ANSI Z244.1: Lockout

ANSI/ASSP Z244.1 is the American national standard for controlling hazardous energy, usually called lockout/tagout. OSHA’s own rule covers many workplaces, and Z244.1 is a voluntary standard that many employers use to build stronger programs. This page is a plain-language overview.

• General Industry
• Maintenance
• Safety Managers

Where it fits

• OSHA 1910.147 is the legal rule for general industry. Construction has other rules (such as 1926.417 for electrical lockout, and lockout provisions in other 1926 sections). See Lockout/Tagout.
• ANSI/ASSP Z244.1 is a consensus standard. It isn’t law by itself, but it describes good practice, and employers, insurers and courts may look to it. It’s updated from time to time; check the current edition.
• If a standard is stricter than OSHA, you can follow it and still meet the OSHA rule. If OSHA is stricter, follow OSHA.

Core ideas

• Hazardous energy includes electrical, mechanical, hydraulic, pneumatic, chemical, thermal and stored energy (like springs, capacitors and gravity).
• A written energy control program with machine-specific procedures
• Lockout devices and tags that are durable, standardized and used only for energy control
• Training for authorized, affected and other employees
• Periodic inspections of procedures and audits of the program

Risk assessment

Z244.1 puts more emphasis than OSHA’s rule does on assessing risk for each task. Before work, you ask: what energy sources can hurt someone, how likely and how severe is the harm, and what controls will remove or reduce it? The hierarchy of controls applies: remove the hazard first, then use engineering controls, then procedures, then PPE. See Hierarchy of Controls.

Energy control procedures

A typical lockout procedure follows these steps (see your own written procedure for the exact sequence):

1. Prepare: know the machine, its energy sources and the hazards.
2. Notify affected employees.
3. Shut down the machine using normal controls.
4. Isolate every energy source.
5. Apply locks and tags. Each authorized person adds a personal lock.
6. Release stored energy: bleed, block, ground, vent.
7. Verify that the machine is de-energized by trying to start it (from a safe spot) and by testing, before anyone reaches in.
8. When done: clear the area, remove locks only by the person who put them on, and restart following the procedure.

Alternative methods

Some tasks, like minor tool changes, routine adjustments or cleaning during normal production, can’t be done with full lockout. OSHA allows minor servicing exceptions only when alternative measures provide effective protection. Z244.1 describes ways to approach this, such as safeguarding and controlled interlocks. See Clearing Jams and Safeguarding Devices. Where an alternative isn’t clearly safe, use lockout.

Groups and shift changes

• When several people work on the same equipment, each person puts on a personal lock using a group lockout device or lockbox. See Group Lockout.
• At shift changes, there must be a procedure to pass on lockout without gaps.
• Outside contractors and the host employer must share their energy control programs.

Training and audits

• Training for authorized employees, affected employees and others who may be near
• Retraining after procedure changes or when a lapse is found
• A periodic inspection of each procedure at least once a year, by someone not using that procedure, and documented
• Records kept and procedures updated when equipment changes

Last updated: October 4, 2026