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Abstract: Elevator Systems

In multi story academic, athletic, and residential buildings, vertical transportation systems typically are composed of elevators and escalators, at significant cost. Proper design, installation, and maintenance are essential to building operations and safety, so facilities managers must effectively manage these assets.

Types of Elevators

Four elevator types are used, with specific characteristics, advantages, and buildings and uses.

Hydraulic Elevators

Common in low-use buildings of two to five stories, hydraulic elevators operate at no more than 150 fpm, moving via hydraulic plunger action in a hydraulic cylinder, with an AC electric motor and electrically operated valves driving a pump.  Three  configurations are available: (1) direct plunger, the most common, with a plunger attached to the car bottom and cylinder depth into the ground equaling vertical travel; (2) indirect telescoping, with plungers offset at the car sides and fastened to the top; and (3) indirect roped, with a plunger acting on steel cables or hoist ropes (similar to traction elevators) on the car bottom.

Geared Traction Elevators

Historically in moderate-use buildings of 5 to 15 stories, geared traction elevators operate at 200 fpm to 500 fpm and are still used, but only for large-capacity service and freight elevators (replaced by machine-room-less [MRL] traction elevators for passenger and standard-capacity service). They move via an AC electric motor directly coupled to a worm gear that rotates a ring gear attached to a drive sheave (linked by steel cables or hoist ropes running from the elevator top over the sheave to a counterweight).

Machine-Room-Less Traction Elevators

Available from all major manufacturers and many third- party providers, MRL traction elevators operate at 200, 350, 500, and soon 700 fpm. They use energy-efficient compact gearless traction hoist machines, typically mounted in the hoistway above the top floor served, which operate on the same counterweight principles as geared traction elevators but provide superior ride quality because the drive sheave connects directly to the motor shaft (eliminating the ring and worm gears).

Gearless Traction Elevators

Used in high-rises of 12 to more than 100 stories, gearless traction elevators usually operate at 500 to 2,400 fpm; the fastest ones run at 3,300 fpm (Taiwan) and soon 3,600 fpm (Shanghai). They use full-size traditional gearless traction hoist machines operating on the same principle as compact gearless MRL traction hoist machines, producing significantly faster speeds and optimum performance and ride quality.

Figure 2.25 summarizes the types of elevators, their applications, and advantages and disadvantages.

Vertical Transportation Design Parameters Building condition evaluations confirm type, capacity, speed, and number of elevators and escalators.

Theoretical performance calculations and evaluation criteria are based on building type, occupancy, and use. Design factors include (1) service quality, the passenger waiting time or average interval (listed for lobbies, corridors, zone populations, residential and classroom uses) and (2) service quantity, the handling capacity for people waiting for elevators and large escalator queues, especially at peak times (listed by pound capacity range for office, classroom, and residential buildings; athletic facilities; service elevators). Equipment type and elevator speed vary with building height and use but deliver smooth acceleration and deceleration with accurate leveling. Elevators should be within sight of the main building entry, never open into pedestrian corridors (or comply with code to prevent fire-related smoke migration), and have visual and audio signals of car position and direction. Athletic facility escalators should be within sight of the populations they serve, with   landing areas large enough to support heavy queueing.

Elevator, Escalator, and Building Codes

In 2007, Canadian and U.S. elevator and escalator codes were harmonized into one, updated annually and reissued every 3 years (ASME A17.1/CSA B44-07); it is referenced (and sometimes supplemented) by building codes in North American states, cities, and municipalities. Facilities managers must identify the current relevant code version—and model building codes and local amendments (e.g., IBC, CBC), NEC, NFPA code, state and local ordinances, and accessibility (ANSI A117.1-2009) and ADA requirements.

Asset Preservation

Elevators and escalators are big infrastructure investments, requiring routine maintenance for safe and reliable operation and maximized useful service life.

Most facilities managers contract with the provider (or a qualified service provider) for routine preventive care, callbacks, and code-required inspections.

Elevator and Escalator Maintenance Contracts. Two contract types are available. Complete (or full) Maintenance (CM) provides the best protection, optimizes life cycle, and includes routine maintenance, repairs, callbacks, and often code-required safety inspections for a monthly fee (other charges are only incurred for vandalism or abuse or for problems outside normal working hours). Oil and Grease (OG) is a routine examination (including cleaning, oiling, adjusting) for a monthly fee; it charges for noted deficiencies, repairs, replacements, callbacks, and code-required safety inspections. CM cost more than OG, but costs are fixed, so it is simpler to budget maintenance and assign monthly costs. Some institutions use in-house staff (who must be fully qualified given liability), with standing contracts for large repairs, replacements, and code-required inspections. The four maintenance areas are (1) housekeeping (roughly 60 percent of maintenance) to reduce fire hazards (especially  in  hoistways  and  pits), detect potential problems (e.g., dirt specks  in  relay contacts), and simplify inspection and maintenance; (2) lubrication (roughly 15 percent) to minimize wear, ensure proper operation, and maximize part life; (3) replacement or repair (roughly 15 percent) to prevent or minimize problems and unplanned shutdowns and optimize equipment life; and (4) adjustments (roughly 10 percent) to run equipment smoothly and quietly and optimize performance.

Elevators and escalators are the safest public transport, but poorly trained or inexperienced maintenance personnel do have accidents. In-house maintenance personnel should be trained on elevator safety and maintenance practices (e.g., courses from ASME, third- party control and equipment suppliers) and be familiar with code inspection and testing. As of January 2014, ANSI certified elevator inspectors and safety and code tests. Facilities managers must routinely tour machine rooms and ride cars and escalators to verify appropriate maintenance control plans for each unit and building, evaluate maintenance level and quality, and identify needed improvements.

Figure 2.25. Elevator Systems
 

Elevator Type

 

Application

 

Building Height

 

Typical Speeds

 

Duty

Life Cycle of Driving Machine Life Cycle of    Controller  

Advantages

 

Disadvantages

Hydraulic Passenger, Service, Freight Low rise, 2-5 floors 100-150 fpm Light use 20 years 20 years Low cost

Minimum installation time

No loads on building structure

Slow speed

Slow acceleration and deceleration rates

“In-ground” units require drilling of well hole

Oil smell throughout building
Geared Traction Large Capacity Service and Freight Low to mid rise, 5-15 floors 100-350 fpm Moderate to heavy use 30-35 years 20 years Moderate cost

Suitable for heavy freight use

Vibration may be noticeable at higher speeds

Imposes all equipment loads on building structure

Higher cost to maintain
Compact Gearless Traction (MRLs) Passenger, Service Low to mid rise, 4-20 floors 200-500 fpm Moderate use 15-20 years 15 years Moderate cost Longer life cycle

Higher speeds

May require greater pit depth depending on manufacturer
Improved ride quality
Energy efficient
Gearless Traction Passenger, Service, Freight High rise, 12-100+

floors

500-2,400

fpm with special applications at 3,600 fpm

Heavy use 50+ years 10-12 years Longest life cycle Fast speeds

Optimum ride quality

Maximum performance

Highest installation cost

Imposes all equipment loads on building structure

Highest cost to maintain

 

Statutory Periodic Elevator and Escalator Safety Inspections

Because of the costs associated with accidents, owners and facilities managers should be familiar with required safety tests and inspections and should verify that certificates are current and available.

Asset Management

Remote monitoring systems can provide real-time data  on status, faults, and troubleshooting, facilitating routine

maintenance and facilities asset management. They are available from major manufacturers for their systems and from third parties for most control systems. Results can be transmitted to a central site and provide automatic paging or email notices, reducing downtime (e.g., at schools with big campuses or multi city campuses).  Some systems can monitor parts inventories and issue reorder and restocking alerts.

Asset Rehabilitation

At some time, old equipment must be upgraded to increase reliability, reduce energy use, meet current code and accessibility requirements, and increase traffic handling capability via microprocessor-based controls (to reduce waiting times, increase reliability, and add security and accessibility features). Grants or student fees fund most modernizations, limiting opportunities for well-planned phased projects with properly selected equipment. Modern microprocessor controllers vary in proprietary features (although root programming is always proprietary) and can require technicians with special training in usually built-in diagnostic devices and repairs (e.g., for high rises).  Low-rise and mid-rise  elevator controllers have built-in displays showing diagnostic, fault, and adjustment codes for cross- reference with the maintenance manual, simplifying troubleshooting and maintenance and providing  access for code-required safety tests. Full modernization can be  as (or more) costly than initial installation; planning must include compliance with current codes.

Independent Elevator Consultants

Facilities managers can consult independent experts for impartial and expert advice about the design, purchase, installation, maintenance, performance evaluation, modernization, and legal implications of elevator and escalator systems. Consultants have varying capabilities and contacts in the industry; facilities managers should always confirm past performance and experience with similar projects.

Figure 2.26. Five Levels of Clean
Level Description 1

Orderly Spotlessness

2

Ordinary Tidiness

FLOORS Floors and base moldings shine and/or are bright and clean, colors are fresh. No dirt buildup in corners or along walls. Floors and base moldings shine and/or are bright and clean. There is no buildup in corners along walls, but there can be up to two days’ worth of dust, dirt, stains, or streaks.
VERTICAL AND HORIZONTAL SURFACES All vertical and horizontal surfaces have a freshly cleaned or polished appearance and have no accumulation of dust, dirt, marks, streaks, smudges, or fingerprints All vertical and horizontal surfaces are clean, but marks, dust, smudges, and fingerprints are noticeable upon close observation.
LIGHTING AND LIGHT FIXTURES Lights all work and fixtures are clean Lights all work and fixtures are clean.
WASHROOMS Washroom, shower, toilet fixtures, and tile gleam and are odor-free. Supplies are adequate. Washroom, shower, toilet fixtures, and tile gleam and are odor-free. Supplies are adequate.
TRASH CONTAINERS Trash containers hold only daily waste, are clean and odor-free Trash containers hold only daily waste, are clean and odor-free

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