[Infographic] Safety Lockout Padlocks: Different Key Systems

tradesafe loto padlock with tag

During routine maintenance of machinery or process equipment, workers servicing may be seriously injured if hazardous energy is not properly controlled. This is why safety lockout padlocks are employed to shut off potential energy hazards to prevent such accidents from happening.

LOTO padlocks are energy-isolating devices that aid in implementing and maintaining the Safety Lockout Tagout Program in compliance with OSHA. But to ensure that your lockout tagout program runs well, it’s imperative that you know which padlock is suitable for your unique needs. In this article, we'll take a look at the differences of some of the most commonly implemented key configurations in commercial and industrial facilities.

OSHA’s Lockout Tagout Standard (1910.147)

According to OSHA Standard 29 CFR 1910.147, lockout tagout devices should be durable, standardized, substantial, and identifiable.

Lockout Safety Padlocks must fulfill these specifications in order to meet OSHA standards:

  • Be able to withstand long-term exposure to extreme environmental conditions and resistant to chemicals.
  • Have standard color, shape, or size within the facility.
  • Be non-reusable type, attachable by hand, self-locking, and non-releasable with a minimum unlocking strength.
  • Indicate the name of persons using the tools and other identifiable details such as padlock numbering, metal tagging, logos, department labels, etc.

Safety Padlock Key Systems

safety padlock keying system

Finding the right key system for your lockout tagout program ensures the right people have access to lockout equipment during maintenance. This infographic will help you determine the right option for your unique needs:

Keyed Different Padlock System (KD)

The key to each padlock is different in this system. It’s the ideal lockout solution if an employee commonly applies a single lock. It also ensures no risk of key duplication when numerous maintenance employees need to access the same piece of equipment. However, it’s possible to compromise safety if keyed-different locks aren’t properly charted, creating a risk that a lockout device will be released prematurely and equipment will be reenergized early.

Keyed Alike Padlock System (KA)

Safety lockout padlocks of this type all have the same key. This means that a single key may be used to open all padlocks of the same set. This type of lock is commonly used by maintenance personnel in charge of several machines or isolation points. With fewer keys on the keyring, it is easier to identify and use the right one.

One important thing to note is that OSHA standards provide that no employee should access a lock that another individual has installed. So, employees should never share keyed similar locks from the same set.

Keyed Alike Unlimited Padlock System (KAU)

Keyed Alike Unlimited Grouping allows you to have an unlimited number of safety padlocks of the same color and keys. It is ideal for large industries with employees operating on many machines and equipment in different business areas at the same time.

Master Keyed Padlock System (MK)

Personnel may access a Master Keyed Padlock System with a designated key or master key. The master key is specifically configured to open different padlocks, whether keyed differently or keyed alike. As such, lockout tagout procedures are more manageable, especially in the case of unprecedented emergencies in a facility.

It’s a suitable LOTO lock system solution when dealing with large teams that work on a significant number of equipment or isolation points with multiple locking points.

Grand Master Keyed Padlock System (GMK)

Grand Master Keyed Padlocks are separate groups of padlocks, each operated by a different master key, yet all accessible with a single key. Thus, such a key has the highest level of access. This way, management can assign multiple levels of responsibility to the lockout team, with only one person in charge of the whole operation.


LOTO Safety Padlocks are a must for every organization. It’s an essential part of industrial safety measures, particularly in areas where energy hazards are present. We hope this infographic has helped you determine which padlock is best suitable for your specific situation.

If you're looking for high-quality, durable, corrosion-resistant, and OSHA-compliant LOTO locks, look no further than our selection! Check out our new safety lockout padlocks, which come in various colors and configurations.

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.


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Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.