Lockout/Tagout (LOTO) Procedure: Energy Isolation Verification and Hardware Checklist

1. Scope and Purpose

This manual covers the Lockout/Tagout (LOTO) procedure for safe energy isolation of machinery and equipment at UNITEC-D GmbH industrial facilities. It is intended for use by technical personnel during maintenance, repair, debugging, or cleaning operations where unexpected equipment start-up, release of stored energy, or movement of components could result in injury. Application of this procedure is mandatory for any work that requires access to hazardous areas or interaction with energy-carrying parts of equipment. Compliance with LOTO procedures meets the requirements of DSTU EN 1037:2018 and ISO 14118:2017 standards.

2. Precautions

DANGER: Failure to follow Lockout/Tagout procedures can result in serious injury or death. Always assume all power sources are active until their isolation is confirmed.

• Lockout/Tagout (LOTO): A complete LOTO procedure must be performed prior to any work on equipment that may unexpectedly start, move, or release stored energy. This includes identification, isolation, blocking, tagging and verification of the absence of energy.
• Personal protective equipment (PPE):
  • Safety glasses or shield (according to DSTU EN 166:2017)
  • Protective gloves (according to DSTU EN 388:2017 for mechanical risks, or DSTU EN 60903:2017 for electrical work)
  • Safety shoes with a metal toe cap (according to DSTU EN ISO 20345:2019)
  • Protective helmet (according to DSTU EN 397:2017)
  • Protective clothing (special clothing that meets the working conditions)
• Dangerous energy:
  • Electrical: Discharging capacitors, disconnecting from the network, locking switches. Always check the absence of voltage with a multimeter with the appropriate safety class (e.g. CAT III 1000V / CAT IV 600V) certified by UkrSEPRO.
  • Mechanical: Springs, lifted loads, rotating components. Use mechanical supports, latches, wedge locking devices.
  • Hydraulic/Pneumatic: Pressure in pipelines, cylinders. Pressure injection, blocking of valves, checking of manometers.
  • Chemical: Substance residues in pipelines. Washing, neutralization, ventilation.
  • Thermal: Hot surfaces, liquids, gases. Cooling, thermal insulation.
• Notification: Be sure to inform all employees who may be involved or affected about the LOTO procedure before it begins and after it is completed.

3. Necessary Tools and Materials

4. Checklist of Inspection Before Service (LOTO)

This checklist is mandatory to complete before using the LOTO procedure.

5. Step-by-Step Blocking/Tag Procedure (LOTO)

Follow these steps to safely isolate your equipment.

1. Step 1: Preparation and Notification

   • Identify equipment that needs maintenance. Use nameplates and stock numbers for accurate identification.
   • Understand all energy sources and potential hazards associated with equipment using up-to-date electrical, hydraulic, pneumatic and process diagrams (P&IDs).
   • Notify all workers who use the equipment or are in the risk area of ​​the upcoming shutdown and the reason (for example, "scheduled maintenance on pump #3"). Mistake: Forgetting to notify the shift staff or employees of adjacent shops, which can lead to an unauthorized start.

2. Step 2: Stop the Equipment

   • Follow the standard equipment shutdown procedure by referring to the manufacturer's (OEM) operating manual or your local operating manual.
   • Ensure that all equipment functions are completely stopped and that there are no moving parts.
   • Error: Stopping too quickly, which may damage equipment or prevent full discharge of stored energy. Always stop the equipment in the order provided by the technological process.

3. Step 3: Energy Isolation

   • Electrical power:
     1. Turn off the main circuit breaker or circuit breaker supplying voltage to the equipment. It should be a visible break in the electrical circuit. If possible, remove the fuses or turn off the disconnector.
     2. Place the interlock on the electrical switch. Make sure the switch is locked in the OFF position. For multi-phase systems, ensure that all phases are isolated.
   • Hydraulic/Pneumatic Power:
     1. Close the inlet and outlet valves for the hydraulic or pneumatic system. Use special blockers for valves.
     2. Completely depressurize the system by opening the exhaust valves or appropriate pressure relief devices. Check the manometer reading: the pressure should be 0 bar. Make sure that the hydraulic cylinders are not under pressure and cannot move freely.
     3. Lock the valves in the closed (or vented) position. If necessary, disconnect the pneumatic hoses and install plugs on the exposed ports.
   • Mechanical energy:
     1. Ensure that all moving parts of the equipment (springs, flywheels, lifted loads, conveyor belts) are fixed using mechanical stops, wedges, locking pins or special devices.
     2. Ensure that all potential movement or falling of components is prevented, for example by mechanical supports for lifted loads.
   • Heat energy:
     1. Close the supply valves of steam, hot water or process liquid.
     2. Open the drain valves to drain and cool the system to a safe temperature.
     3. Measure the surface temperature with an infrared thermometer. The temperature should be below 40°C for safe touch. For high-temperature systems, it is possible to use additional thermal insulation.
   • Chemical energy:
     1. Close chemical supply valves and shut-off valves.
     2. Flush piping and containers in accordance with Material Safety Data Sheets (SDS).
     3. Ensure that no hazardous vapors are present, using gas analyzers as necessary. Install plugs on the pipelines.

4. Step 4: Application of LOTO devices

   • At each point of energy isolation (switch, valve, connector), install the appropriate blocker.
   • Attach your personal lock to the blocker. Each employee who works on the equipment must install his own personal lock. Use a multi-level lock (hasp) if multiple people are working so that everyone can use their own lock.
   • Attach an identification tag to each lock. On the tag, clearly indicate: your name (or identification number), the current date and time of blocking, the expected duration of work and the reason for blocking. Error: Unclear or missing tag completion, which can lead to confusion and dangerous situations.

5. Step 5: Verification of No Power

   • This is a critical security step. DO NOT miss it.
   • Make sure all workers are a safe distance from the equipment, outside the danger zone.
   • Electrical Energy:
     1. Using a calibrated voltmeter that has been tested before use on a known voltage source, check that there is no voltage (0V) at all electrical terminals and components where energy may be present. The test should be performed phase-to-phase and phase-to-earth. A voltage check must be performed for each phase.
     2. Press the "START" button or try to activate the equipment (for example, through the control panel). Make sure the hardware is not starting up. This check should be performed only AFTER confirming the absence of voltage! Do not press the "START" button without first checking with a voltmeter.
   • Hydraulic/Pneumatic Power:
     1. Check pressure gauges in the system. They should show 0 bar.
     2. Try briefly activating hydraulic/pneumatic cylinders or actuators (if possible without risk) to confirm no pressure and no movement.
   • Mechanical Energy: Visually verify that all moving parts are locked and cannot move. Try to manually move them to confirm a secure fit.
   • Heat Energy: Re-measure the temperature with the infrared thermometer. Make sure all surfaces are safe to touch (< 40°C).
   • If any energy is detected, immediately return to Step 3 and check all isolation points and methods of discharging stored energy.

6. Step 6: Performing Maintenance Work

   • After successfully verifying the absence of power, personnel can safely perform scheduled work.
   • Follow all other safety procedures (e.g. working at height, working in confined spaces) and use appropriate tools, including torque wrenches, to tighten fasteners to the required torque (e.g. 45 Nm for M10 grade 8.8 bolts).
   • Error: Removing LOTO devices before work is complete or before all tools are removed from the work area.

7. Step 7: Hardware Recovery

   • Before removing LOTO devices, ensure that:
     • All tools and equipment are removed from the work area and returned to storage.
     • All guards and guards are in place and securely locked.
     • All workers moved to a safe distance from the equipment.
     • The equipment is visually ready to start, all components are assembled correctly.
   • Notify all workers of the upcoming power restoration and possible equipment start-up.
   • Each worker personally removes his lock and tag. The multi-level blocker is removed last after all personal locks have been removed. Error: One person picks the locks of others, which violates the principle of personal responsibility and is a gross breach of security.
   • Restore power to the equipment by reversing the isolation steps (eg, open valves, turn on circuit breakers).
   • Test equipment to make sure it is working properly by observing operating parameters (pressure, temperature, vibration, electrical characteristics).

6. After Service Verification Checklist (LOTO)

7. LOTO Troubleshooting Guide

8. Recommended Maintenance Schedule of LOTO-Devices

Regular inspection and maintenance of LOTO devices is critical for their reliability and efficiency. Follow the schedule below.

9. LOTO Spare Parts Directory

UNITEC-D GmbH offers a wide range of reliable LOTO devices that meet CE and UkrSEPRO standards. To order, please refer to our e-catalog at www.unitecd.com/e-catalog/.