Swing radius hazard controls

Swing radius hazards are areas where an equipment's rotating superstructure can strike or pinch/crush a worker. The standard defines these hazards as a reasonably foreseeable risk of either striking and injuring an employee or pinching/crushing an employee against another part of the equipment or another object (1926.1424(a)(1)).

• These hazard areas move with the rotating superstructure and can include counterweights, booms, jibs, buckets, or other rotating components.
• Employers must treat these zones as strike and pinch/crush risks and implement the controls required in 1926.1424(a)(2).

Each employee assigned to work on or near the equipment ("authorized personnel") must be trained to recognize struck-by and pinch/crush hazard areas posed by the rotating superstructure. The standard requires this training for every authorized person (1926.1424(a)(2)(i)).

• Training must enable workers to identify where swing and pinch/crush zones exist and how to avoid entering them.
• Employers should include practical examples and workplace-specific markings or controls used at the site so workers understand how the rules apply to their tasks.

Employers must erect and maintain control lines, warning lines, railings, or similar barriers to mark the boundaries of swing radius hazard areas. This is the default requirement to prevent employees from entering those hazard areas (1926.1424(a)(2)(ii)).

• Barriers should clearly define where it is unsafe to stand or pass while the superstructure may rotate.
• Examples include temporary fencing, stanchions with high-visibility tape, painted lines combined with cones, or guardrail systems appropriate to the work environment.

If an employer demonstrates it is not feasible to erect barriers on the ground or on the equipment, the hazard areas must be clearly marked by a combination of warning signs (for example, "Danger--Swing/Crush Zone") and high-visibility markings on the equipment, and employees must be trained to understand those markings (1926.1424(a)(2)(ii)).

• The markings and signs must be conspicuous and placed so workers can readily see and understand where the hazard exists.
• Training should explain what each marking/sign means and when workers are allowed to be near those marked areas.

Before going to a location in the hazard area that is out of view of the operator, the employee (or someone instructed by the employee) must ensure the operator is informed that they are going to that location (1926.1424(a)(3)(i)).

• The intent is to make the operator aware so they do not move the rotating superstructure while the worker is exposed.
• Employers should provide a reliable way for workers to notify operators (for example, radio, direct verbal contact, or a designated signal person), and train workers in its use.

If the operator knows an employee went into a swing radius hazard area, the operator must not rotate the superstructure until informed via a pre-arranged system of communication that the employee is in a safe position (1926.1424(a)(3)(ii)).

• The employer must establish and implement the pre-arranged communication method (e.g., radio, hand signals, tag lines, or other agreed signals) and ensure both operators and ground workers are trained in it.
• Operators should always confirm receipt of the communication and the worker’s safe status before moving.

No, the swing radius rule does not specify a numeric distance for control lines or barriers; it requires employers to erect and maintain control lines, warning lines, railings, or similar barriers to mark the hazard boundaries appropriate to the equipment and the work (1926.1424(a)(2)).

• Employers must assess the equipment’s rotating envelope and set boundaries that keep workers clear of the swing and pinch/crush zones.
• Use the equipment manufacturer’s guidance, job hazard analysis, and job-site conditions to determine how far barriers should be placed.

"Authorized personnel" are employees who are assigned to work on or near the equipment and therefore need training to recognize swing radius hazards; the standard requires that each such assigned employee be trained (1926.1424(a)(2)(i)).

• This typically includes operators, signal persons, riggers, maintenance staff, and any workers who enter areas adjacent to the rotating superstructure as part of their duties.
• Employers should identify these workers in their site-specific hazard analysis and document that training was provided.

When barriers are not feasible, employers must clearly mark the hazard areas with a combination of warning signs (for example, "Danger--Swing/Crush Zone") and high-visibility markings on the equipment, and train employees to understand the markings (1926.1424(a)(2)(ii)).

• Signs should be placed where workers approach or could be exposed, and markings on equipment should identify the rotating envelope.
• Training should cover what each sign and marking means and the safe behaviors required when near marked areas.

The standard requires a pre-arranged system of communication but does not prescribe a specific method; employers must institute and use a reliable communication system so operators and workers can inform each other when workers enter or exit hazard areas (1926.1424(a)(3)(ii)).

• Common effective methods include two-way radios, direct verbal contact when in sight, agreed hand signals, or a designated signal person.
• Employers must ensure the system chosen is dependable under site conditions (noise, distance, visibility) and train personnel in its use.

If any part of a crane or derrick is within the working radius of another crane or derrick, the controlling entity must institute a system to coordinate operations; if there is no controlling entity, the employer or employers operating the equipment must institute such a system (1926.1424(b)).

• The coordinating system should prevent collisions, entanglements, or worker exposure to swing radius hazards from multiple machines.
• Coordination methods can include a designated controlling entity, a lift director, pre-lift meetings, radio protocols, and agreed exclusion zones.

No, while line of sight is useful, the standard requires that before an employee goes to a location out of the operator’s view the operator must be informed, and the operator must receive confirmation that the employee is in a safe position before rotating the superstructure (1926.1424(a)(3)(i)-(ii)).

• Employers should not rely solely on visual observation; use the pre-arranged communication system to ensure workers are accounted for and safe.
• This reduces the risk of inadvertent movement that could strike or pinch/crush personnel out of sight.

Yes, temporary controls such as cones with high-visibility tape or temporary stanchions can be acceptable forms of control lines, warning lines, or similar barriers if they effectively mark the hazard boundary and are maintained for the duration of the exposure (1926.1424(a)(2)(ii)).

• The chosen barrier must clearly communicate where the hazard zone begins and must remain in place and visible while the rotating equipment poses a risk.
• Evaluate site conditions (wind, foot traffic, equipment movement) to ensure temporary markers remain effective.

While 1926.1424 does not prescribe specific recordkeeping, employers should document training of authorized personnel, the hazard analysis that determined barrier placement or the exception, and the procedures for communication and coordination required under the standard (1926.1424(a)(2) and 1926.1424(b)).

• Maintain training records showing who was trained, the content, and dates.
• Keep written procedures or site plans showing barrier locations, marking rationale for any exception, and the communication/coordination system used for multi-equipment operations.

Manufacturer-applied high-visibility markings and warnings can help meet the exception, but employers still must ensure the combination of warning signs and high-visibility markings clearly identifies the hazard areas and that employees are trained to understand them (1926.1424(a)(2)(ii)).

• Relying solely on small or obscure manufacturer labels may not be sufficient; markings should be visible from worker approach paths and meet site-specific needs.
• Employers remain responsible for ensuring that equipment markings plus signs provide effective hazard communication and that workers know what they mean.

The employer is responsible for implementing and ensuring use of a pre-arranged system of communication so operators and workers can safely coordinate work in hazard areas (1926.1424(a)(3)(ii)).

• Employers must train operators and workers in the system, provide necessary equipment (radios, signage, tags), and enforce its use on the jobsite.
• Supervisors and competent persons should monitor compliance and take corrective action when the system is not used or fails.

Before allowing cranes or derricks to operate within each other’s working radius, the controlling entity or the employer(s) must institute a system to coordinate operations to prevent interference and hazards (1926.1424(b)).

• The coordination system should define who is in command, establish radio or signal protocols, set exclusion zones, and schedule lifts to avoid overlapping swing paths.
• Employers should document the coordination plan, hold pre-lift meetings, and ensure all operators and rigging crews understand and follow it.

PPE alone does not satisfy the requirement to prevent employees from entering swing radius hazard areas; the standard requires employers to prevent entry by using barriers, markings, and training so that workers do not enter those zones during operation (1926.1424(a)(2)).

• PPE does not eliminate the struck-by or pinch/crush hazard that occurs when a worker is within the rotating envelope.
• If work must be done in the hazard area, use the pre-arranged communication system and other controls to ensure the operator does not move the superstructure until the worker is in a safe position.

The worker (or someone instructed by the worker) must inform the operator before going to the out-of-view location, and the operator must not rotate the superstructure until informed via the employer’s pre-arranged communication system that the worker is in a safe position (1926.1424(a)(3)(i)-(ii)).

• Use the agreed communication method (radio, hand signal via a designated signal person, or direct verbal confirmation) to notify the operator.
• The worker should move only when the operator acknowledges and ensures that no movement will occur until the worker reports clear; the operator should verify the worker’s safe status before resuming rotation.