Elevator and Freight Lift Maintenance Guide: Safety Testing, Rail Inspection and Cable Examination

1. Scope and Objective

This technical guide is aimed at industrial maintenance professionals working on elevators and goods lifts, specifically those used in the aerospace and energy sectors in France. Its purpose is to detail essential preventive maintenance procedures, including testing of safety devices, rigorous inspection of guide rails, and thorough examination of lifting cables.

The strict application of these procedures is critical to guarantee the safety of operators, the operational reliability of equipment and compliance with current regulatory standards, such as the NF EN 81-20 series (Safety rules for the construction and installation of lifts - Passenger lifts and accompanied freight lifts), NF EN 81-50 (Safety rules for the construction and installation of lifts - Examination and testing of lift components), and the Machinery Directive 2006/42/EC.

This maintenance must be carried out according to a pre-established schedule or following detected anomalies, in order to prevent failures and optimize the lifespan of the installations.

2. Safety Precautions

WARNING: Before any intervention, safety is essential. Failure to follow the following procedures could result in serious injury or death.

2.1. Personal Protective Equipment (PPE)

• Safety helmet: Protection against falling objects and head impacts. Complies with the NF EN 397. standard
• Safety shoes: Non-slip, with protective toe cap and anti-perforation sole. Compliant with the NF EN ISO 20345. standard
• Protective gloves: Resistant to cuts and abrasion. Compliant with the NF EN 388. standard
• Protective glasses: Protection against splashes of debris and fluids. Compliant with the NF EN 166. standard
• Fall arrest harness and lanyard: Mandatory when working at height or in areas at risk of falling. Complies with NF EN 361 and NF EN 354. standards

2.2. Lockout/Designation Procedures (LOTO - Lockout/Tagout)

• MANDATORY NOTES: Cut off the main power supply to the elevator at the main circuit breaker.
• Checking for absence of voltage: Use a multimeter or certified VAT (Voltage Absence Tester) to confirm the total absence of voltage on all conductors.
• Lockout and Tagout:Lock the circuit breaker with a personal padlock and affix a visible lockout label stating "Do not energize - Maintenance in progress."
• Operation test: Attempt to operate the elevator after lockout to ensure that any residual energy is dissipated and that the system is truly powered off.

2.3. Dangerous Energy

• Electric energy: Risk of electrocution even after disconnection, if LOTO procedures are not rigorously followed. Capacitors and batteries can retain significant charges.
• Stored mechanical energy: The counterweight and elevator car may move unexpectedly under the influence of gravity if the brakes are not engaged or safety chocks are not in place.
• Risks of falling: Working in the shaft or at the top of the cabin presents risks of falling from a height. Use anchor points and fall arrest equipment.
• Hydraulic pressure (for hydraulic elevators): Release the pressure in the hydraulic circuit before any work on the associated components.

3. Tools and Materials Required

Proper preparation is essential. Make sure you have all the specified tools and materials, checking their calibration and condition before starting the job.

4. Pre-Maintenance Checklist

Before logging the system, perform a quick visual inspection to identify obvious anomalies and prepare the work environment. Any “Non-Compliant” item must be documented and addressed.

5. Walkthrough

This section details the technical steps to follow for complete maintenance. Respect the order and values ​​specified.

5.1. Logging and Securing

1. Take the elevator out of service: Position the car on an intermediate floor or at ground floor level, according to the manufacturer's instructions. Common mistake: Failing to notify users or post warning signs.
2. Apply the LOTO procedure:
   • Cut the general electrical power to the elevator at the main circuit breaker.
   • Check the absence of voltage using the multimeter on the power terminals. Measured voltage: 0V AC/DC.
   • Lock the circuit breaker and attach the lockout label.
   • Ensure that all potential energies are dissipated.
   SAFETY: Confirm visually and by test the absence of movement of the cabin before entering the shaft or on the cabin roof.

5.2. Testing Safety Devices

1. Testing the landing door and car locks:
   • Try to open each landing door with the car in position, then outside the unlocking zone. Doors must remain closed.
   • Operate the emergency release mechanism from inside the cabin (if equipped). Check that it is only functional upstairs.
   • Check the correct operation of the electrical contacts of each lock using the multimeter (continuity). Expected value: Contact closed (0 Ω) when the door is locked, contact open (infinity Ω) otherwise.
   Common mistake: Not testing all doors or ignoring an intermittent contact.
2. Speed ​​limiter test:
   • Manually trigger the speed limiter (if the type allows) or simulate overspeed according to the OEM procedure.
   • Check that the cabin's parachute or emergency brakes activate and bring the cabin to a safe stop. Visual indicator: The jaws of the parachute should have clamped firmly on the guide rails.
   • Reset the speed limiter and the safety gear according to the manufacturer's specific instructions.
   SAFETY: This test must be carried out with the cabin empty and under the supervision of a second technician, if the procedure requires it.
3. Test of the safety limit switches:
   • Manually move the cabin towards the upper and lower ends of the shaft.
   • Check that the upper and lower limit switches act correctly to shut off the engine before the cabin reaches the extreme stops.
   • Measure the remaining stopping distance. Expected value: Distance according to OEM specifications (generally 150-300 mm before bumper).
4. Test of the drive machine brake:
   • For traction elevators, test that the cabin is maintained under nominal load (simulated or real) by the brakes alone, without motor power.
   • Check the holding torque and the absence of slipping. Acceptance criteria: No movement of the cabin after 1 minute.

5.3. Guide Rail Inspection

1. Visual examination:
   • Inspect the entire length of the guide rails for the cabin and the counterweight (if applicable).
   • Look for signs of wear, deformation, corrosion, indentations or embedded debris.
   • Check the condition of the lubrication. Visual indicator: Uniform and clean lubricant film on the rolling surfaces.
   Common mistake: Ignoring minor wear marks that can develop into critical defects.
2. Measuring alignment and flatness:
   • Use a level and a comparator to check the vertical and horizontal alignment of the rails.
   • Vertical alignment tolerance: Maximum 1.5 mm over 5 meters.
   • Flatness tolerance of the rolling surface: Maximum 0.2 mm on a 1 meter rule.
3. Fixing the rails:
   • Check the tightness of all the rail and stirrup fixing bolts.
   • Tighten if necessary to the specified torque. Typical tightening torque: M16 bolts: 80 Nm; M12 bolts: 50 Nm.
   • Check that there is no play in the fixings.
4. Guide shoe inspection:
   • Examine the guide shoe inserts (shoes) of the cabin and counterweight for wear.
   • Measure the clearance between the shoe and the rail with a feeler gauge. Acceptable clearance: 1.5 mm to 2.0 mm on each side. If clearance is greater than 3.0 mm, replacement is required.
   • Replace worn shoes. Common mistake: Underestimating the impact of excessive play on vibrations and premature wear.

5.4. Examination of Lifting Cables

1. Detailed visual inspection:
   • Examine each cable over its entire accessible length, particularly at bending points (pulleys) and anchors.
   • Look for broken strands, excessive wear (diameter reduction), corrosion, deformation (notches, pinching, birdcage).
   • NF rejection criterion EN 81-20: A single visible broken strand (core or outer strand) or a reduction in diameter greater than 10% compared to the nominal diameter.
   SAFETY: A damaged cable seriously compromises the safety of the installation. Any significant anomaly requires immediate replacement of the cable set.
2. Measuring cable tension:
   • Use the cable tension meter to measure the individual tension of each lifting cable.
   • Adjust the tension so that it is uniform between all cables. Tolerance: The maximum variation between cables must not exceed 5% of the average voltage.
   Common mistake: Neglecting tension balancing, leading to uneven wear and risk of premature failure.
3. Inspection of anchor points and fasteners:
   • Check the condition of the brackets, corners, and cable fixing yokes.
   • Look for cracks, corrosion or loosening.
   • Tighten the fasteners to the specified torque.

5.5. Verification of Mechanical Components

1. Inspecting pulleys and sheaves:
   • Examine the grooves of pulleys and sheaves for wear, marks or deformation.
   • Ensure that the cables are correctly seated in the grooves.
   • Check the free rotation of the sheaves.
2. Bearings:
   • Listen for abnormal noises (squealing, clicking) during manual rotation (if possible) or operation.
   • Check for excessive play.
3. Braking system (for traction elevators):
   • Inspect the condition of the brake linings and measure their residual thickness. Minimum thickness: Meets OEM specifications (e.g. > 3.0 mm).
   • Check the brake air gap. Typical clearance: 0.2 mm to 0.4 mm.
   • Test the operation of the brake release and engagement mechanism.
   Common mistake: Do not adjust the air gap, which reduces braking effectiveness.

5.6. Verification of Electrical and Electronic Components

1. Cleaning and inspection of contacts:
   • Inspect all safety contacts (doors, limiters, parachutes) for corrosion or fouling.
   • Clean the contacts with a dielectric cleaner.
   • Check the wiring for signs of degradation, breaks or loose connections.
2. Checking insulation resistance:
   • Measure the insulation resistance of the power and control circuits relative to earth. Minimum value: Complies with standard NF C 15-100, generally > 1 MΩ. For safety circuits, this value is critical.
3. Inspection of electronic boards:
   • Look for burned, swollen components or defective soldering.
   • Gently clean accumulated dust with dry air.

5.7. De-designation and Functional Tests

1. Remove tools and check area: Ensure no tools, debris or materials are left in the shaft or engine room.
2. Remove: Remove the LOTO labels and padlocks. Restore power supply.
3. Complete operating tests:
   • Perform several cycles of moving the cabin, empty and loaded (if possible), from the lowest level to the highest.
   • Check for smooth operation, precise stopping at floors, correct opening and closing of doors.
   • Check the proper functioning of the emergency call system and two-way communication.

6. Post-Maintenance Checklist

After the intervention, these final tests are essential to confirm that the elevator is safe and fully operational.

7. Troubleshooting Guide

This table provides quick assistance for common problems after maintenance or in service. A thorough diagnosis is always recommended.

8. Recommended Maintenance Schedule

This schedule is a general guideline. OEM specifications and usage intensity may require adjustment.

9. Spare Parts Reference

For optimal performance and extended life of your equipment, use original spare parts or certified equivalents. UNITEC-D offers a complete range of premium quality components.

For an accurate selection and availability of parts, consult our online catalog: www.unitecd.com/e-catalog/

10. References

• NF EN 81-20: Safety rules for the construction and installation of elevators - Passenger elevators and accompanied freight elevators.
• NF EN 81-50: Safety regulations for the construction and installation of elevators - Examination and testing of elevator components.
• Machines Directive 2006/42/EC: Concerning machines, and amending Directive 95/16/EC.
• NF C 15-100: Low voltage electrical installations – Rules.
• Technical documentation from the elevator manufacturer (OEM).
• Guides to good maintenance practices AFNOR and certification bodies (e.g. APAVE, VERITAS).