This standard is formulated under the jurisdiction of the National Technical Committee for Elevator Standardization of China. It is applicable to speed governors matched with traction and positive drive lifts with rated speed no more than 25m/s, covering the whole life cycle management of speed governor design, production, inspection, use, calibration and scrapping. Compared with the old version, the core upgrades of this revision include: first, reconstructing the speed governor classification system, dividing speed governors into four categories: one-way action type, two-way action type, explosion-proof type and ultra-high speed special type according to the applicable scenarios, action speed and structural form, adding special technical requirements for speed governors dedicated to ultra-high speed elevators with rated speed greater than 6m/s and intrinsically safe speed governors for explosion-proof elevators; second, greatly improving the core performance indicators, tightening the allowable deviation of the speed governor action speed, the electrical action speed deviation is tightened from the original ±5% to ±3%, and the mechanical action speed deviation is tightened from the original ±7% to ±4%; clarifying the mechanical strength and fatigue life requirements of the speed governor, stipulating that the speed governor must still meet the standard requirements after 2 million action cycle tests; third, refining the electrical safety and explosion-proof performance requirements, clarifying the insulation performance, withstand voltage performance and redundant design requirements of the electrical safety contacts of the speed governor, and formulating special technical specifications for flameproof and intrinsic safety design for speed governors used in explosion-proof elevators, forming a full connection with the national explosion-proof electrical equipment standards; fourth, improving the environmental adaptability and reliability requirements, formulating special test standards for corrosion resistance, high and low temperature resistance, waterproof and dustproof of speed governors for extreme use environments such as high temperature, high humidity, salt spray and low temperature, and clarifying the special protection grade requirements of speed governors for special scenes such as outdoor, coastal and cold storage; fifth, improving the type test and factory inspection rules, adding special test methods and judgment standards for high and low temperature environment performance test, salt spray corrosion test and fatigue life test of speed governors, clarifying the items, procedures and validity period of type tests, and tightening the sampling rules and qualification judgment criteria for factory inspection; sixth, clarifying the calibration, use and scrapping specifications of speed governors, refining the cycle, method and qualification judgment standard of on-site calibration of speed governors, updating the scrapping judgment standards for wear, deformation and action failure of speed governors, and forming a full connection with the Elevator Maintenance Rules and Elevator Supervision Inspection and Regular Inspection Rules. The implementation of this standard has comprehensively built a solid safety line for elevator overspeed protection, reduced the risk of safety accidents such as elevator falling, roof rushing and bottom squatting from the level of core safety components, and also promoted the full integration of China's elevator speed governor products with the international market, further consolidating the core competitiveness of China's elevator core safety components in the global market.