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Planning an elevator upgrade.

In order to solve elevator problems, whether it means a large-scale modernization effort or a simple maintenance procedure, property managers first must develop a clear definition of the problem.

Some problems are easy to define: If an elevator is shut down, for instance, a manager would call a repair crew and have the car repaired. But some other problems are more complex. For instance, what if a building's elevators are operating but are giving poor service? Tenants are complaining of long waits, slow trips between floors, and delayed opening and closing of elevator doors.

A manager facing this situation should answer three questions:

* Is the existing elevator equipment capable of handling the elevatoring needs of the building? Perhaps the system simply is too small to accommodate all of the building's current traffic, and so needs more than modernization to bring it into line with building demands.

* Is the equipment in such a stateoutdated, run down, or otherwise unserviceable-that it requires a major overhaul? If so, which components can be upgraded and which must be replaced?

* Is the existing maintenance program adequate to maintain the system's volume of use? If not, what can be done to improve the maintenance program? If maintenance is inefficient, no modernization program, no matter how elaborate, will allow the system to perform effectively.

When elevator service is substandard, managers must take very deliberate steps to determine the exact cause of the service shortfail before making any decisions to repair, replace, or modernize the system.

Equal car performance

The first step in this analysis is to determine if all elevators in a group are performing equally. To do so, managers can use a stopwatch and chart the time it takes each car to perform its various functions.

First, measure how quickly each car's doors open and close at each floor. Most passengers agree that an elevator's doors should open as quickly as possible. However, the speed at which the doors may close is limited by elevator codes that prevent elevator doors from using more than 7 foot-pounds of kinetic energy and 30 pounds of thrust. Generally speaking, a 42-inch-wide, center-opening, hollow metal door can be expected to close in 2.3 seconds.

Managers next should record how long each car's doors remain open at each floor. Elevator passengers typically can exit a car in two or three seconds, and can enter a car in about four seconds. Doors that remain open for much longer than this only impede service. Also important in this exercise is the performance of the door reversing device. When the doors are blocked, they should open again immediately, and then attempt to close again right away. Again, any delays only reduce service. Once the doors are closed, the car should move away immediately.

When measuring the speed with which a car moves from floor to floor, managers must consider the type of hoisting mechanism, and its horsepower, employed by the elevator. A geared elevator, which typically moves at speeds up to 400 feet per minute, should be able to travel the height of ten floors in five or six seconds. Higher speed gearless elevators, which can move 500 feet per minute or faster, can cover the same ten-floor span in four or five seconds. Conversely, slower hydraulic elevators, which typically are limited to speeds of 150 feet per minute, take up to eight seconds to travel the ten-floor distance.

Assessing traffic demands

If all of the cars in an elevator group are performing at the same level, the next consideration is the specific demands placed on the elevator system by building tenants. To determine elevator demand, managers should conduct a thorough study of the building's traffic patterns.

For instance, managers should answer the following:

* What are the building's daily peak traffic periods?

* How many passengers use the elevators at these times?

* How much freight, such as mail and supplies, is transported?

* What are the most common stops during the peak periods? Do they represent long or short trips?

* How do tenants define a "full" car? (i.e., when do they decide a car is too full and opt to wait for another?)

* When a car is full, does it leave a floor immediately so that another can take its place?

In addition, managers also should determine if elevator cars are spending an inordinate amount of time parked at upper floors when demand exists for service on lower floors. To do so, managers can use lobby indicators and/or video displays to track each car's position during busy periods. If a building is not outfitted with these monitors, a staff member may ride and monitor the elevators during peak hours.

Determining system capability

If all elevator cars are working efficientl% managers next should evaluate the capability of the entire system. Many will want to enlist the help of an elevator maintenance contractor, who can work with the manager to develop a thorough analysis of the system.

The first step in this exercise is to use the information gathered in the study described earlier to create a mathematical model of the elevator system and the demands placed on it. This model will help managers track the effects of any improvements or modifications made to the system later on.

Before spending any money on modernization, managers may decide to implement some changes in elevator assignment or usage that can dramatically improve overall service within the building.

For example, eliminating elevator stops in a building's basement or other seldom-visited floor can reduce undue waiting for tenants. (Basement and other such stops can be serviced by a separate shuttle elevator.) Similarly managers may consider relocating a cafeteria or mail room to allow for easier access and fewer elevator tie-ups.

Other no-cost changes that can do wonders for improving elevator service include: arranging for freight to be moved on an assigned passenger elevator during off-peak hours; encouraging tenants to stagger starting, quitting, and lunch hours; reassigning to general duty any cars that had been reserved for specific tenants' exclusive use; and relocating certain offices or departments so that co-workers need not use the elevators in order to meet with one another. Managers can plot changes like these on the mathematical model to determine exactly how they will benefit building elevator service.

Modernization options

Before managers undertake any major modernization project, they must ensure that any elevators not being serviced are operating at peak capability. Once cars are shut down for modernization work, the building will be totally dependent on the remaining cars.

Managers also must make themselves familiar with the many elevator systems available, lest they be "snowed" by the claims of an elevator contractor.

In addition, managers should evaluate the existing elevator system to determine which components, if any, may be salvaged.

First, take a critical look at the elevator entrances. Doors constructed of modern flush hollow metal can be reused, but panel-type or older glass doors most often will have to be replaced. In many cases, existing frames may be kept and covered, and worn sills can be salvaged by adding a "layon" sill on top of the old one.

Next, managers should evaluate the condition of the elevator's operating mechanism. Pay close attention to the door operator; many openers manufactured in the last 20 years are of good quality and may be overhauled and reused. Similarl% the elevator's tracks, locks, and hangers can be reconditioned.

When evaluating the condition of the leveler, managers should remember that elevator cars today employ a variety of leveling mechanisms. Generally speaking, leveling systems that employ a sensor that is mounted directly on the car in the hoistway (called a cam) can be reused. In contrast, leveling systems that employ a wire or cable that is attached to a separate mechanism located in the machine room are considered obsolete today and so must be replaced.

Managers should note, however, that replacement of an elevator leveler is truly the "ultimate fix;' and usually requires a corresponding upgrade in elevator controllers. In a pinch, a mechanical leveler may be replaced with hoistway switches until a full overhaul is possible.

Controller replacement is the most significant modernization step. In most cases, managers looking to upgrade a group of three or more elevators will replace the group or dispatching controller with a new microprocessor that can direct the overall operation of each elevator in that group. Be sure to select a microprocessor that is compatible with both the existing individual car controllers and with the ones that will be installed to replace them, so that the entire system can continue to operate throughout the modernization process.

Microprocessors have the ability to evaluate many factors and to make split-second decisions to direct cars to serve landing call traffic extremely efficiently. However, managers who decide to install a microprocessor also should contract for continuing maintenance from the manufacturer, as diagnostics and adjustments often are exclusive to that vendor. A second option is to find a supplier who offers "generic" equipment that can be maintained by any competent company.

It is important to note that the modern, solid-state controllers replacing the old motor generators often will require additional power. In addition, microprocessors are heat-sensitive, and so may demand the installation or upgrade of an air-conditioning system in the machine room. These and other factors must be considered when budgeting for a modernization program and considering the merits of various product lines.

Car improvements and fixture upgrades will be necessary in almost any modernization-if not for tenant appeal then to satisfy the newly enacted handicapped-access rules of the Americans with Disabilities Act. The ADA requires the lowering of operating fixtures, special signage, additional lighting, and other modifications.

Many experts also are predicting the widespread adoption of the requirements now in place in most major cities for extra safety fittings in elevator cars. These requirements include smoke detectors and enhanced car-to-centralstation communication capability.

At some point, managers must consider a complete overhaul of the system. Such a move is recommended for all elevators that are 20 or more years old. However, rapidly changing technology and the retirement of technicians with experience on older systems may make it necessary for all systems to be modernized in the foreseeable future.

George R. Strakosch is former director of education services at Elevator World, Inc., Mobile, Alabama, and continues to serve as a technical consultant. He has 45 years of experience in the elevator industry, including 31 years at Otis Elevator Company. Mr. Strakosch has worked extensively in developing ASME/ANSI elevator codes. has written two books on elevators, and has taught the subject at New York University's School of Continuing Education. He has a B.S. degree in electrical engineering from Drexel University and an M.B.A. degree from New York University.
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Title Annotation:Operating Techniques & Products Bulletin 413
Author:Strakosch, George R.
Publication:Journal of Property Management
Date:Mar 1, 1992
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