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Machine Room-Less (MRL) Elevator Disconnect

Elevating Safety: The Impact of Mindful Design on Maintenance Workers

Since the first elevator was designed in a building in 1853, people have had the benefit and convenience of travelling hundreds of feet within minutes. Along with its luxury, such an advanced invention can also be quite dangerous. An average of 26 deaths occur per year in elevator-related accidents, which mainly include elevator maintenance workers rather than passengers. As engineers, there are design considerations we must make to increase safety for maintenance workers that follow codes and help avoid change orders during design.

There are typically three types of elevators used in commercial buildings: Hydraulic Elevators which are usually used in 2-3 story buildings, Traction Type Elevators used in 4+ story buildings, and Machine Room-Less (MRL) Elevators, which are used for a maximum travel distance of 250’. MRL Elevators have become the standard used in various building types and free up space within a building because the main elevator equipment can be installed within the elevator shaft.

Although MRL Elevators allow the main equipment to be installed within the shaft, there is additional electrical equipment feeding the elevator that also requires space to be installed. Every elevator requires separate fusible and lockable safety disconnects for the cab lights, fusible disconnect outside the shaft with axillary contacts, the cab exhaust, and the elevator equipment controller. Depending on the architect or the building manager, this extra space for a separate electrical room may or may not be provided during the initial stages of the design. If the extra space is not accounted for, the electrical equipment feeding the elevator must be installed within the shaft. This means that the elevator mechanics must enter the elevator shaft to turn off power to the electrical equipment during maintenance, which is a safety hazard and violates elevator manufacturer and reviewing agency standards.

The optimal design provides a room to house the electrical equipment feeding the elevator so that it is easily accessible to maintenance and allows the mechanic to turn off power to the equipment without having to enter the shaft. To minimize issues during the final inspection, including space for a separate accessible room will increase safety measures for elevator maintenance workers, as well as reduce the chance for change orders to relocate equipment to a different area due to the elevator manufacturer and reviewing agency standards.

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