Understanding elevator equipment and its expected performance parameters is the first step

— By John Sieracki, assistant editor

No other building system is as visible to tenants or influences their opinion of a facility as much as its elevators; they are the first thing people use when they come to work in the morning and the last thing they use when they leave at night. Poor elevator service can give tenants the impression that they are no longer working in a Class A facility, and it can cause them to look for other problems with a building. First impressions are important, and elevators provide that impression day after day.

So what does it mean when a facility’s elevators aren’t working the way they should? What are the parameters of good elevator operation? And if an elevator or bank of elevators isn’t providing optimum service, what can be done about it?

Before hauling out the big guns by having a complete modernization done, facility managers should understand how their elevators are expected to perform by law and whether or not their elevators are capable of such compliance.

Understanding the Equipment
It is helpful to first look at major innovations in elevator technology: the implementation of solid-state power units, closed loop feedback speed controls and microprocessor logic. Chances are that if a building is less than 20 years old, or if it has undergone a major renovation within the last two decades, its elevators probably already have some or all of this equipment.

“Elevators manufactured since the early 1980s have these features; before this elevators hadn’t changed significantly since the mid 1950s,” says Jonathan Soberman, industrial engineer and general manager of KJA Consultants Inc., Toronto. “All of these changes are aimed at improving reliability and performance as well as reducing ongoing adjustment requirements.”

These technologies have made cab leveling more accurate and have made it possible to change door speed and improve dispatching as well as operating times.

“In newer elevators, microprocessor controls level much better than the old relay-logic systems,” says Soberman. Elevator cabs are now required to level within one-eighth of an inch, compared to three-eighths to one-half inch, which was common in older systems. And dispatching systems, sometimes called group control systems, have also greatly improved through the use of computer controls. The older relay systems incorporated such a large number of relays and contacts that it was difficult to ensure consistent performance.

“Operating time, which is measured from the start of the doors closing until they are three-fourths open at the next floor, used to range from 8.5 to 11.5 seconds on older models,” says Soberman. “For modernized equipment we would expect an operating time of 7.6 seconds, which is a significant time savings during peak usage periods.”

“Doors are required by ADA to remain open for at least three seconds after the doors fully open,” says Sheila Swett of Sheila Swett Consulting, Memphis, Tenn. “Old elevators do not have the capacity to adjust door opening times; these elevators will not meet current requirements. Equipment that is under 15 years old should have changeable parameters.” This requirement is meant to allow a person to go from the call station in the elevator lobby to the middle of the cab before it closes.

Swett points out that elevator performance is not a matter of how fast the doors can open and close. Again, the efficiency of an elevator is dependent upon the way the microprocessor controls dispatch the cars, not the speed with which the doors can open and close. “Facility managers often ask to have the door speeds of their elevators increased in an effort to handle high traffic periods, but this is against ADA guidelines and will not increase capacity,” says Swett. “When having problems with lobby backup, door speed will not have a real impact. Controls are what govern the dispatch system in elevators, and that is where you will gain twice the capacity or more if you are upgrading from a relay system.”

ADA also requires that elevators be equipped with special two-way communication systems in case a passenger is trapped in the elevator. The system must be self-dialing, self-messaging and capable of hands-free operation in case a passenger cannot operate the phone or talk.

Considerations for Upgrading Equipment
“Facility managers should always consider new controls for upgrading elevator performance, and all signal fixtures should be ADA compliant,” says Swett. “If controlling the volume of people who use the elevator every day becomes a problem, then the maintenance contractor should decide if the mechanical controls need updating. It’s also a good time to update parts such as the door operator, which is the most used and abused piece of equipment in the elevator.”

Down time is another consideration when upgrading elevators. “A modernization can take 10 to 12 weeks in a commercial building (for a mechanical change), whereas cosmetic changes, like a cab replacement, usually only take about seven to 10 days,” says Michele O’Toole of J. Martin Associates, New York.

A complete modernization is quite extensive and is comprised of the following upgrades:

• Replacement of the electromechanical relay-type controllers with microprocessor-based controllers;
  
• Replacement of the motor generator sets with SCR or VVVF drive, closed-loop, negative feedback speed control systems;
  
• Replacement of the existing mechanical selectors with modern electronic position transducers;
  
• Replacement of the door-protective device — safety edge — arrangement with infrared sensors;
  
• A cab replacement or cab-panel replacement;
  
• Replacement of the hall and
  car fixtures;
  
• Installation of a two-way intercom
  system.
  

If possible, a modernization should be scheduled during times of low traffic, especially during the first half of the work process, because this is when tenant service will be at its worst. “In lieu of low traffic periods, letting tenants know that the elevators are being replaced and not broken helps them adjust to the work being performed,” says Swett.

Keeping on Top of Maintenance
Modernization is an expensive and time-consuming process that is not always necessary. “You shouldn’t modernize just to make up for poor maintenance,” says Bill Bell of Lerch, Bates & Associates, Littleton, Colo. “The efficiency and performance of elevators have been enhanced in the past 20 years, but as far as safety is concerned, new controls really don’t make the elevators safer; they have always been safe. Sometimes facilities are sold on upgrades just because their systems are a little older and companies want to sell their new products.”

Proactive maintenance is probably the best plan that a facility can follow to ensure that elevators work properly and experience a minimum amount of down time. In this plan, a maintenance company follows a policy of keeping equipment clean and maintaining or replacing parts before they completely wear out and cause a breakdown.

“Proper elevator maintenance is very important,” says Swett. “A good maintenance program that includes detailed records of routine maintenance and repairs is key in keeping elevators working properly, and in a lawsuit good records show that the facility manager has done his job in keeping the facility safe.”

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