WTC Elevator Emergency Brake Questiongreenspun.com : LUSENET : Elevator Problem Discussion : One Thread
(Question at bottom of message)
I read a story in the New York Times about a group of people caught in an express elevator that fell when the 2nd plane hit the 2nd tower. I don't know if it was a free-fall, but I don't think so. They pulled the emergency brake, stopped at the 50th floor, and had no way out as it was a "no-service" floor. They had to scrape and dig through the shaft wall and barely got out of the building in time before it collapsed. If they had pulled the brake a second sooner, and stopped, say, at the 55th floor, they wouldn't have had the time to get out of the building.
Question is: if they had not pulled the brake at all, what would have happened to the elevator?
-- Sara P Subtil (email@example.com), October 11, 2001
what brake? have you seen a brake lever in a elevator?
-- jag (firstname.lastname@example.org), October 12, 2001.
Isn't it right next to the clutch
-- Charlie Mankin Local 37 Columbus, Ohio (KS8L@ee.net), October 18, 2001.
All very well and good, talking about emergency brakes......
But did anyone apart from me pick up on the fact that these people allegedly dug through steel reinforced concrete walls?
I want to know who their manicurist is.....
-- Justin Ward (Transistive@planetaccess.com), October 19, 2001.
1. This was a true incident, as reported in the "New York Region" of the New York Times sometime between Oct. 8 and Oct. 10. 2. Thanks to AKAELEVMAN@aol.com, who sent a timely and informative an e-mail response to my first question. (Did not post.) 3. This is what AKAELEVMAN@aol.com explained: "There is no "emergency brake" activation button in elevators. The "Emergency Stop Switch" interrupts the electric power, but that won't stop a falling elevator. There is a mechanical device to do that and it is activated automatically upon overspeed. This likely is a case of the facts being reported incorrectly in the media, which is very common especially on details. If in fact the passengers activated the Emergency Stop switch and that stopped the car, they probably could just have turned it back on and the car would have proceeded to it destination." 4. So from this information, it is obvious that the elevator was definitely falling and that the "overspeed" safety device kicked in and stopped the elevator. No one "pulled the brake." And yes, they DID dig through the shaft wall -- if you look at an Architectural Graphic Stadards volume, you'll see that shaft walls are NOT CONCRETE, but are 3" to 5" thick gypsum (Sheetrock) and metal stud assemblies that provide between 1-hr and 3-hr fire protection. 5. Thanks all in your interest in my posting.
-- Sara P Subtil (email@example.com), October 19, 2001.
Ive got a question ... doesnt elevator code state that a facia be between the hoistway wall and the elevator car to prevent someone from crawling around the front of the car? and i know that this is the case here cause its in the elevator code and i know the code is inforced on the east coast..
-- jag (firstname.lastname@example.org), October 21, 2001.
elevator shaft walls may be of a variety of materials, although concrete or steel is required for structural areas, the rest can be layers of fire rated drywall. however, codes do require sheet metal facias mounted in all cab door openings not at floor levels to prevent passengers from exiting the cab. to have escaped as described would have been very difficult at best
-- cliff smith (email@example.com), October 28, 2001.
The WTC buildings were built before the current fire codes and probably did not have restrictors. It was common practice to pull the entrance side drywall to 1" clearance and eliminate the need for fascia. John (firstname.lastname@example.org)is correct. Laying on the floor of the cab and applying ones feet to the drywall would work.
-- Fred Baltes (Elman101@pacbell.net), November 03, 2001.
They may not have 'pulled the brake', but digging out can be and was done, according to ELEVATOR WORLD ELENET....
WTC WINDOW WASHER HONORED: The International Window Cleaning Association recognized Jan Demczur at its annual convention recently. He is the window washer who saved himself and five other men trapped in an elevator in the North Tower of the World Trade Center (WTC) on September 11. Demczur and the others used his metal squeegee to cut through the hoistway wall when the express elevator stopped between floors.
-- Don Vollrath (email@example.com), January 24, 2002.
I am now doing my practical semester in Germany and my project is all about emergency braking system in an elevator. From what i know about the braking system, the emergency will only be operated mechanically due to 2 reasons: 1. The elevator is over the speed limit(or free fall). 2. There is no electricity.
-- elevator_beginner (firstname.lastname@example.org), August 04, 2004.
This on if for the person who thinks elevator shafts are made of 3- 5" of gypsum board and built up studs...ok here we go... I am a architectural technologist so ill give you some insight.
First of all a building is composed of posts and platforms.. alone the building would easily tip over, because it has no lateral support. thus we introduce shear walls.. sheer walls extend the entire height of the building in one continous concrete poor. without these walls, the building would be easily pushed over.. other shear walls found in a building is all mechanical duct shafts and all stair case shafts,, and yes elevators. elevators are incased in a 4-5" reinforced concrete box... loaded with steel rebar.. no way anyone got through the shaft... unless they were to use the maintanence ladders in the shaft and crawled up up the next floor and somehow opened the doors.. besides that... breaking through the wall... no dice
-- Sheldon (email@example.com), February 12, 2005.