At what percentage of the rated speed must the overspeed valve of a hydraulic LULA stop the car?

The overspeed valve of a hydraulic Limited Use/Limited Access (LULA) elevator is designed to ensure safety by preventing the elevator car from exceeding a certain speed. According to the standards for hydraulic elevators, the overspeed valve must engage if the elevator car reaches speeds that exceed 110% of the rated speed up to 140%. This range serves to maintain a safety buffer, allowing for safe operation while also accounting for variances in speed that may occur due to operational conditions.

Setting the engagement point at 110%-140% ensures that the system can respond effectively to prevent overspeed conditions, which can lead to unsafe operating scenarios. The specified range is crucial because it reflects engineering standards that prioritize passenger safety and consistent performance under various load conditions and potential malfunctions.

Options outside of this range either do not align with these established safety standards or would not adequately address the potential risks associated with overspeed situations in hydraulic systems.