Escaping a high rise fire.

Discussion in 'Architecture & Engineering' started by kwhilborn, Nov 18, 2012.

  1. kwhilborn Banned Banned

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    Escaping a high rise fire should not be dependent on internal stairs.

    I was watching a story about a proposed personal parachute for high rise employees when it struck me a rail system built upon on the walls of every new high rise could be incorporated into the designs without affecting appearance much, and would be comparatively cheap at 50 (1 or more every side) feet of rail per floor.

    I soon found this was not an original idea and basically common sense, but how come nobody is doing it?

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    This diagram has various sleds that I guess could be put on a specialized rail by a fire department and controlled via remote control with or without firemen aboard depending on risk.

    It also has personal rails where you could attach your personal harness and slowly glide to safety (or perhaps danger on floors below). If the rail is broken somewhere then a battery operated emergency light could warn people on affected floors that "this rail is out of service" and make them stagger through the smoke (or not smoke) to the next escape.

    This could obviously work, and could easily and affordably be incorporated into future buildings.

    Unfortunately public safety features often need to be made law before we would ever see them.

    In other instance of lower buildings perhaps a rail and platform system that automatically returns to the required floor could replace some outdoor stair fire escapes, although that needs some thinking to engineer.

    This is just something that seems obvious. I wish they would do it. It might take courage to use an outdoor rail system, but if your choices are limited it might seem a welcome escape.
     
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  3. Rhaedas Valued Senior Member

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    You might find this PDF from FEMA interesting.

    www.usfa.fema.gov/pdf/efop/efo39062.pdf

    Looks like there's a lot of options out there, but I guess the risks are generally too high. One point even notes that with such systems in place, they need to be a secondary one of last resort. And of course, some people just aren't go to be able to make themselves go outside the building like that, even if they are threatened with death.

    I think the general consensus with the agencies involved is that it's better to try and make the building secure and automatic in its responses to things like fire, rather than go overboard on escape systems. Yes, now and then you'll have situations that are unique, but the costs involved for every high rise to have something, just in case that one time occurs, makes this impractical.

    And then, imagine the law suits that would inevitably occur when people misuse such a system and get hurt.
     
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  5. Buddha12 Valued Senior Member

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    The best way is to prevent a fire from getting started to begin with. Fire supression systems are much easier and cheaper to install throughout the building which can stop a fire from spreading any further than the room it started in.


    Applying physics to put out a fire, as opposed to chemistry, is an idea DARPA has been eyeing for a while, and it might lead to military devices that can better snuff out fires in enclosed places. Now they have demonstrated a new device in action.

    In the video, two speakers are placed on either side of a fuel source. The sound increases air velocity, which disrupts the flame. It also causes higher fuel vaporization, which increases the flame's area while dropping its temperature. That thinning causes a problem in the combustion process.

    It looks like an interesting project, but even DARPA admits they aren't sure how they'll use it. To make it worthwhile, it would have to operate on a much larger scale. They're hoping instead that the project will inspire other ideas in the field, so soak in the video in case it's the last you see of the technique.

    http://www.google.com/url?sa=t&rct=...qoDIDw&usg=AFQjCNE5hxar6U_h_5TJ3CIGXwmFUTFpUA
     
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  7. Rhaedas Valued Senior Member

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    Thought of another example of how overdoing a design can be more of a problem. In some of the planes my company flies (might be true through the industry, don't know), at one time they had an inertia reel to aid in the pilots getting out in case of emergency. Problem is, people got hurt sometimes when they used them. So now they have what they originally had, a simple rope to throw out of the window.

    Now maybe that approach could be used. Have ropes stored in a fire closet near window areas, and have people trained in basics on how to descend a rope using equipment like a mountain climber has (don't know the terminology). That way, in case they cannot use the stairs, another choice is available, but it's not overly complex to fail.
     
  8. kwhilborn Banned Banned

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    @ Rhaedas,
    The fire escape PDF you linked was interesting but they did overlook the plan in OP. They did mention rails with moving platforms, but I also mentioned single rails with controlled decent harnesses that they did have cable versions of. Maybe the rail system is not as common idea as I thought.

    They should have a rail outside the captains window (in aircraft) that they can grab the handles and glide down, although there would be no harness in that set-up. Just a thought

    The rope ladder is a first thought, but could an elderly lady climb down a wobbly ladder the height of a World Trade Tower?

    @ Buddha,
    Smoke is the worst danger. Toronto had an "Inn on the Park" Hotel fire that was confined to the kitchen. The smoke reached upper floors through the elevator shaft and some guests panicked and tried for safety via the stairwells. 6 people died attempting the descent, and if they kept to their rooms they would have been fine.

    http://www.nytimes.com/1981/01/18/w...h-soot-guest-inn-park-accepts-cup-coffee.html

    Quick fire response/prevention would be ideal. Instances involving potential wartime scenarios might also be involved in the lifetime of a highrise.
     
  9. billvon Valued Senior Member

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    A few notes:

    1) In Korea I have stayed at several hotels where the emergency escape system is a rope and a glove in a box. Simple and foolproof, provided you measure the rope correctly.

    1.5) If you like the "personal harness" idea give everyone a rope, a harness and a descender.

    2) If you are relying on rails and have less than one rail per person it's not going to work well. Most people will balk at getting out onto the rail, thus rendering that rail inoperable.

    2.5) Having an automated system that detects rail problems with any degree of accuracy is going to either unreliable or expensive.

    3) Parachutes definitely work but unless you have the experience to use one they will kill more people than they save.

    4) If you really want to do this, use fire escapes. They have a long history and work well.

    You'd have to demonstrate that it would save more people than it would kill, which would be hard to demonstrate.
     
  10. kwhilborn Banned Banned

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    @ Billvon,
    The rope would be good, but I'd want it to be somewhat fire resistant. That was my main concern. Funny that Korea Hotel had one. That would set the grounds for a good nights sleep. If I went to work at the empire state building and HR handed me a rope and a descender I'd probably not return.

    I think balking at getting out on the rails would discourage panic use, but would allow an alternative to jumping.

    When I was thinking of detecting whether the rail was intact, I was more thinking of a completed circuit. If an airplane/missile/melting fire were to destroy some part of the rail then the circuit would fail. It would be like a giant circuit tester (my fav tool btw) from the dollar store. with lights on each floor. It would not show the condition of the rail, but being intact along wth a visual look down might confirm it is a viable exit.

    The word trade center would look silly with fire escapes.

    A rail system would allow fast elevators to be quickly installed, or built into the buildings roof or basement. A building like the World Trade Center could have 2-3 elevators per side running on 4-6 rails.
    Note: The word Trade Center towers had so much damage that even a rail system might have only been operable for a short while on one or two sides.

    Currently there is no escape systems in high rise buildings aside from internal fire escapes which tend to get smokey. This idea seems like common sense.

    Th rope idea is also a good one, but people would be affected by the wind and would be subject to the same amount of fear as rails.

    As in the picture above fire suppression equipment could also ride up rails for that and neighboring buildings.

    I think any idea is better than no idea. It might only save the lives of those brave enough or scared enough to use it, but it beats jumping or burning.

    Todays buildings are virtually fire resistant. I doubt any such escape plan would be necessary in a non war scenario.

    One thing good about a rope and gloves/harness is that a fire department could make possibly kits and fire them through windows into burning buildings from helicopters or neighboring buildings if the building is not prepared.
     
  11. Rhaedas Valued Senior Member

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    If a rope is close enough to a fire to ignite, I doubt anyone is going down it, resistant or not. Unless you're talking from a storage point of view, but the case remains the same. If the fire is around the rope, it's not useful.
     
  12. billvon Valued Senior Member

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    The most important part is that one balking person could not stop 200 people from using the system. A secondary consideration is that it does not need any modifications to the building, it can be inspected before use and is not subject to damage from external events.
     
  13. kwhilborn Banned Banned

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    True. speed control would need to be preset so nobody could slow their decent once embarking.

    I think if one of my kids ever worked that high up I'd give them a personal chute over a rope, but I suppose personal safety will stay primarily the concern of those working high up, and not regulated.

    Ropes are also a lot stronger than they were, and you could probably come up with a thin nylon rope capable of 1000 lbs weight on a quick decent rate reel. If you are the only person with a rope you may get 20 other people attempting to use your rope, so getting down quickly would also be necessary.
     
  14. billvon Valued Senior Member

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    No, way before that. At some point, after you have connected your harness to the descender you have to step out of the building, 100 feet in the air, and trust that the descender/harness will take your weight. I have taught both climbing and static line skydiving, and can tell you firsthand that a lot of people balk at that - and these are people who have already had training, and who know exactly what's going to happen. Untrained people? You'd be lucky if 1 in 2 people was willing to do that. Which means that if you have 10 escape rails you're only going to be able to get 20-30 people out on them before each one has a balker stopping things up.

    The odds of the parachute killing him would be FAR higher than the odds that it would save his life, so I'd suggest against that. (Unless he's a BASE jumper to begin with)

    1000 lb Spectra is 1/8" (3mm.) 5mm nylon rope is around 1100 lbs. Generally for life safety applications you want tensile strength to be 10x working load, so you might have to go a bit thicker.

    Keep in mind that if you are using a reel system no one else can use it. (Unless you plan to "re-reel" the line or something which would not likely work.) If it was designed to accept a descender you could, but those ropes need to be thicker since friction against the rope is what slows you.
     
  15. Rhaedas Valued Senior Member

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    Parachuting within a city, you'll have a lot of people smacking into the sides of other buildings, or worse.

    It just makes sense to try and minimize the impact of the fire right away. Much better to invest a lot into fire suppression systems than trying to get people out in risky ways, relying on their courage and skill.
     
  16. kwhilborn Banned Banned

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    Probably the best bet
     
  17. Peter Dow Registered Senior Member

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    What about an external helical rail - you put on a harness with the appropriate hook and slide down helter-skelter style? This has the advantage that the gravitational potential energy of your body up a sky-scraper is partially converted to rotational velocity and partially converted to heat in the friction between your hook and the rail. The main problem being that buildings are not generally circular and so you'd have an issue designing the rail to be close to the windows for people to hook on yet not have too much of a 90 degree sharp turn as you slide around the corners of the building.

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  18. billvon Valued Senior Member

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    Issues I see there:

    1) The centrifugal forces would be large during a fast descent and thus you'd need to overbuild by a lot.

    2) If you clipped on just as someone else was coming down you'd get a catastrophic result.

    3) It has the "balk" issues mentioned above - one person clipped on but refusing to go stops the entire system.
     
  19. Peter Dow Registered Senior Member

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    125
    Well helter-skelters were and probably still are made out of wood and work fine. Overbuilding by a lot is still a modest weight of steel.

    The one solution to both those issues is to have "pit stop exit rails" leading down and out from the windows to the main helix - this way people balking don't interfere with the main helix, only their pit stop and once they commit to descending down their pit stop exit rail they have no choice but to accelerate down to join the helix at the regular speed so that bumps are at very similar speeds.
     
  20. Peter Dow Registered Senior Member

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    Of course for sky-scrapers in conservative Muslim countries where separation of the sexes is standard, there'd be one helix for men and another for women - a "double helix" so to speak.

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  21. youreyes amorphous ocean Valued Senior Member

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    Meanwhile the Sci-Fi enthusiasts imagine the: inflatable parachutes attached to each window for escapee to jump with, ladders that extend down to the safety of the ground, jetpacks for CEO's, and thin carbon fiber ropes to dwinddle down with a motor slowing down the descent...well here is the reality of how exactly people from high rise building get down...

    http://www.google.com/url?source=im...AoQ8wc&usg=AFQjCNF2NmJSgl86rlD2qI89t4MirlIy9A
     
  22. Peter Dow Registered Senior Member

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    Pit stop exit even sounds like a fire alarm!

    [video=youtube;Snid9jC3nPk]https://www.youtube.com/watch?v=Snid9jC3nPk[/video]

    FIRE!

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  23. billvon Valued Senior Member

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    True, although once you add the factors of a harness plus a track and the issue of evacuating X people in an hour, you're not going to get away with slide speeds.

    If you are going to require everyone to wear a harness and pulley/friction brake anyway, then just give everyone a harness and a one time use friction reel with an appropriate amount of kevlar line. Such devices are pretty commonly available. That way a balk only slows down that user, there's no common track to jam, foul or melt and there's no single point of failure.

    That could work, although I would suspect that a mechanical interlock that accurately sequences new additions might have some trouble working well after spending 20 years in the sun, rain and snow. (You could certainly have a maintenance/testing program to keep them well maintained, but now you're getting pricey.)
     

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