What is required to operate an elevator once it has been recalled by the fire alarm system?

To operate an elevator once it has been recalled by the fire alarm system, a key is required. This requirement is in place to ensure that only authorized personnel can use the elevator during a fire alarm condition. When an elevator receives a recall signal from a fire alarm system, it typically returns to a designated landing and becomes a safe area for firefighters or emergency responders to access the building.

The use of a key adds an additional layer of security and control, preventing unauthorized use of the elevator, which could pose a safety risk during an emergency situation. Additionally, requiring a key helps ensure that those who are allowed to operate the elevator are trained and knowledgeable about the risks and procedures associated with its use in such circumstances.

In contrast, other methods such as a button press, passcode, or biometric scan might not provide the immediate control and security needed in emergency situations, making them less suitable for this critical function.