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ISO 25760:2010 – Lifts — Safety Rules for Design, Installation and Operation
Comprehensive safety requirements for lift systems
1. Scope and Safety Philosophy
ISO 25760:2010 establishes safety rules for the design, installation, and operation of lifts (elevators). It addresses the full lifecycle safety considerations covering mechanical hazards, electrical hazards, trapped passenger scenarios, and emergency operations. The standard applies to permanently installed electric and hydraulic lifts serving defined landing levels with a car designed for the transportation of persons or goods.
Lift safety incidents, while rare, can result in serious injury or fatality. Historical data indicates that approximately 75% of serious lift accidents involve door-related hazards or unintended car movement.
The standard’s safety framework is based on risk assessment methodology, requiring manufacturers and installers to identify all reasonably foreseeable hazards throughout the lift’s lifecycle. Key safety principles include redundancy for critical safety functions, fail-safe design, prevention of unintended movement, and protection against overspeed and overtravel. The standard references the ISO 14798 risk assessment methodology for lifts.
| Safety Function | Protection Method | Required Redundancy |
|---|---|---|
| Overspeed protection | Governor + safety gear | Dual mechanical |
| Door trapping prevention | Re-opening device + force limiter | Single with monitoring |
| Unintended car movement | Brake + overspeed governor | Dual independent |
| Terminal limit stopping | Normal + final limit switches | Dual electrical |
| Emergency communication | Two-way communication + alarm | Battery backup |
2. Critical Safety Requirements
ISO 25760 specifies detailed requirements for lift machine rooms, shaft enclosures, landing doors, and car construction. The machine room must provide safe access with adequate working space, ventilation, and lighting. Landing doors must withstand a force of at least 300 N applied at the most unfavorable point without permanent deformation. The standard requires mechanical locking of landing doors with electrical monitoring to prevent the car from moving when any door is not locked.
Modern lift designs implementing the full ISO 25760 safety framework have achieved mean time between dangerous failures (MTBF-D) exceeding 108 operating cycles for critical safety functions.
Buffer requirements are specified based on rated speed and kinetic energy. For hydraulic lifts, the standard addresses hose rupture protection, pipe failure protection, and descent limiting devices. Electrical safety requirements include protection against electric shock, short-circuit protection, and safe isolation means for maintenance activities. All safety circuits must comply with the principles of fault exclusion as defined in ISO 13849.
3. Engineering Insights and Implementation
From an engineering perspective, several aspects of ISO 25760 deserve special attention. The safe braking distance calculation must account for worst-case loading conditions (125% rated load for traction lifts) and friction coefficient variations. The car and counterweight guide rail design must consider both normal service loads and safety gear engagement loads, with safety gear engagement generating forces up to 5 times the static load.
A commonly overlooked requirement is the need for electrical protection against phase reversal and phase failure in three-phase supplies. An incorrect phase sequence can cause the brake to release in the wrong direction, creating a hazardous unintended movement condition.
Emergency operation requirements include battery-powered emergency lighting, automatic rescue devices for power failure scenarios, and firefighter operation interfaces. The standard also mandates periodic inspection and testing intervals for all safety devices, with documented records maintained for the entire life of the installation.
4. Frequently Asked Questions
Q: Are there different requirements for passenger vs. freight lifts?
A: Yes — freight lifts with restricted access have reduced requirements for car dimensions and door protection, but safety gear and overspeed protection requirements are similar.
A: Yes — freight lifts with restricted access have reduced requirements for car dimensions and door protection, but safety gear and overspeed protection requirements are similar.
Q: What is the maximum allowed door closing force?
A: Maximum 150 N average force, with kinetic energy limited to 10 J for sliding doors and 4 J for hinged doors.
A: Maximum 150 N average force, with kinetic energy limited to 10 J for sliding doors and 4 J for hinged doors.
Q: Can a single brake be used for emergency stopping?
A: No — at least two independent braking systems are required, each capable of stopping and holding the car with 125% rated load.
A: No — at least two independent braking systems are required, each capable of stopping and holding the car with 125% rated load.
Q: What inspection frequency does the standard recommend?
A: Full inspection annually; safety device testing every 5 years or according to national regulations.
A: Full inspection annually; safety device testing every 5 years or according to national regulations.
