Gilco Blog

Seismic sensors, emergency stopping, ARDs and the engineering that protects passengers when a building begins to shake.

At 5:46:52 on the morning of 17 January 1995, the ground beneath Kobe, Japan, moved with devastating force. Buildings swayed. Roads fractured. Electrical systems failed. Across the city, ordinary routines were interrupted in seconds. The United States Geological Survey records the earthquake as occurring near Kobe at precisely that time.

Inside the vertical spaces of the city, another story was unfolding—one largely hidden from view.

Lift cars hung between floors. Counterweights moved inside shafts. Steel guide rails, suspension ropes, landing doors, controllers and electrical systems were all being subjected to forces they did not encounter during an ordinary journey.

For anyone standing inside a lift, the questions would have been immediate:

Will the lift fall?

Can it tell that an earthquake has begun?

Will it stop at the next floor?

What happens if the electricity fails?

And who decides when it is safe to use the lift again?

The reassuring answer is that modern elevators are protected by several layers of engineering. The more important answer, however, is that earthquake safety depends on much more than a single device.

It begins with the design of the lift and the building. It continues through installation, commissioning, maintenance and emergency planning. And after an earthquake, it depends on something technology cannot replace: a careful inspection by qualified professionals.

A Lift Is Not Simply a Box Hanging from a Cable

Popular films have given us a dramatic image of an elevator: one cable snaps, the car plunges and passengers fall through the shaft.

That is not how a modern traction elevator is constructed.

The lift car is typically suspended by multiple steel ropes or engineered belts and balanced by a counterweight. Both the car and the counterweight travel along rigid guide rails fixed to the building. The drive machine controls movement, while the machine brake holds the car when it stops.

An overspeed governor continuously monitors car speed. If the car exceeds a defined limit, the governor can activate the safety gear, causing the car to grip its guide rails.

These systems address vertical movement. An earthquake introduces a different challenge: the building and lift equipment may also move laterally.

That sideways motion can affect:

• Guide rails and their brackets
• The car and counterweight
• Suspension ropes, governor ropes and travelling cables
• Landing doors and interlocks
• Machinery, controllers and electrical connections
• Buffers, switches and other equipment in the lift pit

The danger, therefore, is not simply that “the cable may break.” The larger engineering concern is that components may become displaced, misaligned or damaged while the building is moving.

Historical earthquake investigations have shown that elevators can sustain damage even when a building appears relatively intact. FEMA’s earthquake-mitigation guidance consequently asks building owners to examine the anchorage of guide rails, cars, counterweights, cables, machinery and controls—and whether an appropriate seismic switch is installed. FEMA’s elevator and escalator earthquake checklist

Can an Elevator Detect an Earthquake?

Some can. Not all do.

A lift designed for seismic operation may be connected to a seismic sensor or switch. The device monitors vibration or building acceleration. When movement exceeds its configured threshold, it sends a signal to the elevator controller.

The controller may then initiate a predetermined earthquake emergency sequence. Depending on the lift, the applicable safety code and the condition detected, this may include:

1. Cancelling normal passenger calls.
2. Reducing speed or stopping the car.
3. Moving the car to a permitted nearby landing, when it is safe to do so.
4. Opening the doors to allow passengers to leave.
5. Removing the lift from normal service until it has been checked.

Additional displacement or derailment switches may be used to identify abnormal movement of the counterweight or other equipment. If a critical safety circuit is interrupted, the controller may stop the car rather than attempt to continue to a floor.

This distinction matters: a seismic sensor does not predict an earthquake. It reacts when it detects a defined level of movement. Some advanced systems may integrate with external earthquake early-warning networks, but that capability should never be assumed in an ordinary lift.

International safety frameworks contain dedicated provisions for earthquake-related elevator equipment and emergency operation. The precise requirements depend on the jurisdiction, seismic risk and adopted code. ASME A17.1/CSA B44 identifies specific earthquake equipment and emergency-operation provisions, while India’s National Building Code guidance also recognises lifts with seismic-resistance features. BIS guide to NBC 2016

The important phrase is where provided and appropriately configured. Not every existing elevator has dedicated earthquake detection or automatic seismic operation.

What Happens to a Moving Lift When Shaking Begins?

There is no single response that applies to every elevator.

A seismically equipped lift may attempt to reach a safe landing before opening its doors and shutting down. Another lift may stop immediately because a safety circuit has opened. An older system without seismic operation may continue until the power fails, a fault is detected or the controller removes it from service.

This is why passengers should not try to predict what the lift will do.

A sudden stop does not necessarily mean the lift has failed catastrophically. It may mean the safety system has detected a condition under which continuing would be riskier than remaining stationary.

Similarly, a lift stopping between floors can be frightening, but remaining inside the car is generally safer than forcing the doors or attempting to climb out without trained assistance. The car may not be level with the landing, and the space beyond the doors may open directly into the shaft.

Use the alarm button or emergency communication system and wait for instructions. Do not attempt self-rescue.

Power Failure and Earthquake Detection Are Not the Same Thing

This is one of the most frequently misunderstood parts of elevator safety.

An Automatic Rescue Device, commonly called an ARD, is primarily designed to respond to a loss of normal electrical power. Using backup energy, it may move the car slowly in the most suitable direction to a nearby landing, level the car and open the doors.

An ARD is valuable, but it is not an earthquake detector.

If an earthquake damages equipment, activates a displacement switch or opens a safety circuit, the control system may prevent the lift from moving—even if backup power is available. Moving the car under those conditions could create a greater hazard.

The same principle applies to a building generator. Emergency power may be available, but that does not automatically mean every lift should resume operation. The building’s emergency plan determines which lifts receive backup power and under what conditions they may operate.

Think of the systems as performing different jobs:

• A seismic sensor responds to abnormal ground or building movement.
• An ARD responds primarily to a mains power failure.
• A generator provides an alternative source of electrical power.
• The elevator safety circuit decides whether movement is permitted.
• A qualified inspection determines whether the equipment may safely return to service.

No single device replaces the others.

What Should Passengers Do?

If you are outside a lift when shaking begins, do not enter it. Move away from glass and unsecured objects and follow the recognised “Drop, Cover and Hold On” response.

Do not rush towards the stairs while the building is actively shaking. Once the shaking stops, follow the building’s emergency instructions and use a designated staircase or evacuation route only when it is considered safe.

Both Indian and international disaster authorities advise against using elevators during and immediately after an earthquake. NDMA’s disaster-safety guidance recommends using stairs rather than lifts, and the CDC’s high-rise earthquake guidance gives the same warning.

If you are already inside a lift:

• Stay calm and brace yourself against sudden movement.
• Protect your head and neck if objects are falling.
• If the car reaches a floor and the doors open normally, leave carefully.
• If the car stops between floors, use the alarm or emergency communication system.
• Do not jump inside the car.
• Do not force the doors open.
• Do not climb out unless trained rescue personnel instruct and assist you.

Most importantly, remember that a stationary lift car is not automatically an unsafe lift car. An intentional shutdown may be the system’s safest available response.

Why a Lift Must Be Inspected After an Earthquake

When the shaking ends, the building may look normal. The lift may even respond when someone presses the call button.

Neither is proof that it is safe.

Damage inside a shaft can be difficult to see from a landing. A rail bracket may have shifted. A counterweight guide shoe may be damaged. A rope may have moved out of its intended position. A landing-door lock may no longer align correctly. Water, dust or debris may have entered the pit or machinery area.

Before returning a lift to service, the building itself may first require structural clearance. A competent elevator technician should then inspect the installation in accordance with applicable codes, manufacturer instructions and local authority requirements.

The inspection may include:

• Car and counterweight guide rails, brackets and fastenings
• Counterweight retainers and displacement devices
• Suspension ropes or belts and their terminations
• Governor rope, overspeed governor and safety gear
• Machine, brake and supporting structure
• Landing doors, car doors and interlocks
• Buffers, limit switches and pit equipment
• Controllers, wiring and safety circuits
• Emergency communication and alarm systems
• ARD, batteries and standby-power interfaces
• Ride quality, levelling and controlled test operation

Only after the installation has been examined and tested should normal passenger service resume. FEMA’s post-disaster guidance similarly treats building reoccupation as an evaluated decision, not an assumption based on outward appearance. FEMA post-disaster building-safety evaluation guidance

Aftershocks make this caution especially important.

Earthquake Safety Begins Before the Earthquake

The best time to think about seismic elevator safety is not while passengers are waiting inside a stopped car.

For architects, developers and building owners, earthquake readiness should be considered at the design stage. The building’s location and seismic classification, lift speed, travel height, equipment arrangement, shaft design, component anchorage and applicable regulations all influence the required solution.

For facility managers, preparedness means knowing:

• Whether each lift has dedicated seismic detection.
• What emergency sequence the controller is programmed to perform.
• Which lifts are connected to standby power.
• How the ARD behaves during a power failure.
• Who receives an emergency or entrapment call.
• Who is authorised to shut down or restore the lifts.
• Which elevator service provider will conduct the post-earthquake inspection.
• How passengers with limited mobility will be assisted if lifts are unavailable.

These details should be written into the building’s emergency plan and practised during drills. Security personnel, reception teams and facility staff should know that forcibly resetting a lift after an earthquake is not a rescue procedure.

The Most Important Safety System Is a Chain

Earthquake elevator safety is sometimes described as though one intelligent sensor will solve everything.

It will not.

Real safety comes from a chain: appropriate design, secure installation, layered protective devices, correct commissioning, preventive maintenance, reliable communication, trained building personnel and disciplined post-event inspection.

If one link is neglected, the entire response becomes weaker.

That is the hidden lesson inside every elevator shaft. During an ordinary journey, hundreds of mechanical and electrical decisions happen quietly. During an earthquake, those same systems must decide something even more important than how to keep moving.

They must know when not to.

At Gilco Global, we believe vertical mobility safety must be considered throughout the equipment lifecycle—from planning and engineering to commissioning, maintenance and emergency preparedness. Because when the ground moves, a safe response should never depend on guesswork.

T: 1800 313 333 551 · M: info@gilcoglobal.in