Which of the following is NOT essential knowledge for on-site building staff regarding elevators?

Understanding the operational aspects of elevators is critical for on-site building staff, especially in emergencies. Knowledge of how to recall elevators is essential for ensuring that they return to a designated floor during an emergency. This is important for the safety of both building occupants and emergency responders.

Communication with occupants of stalled elevators is another vital skill. Staff must know how to reassure and communicate effectively with individuals who may be trapped, providing instructions and maintaining calm until help arrives.

Awareness of the locations of freight elevators is necessary as these may be utilized by emergency services for moving equipment or evacuating individuals. Knowing where these elevators are located helps in efficiently managing the building during an emergency.

In contrast, while knowledge of fire extinguisher types is certainly useful, it is not specifically essential for understanding elevator operation or responding to elevator-related emergencies. Staff may need to know how to use fire extinguishers but that knowledge does not directly relate to managing elevators in the context of life safety in a high-rise building. Therefore, familiarity with the types of fire extinguishers is not as crucial in the specific context of elevator safety as the other options listed.