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LOTO : Different types of locks for different purposes

9 November 2023

Throughout the years, I’ve seen a lot of things in the industry when it comes to padlocks. Single personal padlocks, multiple personal padlocks, control padlocks, padlock series, etc. Here’s a quick guide on the different types of padlocks you should consider for your facility.

Safety padlocks

This first set of padlocks are used to guarantee the safety of workers while work is being performed.

Personal padlocks (mandatory)

  • Registered to the employee using his name and a unique reference number.
  • Each authorized employee has one uniquely keyed padlock with a single non-reproducible numbered key.
  • The personal padlock and its key are at all times under the responsibility of its owner.
  • The personal padlock must only be installed on the isolation device or isolation box on which the authorized employee is currently carrying out work and used only for lockout purposes.
  • Lending its personal padlock to somebody else is prohibited as is the use of another person’s personal padlock.

It is generally not recommended to issue more than a single personal padlock to each authorized employee. Although it can work in certain specific cases (facilities where 90% of the machines have 2 isolation points), multiple personal padlocks should never be used to lockout 2 different equipment. You can’t be working at 2 places at once, so neither should your personal padlocks.

Borrowing padlocks (recommended)

  • Uniquely keyed padlock with a single non-reproducible numbered key.
  • Registered to one person.
  • Provided temporarily to a person who is not an authorized employee, to visitors without their own compliant Personal Padlock or for loss of personal padlock in order to serve as a personal padlock.
  • Always accompanied by a borrowing padlock tag.

Relatively self explanatory, these types of padlocks serve the same function as personal padlocks but, are borrowed by either an external resource that has to visit a locked out area or an employee who lost their personal padlock.

Equipment padlock (recommended)

  • Used during multiple lockout (where there is more Energy Isolation Points than the standard number of Personal Padlocks provided to each Authorized Employees) to lock individual energy isolating device.
  • Available in series each with a unique keying and a single non-reproducible key
  • Stored in a lockout station.
  • The quantity of locks per series is established according to the needs.
  • More than one series can be used to lockout an equipment.
  • All keys of the series used and unused padlocks (if any) must be placed in the same lockout box once lockout is complete.

These locks are used whenever the amount of energy isolation device for a given lockout exceeds the number of personal padlocks provided to each employee. When every energy isolating device will have been locked, the key to the equipment padlocks and the remaining equipment padlocks will go in the lockout box onto which individual employees will put their personal padlock. This will ensure that, as long as there is a single personal padlock on the box, all of the energy isolating devices cannot be unlocked, thus guaranteeing the safety of workers.

Continuity padlocks

This second set of padlocks are mostly used to control the equipment’s return to service. Each of these locks could potentially have more than a single key, thus making them unsafe to use by themselves to guarantee the safety of individual employees.

Departmental padlocks

  • Available in series each with a unique keying and several non-reproducible numbered keys.
  • Each key is registered to each employee of a specific department.
  • It is forbidden for any owner of a departmental key to lend it.
  • Always accompanied by a tag.
  • Stored in the lockout station.
  • These padlocks are used to allow a specific department to control when an equipment can be returned to service

The reason why the departmental padlocks cannot be used to guarantee the safety of individual workers or even the integrity of a lockout is that multiple employees from a department may have the key to unlock it. The main purpose of these locks is really just to signal to employees who would want to return the equipment to service that they have to get in touch with a specific department to do so. On larger outages, there might sometimes be multiple departmental padlocks on a given lockout box, signaling that multiple groups of people have to give their consent before the equipment can be safely restarted.

Control padlocks

  • Available in series each with a unique keying and several non-reproducible numbered keys.
  • Each key is registered to each foreman/supervisor/superintendant.
  • It is forbidden for any owner of a control key to lend it.
  • Always accompanied by a control tag.
  • Stored in the lockout station.
  • These padlocks are used:
    • For shift or assignment change while the work is not completed.
    • To maintain lockout application during long duration shutdown.
    • Allowing maintaining the lockout by the foreman when he wants to control the equipment return to service (for example, when a contractor is present).

Although the basics of the control padlocks are similar to departmental padlocks, there is one key difference: The keys belong to management personnel. Legally speaking, the management personnel represents the employer and therefore have specific responsibilities towards employees. This allows you to use control padlocks not only as a continuity item, like a departmental padlock, but also as an integrity item, like a car seal.

Car seal

  • Used with a departmental or control padlock to confirm that the multiple lockout has not been altered if there is no personal lock:
    • During shift changes;
    • When work is not completed ;
    • During long duration shutdown;
  • Can not be used alone.
  • The seal number must be indicated on the Energy Control Procedure and only one number without any error must appear.

I know, this isn’t really a padlock, but it’s common enough as a lockout tool that I wanted to include it as well. Alone, the car seal cannot be used to properly secure a lockout box. In combination with a departmental padlock or especially a control padlock, the car seal can be used to guarantee the lockout hasn’t been tampered with, giving employees the confidence to execute the work.

There are additional types of locks, but they are mostly variations on the major types we just talked about. If you would like to know more or think we forgot something, feel free to reach out to us!

Written by Ludovic Tremblay