ANSI/ASSP Z244.1-2024: Control of Hazardous Energy: Lockout, Tagout

Hazardous energy, whether deriving from electrical, mechanical, hydraulic, pneumatic, chemical, or thermal sources in machinery and equipment, is the basis of a longstanding issue in many industries.

Due to the high frequency of casualties resulting from the unexpected release of hazardous energy and related machine start-ups, substantial measures have been taken by employers, unions, trade associations, and government to mitigate accidents, including the development of the ANSI/ASSP Z244.1-2024 standard.

Injuries from Hazardous Energy

Hazards deriving from the unexpected startup or release of stored energy are abundant. If a steam valve is automatically turned on, it can burn workers who repair a downstream connection in the piping. A jammed conveyor system, if suddenly released, can crush a worker. The range of possibilities with hazardous energy release leads to a variation in potential injuries, including electrocution, burns, crushing, cutting, and lacerating, amputating, or fracturing body parts.

As such, accidents caused from hazardous energy release remain alarmingly high, injuring around 50,000 workers each year.

Lockout, Tagout, and Methods for Controlling Hazardous Energy with ANSI/ASSP Z244.1

ANSI/ASSP Z244.1-2024: The Control of Hazardous Energy Lockout, Tagout and Alternative Methods exists to provide a reliable standard practice that, if followed correctly, can assure safety from hazardous energy in machinery.

The ANSI/ASSP Z244.1-2024 standard establishes guidelines for the control for hazardous energy associated with machinery, equipment, or processes that could do harm to the personnel. Specifically, it does this by establishing lockout, tagout, or alternative methods to control the hazardous energy. It is applicable to many activities, including erecting, installing, constructing, repairing, adjusting, inspecting, unjamming, set up, testing, troubleshooting, cleaning, dismantling, servicing, and maintaining machines, equipment, or processes.

ANSI/ASSE Z244.1 or ANSI/ASSP Z244.1?

Some past users of this standard might be confused but the designation of ASSP in the title.

Due to the ANSI-accredited standards developing organization (SDO) the American Society of Safety Engineers (ASSE) changing its name to the American Society of Safety Professionals (ASSP), all ASSP standards revised and reaffirmed from 2018 onward bear the new standard designation in their titles.

Changes to ANSI/ASSP Z244.1-2024

ANSI/ASSP Z244.1-2024 revises the previous edition of the same American National Standard, which had been last revised in 2016 and reaffirmed in 2020. In addition to reorganization of the document and updates to the annexes, the 2024 edition underwent the following changes of note:

• Added new definitions for “equipment,” “feasible,” “isolation (and energy dissipation),” “processes,” “shall,” and “should” and updated several other definitions.
• Elevated alternative methods to be co-equal choice with lockout/tagout (LOTO) for the control of hazardous energy.
• Added new Section 5, “Hazardous Energy Control Methods.”
• Updated Figure 1, “Flowchart for Controlling Hazardous Energy.”
• Addressed cybersecurity aspects.
• Added new Section 7.11, “Mobile Applications.”
• Modified text to become Group Energy Control and Complex Energy Control.
• Added new Section 8.9, “Piping Systems.”
• Added new Section 9, “Alternative Methods of Hazardous Energy Control.”
• Added content on feasible risk reduction.
• Added content on fault annunciation.
• Added new content on zoned or partitioned machines or equipment.
• Developed new content for energy for processes.

Responsibilities for an ANSI/ASSP Z244.1 Lockout System

At the core of the standard’s specifications is the user and the supplier of the machinery, and the interaction between these two groups determines the success of the lockout system. The supplier, who is responsible for designing, building, integrating, and installing machines, equipment, or processes, should incorporate all applicable provisions of this standard into their products, so that the user can assure compliance through the establishment of a protection program.

The third group bearing responsibility during this process is the personnel, who should comply with the hazardous energy control program.

Hazardous Energy Control Program

A hazardous energy control program consists of the following activities: identifying (assigning responsibilities, identifying tasks), operational procedures (documented procedures, for hazardous energy control, provisions for hazardous energy control interruption), implementation (selecting protective materials, communication and training), and program maintenance (monitoring/measuring, auditing of program elements).

Of course, in the control of hazardous energy, the design phase of the machinery plays a key role, since risk assessment conducted during this stage can determine the suitability of the equipment for its intended purpose. Hazardous energy control methods selected by the supplier can include identification of energy that is necessary to perform a given task(s), elimination of hazardous energy sources whenever practicable, control of hazardous energy, or control methods.

For example, ANSI/ASSP Z244.1-2024 discusses energy-isolating devices, which are installed as integral parts of a machine as a means of preventing the transmission or release of energy. The standard specifies that these devices be conveniently located, clearly identified, capable of being locked, and evaluated to determine their suitability for their intended purpose.

Using Lockout or Tagout to Control Hazardous Energy

As for the control process itself, lockout or tagout can be used. Under lockout, hazardous energy is isolated by securing a lockout device (or devices) of suitable construction placed on an energy-isolating device that prevents the inadvertent re-energization of machinery or equipment. Lockout devices should be placed by each authorized participating person.

In previous editions of ANSI Z244.1, lockout was the preferred method. However, in the 2024 edition, alternative methods have been elevated to be a co-equal choice with LOTO for the control of
hazardous energy.

According to ANSI/ASSP Z244.1-2024, lockout has to be used when no risk assessment has been completed or the tasks and/or hazards are unknown.

Under tagout, hazardous energy is isolated by using tags secured to an energy-isolating device that prevents the inadvertent re-energization of machinery or equipment. Every participating authorized person should either place an individual tag at each isolated source or be named in a group tagging method. The tags display the name of person placing the tagout, the contact information for the authorized person, a statement not to operate the equipment, and a statement not to remove the tagout device.

According to ANSI/ASSP Z244.1-2024, tagout is less preferred for the following reasons:

• Tagout does not provide exclusive control (lockout usually does).
• Tags can be subject to damage.
• Tagout is more susceptible to malicious tampering.
• Tagout is more easily defeated (wire cutters can be used rather than bolt cutters).

Other aspects of the procedures detailed in ANSI/ASSP Z244.1-2024 serve to establish the methods of the standard as reliable in preventing accidents from hazardous energy.

ANSI/ASSP Z244.1-2024: The Control of Hazardous Energy Lockout, Tagout, and Alternative Methods is available on the ANSI Webstore.