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 $35,000 by not having to construct this enclosure, or provide heating, ventilating and air conditioning (HVAC), lighting and fire protection. This new concept also eliminates the need for elevator machine rooms, which take up valuable space within the tower when there are multiple elevator banks involved (i.e., low, mid and high banks). All fire departments should be aware of this, since it can affect standard operating procedures (SOPs) for elevator emergency responses.
Although there are several variations of this new concept, this article will focus primarily on the introduction of the "Gen2" elevator system, which is patented and manufactured by Otis Elevator Co. It is indeed the "next generation" of elevators. By seeing beyond the limitations of conventional wire ropes, Otis found a way to increase flexibility and strength with the use of polyurethane-coated galvanized steel belts that provide greater traction and are two-to three times more durable than conventional wire ropes.
The new design also eliminates the problems associated with rust and lubrication requirements of wire ropes. Traditional wire ropes require a large bending radius, which requires a sheave at least 40 times the diameter of the wire rope.
In a conventional traction system, the drive sheave and hoist motor are located in the machine room above the hoistway, along with the governor and a controller. In a conventional traction configuration, a single machine room may contain the controls, governors, hoist motors and associated electrical equipment for several elevators. Structural steel or concrete support is required for each elevator.
In the Gen2 system, the machine, governor and support elements are combined into a compact machine mounting structure housed within the upper region of the hoistway, eliminating the need for a rooftop machine room. The Gen2 coated-steel flat belts allow a significantly smaller bending radius over conventional wire ropes. The sheave height requirements are reduced to only four inches, which means the elevator motor runs at a faster, more efficient speed. The typical sheave height on regular traction elevators is about 36 inches high (see photo on page 118). The smaller sheave requirement allowed Otis to engineer a unit that is 70% smaller and 50% more efficient than conventional geared machines.
The new, permanent-magnet gearless machine's sealed bearings require no oil and eliminate the energy loss of larger systems, reducing power consumption. The unique, lubrication-free system eliminates the repeated lubrication, clean-up and hazardous waste disposal of conventional systems. The Gen2 roller guides are also lubrication-free, unlike conventional hoistway slide guides.
Another advantage of the Gen2's design includes the reduction of car noise by 30% over traditional systems, as well as reducing vertical and horizontal vibration by as much as 75% when compared to conventional equipment. The end result is a much quieter, smoother ride. Harnessing new technologies to fit within existing industry standards, Otis has created a smart, compact system that defines the next generation in efficient elevator operation. It should be noted that, at present, the maximum rise with this system is 300 feet, or around 30 floors in a hotel/residential setting where the floor-to-floor ratios are about 10 feet. It can handle up to eight cars in a group or four cars in a "bank," which is mandated by code.
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.
Technology advancements are unquestionably outpacing the fire service's ability to keep up with it all. Tour your buildings as much as possible and ask questions about "new-age" systems that may have been installed. The public expects you to stay on top of these changes, yet education in bridging the communication gap between the private sector and the fire service is just not taking place, except in articles like this one. As building system technology continues to evolve, firefighters must remain constantly vigilant to these changes that will impact their operations on a particular incident. Ideally, the situation would never occur where fire crews are caught unaware regarding new technology in the middle of a working incident and not know what to do in managing it. Be aware, be knowledgeable and be safe.
Many thanks to Otis Elevator Co. and its highly knowledgeable technical personnel for their assistance with this article.
CURTIS S.D. MASSEY is president of Massey Enterprises Inc., the world's leading disaster-planning firm. Massey Disaster/Pre-Fire Plans protect the vast majority of the tallest and highest-profile buildings in North America. He also teaches an advanced course on High-Rise Fire Department Emergency Operations to major city fire departments throughout the U.S. and Canada. Massey also regularly writes articles regarding "new-age" technology that impacts firefighter safety.
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