Elevator Recall
Phase I & Phase II Fire Service Operations

Why Elevators Need Fire Alarm Integration

Elevators present a unique hazard during a fire. A car that responds to a hall call could deliver occupants directly into a smoke-filled lobby, or the hoistway could act as a chimney, channeling smoke and heat to upper floors. To address these risks, fire codes require elevators to be recalled to a designated floor during a fire alarm event — removing them from normal passenger service and making them available exclusively for fire department use NFPA 72, §21.3.

The interface between the fire alarm system and the elevator controller is governed by two primary standards: NFPA 72 (which specifies the detection and signaling requirements) and ASME A17.1 (which specifies the elevator’s mechanical and electrical response). Together, they define two operational phases: Phase I (automatic recall) and Phase II (manual firefighter operation).

Phase I: Automatic Recall

Phase I recall is triggered automatically by the fire alarm system and causes all elevators in the affected group to return to a designated floor — typically the main lobby or an alternate floor if the lobby itself is compromised. The sequence is as follows:

1. Initiating device activation: A smoke detector in an elevator lobby, the hoistway, or the machine room activates. NFPA 72 §21.3 specifies exactly which detector locations trigger Phase I recall.

2. Signal to elevator controller: The FACP sends a dedicated relay output or digital signal to the elevator controller. This is a dedicated circuit — it must not be shared with general alarm notification.

3. Car response: All elevators in the group immediately cancel any registered hall or car calls and travel non-stop to the designated recall floor. Doors open and remain open. The cars are taken out of normal service and will not respond to hall calls ASME A17.1, §2.27.3.

4. Alternate floor recall: If the detector that triggered Phase I is on the designated recall floor (e.g., the lobby detector activated), the elevator must recall to a pre-programmed alternate floor instead. The system must be programmed with both a primary and an alternate recall floor.

Phase I recall is fully automatic and requires no human intervention. The elevator remains parked with doors open at the recall floor until either the fire alarm is reset or a firefighter activates Phase II.

Phase II: Manual Firefighter Operation

Phase II is activated by a firefighter using a keyed switch inside the elevator car. This gives the firefighter manual control of the elevator for rescue operations and fire attack. Phase II operation has important safety features:

Door control: Doors only open and close when the firefighter holds the door open/close button. Releasing the button stops door movement immediately, preventing the door from opening into a fire floor unexpectedly.

Call cancel: The firefighter can cancel a floor selection at any time by pressing and holding the corresponding button.

No automatic floor response: The car only responds to buttons pressed inside the car. Hall calls are completely disabled.

Machine room detector response: If the machine room smoke detector activates during Phase II operation, the elevator may be required to shut down entirely, depending on the jurisdiction and the system design. Some codes allow the firefighter to override this shutdown with an additional keyed switch ASME A17.1, §2.27.3.3.

Required Smoke Detector Locations

NFPA 72 §21.3 and ASME A17.1 specify mandatory smoke detector locations for elevator recall:

Elevator lobby (each floor): A smoke detector must be installed in or adjacent to each elevator lobby on every floor served by the elevator. The lobby detector is the primary trigger for Phase I recall. In buildings with multiple elevator groups, each group must have its own lobby detector circuit NFPA 72, §21.3.4.

Elevator machine room: A dedicated smoke detector must be installed in each elevator machine room. Activation of the machine room detector triggers Phase I recall and may also initiate a shunt trip of the main line disconnect if sprinklers are present in the machine room NFPA 72, §21.3.5.

Elevator hoistway: If the hoistway is sprinklered, a smoke detector or heat detector must be installed at the top of the hoistway. The purpose is to detect fire or smoke conditions within the shaft before sprinkler water begins flowing, which could cause elevator malfunction. In practice, the hoistway detector activates the shunt trip to disconnect power to the elevator before sprinkler water can cause a short circuit NFPA 72, §21.3.6.

Machine room-less (MRL) elevators: For MRL designs where the machine is located in the hoistway or adjacent space, detectors must be placed in the control space that replaces the traditional machine room. The same recall logic applies.

Shunt Trip and Sprinkler Interaction

When sprinklers are installed in the elevator hoistway or machine room, there is a risk that water flowing onto elevator equipment could cause a short circuit, potentially trapping passengers. To address this, codes may require a shunt trip breaker that disconnects power to the elevator before the sprinklers activate.

The shunt trip sequence is typically: hoistway or machine room detector activates, which triggers both Phase I recall and a timer. After the elevator has had time to reach the recall floor (typically 30 to 60 seconds), the shunt trip breaker disconnects main power. The timing must be coordinated so the elevator completes its travel before power is cut NFPA 72, §21.3.12.

Inspection, Testing & Maintenance

Testing elevator recall is a coordinated effort between the fire alarm contractor and the elevator technician. NFPA 72 Chapter 14 requires:

Coordination is essential: the fire alarm technician activates the detector, and the elevator technician verifies the car responds correctly. Both trades must be on site simultaneously for a valid test.

Common Deficiencies

Missing lobby detectors: Building renovations that modify the lobby layout sometimes result in detectors that no longer cover the elevator lobby properly. Verify detector placement against the current architectural layout.

Incorrect recall floor programming: After lobby renumbering or building additions, the primary or alternate recall floor in the elevator controller may not match the fire alarm programming. Cross-check both systems.

Untested shunt trip: Shunt trip testing requires cutting power to the elevator, which facility managers are reluctant to do. However, an untested shunt trip is an unverified safety feature.

Missing Phase II key: The fire service key must be available inside a Knox box or at the building command center. A missing key prevents firefighter elevator operation.

Smoke detector placement changes: Moving from a traditional machine room to an MRL design requires relocating the machine room detector to the new control space. This is sometimes overlooked during elevator modernization projects.

Practical Inspection Tips

Test from every lobby: During the annual test, activate a detector on at least two different floors to confirm the elevator recalls correctly from each location. Also test from the designated floor to verify alternate-floor recall works.

Time the recall: From detector activation to doors open at the recall floor, note the elapsed time. If shunt trip is involved, confirm the elevator arrives before power is cut.

Verify the firefighter key: Check the key location, confirm it operates the Phase II switch, and test manual door control.

Check the annunciator: If a building annunciator is present, confirm that elevator recall status is displayed correctly — which group recalled, which floor, and which detector initiated recall.

References