Which type of safety is not allowed to be used on elevators with a rated speed exceeding 150 FPM?

Elevators that have a rated speed exceeding 150 feet per minute (FPM) are required to adhere to specific safety regulations to ensure safe operation and prevent accidents. Type A safety systems are generally designed for lower-speed applications and do not provide the necessary level of performance and reliability required for higher-speed elevators.

For elevators operating at speeds above 150 FPM, safety systems must meet stricter safety standards and typically involve more advanced mechanisms, such as Type B, Type C, or Type D systems. These types incorporate features that provide enhanced braking and control, ensuring that if an emergency occurs, the elevator can respond appropriately, minimizing risk to passengers.

Thus, the reason Type A is not permitted in this context relates to the limitations of its safety features when dealing with the higher operational speeds and the corresponding increased risks associated with those speeds. Only more advanced types of safety mechanisms can adequately protect against potential failures and ensure compliance with safety regulations for faster-moving elevators.