Definitions for cranes and derricks

An A/D director is an individual who meets the subpart's specific requirements for directing crane assembly or disassembly, regardless of their job title or management status. The definition and scope are given in 1926.1401. Employers must ensure the person designated as the A/D director satisfies the training, experience, and authority requirements established elsewhere in this subpart before they perform assembly/disassembly duties.

An articulating crane is a crane whose boom is made of a series of folding, pin-connected members that typically extend or retract by hydraulic cylinders. The definition is in 1926.1401. Unlike latticed or telescopic booms, articulating booms have multiple hinged sections and are commonly used where maneuverability in confined spaces is needed.

For tower cranes, "assembly/disassembly" is expressed as "erecting and climbing" (for increasing height) and "dismantling" (for decreasing height); the process of increasing a tower crane's height at any stage is an erection process. This is specified in 1926.1401. Employers must treat tower crane erection/climb and dismantling as assembly/disassembly activities subject to the subpart's safety requirements for those operations.

An assist crane is a crane used specifically to help assemble or disassemble another crane. That definition appears in 1926.1401. Use an assist crane when required to lift, stabilize, or position components safely during the assembly/disassembly process as part of a planned procedure governed by the subpart's assembly/disassembly rules.

Attachments are devices that expand the range of tasks equipment can perform; examples include augers, drills, magnets, pile‑drivers, and boom‑attached personnel platforms. The definition and examples are in 1926.1401. Employers must follow manufacturers' equipment criteria and applicable subpart requirements when using attachments.

An audible signal is a distinct sound or series of sounds—such as a bell, horn, or whistle—used to communicate crane movements or warnings. See the definition in 1926.1401. Employers should use clear, recognized audible signals as part of their crane signaling plan and ensure signal persons and operators understand the meanings.

Blocking (also called cribbing) is wood or other material used to support equipment or components and to spread loads to the ground—commonly used to support lattice boom sections and under outrigger floats. The term is defined in 1926.1401. Employers must select blocking materials and configurations that safely support loads, follow manufacturer's guidance, and involve a competent person in decisions about cribbing during assembly/disassembly.

A boom (for equipment other than tower cranes) is an inclined spar, strut, or long structural member that supports the upper hoisting tackle; its length and vertical angle are often varied to change height or reach. The definition is in 1926.1401. Changing boom length or angle alters the load radius and stability—employers must follow load charts, use load‑moment indicators/limiters when required, and consider overturn or tip hazards.

A boom hoist limiting device is a system that disengages boom hoist power when the boom reaches a preset angle and prevents the boom from lowering further, such as kick‑outs, automatic stops, or derricking limiters. This is defined in 1926.1401. These devices protect equipment and workers by preventing uncontrolled lowering or over‑travel of the boom—employers must ensure such devices are functioning per equipment criteria.

A boom angle indicator measures the boom's angle relative to horizontal and is defined in 1926.1401. Operators must use angle indicators as required by the equipment's instructions or site procedures to verify safe lifting configurations and to avoid exceeding rated capacities for given boom angles.

A competent person is someone capable of identifying existing and predictable hazards in the workplace and authorized to take prompt corrective action to eliminate them. The definition appears in 1926.1401. In crane work, a competent person inspects rigging, assesses ground conditions, and stops work or corrects hazards when necessary.

Controlled load lowering is lowering a load using the hoist drive motor (gear train or hydraulic components) for maximum control rather than relying solely on the load hoist brake. The definition is in 1926.1401. This method gives finer control during delicate placements; employers must ensure equipment is designed and maintained for controlled lowering and operators are trained.

A dedicated spotter for power lines is someone whose sole job is to watch the separation between the power line and equipment, load lines, and loads and to communicate with the operator to prevent breaching minimum approach distances; they must meet the requirements of 1926.1428 for signal person qualifications. The definition is in 1926.1401. Employers should assign a dedicated spotter when needed and verify their qualification per 1926.1428.

"Directly under the load" means that part or all of an employee is positioned beneath a suspended load. This definition is in 1926.1401. Employers must keep employees out of the fall zone and not place them directly under suspended loads except where specific controls (e.g., tagging, barriers, or personnel platforms used per rules) allow it.

Encroachment is when any part of the crane, load line, or load (including rigging and lifting accessories) breaches a minimum clearance distance required from a power line. The definition is in 1926.1401. Employers must identify power lines, maintain required minimum approach distances, and use measures such as deenergizing, grounding, insulating, or a dedicated spotter qualified under 1926.1428 to prevent encroachment.

A fall zone is the area—often including the area directly beneath a suspended load—where materials could reasonably fall in an accident. This definition is in 1926.1401. Employers should control the fall zone by keeping personnel out of it, using tag lines, exclusion barriers, and ensuring lifts are planned and supervised by competent persons.

Free fall of the load line means only the brake is used to regulate the descent (the drive mechanism is not used to control lowering). The definition is in 1926.1401. Free fall is hazardous because it provides minimal control and increases the risk of dropping the load; employers must follow equipment criteria and safe work procedures to avoid uncontrolled lowering.

A floating crane/derrick is equipment designed by the manufacturer (or employer) for marine use by permanent attachment to a barge, pontoons, or vessel; a land crane/derrick is equipment not originally designed for marine use. Both definitions are in 1926.1401. Employers must apply the subpart requirements to the appropriate equipment type and consider marine stability hazards (e.g., free surface effect) for floating cranes.

Hoisting is the act of raising, lowering, or otherwise moving a load in the air with equipment covered by this standard, and the subpart clarifies that hoisting can be done by means other than wire rope/hoist drum equipment. The definition is in 1926.1401. Employers must treat any method that raises or lowers loads as hoisting under the subpart and follow applicable safety and equipment criteria.

A multi‑purpose machine is one configurable in different ways, at least one of which allows it to hoist and horizontally move a suspended load (e.g., when fitted with a winch pack or jib); when configured to hoist, it is covered by this subpart. The definition is in 1926.1401. Employers must determine the machine's current configuration—if it is rigged to hoist, apply the crane/derrick rules and training requirements.

A load moment (or rated capacity) indicator senses the overturning moment (load × radius) and indicates to the operator the percentage of equipment capacity being used; lights, bells, or buzzers may warn of an approaching overload. The definition is in 1926.1401. Operators use this information to avoid exceeding rated capacity; when equipment includes a load moment limiter that will cut power at capacity, operators must understand how it affects functions like hoisting or slewing.

A load moment limiter senses overturning moment and, when rated capacity is reached, shuts off power to functions that could increase loading (e.g., hoisting or telescoping out) while leaving functions that reduce loading operable (e.g., lowering). The definition is in 1926.1401. Unlike an indicator that only alerts the operator, a limiter actively prevents movements that would exceed capacity and is a critical safety control where required by equipment criteria.

A marine hoisted personnel transfer device is a device (like a transfer net) designed to protect employees being hoisted during a marine transfer and facilitate rapid entry and exit; such devices do not include boatswain's chairs when hoisted by equipment covered by this standard. The definition and exclusion are in 1926.1401. Employers must ensure personnel transfer devices meet the subpart's equipment and operational criteria and use appropriate fall protection.

An insulating link/device is an insulating device listed, labeled, or accepted by a Nationally Recognized Testing Laboratory in accordance with 29 CFR 1910.7. The definition appears in 1926.1401 and relies on the recognition criteria in 1910.7. When employers use insulating links to reduce the risk of electrical contact with power lines, they must ensure devices are appropriately tested, certified, and used consistent with equipment criteria and electrical safety procedures.

If the operator faces a potential for head injury from falling objects or overhead hazards while operating a crane, the employer must provide and require a protective helmet. OSHA's head protection requirements are explained in the letter Head protection for crane operators and relate to general industry standard 29 CFR 1910.135 (see also 1926.1401). Employers must assess job hazards and, when head protection is required, provide helmets that meet an applicable ANSI Z89.1 consensus standard.

A dedicated channel is a line of communication assigned by the controlling employer for exclusive use by one signal person and crane/derrick or a coordinated group; the term is defined in 1926.1401. Using a dedicated channel avoids interference and miscommunication between signal persons and operators—employers should assign, test, and train on dedicated communications for coordinated lifts.

An object is "nonconductive" when its materials and condition make it unlikely to become energized — that is, it has high dielectric properties and high resistance to current under the expected environmental and use conditions, per the definition in 1926.1401.

• This is a functional, condition-based definition: the same material can be nonconductive in one environment (dry, intact) and conductive in another (wet, damaged).
• Employers must evaluate material type, environmental conditions (moisture, contaminants), and the condition of the object when deciding whether it qualifies as nonconductive.

(See Definition in 1926.1401.)

Operational aids are devices that help the operator safely operate a crane by giving information or automatically controlling a crane function, as defined in 1926.1401.

• The rule explicitly points to the list of such devices in 1926.1416, which covers "listed operational aids" and examples of devices used to assist operators.

(See Operational aids in 1926.1401 and 1926.1416.)

An "operator" is simply a person who is operating the equipment, per the definition in 1926.1401.

• This means anyone actively controlling crane functions (levers, switches, pedals, etc.) is an operator, regardless of job title.
• Employers must ensure operators are qualified and understand manufacturer controls and limitations; see the broader crane standards in 1926 for operator qualification and duties.

The term "overhead and gantry cranes" covers bridge cranes, semigantry, cantilever gantry, wall cranes, storage bridge cranes, launching gantry cranes, and similar equipment — and it applies whether they travel on tracks, wheels, or other means, according to 1926.1401.

• The definition is intentionally broad so the same safety rules apply regardless of mobility method.
• If you are responsible for these cranes, follow the applicable requirements in the crane and derrick subpart of 1926.

Under 1926.1401, "pendants" include both wire and bar types and are fixed-length components used in latticed boom crane systems to change boom suspension length without re-spooling the drum.

• Wire-type pendants are wire rope segments with fittings at both ends for pinning; bar-type pendants substitute a bar for the rope.
• Use the type recommended by the equipment manufacturer and ensure pendants (and their fittings) are inspected per the crane maintenance and inspection rules in 1926.

A "personal fall arrest system" is a system used to stop an employee's fall from a working level and consists of an anchorage, connectors, a body harness, and may include a lanyard, deceleration device, lifeline, or combinations, per 1926.1401.

• For crane-related work at elevations (e.g., working on booms or upperworks), employers must provide systems that meet applicable performance and inspection requirements found elsewhere in 1926 and the fall protection standards.
• Always follow manufacturer anchorage capacity and competent-person inspections before use.

A "portal crane" is a crane with a rotating upperstructure, hoist machinery, and boom mounted on top of a structural gantry that may be fixed or have travel capability, per 1926.1401.

• Watch for hazards typical of gantry systems: overhead clearance, traffic passing beneath the gantry, stability of the supporting structure, and proper runway preparation.
• Ensure the runway meets the definition in 1926.1401 as a firm, level surface prepared for the crane configuration, and follow inspection and load-handling rules in 1926.

OSHA defines "power lines" as electric transmission and distribution lines in 1926.1401.

• For crane operations near power lines, this definition triggers the specific power-line clearance, proximity, and contact prevention requirements in the crane and derrick rules in 1926.
• Use approved proximity alarms and maintain required clearances; see the proximity alarm definition which references listing by a NRTL in accordance with 29 CFR 1910.7.

A "proximity alarm" is a device that warns of proximity to a power line and must be listed, labeled, or accepted by a Nationally Recognized Testing Laboratory (NRTL) in accordance with 29 CFR 1910.7, as defined in 1926.1401.

• In practice, use only proximity alarms that carry an NRTL listing or similar acceptance consistent with 29 CFR 1910.7 to meet the regulatory requirement.
• Keep documentation of the device listing and the manufacturer's specifications as part of your safety program.

A "qualified evaluator (not a third party)" is a person employed by the signal person's employer who has demonstrated competence in accurately assessing whether individuals meet the signal-person qualification requirements in the subpart, according to 1926.1401.

• The difference is employment relationship and independence: a non-third-party evaluator is an internal employee, while a "qualified evaluator (third party)" is an independent entity recognized for its expertise and objectivity.
• See the signal-person qualification and evaluation requirements in 1926.1428 for how evaluations must be performed and documented.

A "qualified person" is someone who, by degree, certificate, or extensive knowledge, training, and experience, has demonstrated the ability to solve problems related to the work, per 1926.1401.

• A "qualified rigger" is simply a rigger who meets that "qualified person" criteria and therefore can perform rigging tasks that require recognized skill and judgment.
• Employers should document the qualifications (training, certifications, experience) that demonstrate a rigger meets the definition and follow the applicable crane and rigging requirements in 1926.

A "range control limit device" is a device set by the operator to limit boom or jib tip movement to a plane or planes, while a "range control warning device" warns the operator when the boom or jib tip reaches that plane, as defined in 1926.1401.

• Use the limiter to prevent movement past preset boundaries; use the warning device to notify the operator before or as boundaries are reached.
• Both devices are operational aids under 1926.1401 and examples of operational aids are listed in 1926.1416.

"Rated capacity" means the maximum working load the manufacturer permits under specified working conditions, per 1926.1401.

• It's crucial because operators and riggers must not exceed the manufacturer's rated capacity for the configuration in use (boom length, radius, attachments).
• Determining rated capacity requires considering equipment configuration and load charts; follow manufacturer guidance and the crane rules in 1926 when planning lifts.

"Repetitive pickup points" refer to a short-cycle operation where the rope is used on a single layer and is spooled repetitively over a small portion of the drum, as defined in 1926.1401.

• This can increase wear on the running wire rope and the drum; employers must monitor rope condition, inspect frequently, and follow the manufacturer's guidance for rope use and rotation.
• Treat repetitive pickup operations as a maintenance and inspection consideration under the broader crane safety requirements in 1926.

"Running wire rope" is wire rope that moves over sheaves or drums, per 1926.1401.

• Hazards include abrasion, crushing, kinking, broken wires, and improper spooling; these can lead to rope failure and dropped loads.
• Regular inspection, correct reeving, correct drum layering, and following manufacturer replacement criteria are required under the crane rules in 1926.

A "runway" is a firm, level surface designed and prepared as a path of travel for the weight and configuration of the crane being used to lift and travel with the suspended crane platform, according to 1926.1401.

• Employers must ensure an existing surface meets these criteria for the specific crane (weight, wheelbase, travel) before use and make any needed repairs or reinforcements.
• Document runway capacity and inspect it as part of pre-operation planning under the crane requirements in 1926.

A "sideboom crane" is a track-type or wheel-type tractor with a boom mounted on the side used for lifting, lowering, or transporting a load on the load hook, per 1926.1401.

• Unlike a conventional crawler crane (where the boom is typically center-mounted), a sideboom's boom is mounted to the side of the tractor, which affects stability, rigging, and ground-bearing requirements.
• Operators and employers must account for the unique stability and lift-planning considerations of sidebooms under the crane standards in 1926.

"Special hazard warnings" are warnings of site-specific hazards (for example, proximity of power lines) as defined in 1926.1401.

• Employers should identify site-specific hazards during planning, communicate them to workers (signs, briefings), and implement controls (clearances, exclusion zones, PPE, proximity alarms).
• Use documented procedures and follow the applicable crane rules in 1926 to manage those hazards.

Crane operators who are exposed to the potential for head injury from falling objects must wear protective helmets when hazards exist, consistent with OSHA head-protection rules and the interpretation addressing cranes and helmets in the letter at https://www.osha.gov/laws-regs/standardinterpretations/2024-06-06-2.

• OSHA's head protection standard requirements are contained in 29 CFR 1910.135 and the crane-specific interpretation states employers must assess hazards and require helmets when overhead hazards exist; see 1910.7 for NRTL references and 1926.1401 for crane definitions.
• Helmets must meet the consensus standards incorporated in 29 CFR 1910.135 (e.g., ANSI Z89.1 variants noted in the interpretation) and employers must document their hazard assessment and helmet policy.

"Two blocking" is when an uppermost component on the hoist line (load block, hook block, overhaul ball, etc.) comes into contact with the boom tip or an upper block, and continued power can cause failure of the hoist rope or other components, as defined in 1926.1401.

• This condition can cause sudden catastrophic failures, so operators must avoid two-blocking and use devices (two-blocking prevention, limit switches, rated procedures) to prevent it.
• Employ operational aids listed in 1926.1416 and follow manufacturer guidance and inspection rules in 1926.

The "upperworks" or "upperstructure" is the revolving frame that carries the operating machinery, engine, operator cab, and counterweight, with the boom or front attachment mounted forward, as defined in 1926.1401.

• Working on or near the upperworks requires lockout/tagout of relevant energy sources, fall protection when elevated, and safe procedures for maintenance and inspection per the crane standards in 1926.
• Follow manufacturer maintenance schedules, ensure competent-person inspections, and address access and guarding to prevent caught‑between and fall hazards.

OSHA defines "wire rope" as flexible rope made by laying steel wires into strands around a core to form a helically wound rope in 1926.1401.

• Maintain wire rope by performing regular inspections for broken wires, corrosion, kinks, wear, and proper spooling; lubricate per manufacturer recommendations and replace rope when inspection criteria are met.
• Follow crane inspection, maintenance, and replacement guidance in the crane subpart of 1926 to prevent rope failures and dropped loads.