've ever seen have said "Do Not Use The Lifts"

 

Er, that is because they are not fireproof, which is what I am talking about.

[Joseph_Pestell]

Not the case at Grenfell, but a lot of tower blocks are in groups of similar buildings (estates). Should not be difficult to link them with permanent wires that could be used in an emergency.

 

Permanently pressurising the escape routes would be expensive in operation. But should be possible to have a system that kicks in with the fire alarm system.

Edited July 19, 2018 by Joseph_Pestell

[jjb1970]

I think the problem with lifts is less about their fire retarding properties than the possibility of becoming trapped inside if the power supply fails. And it is probably undesirable to create a situation where people are stood around waiting for the lift rather than just getting out via the stairs.

[Nearholmer]

"Permanently pressurising the escape routes would be expensive in operation. But should be possible to have a system that kicks in with the fire alarm system."

 

Yes, that is often what is done.

[jjb1970]

As a rule of thumb simple passive technologies are best where possible for things like this as they are inherently more dependable.

[jjb1970]

Duplicate post, sorry.

Edited July 19, 2018 by jjb1970

[Pacific231G]

I'm no expert on fire fighting and evacuation (though I am used to carrying out hazard assessments) but the thing that struck and surprised me about the Grenfell Tower disaster was that there was only one staircase.

 

Since the Hartley pit disaster in 1862 it's been compulsory for coal mines (and for decades almost all mines)to have more than one means of escape, usually a second shaft well separated from the main. 

Being trapped in a high rise building with no realistic means of external escape (helicopters and zip wires are pure fantasy when it comes to a mass evacuation)  is rather analogous to being trapped in a mine so surely the same rules should apply. I think every high rise office building I've worked in has had two sets of stairs in separate wells each protected by fire doors. Pressurising the escape routes has to be a complete non-starter. I don't know how you'd even do it structurally and it would make pushing open the fire doors to escape into the stairwell virtually impossible. 

 

Whenever I stay in a hotel of any size the first thing I do after checking in is  to locate the fire exits; it would worry me greatly to find the main staircase to be the only means of escape even on the second or third floor but that seems to have been the situation in the 24 storey Grenfell Tower. 

 

WTC was a different case but even without evil intent it shows the risks inherent to any very tall building. An accidental collision by a loaded airliner was always a possibility. The Empire State Building was hit by a B25 bomber in fog in 1945 but fortunately its structure was strong enough to resist the ensuing fire and there were just eight deaths of people within the buildng (plus the crew of three of the aircraft) Gas explosions, electrical fires, illicit storage of inflammable materials (fireworks?) are just a few of the things that any hazard assessment should be considering.

Edited July 20, 2018 by Pacific231G

[PhilJ W]

Its time for a complete rethink of the design of high rise tower blocks. I would suggest separate lift towers connected to the tower block by walkways. In some cases they could serve more than one tower block (the existing lifts/stairs to be retained). Or if the blocks are close enough to each other connect them with walkways. This will provide a safe means of escape and/or access to the fire brigade.

[Nearholmer]

"Pressurising the escape routes has to be a complete non-starter. I don't know how you'd even do it structurally and it would make pushing open the fire doors to escape into the stairwell virtually impossible."

 

Pressurisation is used in some circumstances, and it does indeed have to be designed very carefully to prevent it making the doors ludicrously difficult to open.

[Fat Controller]

Its time for a complete rethink of the design of high rise tower blocks. I would suggest separate lift towers connected to the tower block by walkways. In some cases they could serve more than one tower block (the existing lifts/stairs to be retained). Or if the blocks are close enough to each other connect them with walkways. This will provide a safe means of escape and/or access to the fire brigade.

The idea of separate lift towers has been tried; Trellick Tower, on the approach to Paddington has a 'stand-alone' lift tower ( https://www.google.co.uk/maps/place/Trellick+Tower/@51.5236663,-0.2054475,3a,75y,90t/data=!3m8!1e2!3m6!1sAF1QipPbtv1UTw2J9s0y4Xqtudnfi0rl8gbUrF9NCRtk!2e10!3e12!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipPbtv1UTw2J9s0y4Xqtudnfi0rl8gbUrF9NCRtk%3Dw128-h86-k-no!7i3872!8i2592!4m13!1m7!3m6!1s0x48760552b7757447:0xa252c3f55901004!2sPaddington,+London!3b1!8m2!3d51.515973!4d-0.174943!3m4!1s0x4876101a26afafcf:0x1272e6d62fa5cbf7!8m2!3d51.5236661!4d-0.2054478?hl=en)

[EddieB]

I see that laundry chutes have gone out of favour in the US because of fire regulations, but the idea of harnessing gravity for rapid evacuation must have been considered many times before.  Of course there are many problems, such as fire-proofing, keeping clear of smoke, controlling the rate of descent, separating descenders with suitable intervals and ensuring a safe landing site (and dispersal once landed).  Being able to utilise a force which isn't dependent upon external sources of power, is invariable in light or darkness and different temperatures seems to make some sense if such obstacles could be overcome.

[Pacific231G]

"Pressurising the escape routes has to be a complete non-starter. I don't know how you'd even do it structurally and it would make pushing open the fire doors to escape into the stairwell virtually impossible."

 

Pressurisation is used in some circumstances, and it does indeed have to be designed very carefully to prevent it making the doors ludicrously difficult to open.

Are you talking about actual pressurisation or simply positive ventilation flows - as used in say operating theatres and indeed in ventilating mines- where air would generally be moving from the stairwell into the floors rather than vice-versa?

 

I assume the problem with laundry chutes was that they could become a chimney intensifying the fire and possibly spreading it. I think that was one of the reasons for the disastrous scale of the Kings Cross fire in 1987 that claimed 31 lives and the even worse loss of life from the Gletscherbahn Kaprun 2 funicular disaster in Austria in 2000 in which 155 people died, the only survivors being twelve passengers who, on the advice of a volunteeer fire fighter, walked down the tunnel past the fire after escaping from the burning train. Everyone else who got out of the train tried to escape up the tunnel  were overcome by smoke and fire.   

 

I think the most fundamental rethink we need about tower blocks is why we choose to build them in the first place. I'm not sure that they really do allow for higher housing densities given the amount of space around each of them and, certainly for low cost housing, the chances that  corners in building, refurbishment and maintenance won't sometimes be cut are fairly remote.

Edited July 20, 2018 by Pacific231G

[Nearholmer]

“A pressurisation system for smoke and fire ventilation should meet the recommendations of Approved Document B and BS EN 12101-6 "Specification for Pressure Differential Systems" or BS 5588-4 - "Code of practice for smoke control using pressure differentials".”

[Joseph_Pestell]

Of course, the fire brigade themselves have a solution for getting people down from one floor to the next quickly - a pole.

[How about a Dictator Loco Class?]

How far do you go with saving lives though?

Many years ago, during my formative and no doubt naive era, a friend and I were discussing an idea where, in the case of a plane crash, the fuselage could separate and land safely to terra firma via parachutes.

 

Let's be honest, if Air Force One doesn't have it, then commercial airliners won't get it either!

 

 

There are light aircraft with parachutes now! I hope they'll start trying it on slightly bigger aircraft.

[How about a Dictator Loco Class?]

I think the main advantage of fireproof lifts would be to get the firemen to the top floors without using up all their air climbing stairs, this was a big problem at Grenfell, as well as the fireman having to fight past all the people coming down stairs. If the firemen had control of the lifts from within then with radio contact they could stop only at the floors where there was a need - for example evacuating someone who was incapacitated quickly.

 

 

Er, that is because they are not fireproof, which is what I am talking about.

Those are good points! I hope they learn from whats happened and then actually apply the lessons. Also if possible I hope blame isn't diluted away to the point that no people get any punishment.

[How about a Dictator Loco Class?]

Not the case at Grenfell, but a lot of tower blocks are in groups of similar buildings (estates). Should not be difficult to link them with permanent wires that could be used in an emergency.

 

Permanently pressurising the escape routes would be expensive in operation. But should be possible to have a system that kicks in with the fire alarm system.

Those are really good points surely! It's doable.

[Pacific231G]

“A pressurisation system for smoke and fire ventilation should meet the recommendations of Approved Document B and BS EN 12101-6 "Specification for Pressure Differential Systems" or BS 5588-4 - "Code of practice for smoke control using pressure differentials".”

Interesting. I wouldn't have seen the pressure differentials they use which are typically 50Pa as a very significant pressure difference. 50Pa is the equivalent of 0.5Hp (0.5 millibars in old money) which equates to the difference in atmospheric pressure you'd get over a height of about 4 metres. Presumably though that's enough to  ensure that air flows are where they need to be.

[E3109]

Fire protected lifts, with precautions such as pressurised shafts, protected lobbies etc are used for escape in some very specialised circumstances.

Indeed. But such extravagance is not for The Mere Plebs. (aka us).