21ST CENTURY HIGH-RISE TRAINING SERIES To meet the demand for an ever-more efficient and cost-effective elevator system for high-rise buildings, manufacturers have developed a new concept that can eliminate the need for roof elevator penthouses. Doing so saves building owners an average of...
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How does this affect fire department operations for elevator emergencies? For many years, when fire personnel dealt with elevator entrapments in traction type systems, they would either call the elevator company and have it respond to fix the problem or provide direct intervention themselves. Sometimes, a stalled car can be "drifted" to a designated landing if it is situated between floors, but keep in mind where the car drifts depends on its occupancy load — a full elevator will drift down and a lightly loaded car will drift up. Elevator technicians are in agreement though that this is not a safe procedure to undertake.
Safe Rescue Procedures
Technically, unless there is a true medical emergency taking place within the stalled car or the car is exposed in some way to the effects of fire, there is no "elevator emergency." Occupants may be uncomfortable or inconvenienced, but they are safe. If an immediately pressing event were to occur, the fire department normally would send a member or two-person team to the elevator machine room to isolate power to the equipment so the car will not move from that point on. One member then locks out and tags the switch to prevent someone from inadvertently re-energizing the equipment while the extrication may be taking place. That member should stand by at that location to absolutely ensure the security of the power is maintained. (Note that transmitting on radios near modern elevator machinery may incur damage to the electronics — or microprocessor chip memory — resulting in a possible loss of all cars in that bank). Traditionally, firefighters are sent to where the machinery is located, which is typically one or two floors above the last floor served. The machine room houses the main-line disconnects the fire department looks for in these incidents.
With this new generation system, the driving machinery is now condensed into a "pod" of sorts and can now be located within the shaftway. The most important factor involved here pertinent to fire department operations is that the electronics (and shutoffs) can be located virtually anywhere — up to 200 feet from the hoistway machinery.
You could imagine a call where fire personnel respond to a heart attack victim or a woman giving birth in a stalled elevator after hours when the engineer is off site. You are greeted by a security guard who knows nothing about the building's systems. You immediately send a member up above the last floor served by that bank to secure the hoistway equipment to perform the rescue — only to find out it isn't there. You have the guard call the engineer at home, only to discover he's on vacation. Now what? You would certainly hate that sinking feeling when things are suddenly not going well, leaving you scratching your head as the mystery unfolds before you. I can see where an inexperienced officer panics and chooses to try and effect the rescue with the cab still under power. Dangerous, indeed.
It should be noted that another manufacturer locates the control space adjacent to the elevator hoistway and uses a mechanical brake release device (a lever with a cable, to drift the car). The device is labeled "Emergency Brake." This can be somewhat misleading to first responders. For instance, at the end of every subway car in New York City, there is a handle labeled "Emergency Brake." When you pull it, the train stops. If you pull the lever with the aforementioned elevator setup, the car starts to move — not stop. It probably should be labeled "Emergency Brake Release."
The Gen2 control system has a built-in manual rescue feature that allows the use of battery power control to pulse the brakes and bring the elevator to a stop at the next-closest set of doors/landing, which may be above or below where it stalled. Once stopped at a set of doors — with the power off — the passengers can manually open the doors with less than 70 pounds of effort (provided there are no restrictor bars present which prevent the doors from being opened by the car's occupants).
Gen2's application is not restricted to replacement of traction elevators, as they are becoming popular in replacing costly and mostly inefficient hydraulic elevators as well. Hydraulic systems will probably cease to exist in new construction within 10 years, particularly those with in-ground cylinders, and replaced with Gen2 type applications.