How to Read Elevator Drawings

Elevator drawings come from two sources: the architect, who shows the shaft and openings, and the elevator manufacturer's shop drawings, which detail the rails, machine, controls, and cab. The two sets have to reconcile, and neither is complete without the other. ASME A17.1, the IBC, and local AHJ amendments all apply.

Hoistway Plan and Section

The hoistway plan shows the shaft footprint, the door opening size and location, the cab dimensions, and the running clearances on each side. Critical dimensions include shaft inside-to-inside, door opening width, sill recess, and the working clearance behind the cab where applicable.

The hoistway section shows the pit depth, the overhead height, and the floor-to-floor dimensions. Pit and overhead requirements are driven by the elevator speed and capacity. A passenger elevator typically needs 5-7 feet of pit and 14-18 feet of overhead. Service and freight elevators need more. If the pit isn't deep enough, the buffer doesn't fit. If the overhead isn't tall enough, the cab can't reach the top floor.

Machine Room and MRL Configurations

Traditional traction elevators have a machine room above the shaft. The drawings should show the machine room with the equipment layout, working clearances, ventilation, lighting, and door access. Code-required signage and disconnects are typically called out on the electrical drawings.

Machine-room-less (MRL) elevators have the machine inside the hoistway, usually at the top. The drawings show the controller location, which is often in a closet adjacent to the shaft. MRL designs save building height but make service access more constrained — the controller and the machine both have to be reachable for maintenance, which limits the kind of items that can occupy the space around them.

Hydraulic elevators have a machine room at the lowest level, with a ground tank that connects to the cylinder under the cab. The drawings should show the tank location and the piping path back to the shaft.

Hoistway Vents and Smoke Control

IBC requires hoistways to be vented to the outside under specified conditions, with smoke control coordination through the elevator lobbies. The drawings should show the vent location, the damper, and the controls integration with the building fire alarm system.

Cars in fire service mode (Phase I and Phase II per ASME A17.1) need specific recall behavior, signage, and fire-fighters' key access. The drawings should show the smoke detector locations that trigger Phase I recall, typically in elevator lobbies on each floor and in the machine room.

Structural Items in the Shaft

Elevator rails attach to the shaft walls or to a separate rail-support structure. The structural drawings should show the rail attachment points and the load they impose. Cab and counterweight loads transfer to the building structure at the machine beams above the shaft (in traction systems) or at the buffer pads in the pit (in hydraulic systems).

Penetrations through the shaft wall are restricted. ASME A17.1 limits what can pass through the hoistway and what can be located against the shaft wall. The architectural drawings should show clearance from the shaft for items like sprinkler piping, low-voltage cable, and HVAC ducts. Sprinklers in the pit and at the top of the shaft are typically required, with specific clearances and protection.

Door and Lobby Coordination

Elevator entrances are fire-rated assemblies — usually 90-minute or 2-hour ratings depending on the building's occupancy and construction type. The architectural drawings show the door, frame, sill, and the surrounding wall assembly. The fire-rating must be continuous, with the elevator entrance and the wall both achieving the required rating.

Elevator lobbies, where required, have to maintain fire and smoke separation from adjacent floor areas. The drawings should show the lobby boundaries, the door positions, and the smoke detector locations.

Specialty Items

Elevators in healthcare facilities have additional requirements: stretcher-size cabs, redundant power, and pressure-balanced lobbies in some hospital design models. Elevators in seismic zones need car retention devices and seismic switches that recall the car in an earthquake. Service and freight elevators have larger cabs, heavier capacities, and different door operators.

Drawing review should confirm the elevator type and intended use are reflected in all the supporting drawings. Specialty elevators have specialty requirements; generic shaft drawings won't catch them.

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