Exterior Access to High-Rise Buildings
APPARATUS INNOVATIONS
STAFF REPORT
When the need for more living and working space was realized, the construction industry built up, adding story on top of story. The fire service met this construction trend with tower ladders and aerials, the newer ones reaching to heights over 100 feet.
But with still more and more space being needed, and more and more stories being added, emergency access to floors above the reach of firefighting apparatus is often delayed. Also, staging areas, which must be set up as close to the incident as possible, are sometimes located five to six stories below the fire floor due to the often impossibility of performing necessary horizontal ventilation.
Photos by Glenn usdin
Although venting will frequently be a problem with high-rise fires, getting fresh firefighters and adequate equipment up to the incident and civilians down may not have to be.
A high-rise rescue system developed by Gebr. Wahlefeld of West Germany is capable of reaching the fiftieth floor of a high-rise within 10 to 12 minutes after arrival at the fire scene, says Douglas G. Eastwood, president of Wahlefeld Safety Corporation, Gebr. Wahlefeld’s United States representative in Butner, NC.
The rescue system, which operates on the same principle as an exterior elevator, is made up of:
- Two fixed parts: a hinged rooftop boom (jib) and leader cables permanently affixed to the face of the building.
- A gondola or cradle that travels along the cables up the side of the building in a horizontal or vertical mode.
- Hydraulic winch units with load and control cables.
- A truck-mounted hydraulic winch system that transports the equipment and powers the winches.
The building’s cables, 1/4-inch rustproof steel, pass over the sheaves on the rooftop booms and are fastened with quick-disconnect couplings.
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The double wall aluminum, rubber insulated gondola is capable of carrying 2,200 pounds and moving at a speed of 10 to 20 floors per minute. Fold down litter wings (ramps) on either side of the gondola and a drawbridge in front makes for easier evacuation of handicapped or disabled people. When the side ramps are fully extended, the gondola measures approximately 21 feet long. Inside the gondola, special controls allow for precise positioning of the gondola at any point on the building.
The main hydraulic load cables (actual rescue cables) are exchanged with the pre-mounted building cables over the top roof jib by the winch unit so that actual exterior operations are performed with a heavy emergency load 1/2-inch steel cable. Safety features built into the winches include: an electronic cable-tension monitor for each cable; a spring-loaded, hydraulically released (fail-safe) multipledisc brake; and an electronic cable payout rate monitor to ensure that the gondola remains level at all times. Since the mobile unit powers the winches, dependency on external electricity supplies is eliminated.
The main controls in the rear of the mobile unit steer the gondola up the cables. A minimum of two to three people is required to get the system into operation, and two people are required to operate it: the main pilot in the mobile unit, a second pilot in the gondola.
The rescue system is reported to be able to begin operations from 320 feet away from the foot of the building. The triangle formed by the rooftop boom, the truck and the gondola allows the gondola to reach any point of the building and still avoid obstacles such as cars, adjacent single-story structures, etc. The high-rise system is also unhampered by balconies and terraces, says Eastwood, because the cables can steer the gondola vertically, horizontally, and diagonally, unlike the maneuvers of conventional aerial equipment. Depending on the decision of the fire officer, the rescue system is not put into operation when winds reach 40-45 mph, according to Eastwood.
The system has been demonstrated in major metropolitan cities throughout the United States. According to fire officials in Detroit and New York, the high-rise rescue is an excellent system, its only drawback being cost.
John J. O’Rourke, chief of the New York City Fire Department, says that the high-rise rescue system has a lot of potential. “It is a good alternative to interior evacuation of otherwise trapped civilians. There is nothing available to externally remove victims who are above the reach of present-day fire apparatus.” The system could also be used as an access platform for exterior hose operations or movement of additional resources.
Chief O’Rourke too commented that the cost factor of such a system makes it prohibitive. “If I had unlimited funding, I would opt to have this system in the city…. However, the fire department would need support from the real estate industry.”
