Steel erection definitions

Under 1926.751, "anchored bridging" means that the steel joist bridging is connected to a bridging terminus point and is used to stabilize joists by tying the bridging into an anchor such as a wall, beam, or tandem joists, as defined in 1926.751.

• Use anchored bridging when bridging must be secured to a termination point (a bridging terminus) to provide lateral stability to joists during erection.
• See also the general steel erection provisions in Part 1926 Subpart R for related requirements.

Under 1926.751, "bolted diagonal bridging" means diagonal bridging that is bolted to a steel joist or joists, which distinguishes it from other bridging methods that might be welded or otherwise attached, as stated in 1926.751.

• Bolted diagonal bridging provides mechanical connection points for stability and is typically installed per manufacturer or project specifications.
• For performance requirements and sequencing, consult the broader steel erection rules in Part 1926 Subpart R.

Under 1926.751, a "bridging clip" means a device that is attached to the steel joist to allow the bolting of the bridging to the steel joist, and it is important because it provides a secure point for fastening bolted diagonal bridging, as defined in 1926.751.

• Bridging clips help ensure that bridging is properly attached and that joists achieve the intended lateral stability during erection.
• Follow manufacturer instructions and Subpart R erection sequencing in Part 1926.

Under 1926.751, a "bridging terminus point" means a wall, a beam, tandem joists (with all bridging installed and a horizontal truss in the plane of the top chord), or other element at an end or intermediate point(s) of a line of bridging that provides an anchor point for the steel joist bridging, as defined in 1926.751.

• Typical terminus points include walls, primary beams, or properly prepared tandem joists.
• Ensure the terminus chosen is capable of resisting the loads imposed by the bridging per the project structural design and Subpart R requirements in Part 1926.

Under 1926.751, a "choker" means a wire rope or synthetic fiber rigging assembly that is used to attach a load to a hoisting device, and it is used for rigging loads for lifting or moving steel members, as defined in 1926.751.

• Chokers are commonly used to secure irregular loads or members that lack lifting points.
• Use appropriate rigging practices and qualified riggers; refer to the hoisting equipment definition in 1926.751 and other crane/rigging provisions in Part 1926.

Under 1926.751, "cold forming" means the process of using press brakes, rolls, or other methods to shape steel into desired cross sections at room temperature, and it applies to fabrication of members (for example, purlins and girts) that are field-assembled or pre-manufactured for erection, as defined in 1926.751.

• Cold-formed shapes are common in systems-engineered metal buildings and may be part of the structural framing subject to Subpart R.
• For how cold-formed members integrate with structural steel, see the definition of "systems-engineered metal building" in 1926.751.

Under 1926.751 (and defined in 1926.32), a "competent person" is capable of identifying existing and predictable hazards in the surroundings or working conditions and has the authority to take prompt corrective measures, while a "qualified person" is someone who by degree, certificate, or extensive knowledge and experience has demonstrated the ability to solve or resolve problems relating to the work, as provided in 1926.751 and 1926.32.

• Competent person: focused on hazard recognition and immediate corrective action on site (e.g., shoring, bracing).
• Qualified person: typically provides technical or design judgments (e.g., evaluating member capacities or design compliance).
• Both definitions are found in 1926.751 and 1926.32.

Under 1926.751, a "connector" means an employee who, working with hoisting equipment, is placing and connecting structural members and/or components, and their responsibilities include guiding, placing, and making initial connections while crane or rigging equipment positions members, as defined in 1926.751.

• Connectors must follow rigging and fall protection procedures and coordinate with crane operators and riggers.
• The employer should ensure connectors are trained and supervised per Subpart R requirements in Part 1926.

Under 1926.751, "constructibility" means the ability to erect structural steel members in accordance with Subpart R without having to alter the overall structural design, and it matters because lack of constructibility can create unsafe conditions or require on-site changes that affect stability and sequencing, as defined in 1926.751.

• Ensuring constructibility reduces the need for field modifications and helps maintain safe erection sequences consistent with manufacturer's and engineer's plans.
• Consult the project structural engineer of record for design or constructibility issues per 1926.751.

Under 1926.751, the "construction load (for joist erection)" means any load other than the weight of the employee(s), the joists and the bridging bundle, so materials or equipment placed on joists that add load beyond those listed would be considered construction loads, as defined in 1926.751.

• Excluded from the construction load are the weight of the workers, the joists themselves, and the bridging bundle.
• Employers should ensure joists are not overloaded during erection and follow relevant Subpart R requirements in Part 1926.

Under 1926.751, a "Controlled Decking Zone (CDZ)" means an area in which certain work (for example, initial installation and placement of metal decking) may take place without the use of guardrail systems, personal fall arrest systems, fall restraint systems, or safety net systems and where access to the zone is controlled, as defined in 1926.751.

• A CDZ is limited to specific decking tasks and requires access control and competent person oversight.
• For metal decking strength and related requirements, see 1926.754 which addresses decking performance during erection.

Under 1926.751, "controlled load lowering" means lowering a load by means of a mechanical hoist drum device that allows a hoisted load to be lowered with maximum control using the gear train or hydraulic components of the hoist mechanism, and it requires use of the hoist drive motor rather than the load hoist brake, as explained in 1926.751.

• Use controlled load lowering to minimize uncontrolled descent of loads; follow equipment manufacturer guidance and crane/derrick rules in Part 1926.

Under 1926.751, a "controlling contractor" means a prime contractor, general contractor, construction manager or any other legal entity which has the overall responsibility for the construction of the project—its planning, quality and completion, and their role includes coordinating safety and compliance among subcontractors on site, as defined in 1926.751.

• The controlling contractor typically coordinates site-wide safety measures, schedules, and ensures Subpart R requirements are followed.
• See other Subpart R provisions in Part 1926 for overlapping responsibilities.

Under 1926.751, a "critical lift" means a lift that (1) exceeds 75 percent of the rated capacity of the crane or derrick, or (2) requires the use of more than one crane or derrick, and operations meeting either condition are treated as critical lifts, as defined in 1926.751.

• Critical lifts require special planning, designated qualified personnel, and coordination consistent with applicable crane safety provisions in Part 1926.

Under 1926.751, a "decking hole" means a gap or void more than 2 inches (5.1 cm) in its least dimension and less than 12 inches (30.5 cm) in its greatest dimension in a floor, roof or other walking/working surface, while an "opening" means a gap or void 12 inches (30.5 cm) or more in its least dimension; skylights that do not meet the strength requirements of 1926.754(e)(3) shall be regarded as openings, as defined in 1926.751 and 1926.754(e)(3).

• Use appropriate covers, guardrails, or fall protection for openings (>=12 inches).
• For skylight strength and protection guidance, see 1926.754(e)(3).

Under 1926.751, a "derrick floor" means an elevated floor of a building or structure that has been designated to receive hoisted pieces of steel prior to final placement, and it is designated to provide a planned, safe staging area for hoisted materials during erection, as defined in 1926.751.

• A derrick floor must be capable of supporting hoisted pieces and follow load and access controls consistent with Subpart R in Part 1926.

Under 1926.751, a "double connection" means an attachment method where the connection point is intended for two pieces of steel which share common bolts on either side of a central piece, and a "double connection seat" is a structural attachment that, during the installation of a double connection, supports the first member while the second member is connected, as defined in 1926.751.

• Double connection seats provide temporary support to maintain stability while completing the second connection.
• Follow engineered procedures and competent person oversight when using these connection methods (see Part 1926 Subpart R).

Under 1926.751, "erection bridging" means the bolted diagonal bridging that is required to be installed prior to releasing the hoisting cables from the steel joists, and it must be installed to maintain joist stability before the hoist is detached, as defined in 1926.751.

• Install erection bridging per the manufacturer's or project erection sequence before removing hoisting rigging from the member.
• See Subpart R sequencing requirements in Part 1926 for additional controls.

Under 1926.751, a "fall restraint system" means a system that prevents the user from falling any distance (usually via anchorage and lanyard limiting travel), a "personal fall arrest system" arrests an employee in a fall from a working level and typically includes a harness and deceleration device, and a "positioning device system" is a body belt or harness rigged to allow an employee to be supported on an elevated, vertical surface and work with both hands free while leaning, as defined in 1926.751.

• Fall restraint: prevents reaching the fall hazard.
• Personal fall arrest: allows a fall but stops it safely; note 1926.751 states the use of a body belt for fall arrest is prohibited.
• Positioning device: supports worker at height to allow hands-free work.
• For system selection and use, consult Subpart R and fall protection rules in Part 1926.

Under 1926.751, "final interior perimeter" means the perimeter of a large permanent open space within a building such as an atrium or courtyard, and it excludes openings for stairways, elevator shafts, and similar penetrations, as defined in 1926.751.

• Treat final interior perimeters as fixed edges requiring appropriate fall protection and guarding per Subpart R and related fall protection rules in Part 1926.

Under 1926.751, a "permanent floor" means a structurally completed floor at any level or elevation (including slab on grade), and it indicates that the floor is complete and can serve as a walking/working surface without temporary decking requirements, as defined in 1926.751.

• Permanent floors change the applicable fall protection and deck installation rules under Subpart R in Part 1926.

Under 1926.751, "steel erection" means the construction, alteration or repair of steel buildings, bridges and other structures, including the installation of metal decking and all planking used during the process of erection, and it encompasses erection tasks covered by Subpart R, as defined in 1926.751.

• Activities include placing and connecting structural steel, installing decking, and other erection-phase tasks.
• Follow the full Subpart R requirements in Part 1926 for compliance.

Under 1926.751, a "steel joist" means an open web, secondary load-carrying member of 144 feet (43.9 m) or less, designed by the manufacturer, used for the support of floors and roofs; the definition does not include structural steel trusses or cold-formed joists, as stated in 1926.751.

• Steel joists are secondary framing members; longer or primary members are classified differently (e.g., joist girders or trusses).
• For primary members see "steel joist girder" and "steel truss" definitions in 1926.751.

Under 1926.751, a "steel joist girder" means an open web, primary load-carrying member, designed by the manufacturer, used for the support of floors and roofs (and does not include structural steel trusses), while a "steel truss" means an open web member designed of structural steel components by the project structural engineer of record and, for Subpart R purposes, is considered equivalent to a solid web structural member, as defined in 1926.751.

• Joist girders are manufacturer-designed primary members; steel trusses are engineered by the project structural engineer of record.
• Treat trusses as primary structural members requiring engineer oversight per Subpart R in Part 1926.

Under 1926.751, "structural steel" means a steel member, or a member made of a substitute material (such as fiberglass, aluminum or composite members), and these members include, but are not limited to, steel joists, joist girders, purlins, columns, beams, trusses, splices, seats, metal decking, girts, and all bridging, and cold-formed metal framing which is integrated with the structural steel framing of a building, as defined in 1926.751.

• The broad definition means many components used during erection fall under Subpart R protections in Part 1926.

Under 1926.751, "multiple lift rigging" means a rigging assembly manufactured by wire rope rigging suppliers that facilitates the attachment of up to five independent loads to the hoist rigging of a crane, and it is designed to lift and control multiple smaller loads as a single rigging operation, as defined in 1926.751.

• Multiple lift rigging must be used and inspected according to rigging and crane manufacturer guidance and applicable Subpart R and crane rules in Part 1926.

Under 1926.751, a "steel truss" is an open web member designed of structural steel components by the project structural engineer of record and, for the purposes of Subpart R, is considered equivalent to a solid web structural member, as defined in 1926.751.

• Because trusses are treated as solid web members, they require engineer oversight and appropriate erection procedures specified by the project structural engineer of record.
• See the definition of "project structural engineer of record" in 1926.751.

Under 1926.751, after installation and proper fastening, metal decking serves a combination of functions including acting as a structural element to resist, distribute and transfer loads, stiffen the structure and provide diaphragm action; as a walking/working surface; as a form for concrete slabs; as a support for roofing systems; and as a finished floor or roof, as described in 1926.751 and related decking provisions in 1926.754.

• Because decking serves structural and access functions, installation and fastening must meet manufacturer and project specifications and Subpart R requirements in Part 1926.

Under 1926.751, a "safety deck attachment" means an initial attachment that is used to secure an initially placed sheet of decking to keep proper alignment and bearing with structural support members, and it is used to prevent decking sheets from slipping during erection, as defined in 1926.751.

• Use safety deck attachments during the early stages of decking placement until final fastening is completed per project and manufacturer instructions and Subpart R decking rules in 1926.754.

Under 1926.751, a "shear connector" means headed steel studs, steel bars, steel lugs, and similar devices which are attached to a structural member for the purpose of achieving composite action with concrete, and they are used to transfer shear between steel members and concrete slabs to create composite behavior, as defined in 1926.751.

• Installation of shear connectors must follow the structural engineer's design and erection sequencing in Part 1926 Subpart R.

Under 1926.751, a "systems-engineered metal building" means a metal, field-assembled building system consisting of framing, roof and wall coverings—typically many components are cold-formed shapes fabricated off-site and shipped for assembly—and the individual parts are assembled into the final structure, as defined in 1926.751.

• Typical components include cold-formed purlins, girts, panels, and primary framing members; ensure assembly follows manufacturer instructions and Subpart R where structural steel integration occurs (see Part 1926).

Under 1926.751, a "post" means a structural member with a longitudinal axis that is essentially vertical that either (1) weighs 300 pounds or less and is axially loaded, or (2) is not axially loaded but is laterally restrained by the above member; OSHA distinguishes posts from columns by noting that columns are load-carrying vertical members that are part of the primary skeletal framing system and that columns do not include posts, as defined in 1926.751.

• Posts typically support stair landings, wall framing, mezzanines and other substructures, while columns are primary structural members.
• Consider classification when planning lifts and connections under Subpart R in Part 1926.

Under 1926.751, the "project structural engineer of record" means the registered, licensed professional responsible for the design of structural steel framing whose seal appears on the structural contract documents, and you must consult them for design questions, structural capacities, and where the erection sequence or field conditions require engineering judgment, as defined in 1926.751.

• Project engineers provide design details for members treated as primary structural elements (for example, steel trusses).
• For technical disputes or constructibility issues, involve the project structural engineer of record per Subpart R in Part 1926.