§ 1926.751 Definitions.

Anchored bridging means that the steel joist bridging is connected to a bridging terminus point.
Bolted diagonal bridging means diagonal bridging that is bolted to a steel joist or joists.
Bridging clip means a device that is attached to the steel joist to allow the bolting of the bridging to the steel joist.
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.
Choker means a wire rope or synthetic fiber rigging assembly that is used to attach a load to a hoisting device.
Cold forming means the process of using press brakes, rolls, or other methods to shape steel into desired cross sections at room temperature.
Column means a load-carrying vertical member that is part of the primary skeletal framing system. Columns do not include posts.
Competent person (also defined in § 1926.32) means one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.
Connector means an employee who, working with hoisting equipment, is placing and connecting structural members and/or components.
Constructibility means the ability to erect structural steel members in accordance with subpart R without having to alter the over-all structural design.
Construction load (for joist erection) means any load other than the weight of the employee(s), the joists and the bridging bundle.
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.
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. Controlled load lowering requires the use of the hoist drive motor, rather than the load hoist brake, to lower the load.
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.
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.
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. Pre-engineered holes in cellular decking (for wires, cables, etc.) are not included in this definition.
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.
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.
Double connection seat means a structural attachment that, during the installation of a double connection, supports the first member while the second member is connected.
Erection bridging means the bolted diagonal bridging that is required to be installed prior to releasing the hoisting cables from the steel joists.
Fall restraint system means a fall protection system that prevents the user from falling any distance. The system is comprised of either a body belt or body harness, along with an anchorage, connectors and other necessary equipment. The other components typically include a lanyard, and may also include a lifeline and other devices.
Final interior perimeter means the perimeter of a large permanent open space within a building such as an atrium or courtyard. This does not include openings for stairways, elevator shafts, etc.
Girt (in systems-engineered metal buildings) means a “Z” or “C” shaped member formed from sheet steel spanning between primary framing and supporting wall material.
Headache ball means a weighted hook that is used to attach loads to the hoist load line of the crane.
Hoisting equipment means commercially manufactured lifting equipment designed to lift and position a load of known weight to a location at some known elevation and horizontal distance from the equipment's center of rotation. “Hoisting equipment” includes but is not limited to cranes, derricks, tower cranes, barge-mounted derricks or cranes, gin poles and gantry hoist systems. A “come-a-long” (a mechanical device, usually consisting of a chain or cable attached at each end, that is used to facilitate movement of materials through leverage) is not considered “hoisting equipment.”
Leading edge means the unprotected side and edge of a floor, roof, or formwork for a floor or other walking/working surface (such as deck) which changes location as additional floor, roof, decking or formwork sections are placed, formed or constructed.
Metal decking means a commercially manufactured, structural grade, cold rolled metal panel formed into a series of parallel ribs; for this subpart, this includes metal floor and roof decks, standing seam metal roofs, other metal roof systems and other products such as bar gratings, checker plate, expanded metal panels, and similar products. After installation and proper fastening, these decking materials serve a combination of functions including, but not limited to: a structural element designed in combination with the structure to resist, distribute and transfer loads, stiffen the structure and provide a diaphragm action; a walking/working surface; a form for concrete slabs; a support for roofing systems; and a finished floor or roof.
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.
Opening means a gap or void 12 inches (30.5 cm) or more in its least dimension in a floor, roof or other walking/working surface. For the purposes of this subpart, skylights and smoke domes that do not meet the strength requirements of § 1926.754(e)(3) shall be regarded as openings.
Permanent floor means a structurally completed floor at any level or elevation (including slab on grade).
Personal fall arrest system means a system used to arrest an employee in a fall from a working level. A personal fall arrest system consists of an anchorage, connectors, a body harness and may include a lanyard, deceleration device, lifeline, or suitable combination of these. The use of a body belt for fall arrest is prohibited.
Positioning device system means a body belt or body harness rigged to allow an employee to be supported on an elevated, vertical surface, such as a wall or column and work with both hands free while leaning.
Post means a structural member with a longitudinal axis that is essentially vertical, that: (1) weighs 300 pounds or less and is axially loaded (a load presses down on the top end), or (2) is not axially loaded, but is laterally restrained by the above member. Posts typically support stair landings, wall framing, mezzanines and other substructures.
Project structural engineer of record means the registered, licensed professional responsible for the design of structural steel framing and whose seal appears on the structural contract documents.
Purlin (in systems-engineered metal buildings) means a “Z” or “C” shaped member formed from sheet steel spanning between primary framing and supporting roof material.
Qualified person (also defined in § 1926.32) means one who, by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training, and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject matter, the work, or the project.
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.
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.
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.
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. This does not include structural steel trusses or cold-formed joists.
Steel joist girder means an open web, primary load-carrying member, designed by the manufacturer, used for the support of floors and roofs. This does not include structural steel trusses.
Steel truss means an open web member designed of structural steel components by the project structural engineer of record. For the purposes of this subpart, a steel truss is considered equivalent to a solid web structural member.
Structural steel means a steel member, or a member made of a substitute material (such as, but not limited to, fiberglass, aluminum or composite members). 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.
Systems-engineered metal building means a metal, field-assembled building system consisting of framing, roof and wall coverings. Typically, many of these components are cold-formed shapes. These individual parts are fabricated in one or more manufacturing facilities and shipped to the job site for assembly into the final structure. The engineering design of the system is normally the responsibility of the systems-engineered metal building manufacturer.
Tank means a container for holding gases, liquids or solids.
Unprotected sides and edges means any side or edge (except at entrances to points of access) of a walking/working surface, for example a, floor, roof, ramp or runway, where there is no wall or guardrail system at least 39 inches (1.0 m) high.


§ 1926.752 Site layout, site-specific erection plan and construction sequence.

(a) Approval to begin steel erection. Before authorizing the commencement of steel erection, the controlling contractor shall ensure that the steel erector is provided with the following written notifications:
(1) The concrete in the footings, piers and walls and the mortar in the masonry piers and walls has attained, on the basis of an appropriate ASTM standard test method of field-cured samples, either 75 percent of the intended minimum compressive design strength or sufficient strength to support the loads imposed during steel erection.
(2) Any repairs, replacements and modifications to the anchor bolts were conducted in accordance with § 1926.755(b).
(b) Commencement of steel erection. A steel erection contractor shall not erect steel unless it has received written notification that the concrete in the footings, piers and walls or the mortar in the masonry piers and walls has attained, on the basis of an appropriate ASTM standard test method of field-cured samples, either 75 percent of the intended minimum compressive design strength or sufficient strength to support the loads imposed during steel erection.
(c) Site layout. The controlling contractor shall ensure that the following is provided and maintained:
(1) Adequate access roads into and through the site for the safe delivery and movement of derricks, cranes, trucks, other necessary equipment, and the material to be erected and means and methods for pedestrian and vehicular control. Exception: this requirement does not apply to roads outside of the construction site.
(2) A firm, properly graded, drained area, readily accessible to the work with adequate space for the safe storage of materials and the safe operation of the erector's equipment.
(d) Pre-planning of overhead hoisting operations. All hoisting operations in steel erection shall be pre-planned to ensure that the requirements of § 1926.753(d) are met.
(e) Site-specific erection plan. Where employers elect, due to conditions specific to the site, to develop alternate means and methods that provide employee protection in accordance with § 1926.753(c)(5), § 1926.757(a)(4) or § 1926.757(e)(4), a site-specific erection plan shall be developed by a qualified person and be available at the work site. Guidelines for establishing a site-specific erection plan are contained in appendix A to this subpart.


§ 1926.753 Hoisting and rigging.

(a) All the provisions of subpart CC apply to hoisting and rigging with the exception of § 1926.1431(a).
(b) In addition, paragraphs (c) through (e) of this section apply regarding the hazards associated with hoisting and rigging.
(c) General. (1) Pre-shift visual inspection of cranes.
(i) Cranes being used in steel erection activities shall be visually inspected prior to each shift by a competent person; the inspection shall include observation for deficiencies during operation. At a minimum this inspection shall include the following:
(A) All control mechanisms for maladjustments;
(B) Control and drive mechanism for excessive wear of components and contamination by lubricants, water or other foreign matter;
(C) Safety devices, including but not limited to boom angle indicators, boom stops, boom kick out devices, anti-two block devices, and load moment indicators where required;
(D) Air, hydraulic, and other pressurized lines for deterioration or leakage, particularly those which flex in normal operation;
(E) Hooks and latches for deformation, chemical damage, cracks, or wear;
(F) Wire rope reeving for compliance with hoisting equipment manufacturer's specifications;
(G) Electrical apparatus for malfunctioning, signs of excessive deterioration, dirt, or moisture accumulation;
(H) Hydraulic system for proper fluid level;
(I) Tires for proper inflation and condition;
(J) Ground conditions around the hoisting equipment for proper support, including ground settling under and around outriggers, ground water accumulation, or similar conditions;
(K) The hoisting equipment for level position; and
(L) The hoisting equipment for level position after each move and setup.
(ii) If any deficiency is identified, an immediate determination shall be made by the competent person as to whether the deficiency constitutes a hazard.
(iii) If the deficiency is determined to constitute a hazard, the hoisting equipment shall be removed from service until the deficiency has been corrected.
(iv) The operator shall be responsible for those operations under the operator's direct control. Whenever there is any doubt as to safety, the operator shall have the authority to stop and refuse to handle loads until safety has been assured.
(2) A qualified rigger (a rigger who is also a qualified person) shall inspect the rigging prior to each shift in accordance with § 1926.251.
(3) The headache ball, hook or load shall not be used to transport personnel except as provided in paragraph (c)(4) of this section.
(4) Cranes or derricks may be used to hoist employees on a personnel platform when work under this subpart is being conducted, provided that all provisions of § 1926.1431 (except for § 1926.1431(a)) are met.
(5) Safety latches on hooks shall not be deactivated or made inoperable except:
(i) When a qualified rigger has determined that the hoisting and placing of purlins and single joists can be performed more safely by doing so; or
(ii) When equivalent protection is provided in a site-specific erection plan.
(d) Working under loads. (1) Routes for suspended loads shall be pre-planned to ensure that no employee is required to work directly below a suspended load except for:
(i) Employees engaged in the initial connection of the steel; or
(ii) Employees necessary for the hooking or unhooking of the load.
(2) When working under suspended loads, the following criteria shall be met:
(i) Materials being hoisted shall be rigged to prevent unintentional displacement;
(ii) Hooks with self-closing safety latches or their equivalent shall be used to prevent components from slipping out of the hook; and
(iii) All loads shall be rigged by a qualified rigger
(e) Multiple lift rigging procedure. (1) A multiple lift shall only be performed if the following criteria are met:
(i) A multiple lift rigging assembly is used;
(ii) A maximum of five members are hoisted per lift;
(iii) Only beams and similar structural members are lifted; and
(iv) All employees engaged in the multiple lift have been trained in these procedures in accordance with § 1926.761(c)(1).
(v) No crane is permitted to be used for a multiple lift where such use is contrary to the manufacturer's specifications and limitations.
(2) Components of the multiple lift rigging assembly shall be specifically designed and assembled with a maximum capacity for total assembly and for each individual attachment point. This capacity, certified by the manufacturer or a qualified rigger, shall be based on the manufacturer's specifications with a 5 to 1 safety factor for all components.
(3) The total load shall not exceed:
(i) The rated capacity of the hoisting equipment specified in the hoisting equipment load charts;
(ii) The rigging capacity specified in the rigging rating chart.
(4) The multiple lift rigging assembly shall be rigged with members:
(i) Attached at their center of gravity and maintained reasonably level;
(ii) Rigged from top down; and
(iii) Rigged at least 7 feet (2.1 m) apart.
(5) The members on the multiple lift rigging assembly shall be set from the bottom up.
(6) Controlled load lowering shall be used whenever the load is over the connectors.
[66 FR 5265, Jan. 18, 2001, as amended at 75 FR 48134, Aug. 9, 2010]


§ 1926.754 Structural steel assembly.

(a) Structural stability shall be maintained at all times during the erection process.
Note to paragraph ( a ): Federal Highway Administration (FHWA) regulations incorporate by reference a number of standards, policies, and standard specifications published by the American Association of State Highway and Transportation Officials (AASHTO) and other organizations. ( See 23 CFR 625.4). Many of these incorporated provisions may be relevant to maintaining structural stability during the erection process. For instance, as of May 17, 2010, in many cases FHWA requires a Registered Engineer to prepare and seal working drawings for falsework used in highway bridge construction. ( See AASHTO Specifications for Highway Bridges, Div. II, § 3.2.1, 15th edition, 1992, which FHWA incorporates by reference in 23 CFR 625.4). FHWA also encourages compliance with AASHTO Specifications that the FHWA regulations do not currently incorporate by reference. ( See http://www.fhwa.dot.gov/bridge/lrfd/index.htm. )
(b) The following additional requirements shall apply for multi-story structures:
(1) The permanent floors shall be installed as the erection of structural members progresses, and there shall be not more than eight stories between the erection floor and the upper-most permanent floor, except where the structural integrity is maintained as a result of the design.
(2) At no time shall there be more than four floors or 48 feet (14.6 m), whichever is less, of unfinished bolting or welding above the foundation or uppermost permanently secured floor, except where the structural integrity is maintained as a result of the design.
(3) A fully planked or decked floor or nets shall be maintained within two stories or 30 feet (9.1 m), whichever is less, directly under any erection work being performed.
(c) Walking/working surfaces—shear connectors and other similar devices —(1) Tripping hazards. Shear connectors (such as headed steel studs, steel bars or steel lugs), reinforcing bars, deformed anchors or threaded studs shall not be attached to the top flanges of beams, joists or beam attachments so that they project vertically from or horizontally across the top flange of the member until after the metal decking, or other walking/working surface, has been installed.
(2) Installation of shear connectors on composite floors, roofs and bridge decks. When shear connectors are used in construction of composite floors, roofs and bridge decks, employees shall lay out and install the shear connectors after the metal decking has been installed, using the metal decking as a working platform. Shear connectors shall not be installed from within a controlled decking zone (CDZ), as specified in § 1926.760(c)(7).
(d) Plumbing-up. (1) When deemed necessary by a competent person, plumbing-up equipment shall be installed in conjunction with the steel erection process to ensure the stability of the structure.
(2) When used, plumbing-up equipment shall be in place and properly installed before the structure is loaded with construction material such as loads of joists, bundles of decking or bundles of bridging.
(3) Plumbing-up equipment shall be removed only with the approval of a competent person.
(e) Metal decking —(1) Hoisting, landing and placing of metal decking bundles. (i) Bundle packaging and strapping shall not be used for hoisting unless specifically designed for that purpose.
(ii) If loose items such as dunnage, flashing, or other materials are placed on the top of metal decking bundles to be hoisted, such items shall be secured to the bundles.
(iii) Bundles of metal decking on joists shall be landed in accordance with § 1926.757(e)(4).
(iv) Metal decking bundles shall be landed on framing members so that enough support is provided to allow the bundles to be unbanded without dislodging the bundles from the supports.
(v) At the end of the shift or when environmental or jobsite conditions require, metal decking shall be secured against displacement.
(2) Roof and floor holes and openings. Metal decking at roof and floor holes and openings shall be installed as follows:
(i) Framed metal deck openings shall have structural members turned down to allow continuous deck installation except where not allowed by structural design constraints or constructibility.
(ii) Roof and floor holes and openings shall be decked over. Where large size, configuration or other structural design does not allow openings to be decked over (such as elevator shafts, stair wells, etc.) employees shall be protected in accordance with § 1926.760(a)(1).
(iii) Metal decking holes and openings shall not be cut until immediately prior to being permanently filled with the equipment or structure needed or intended to fulfill its specific use and which meets the strength requirements of paragraph (e)(3) of this section, or shall be immediately covered.
(3) Covering roof and floor openings. (i) Covers for roof and floor openings shall be capable of supporting, without failure, twice the weight of the employees, equipment and materials that may be imposed on the cover at any one time.
(ii) All covers shall be secured when installed to prevent accidental displacement by the wind, equipment or employees.
(iii) All covers shall be painted with high-visibility paint or shall be marked with the word “HOLE” or “COVER” to provide warning of the hazard.
(iv) Smoke dome or skylight fixtures that have been installed, are not considered covers for the purpose of this section unless they meet the strength requirements of paragraph (e)(3)(i) of this section.
(4) Decking gaps around columns. Wire mesh, exterior plywood, or equivalent, shall be installed around columns where planks or metal decking do not fit tightly. The materials used must be of sufficient strength to provide fall protection for personnel and prevent objects from falling through.
(5) Installation of metal decking. (i) Except as provided in § 1926.760(c), metal decking shall be laid tightly and immediately secured upon placement to prevent accidental movement or displacement.
(ii) During initial placement, metal decking panels shall be placed to ensure full support by structural members.
(6) Derrick floors. (i) A derrick floor shall be fully decked and/or planked and the steel member connections completed to support the intended floor loading.
(ii) Temporary loads placed on a derrick floor shall be distributed over the underlying support members so as to prevent local overloading of the deck material.
[66 FR 5265, Jan. 18, 2001, as amended at 71 FR 2885, Jan. 18, 2006; 71 FR 16674, Apr. 3, 2006; 75 FR 27429, May 17, 2010; 85 FR 8745, Feb. 18, 2020]


§ 1926.755 Column anchorage.

(a) General requirements for erection stability. (1) All columns shall be anchored by a minimum of 4 anchor rods (anchor bolts).
(2) Each column anchor rod (anchor bolt) assembly, including the column-to-base plate weld and the column foundation, shall be designed to resist a minimum eccentric gravity load of 300 pounds (136.2 kg) located 18 inches (.46m) from the extreme outer face of the column in each direction at the top of the column shaft.
(3) Columns shall be set on level finished floors, pre-grouted leveling plates, leveling nuts, or shim packs which are adequate to transfer the construction loads.
(4) All columns shall be evaluated by a competent person to determine whether guying or bracing is needed; if guying or bracing is needed, it shall be installed.
(b) Repair, replacement or field modification of anchor rods (anchor bolts). (1) Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record.
(2) Prior to the erection of a column, the controlling contractor shall provide written notification to the steel erector if there has been any repair, replacement or modification of the anchor rods (anchor bolts) of that column.


§ 1926.756 Beams and columns.

(a) General. (1) During the final placing of solid web structural members, the load shall not be released from the hoisting line until the members are secured with at least two bolts per connection, of the same size and strength as shown in the erection drawings, drawn up wrench-tight or the equivalent as specified by the project structural engineer of record, except as specified in paragraph (b) of this section.
(2) A competent person shall determine if more than two bolts are necessary to ensure the stability of cantilevered members; if additional bolts are needed, they shall be installed.
(b) Diagonal bracing. Solid web structural members used as diagonal bracing shall be secured by at least one bolt per connection drawn up wrench-tight or the equivalent as specified by the project structural engineer of record.
(c)(1) Double connections at columns and/or at beam webs over a column. When two structural members on opposite sides of a column web, or a beam web over a column, are connected sharing common connection holes, at least one bolt with its wrench-tight nut shall remain connected to the first member unless a shop-attached or field-attached seat or equivalent connection device is supplied with the member to secure the first member and prevent the column from being displaced (See appendix H to this subpart for examples of equivalent connection devices).
(2) If a seat or equivalent device is used, the seat (or device) shall be designed to support the load during the double connection process. It shall be adequately bolted or welded to both a supporting member and the first member before the nuts on the shared bolts are removed to make the double connection.
(d) Column splices. Each column splice shall be designed to resist a minimum eccentric gravity load of 300 pounds (136.2 kg) located 18 inches (.46 m) from the extreme outer face of the column in each direction at the top of the column shaft.
(e) Perimeter columns. Perimeter columns shall not be erected unless:
(1) The perimeter columns extend a minimum of 48 inches (1.2 m) above the finished floor to permit installation of perimeter safety cables prior to erection of the next tier, except where constructibility does not allow (see appendix F to this subpart);
(2) The perimeter columns have holes or other devices in or attached to perimeter columns at 42-45 inches (107-114 cm) above the finished floor and the midpoint between the finished floor and the top cable to permit installation of perimeter safety cables required by § 1926.760(a)(2), except where constructibility does not allow. (See appendix F to this subpart).


§ 1926.757 Open web steel joists.

(a) General. (1) Except as provided in paragraph (a)(2) of this section, where steel joists are used and columns are not framed in at least two directions with solid web structural steel members, a steel joist shall be field-bolted at the column to provide lateral stability to the column during erection. For the installation of this joist:
(i) A vertical stabilizer plate shall be provided on each column for steel joists. The plate shall be a minimum of 6 inch by 6 inch (152 mm by 152 mm) and shall extend at least 3 inches (76 mm) below the bottom chord of the joist with a 13/16 inch (21 mm) hole to provide an attachment point for guying or plumbing cables.
(ii) The bottom chords of steel joists at columns shall be stabilized to prevent rotation during erection.
(iii) Hoisting cables shall not be released until the seat at each end of the steel joist is field-bolted, and each end of the bottom chord is restrained by the column stabilizer plate.
(2) Where constructibility does not allow a steel joist to be installed at the column:
(i) an alternate means of stabilizing joists shall be installed on both sides near the column and shall:
(A) provide stability equivalent to paragraph (a)(1) of this section;
(B) be designed by a qualified person;
(C) be shop installed; and
(D) be included in the erection drawings.
(ii) hoisting cables shall not be released until the seat at each end of the steel joist is field-bolted and the joist is stabilized.
(3) Where steel joists at or near columns span 60 feet (18.3 m) or less, the joist shall be designed with sufficient strength to allow one employee to release the hoisting cable without the need for erection bridging.
(4) Where steel joists at or near columns span more than 60 feet (18.3 m), the joists shall be set in tandem with all bridging installed unless an alternative method of erection, which provides equivalent stability to the steel joist, is designed by a qualified person and is included in the site-specific erection plan.
(5) A steel joist or steel joist girder shall not be placed on any support structure unless such structure is stabilized.
(6) When steel joist(s) are landed on a structure, they shall be secured to prevent unintentional displacement prior to installation.
(7) No modification that affects the strength of a steel joist or steel joist girder shall be made without the approval of the project structural engineer of record.
(8) Field-bolted joists. (i) Except for steel joists that have been pre-assembled into panels, connections of individual steel joists to steel structures in bays of 40 feet (12.2 m) or more shall be fabricated to allow for field bolting during erection.
(ii) These connections shall be field-bolted unless constructibility does not allow.
(9) Steel joists and steel joist girders shall not be used as anchorage points for a fall arrest system unless written approval to do so is obtained from a qualified person.
(10) A bridging terminus point shall be established before bridging is installed. (See appendix C to this subpart.)
(b) Attachment of steel joists and steel joist girders. (1) Each end of “K” series steel joists shall be attached to the support structure with a minimum of two 1/8 -inch (3 mm) fillet welds 1 inch (25 mm) long or with two 1/2 -inch (13 mm) bolts, or the equivalent.
(2) Each end of “LH” and “DLH” series steel joists and steel joist girders shall be attached to the support structure with a minimum of two 1/4 -inch (6 mm) fillet welds 2 inches (51 mm) long, or with two 3/4 -inch (19 mm) bolts, or the equivalent.
(3) Except as provided in paragraph (b)(4) of this section, each steel joist shall be attached to the support structure, at least at one end on both sides of the seat, immediately upon placement in the final erection position and before additional joists are placed.
(4) Panels that have been pre-assembled from steel joists with bridging shall be attached to the structure at each corner before the hoisting cables are released.
(c) Erection of steel joists. (1) Both sides of the seat of one end of each steel joist that requires bridging under Tables A and B shall be attached to the support structure before hoisting cables are released.
(2) For joists over 60 feet, both ends of the joist shall be attached as specified in paragraph (b) of this section and the provisions of paragraph (d) of this section met before the hoisting cables are released.
(3) On steel joists that do not require erection bridging under Tables A and B, only one employee shall be allowed on the joist until all bridging is installed and anchored.
Table A—Erection Bridging for Short Span Joists Joist Span 8L1 NM 10K1 NM 12K1 23-0 12K3 NM 12K5 NM 14K1 27-0 14K3 NM 14K4 NM 14K6 NM 16K2 29-0 16K3 30-0 16K4 32-0 16K5 32-0 16K6 NM 16K7 NM 16K9 NM 18K3 31-0 18K4 32-0 18K5 33-0 18K6 35-0 18K7 NM 18K9 NM 18K10 NM 20K3 32-0 20K4 34-0 20K5 34-0 20K6 36-0 20K7 39-0 20K9 39-0 20K10 NM 22K4 34-0 22K5 35-0 22K6 36-0 22K7 40-0 22K9 40-0 22K10 40-0 22K11 40-0 24K4 36-0 24K5 38-0 24K6 39-0 24K7 43-0 24K8 43-0 24K9 44-0 24K10 NM 24K12 NM 26K5 38-0 26K6 39-0 26K7 43-0 26K8 44-0 26K9 45-0 26K10 49-0 26K12 NM 28K6 40-0 28K7 43-0 28K8 44-0 28K9 45-0 28K10 49-0 28K12 53-0 30K7 44-0 30K8 45-0 30K9 45-0 30K10 50-0 30K11 52-0 30K12 54-0 10KCS1 NM 10KCS2 NM 10KCS3 NM 12KCS1 NM 12KCS2 NM 12KCS3 NM 14KCS1 NM 14KCS2 NM 14KCS3 NM 16KCS2 NM 16KCS3 NM 16KCS4 NM 16KCS5 NM 18KCS2 35-0 18KCS3 NM 18KCS4 NM 18KCS5 NM 20KCS2 36-0 20KCS3 39-0 20KCS4 NM 20KCS5 NM 22KCS2 36-0 22KCS3 40-0 22KCS4 NM 22KCS5 NM 24KCS2 39-0 24KCS3 44-0 24KCS4 NM 24KCS5 NM 26KCS2 39-0 26KCS3 44-0 26KCS4 NM 26KCS5 NM 28KCS2 40-0 28KCS3 45-0 28KCS4 53-0 28KCS5 53-0 30KC53 45-0 30KCS4 54-0 30KCS5 54-0 NM = diagonal bolted bridging not mandatory.
Table B—Erection Bridging for Long Span Joists Joist Span 18LH02 33-0. 18LH03 NM. 18LH04 NM. 18LH05 NM. 18LH06 NM. 18LH07 NM. 18LH08 NM. 18LH09 NM. 20LH02 33-0. 20LH03 38-0. 20LH04 NM. 20LH05 NM. 20LH06 NM. 20LH07 NM. 20LH08 NM. 20LH09 NM. 20LH10 NM. 24LH03 35-0. 24LH04 39-0. 24LH05 40-0. 24LH06 45-0. 24LH07 NM. 24LH08 NM. 24LH09 NM. 24LH10 NM. 24LH11 NM. 28LH05 42-0. 28LH06 42-0. 28LH07 NM. 28LH08 NM. 28LH09 NM. 28LH10 NM. 28LH11 NM. 28LH12 NM. 28LH13 NM. 32LH06 47-0 through 60-0. 32LH07 47-0 through 60-0. 32LH08 55-0 through 60-0. 32LH09 NM through 60-0. 32LH10 NM through 60-0. 32LH11 NM through 60-0. 32LH12 NM through 60-0. 32LH13 NM through 60-0. 32LH14 NM through 60-0. 32LH15 NM through 60-0. 36LH07 47-0 through 60-0. 36LH08 47-0 through 60-0. 36LH09 57-0 through 60-0. 36LH10 NM through 60-0. 36LH11 NM through 60-0. 36LH12 NM through 60-0. 36LH13 NM through 60-0. 36LH14 NM through 60-0. 36LH15 NM through 60-0. NM = diagonal bolted bridging not mandatory.
(4) Employees shall not be allowed on steel joists where the span of the steel joist is equal to or greater than the span shown in Tables A and B except in accordance with § 1926.757(d).
(5) When permanent bridging terminus points cannot be used during erection, additional temporary bridging terminus points are required to provide stability. (See appendix C of this subpart.)
(d) Erection bridging. (1) Where the span of the steel joist is equal to or greater than the span shown in Tables A and B, the following shall apply:
(i) A row of bolted diagonal erection bridging shall be installed near the midspan of the steel joist;
(ii) Hoisting cables shall not be released until this bolted diagonal erection bridging is installed and anchored; and
(iii) No more than one employee shall be allowed on these spans until all other bridging is installed and anchored.
(2) Where the span of the steel joist is over 60 feet (18.3 m) through 100 feet (30.5 m), the following shall apply:
(i) All rows of bridging shall be bolted diagonal bridging;
(ii) Two rows of bolted diagonal erection bridging shall be installed near the third points of the steel joist;
(iii) Hoisting cables shall not be released until this bolted diagonal erection bridging is installed and anchored; and
(iv) No more than two employees shall be allowed on these spans until all other bridging is installed and anchored.
(3) Where the span of the steel joist is over 100 feet (30.5 m) through 144 feet (43.9 m), the following shall apply:
(i) All rows of bridging shall be bolted diagonal bridging;
(ii) Hoisting cables shall not be released until all bridging is installed and anchored; and
(iii) No more than two employees shall be allowed on these spans until all bridging is installed and anchored.
(4) For steel members spanning over 144 feet (43.9 m), the erection methods used shall be in accordance with § 1926.756.
(5) Where any steel joist specified in paragraphs (c)(2) and (d)(1), (d)(2), and (d)(3) of this section is a bottom chord bearing joist, a row of bolted diagonal bridging shall be provided near the support(s). This bridging shall be installed and anchored before the hoisting cable(s) is released.
(6) When bolted diagonal erection bridging is required by this section, the following shall apply:
(i) The bridging shall be indicated on the erection drawing;
(ii) The erection drawing shall be the exclusive indicator of the proper placement of this bridging;
(iii) Shop-installed bridging clips, or functional equivalents, shall be used where the bridging bolts to the steel joists;
(iv) When two pieces of bridging are attached to the steel joist by a common bolt, the nut that secures the first piece of bridging shall not be removed from the bolt for the attachment of the second; and
(v) Bridging attachments shall not protrude above the top chord of the steel joist.
(e) Landing and placing loads. (1) During the construction period, the employer placing a load on steel joists shall ensure that the load is distributed so as not to exceed the carrying capacity of any steel joist.
(2) Except for paragraph (e)(4) of this section, no construction loads are allowed on the steel joists until all bridging is installed and anchored and all joist-bearing ends are attached.
(3) The weight of a bundle of joist bridging shall not exceed a total of 1,000 pounds (454 kg). A bundle of joist bridging shall be placed on a minimum of three steel joists that are secured at one end. The edge of the bridging bundle shall be positioned within 1 foot (.30 m) of the secured end.
(4) No bundle of decking may be placed on steel joists until all bridging has been installed and anchored and all joist bearing ends attached, unless all of the following conditions are met:
(i) The employer has first determined from a qualified person and documented in a site-specific erection plan that the structure or portion of the structure is capable of supporting the load;
(ii) The bundle of decking is placed on a minimum of three steel joists;
(iii) The joists supporting the bundle of decking are attached at both ends;
(iv) At least one row of bridging is installed and anchored;
(v) The total weight of the bundle of decking does not exceed 4,000 pounds (1816 kg); and
(vi) Placement of the bundle of decking shall be in accordance with paragraph (e)(5) of this section.
(5) The edge of the construction load shall be placed within 1 foot (.30 m) of the bearing surface of the joist end.
[66 FR 5265, Jan. 18, 2001, as amended at 85 FR 8745, Feb. 18, 2020]


§ 1926.758 Systems-engineered metal buildings.

(a) All of the requirements of this subpart apply to the erection of systems-engineered metal buildings except §§ 1926.755 (column anchorage) and 1926.757 (open web steel joists).
(b) Each structural column shall be anchored by a minimum of four anchor rods (anchor bolts).
(c) Rigid frames shall have 50 percent of their bolts or the number of bolts specified by the manufacturer (whichever is greater) installed and tightened on both sides of the web adjacent to each flange before the hoisting equipment is released.
(d) Construction loads shall not be placed on any structural steel framework unless such framework is safely bolted, welded or otherwise adequately secured.
(e) In girt and eave strut-to-frame connections, when girts or eave struts share common connection holes, at least one bolt with its wrench-tight nut shall remain connected to the first member unless a manufacturer-supplied, field-attached seat or similar connection device is present to secure the first member so that the girt or eave strut is always secured against displacement.
(f) Both ends of all steel joists or cold-formed joists shall be fully bolted and/or welded to the support structure before:
(1) Releasing the hoisting cables;
(2) Allowing an employee on the joists; or
(3) Allowing any construction loads on the joists.
(g) Purlins and girts shall not be used as an anchorage point for a fall arrest system unless written approval is obtained from a qualified person.
(h) Purlins may only be used as a walking/working surface when installing safety systems, after all permanent bridging has been installed and fall protection is provided.
(i) Construction loads may be placed only within a zone that is within 8 feet (2.5 m) of the center-line of the primary support member.


§ 1926.759 Falling object protection.

(a) Securing loose items aloft. All materials, equipment, and tools, which are not in use while aloft, shall be secured against accidental displacement.
(b) Protection from falling objects other than materials being hoisted. The controlling contractor shall bar other construction processes below steel erection unless overhead protection for the employees below is provided.


§ 1926.760 Fall protection.

(a) General requirements. (1) Except as provided by paragraph (a)(3) of this section, each employee engaged in a steel erection activity who is on a walking/working surface with an unprotected side or edge more than 15 feet (4.6 m) above a lower level shall be protected from fall hazards by guardrail systems, safety net systems, personal fall arrest systems, positioning device systems or fall restraint systems.
(2) Perimeter safety cables. On multi-story structures, perimeter safety cables shall be installed at the final interior and exterior perimeters of the floors as soon as the metal decking has been installed.
(3) Connectors and employees working in controlled decking zones shall be protected from fall hazards as provided in paragraphs (b) and (c) of this section, respectively.
(b) Connectors. Each connector shall:
(1) Be protected in accordance with paragraph (a)(1) of this section from fall hazards of more than two stories or 30 feet (9.1 m) above a lower level, whichever is less;
(2) Have completed connector training in accordance with § 1926.761; and
(3) Be provided, at heights over 15 and up to 30 feet above a lower level, with a personal fall arrest system, positioning device system or fall restraint system and wear the equipment necessary to be able to be tied off; or be provided with other means of protection from fall hazards in accordance with paragraph (a)(1) of this section.
(c) Controlled Decking Zone (CDZ). A controlled decking zone may be established in that area of the structure over 15 and up to 30 feet above a lower level where metal decking is initially being installed and forms the leading edge of a work area. In each CDZ, the following shall apply:
(1) Each employee working at the leading edge in a CDZ shall be protected from fall hazards of more than two stories or 30 feet (9.1 m), whichever is less.
(2) Access to a CDZ shall be limited to only those employees engaged in leading edge work.
(3) The boundaries of a CDZ shall be designated and clearly marked. The CDZ shall not be more than 90 feet (27.4 m) wide and 90 (27.4 m) feet deep from any leading edge. The CDZ shall be marked by the use of control lines or the equivalent. Examples of acceptable procedures for demarcating CDZ's can be found in appendix D to this subpart.
(4) Each employee working in a CDZ shall have completed CDZ training in accordance with § 1926.761.
(5) Unsecured decking in a CDZ shall not exceed 3,000 square feet (914.4 m 2 ).
(6) Safety deck attachments shall be performed in the CDZ from the leading edge back to the control line and shall have at least two attachments for each metal decking panel.
(7) Final deck attachments and installation of shear connectors shall not be performed in the CDZ.
(d) Criteria for fall protection equipment. (1) Guardrail systems, safety net systems, personal fall arrest systems, positioning device systems and their components shall conform to the criteria in § 1926.502 (see appendix G to this subpart).
(2) Fall arrest system components shall be used in fall restraint systems and shall conform to the criteria in § 1926.502 (see appendix G). Either body belts or body harnesses shall be used in fall restraint systems.
(3) Perimeter safety cables shall meet the criteria for guardrail systems in § 1926.502 (see appendix G).
(e) Custody of fall protection. Fall protection provided by the steel erector shall remain in the area where steel erection activity has been completed, to be used by other trades, only if the controlling contractor or its authorized representative:
(1) Has directed the steel erector to leave the fall protection in place; and
(2) Has inspected and accepted control and responsibility of the fall protection prior to authorizing persons other than steel erectors to work in the area.


§ 1926.761 Training.

The following provisions supplement the requirements of § 1926.21 regarding the hazards addressed in this subpart.
(a) Training personnel. Training required by this section shall be provided by a qualified person(s).
(b) Fall hazard training. The employer shall train each employee exposed to a fall hazard in accordance with the requirements of this section. The employer shall institute a training program and ensure employee participation in the program. The program shall include training and instruction in the following areas:
(1) The recognition and identification of fall hazards in the work area;
(2) The use and operation of guardrail systems (including perimeter safety cable systems), personal fall arrest systems, positioning device systems, fall restraint systems, safety net systems, and other protection to be used;
(3) The correct procedures for erecting, maintaining, disassembling, and inspecting the fall protection systems to be used;
(4) The procedures to be followed to prevent falls to lower levels and through or into holes and openings in walking/working surfaces and walls; and
(5) The fall protection requirements of this subpart.
(c) Special training programs. In addition to the training required in paragraphs (a) and (b) of this section, the employer shall provide special training to employees engaged in the following activities.
(1) Multiple lift rigging procedure. The employer shall ensure that each employee who performs multiple lift rigging has been provided training in the following areas:
(i) The nature of the hazards associated with multiple lifts; and
(ii) The proper procedures and equipment to perform multiple lifts required by § 1926.753(e).
(2) Connector procedures. The employer shall ensure that each connector has been provided training in the following areas:
(i) The nature of the hazards associated with connecting; and
(ii) The establishment, access, proper connecting techniques and work practices required by § 1926.756(c) and § 1926.760(b).
(3) Controlled Decking Zone Procedures. Where CDZs are being used, the employer shall assure that each employee has been provided training in the following areas:
(i) The nature of the hazards associated with work within a controlled decking zone; and
(ii) The establishment, access, proper installation techniques and work practices required by § 1926.760(c) and § 1926.754(e).
[66 FR 5265, Jan. 18, 2001, as amended at 73 FR 75589, Dec. 12, 2008; 85 FR 8745, Feb. 18, 2020]


§ 1926.800 Underground construction.

Subpart S—Underground Construction, Caissons, Cofferdams and Compressed Air

(a) Scope and application. (1) This section applies to the construction of underground tunnels, shafts, chambers, and passageways. This section also applies to cut-and-cover excavations which are both physically connected to ongoing underground construction operations within the scope of this section, and covered in such a manner as to create conditions characteristic of underground construction.
(2) This section does not apply to the following:
(i) Excavation and trenching operations covered by subpart P of this part, such as foundation operations for above-ground structures that are not physically connected to underground construction operations, and surface excavation; nor
(ii) Underground electrical transmission and distribution lines, as addressed in subpart V of this part.
(b) Access and egress. (1) The employer shall provide and maintain safe means of access and egress to all work stations.
(2) The employer shall provide access and egress in such a manner that employees are protected from being struck by excavators, haulage machines, trains and other mobile equipment.
(3) The employer shall control access to all openings to prevent unauthorized entry underground. Unused chutes, manways, or other openings shall be tightly covered, bulkheaded, or fenced off, and shall be posted with warning signs indicating “Keep Out” or similar language. Completed or unused sections of the underground facility shall be barricaded.
(c) Check-in/check-out. The employer shall maintain a check-in/check-out procedure that will ensure that above-ground personnel can determine an accurate count of the number of persons underground in the event of an emergency. However, this procedure is not required when the construction of underground facilities designed for human occupancy has been sufficiently completed so that the permanent environmental controls are effective, and when the remaining construction activity will not cause any environmental hazard or structural failure within the facilities.
(d) Safety instruction. All employees shall be instructed in the recognition and avoidance of hazards associated with underground construction activities including, where appropriate, the following subjects:
(1) Air monitoring;
(2) Ventilation;
(3) Illumination;
(4) Communications;
(5) Flood control;
(6) Mechanical equipment;
(7) Personal protective equipment;
(8) Explosives;
(9) Fire prevention and protection; and
(10) Emergency procedures, including evacuation plans and check-in/check-out systems.
(e) Notification. (1) Oncoming shifts shall be informed of any hazardous occurrences or conditions that have affected or might affect employee safety, including liberation of gas, equipment failures, earth or rock slides, cave-ins, floodings, fires or explosions.
(2) The employer shall establish and maintain direct communications for coordination of activities with other employers whose operations at the jobsite affect or may affect the safety of employees underground.
(f) Communications. (1) When natural unassisted voice communication is ineffective, a power-assisted means of voice communication shall be used to provide communication between the work face, the bottom of the shaft, and the surface.
(2) Two effective means of communication, at least one of which shall be voice communication, shall be provided in all shafts which are being developed or used either for personnel access or for hoisting. Additional requirements for hoist operator communication are contained in paragraph (t)(3)(xiv) of this section.
(3) Powered communication systems shall operate on an independent power supply, and shall be installed so that the use of or disruption of any one phone or signal location will not disrupt the operation of the system from any other location.
(4) Communication systems shall be tested upon initial entry of each shift to the underground, and as often as necessary at later times, to ensure that they are in working order.
(5) Any employee working alone underground in a hazardous location, who is both out of the range of natural unassisted voice communication and not under observation by other persons, shall be provided with an effective means of obtaining assistance in an emergency.
(g) Emergency provisions —(1) Hoisting capability. When a shaft is used as a means of egress, the employer shall make advance arrangements for power-assisted hoisting capability to be readily available in an emergency, unless the regular hoisting means can continue to function in the event of an electrical power failure at the jobsite. Such hoisting means shall be designed so that the load hoist drum is powered in both directions of rotation and so that the brake is automatically applied upon power release or failure.
(2) Self-rescuers. The employer must provide self-rescuers approved by the National Institute for Occupational Safety and Health under 42 CFR part 84. The respirators must be immediately available to all employees at work stations in underground areas where employees might be trapped by smoke or gas. The selection, issuance, use, and care of respirators must be in accordance with 29 CFR 1926.103.
(3) Designated person. At least one designated person shall be on duty above ground whenever any employee is working underground. This designated person shall be responsible for securing immediate aid and keeping an accurate count of employees underground in case of emergency. The designated person must not be so busy with other responsibilities that the counting function is encumbered.
(4) Emergency lighting. Each employee underground shall have an acceptable portable hand lamp or cap lamp in his or her work area for emergency use, unless natural light or an emergency lighting system provides adequate illumination for escape.
(5) Rescue teams. (i) On jobsites where 25 or more employees work underground at one time, the employer shall provide (or make arrangements in advance with locally available rescue services to provide) at least two 5-person rescue teams, one on the jobsite or within one-half hour travel time from the entry point, and the other within 2 hours travel time.
(ii) On jobsites where less than 25 employees work underground at one time, the employer shall provide (or make arrangements in advance with locally available rescue services to provide) at least one 5-person rescue team to be either on the jobsite or within one-half hour travel time from the entry point.
(iii) Rescue team members shall be qualified in rescue procedures, the use and limitations of breathing apparatus, and the use of firefighting equipment. Qualifications shall be reviewed not less than annually.
(iv) On jobsites where flammable or noxious gases are encountered or anticipated in hazardous quantities, rescue team members shall practice donning and using self-contained breathing apparatus monthly.
(v) The employer shall ensure that rescue teams are familiar with conditions at the jobsite.
(h) Hazardous classifications —(1) Potentially gassy operations. Underground construction operations shall be classified as potentially gassy if either:
(i) Air monitoring discloses 10 percent or more of the lower explosive limit for methane or other flammable gases measured at 12 inches (304.8 mm) ±0.25 inch (6.35 mm) from the roof, face, floor or walls in any underground work area for more than a 24-hour period; or
(ii) The history of the geographical area or geological formation indicates that 10 percent or more of the lower explosive limit for methane or other flammable gases is likely to be encountered in such underground operations.
(2) Gassy operations. Underground construction operations shall be classified as gassy if:
(i) Air monitoring discloses 10 percent or more of the lower explosive limit for methane or other flammable gases measured at 12 inches (304.8 mm) ±0.25 inch (6.35 mm) from the roof, face, floor or walls in any underground work area for three consecutive days; or
(ii) There has been an ignition of methane or of other flammable gases emanating from the strata that indicates the presence of such gases; or
(iii) The underground construction operation is both connected to an underground work area which is currently classified as gassy and is also subject to a continuous course of air containing the flammable gas concentration.
(3) Declassification to potentially gassy operations. Underground construction gassy operations may be declassified to Potentially Gassy when air monitoring results remain under 10 percent of the lower explosive limit for methane or other flammable gases for three consecutive days.
(i) Gassy operations-additional requirements. (1) Only acceptable equipment, maintained in suitable condition, shall be used in gassy operations.
(2) Mobile diesel-powered equipment used in gassy operations shall be either approved in accordance with the requirements of 30 CFR part 36 (formerly Schedule 31) by MSHA, or shall be demonstrated by the employer to be fully equivalent to such MSHA-approved equipment, and shall be operated in accordance with that part.
(3) Each entrance to a gassy operation shall be prominently posted with signs notifying all entrants of the gassy classification.
(4) Smoking shall be prohibited in all gassy operations and the employer shall be responsible for collecting all personal sources of ignition, such as matches and lighters, from all persons entering a gassy operation.
(5) A fire watch as described in § 1926.352(e) shall be maintained when hot work is performed.
(6) Once an operation has met the criteria in paragraph (h)(2) warranting classification as gassy, all operations in the affected area, except the following, shall be discontinued until the operation either is in compliance with all of the gassy operation requirements or has been declassified in accordance with paragraph (h)(3) of this section:
(i) Operations related to the control of the gas concentration;
(ii) Installation of new equipment, or conversion of existing equipment, to comply with this paragraph (i); and
(iii) Installation of above-ground controls for reversing the air flow.
(j) Air quality and monitoring —(1) General. Air quality limits and control requirements for construction are found in § 1926.55, except as modified by this section.
(i)(A) The employer shall assign a competent person who shall perform all air monitoring required by this section.
(B) Where this paragraph requires monitoring of airborne contaminants “as often as necessary,” the competent person shall make a reasonable determination as to which substances to monitor and how frequently to monitor, considering at least the following factors:
( 1 ) Location of jobsite: Proximity to fuel tanks, sewers, gas lines, old landfills, coal deposits, and swamps;
( 2 ) Geology: Geological studies of the jobsite, particularly involving the soil type and its permeability;
( 3 ) History: Presence of air contaminants in nearby jobsites, changes in levels of substances monitored on the prior shift; and
( 4 ) Work practices and jobsite conditions: The use of diesel engines, use of explosives, use of fuel gas, volume and flow of ventilation, visible atmospheric conditions, decompression of the atmosphere, welding, cutting and hot work, and employees' physical reactions to working underground.
(ii)(A) The atmosphere in all underground work areas shall be tested as often as necessary to assure that the atmosphere at normal atmospheric pressure contains at least 19.5 percent oxygen and no more than 22 percent oxygen.
(B) Tests for oxygen content shall be made before tests for air contaminants.
(iii)(A) The atmosphere in all underground work areas shall be tested quantitatively for carbon monoxide, nitrogen dioxide, hydrogen sulfide, and other toxic gases, dusts, vapors, mists, and fumes as often as necessary to ensure that the permissible exposure limits prescribed in § 1926.55 are not exceeded.
(B) The atmosphere in all underground work areas shall be tested quantitatively for methane and other flammable gases as often as necessary to determine:
( 1 ) Whether action is to be taken under paragraphs (j)(1)(vii), (viii), and (ix), of this section; and
( 2 ) Whether an operation is to be classified potentially gassy or gassy under paragraph (h) of this section.
(C) If diesel-engine or gasoline-engine driven ventilating fans or compressors are used, an initial test shall be made of the inlet air of the fan or compressor, with the engines operating, to ensure that the air supply is not contaminated by engine exhaust.
(D) Testing shall be performed as often as necessary to ensure that the ventilation requirements of paragraph (k) of this section are met.
(iv) When rapid excavation machines are used, a continuous flammable gas monitor shall be operated at the face with the sensor(s) placed as high and close to the front of the machine's cutter head as practicable.
(v)(A) Whenever air monitoring indicates the presence of 5 ppm or more of hydrogen sulfide, a test shall be conducted in the affected underground work area(s), at least at the beginning and midpoint of each shift, until the concentration of hydrogen sulfide has been less than 5 ppm for 3 consecutive days.
(B) Whenever hydrogen sulfide is detected in an amount exceeding 10 ppm, a continuous sampling and indicating hydrogen sulfide monitor shall be used to monitor the affected work area.
(C) Employees shall be informed when a concentration of 10 ppm hydrogen sulfide is exceeded.
(D) The continuous sampling and indicating hydrogen sulfide monitor shall be designed, installed, and maintained to provide a visual and aural alarm when the hydrogen sulfide concentration reaches 20 ppm to signal that additional measures, such as respirator use, increased ventilation, or evacuation, might be necessary to maintain hydrogen sulfide exposure below the permissible exposure limit.
(vi) When the competent person determines, on the basis of air monitoring results or other information, that air contaminants may be present in sufficient quantity to be dangerous to life, the employer shall:
(A) Prominently post a notice at all entrances to the underground jobsite to inform all entrants of the hazardous condition; and
(B) Ensure that the necessary precautions are taken.
(vii) Whenever five percent or more of the lower explosive limit for methane or other flammable gases is detected in any underground work area(s) or in the air return, steps shall be taken to increase ventilation air volume or otherwise control the gas concentration, unless the employer is operating in accordance with the potentially gassy or gassy operation requirements. Such additional ventilation controls may be discontinued when gas concentrations are reduced below five percent of the lower explosive limit, but shall be reinstituted whenever the five percent level is exceeded.
(viii) Whenever 10 percent or more of the lower explosive limit for methane or other flammable gases is detected in the vicinity of welding, cutting, or other hot work, such work shall be suspended until the concentration of such flammable gas is reduced to less than 10 percent of the lower explosive limit.
(ix) Whenever 20 percent or more of the lower explosive limit for methane or other flammable gases is detected in any underground work area(s) or in the air return:
(A) All employees, except those necessary to eliminate the hazard, shall be immediately withdrawn to a safe location above ground; and
(B) Electrical power, except for acceptable pumping and ventilation equipment, shall be cut off to the area endangered by the flammable gas until the concentration of such gas is reduced to less than 20 percent of the lower explosive limit.
(2) Additional monitoring for potentially gassy and gassy operations. Operations which meet the criteria for potentially gassy and gassy operations set forth in paragraph (h) of this section shall be subject to the additional monitoring requirements of this paragraph.
(i) A test for oxygen content shall be conducted in the affected underground work areas and work areas immediately adjacent to such areas at least at the beginning and midpoint of each shift.
(ii) When using rapid excavation machines, continuous automatic flammable gas monitoring equipment shall be used to monitor the air at the heading, on the rib, and in the return air duct. The continuous monitor shall signal the heading, and shut down electric power in the affected underground work area, except for acceptable pumping and ventilation equipment, when 20 percent or more of the lower explosive limit for methane or other flammable gases is encountered.
(iii) A manual flammable gas monitor shall be used as needed, but at least at the beginning and midpoint of each shift, to ensure that the limits prescribed in paragraphs (h) and (j) are not exceeded. In addition, a manual electrical shut down control shall be provided near the heading.
(iv) Local gas tests shall be made prior to and continuously during any welding, cutting, or other hot work.
(v) In underground operations driven by drill-and-blast methods, the air in the affected area shall be tested for flammable gas prior to re-entry after blasting, and continuously when employees are working underground.
(3) Recordkeeping. A record of all air quality tests shall be maintained above ground at the worksite and be made available to the Secretary of Labor upon request. The record shall include the location, date, time, substance and amount monitored. Records of exposures to toxic substances shall be retained in accordance with § 1910.33 of this chapter. All other air quality test records shall be retained until completion of the project.
(k) Ventilation. (1)(i) Fresh air shall be supplied to all underground work areas in sufficient quantities to prevent dangerous or harmful accumulation of dusts, fumes, mists, vapors or gases.
(ii) Mechanical ventilation shall be provided in all underground work areas except when the employer can demonstrate that natural ventilation provides the necessary air quality through sufficient air volume and air flow.
(2) A minimum of 200 cubic feet (5.7 m 3 ) of fresh air per minute shall be supplied for each employee underground.
(3) The linear velocity of air flow in the tunnel bore, in shafts, and in all other underground work areas shall be at least 30 feet (9.15 m) per minute where blasting or rock drilling is conducted, or where other conditions likely to produce dust, fumes, mists, vapors, or gases in harmful or explosive quantities are present.
(4) The direction of mechanical air flow shall be reversible.
(5) Following blasting, ventilation systems shall exhaust smoke and fumes to the outside atmosphere before work is resumed in affected areas.
(6) Ventilation doors shall be designed and installed so that they remain closed when in use, regardless of the direction of the air flow.
(7) When ventilation has been reduced to the extent that hazardous levels of methane or flammable gas may have accumulated, a competent person shall test all affected areas after ventilation has been restored and shall determine whether the atmosphere is within flammable limits before any power, other than for acceptable equipment, is restored or work is resumed.
(8) Whenever the ventilation system has been shut down with all employees out of the underground area, only competent persons authorized to test for air contaminants shall be allowed underground until the ventilation has been restored and all affected areas have been tested for air contaminants and declared safe.
(9) When drilling rock or concrete, appropriate dust control measures shall be taken to maintain dust levels within limits set in § 1926.55. Such measures may include, but are not limited to, wet drilling, the use of vacuum collectors, and water mix spray systems.
(10)(i) Internal combustion engines, except diesel-powered engines on mobile equipment, are prohibited underground.
(ii) Mobile diesel-powered equipment used underground in atmospheres other than gassy operations:
(A) Shall comply with MSHA provisions in 30 CFR 57.5067; or
(B) If purchased on or before July 15, 2019, may alternatively comply with MSHA provisions under 30 CFR part 32 (revised as of July 1, 1996) (formerly Schedule 24), or be demonstrated by the employer to be fully equivalent to such MSHA-approved equipment, and be operated in accordance with that part.
(iii) For purposes of this paragraph (k)(10), when an applicable MSHA provision uses the term “mine,” use the phrase “underground construction site.” (Each brake horsepower of a diesel engine requires at least 100 cubic feet (2.832 m 3 ) of air per minute for suitable operation in addition to the air requirements for personnel. Some engines may require a greater amount of air to ensure that the allowable levels of carbon monoxide, nitric oxide, and nitrogen dioxide are not exceeded.)
(11) Potentially gassy or gassy operations shall have ventilation systems installed which shall:
(i) Be constructed of fire-resistant materials; and
(ii) Have acceptable electrical systems, including fan motors.
(12) Gassy operations shall be provided with controls located above ground for reversing the air flow of ventilation systems.
(13) In potentially gassy or gassy operations, wherever mine-type ventilation systems using an offset main fan installed on the surface are used, they shall be equipped with explosion-doors or a weak-wall having an area at least equivalent to the cross-sectional area of the airway.
(l) Illumination. (1) Illumination requirements applicable to underground construction operations are found in Table D-3 of § 1926.56 of this part.
(2) Only acceptable portable lighting equipment shall be used within 50 feet (15.24 m) of any underground heading during explosives handling.
(m) Fire prevention and control. Fire prevention and protection requirements applicable to underground construction operations are found in subpart F of this part, except as modified by the following additional standards.
(1) Open flames and fires are prohibited in all underground construction operations except as permitted for welding, cutting and other hot work operations in paragraph (n) of this section.
(2)(i) Smoking may be allowed only in areas free of fire and explosion hazards.
(ii) Readily visible signs prohibiting smoking and open flames shall be posted in areas having fire or explosion hazards.
(3) The employer may store underground no more than a 24-hour supply of diesel fuel for the underground equipment used at the worksite.
(4) The piping of diesel fuel from the surface to an underground location is permitted only if:
(i) Diesel fuel is contained at the surface in a tank whose maximum capacity is no more than the amount of fuel required to supply for a 24-hour period the equipment serviced by the underground fueling station; and
(ii) The surface tank is connected to the underground fueling station by an acceptable pipe or hose system that is controlled at the surface by a valve, and at the shaft bottom by a hose nozzle; and
(iii) The pipe is empty at all times except when transferring diesel fuel from the surface tank to a piece of equipment in use underground; and
(iv) Hoisting operations in the shaft are suspended during refueling operations if the supply piping in the shaft is not protected from damage.
(5)(i) Gasoline shall not be carried, stored, or used underground.
(ii) Acetylene, liquefied petroleum gas, and Methylacetylene Propadiene Stabilized gas may be used underground only for welding, cutting and other hot work, and only in accordance with subpart J of this part, and paragraphs (j), (k), (m), and (n) of this section.
(6) Oil, grease, and diesel fuel stored underground shall be kept in tightly sealed containers in fire-resistant areas at least 300 feet (91.44 m) from underground explosive magazines, and at least 100 feet (30.48 m) from shaft stations and steeply inclined passageways. Storage areas shall be positioned or diked so that the contents of ruptured or overturned containers will not flow from the storage area.
(7) Flammable or combustible materials shall not be stored above ground within 100 feet (30.48 m) of any access opening to any underground operation. Where this is not feasible because of space limitations at the jobsite, such materials may be located within the 100-foot limit, provided that:
(i) They are located as far as practicable from the opening; and
(ii) Either a fire-resistant barrier of not less than one-hour rating is placed between the stored material and the opening, or additional precautions are taken which will protect the materials from ignition sources.
(8) Fire-resistant hydraulic fluids shall be used in hydraulically-actuated underground machinery and equipment unless such equipment is protected by a fire suppression system or by multi-purpose fire extinguisher(s) rated at of sufficient capacity for the type and size of hydraulic equipment involved, but rated at least 4A:40B:C.
(9)(i) Electrical installations in underground areas where oil, grease, or diesel fuel are stored shall be used only for lighting fixtures.
(ii) Lighting fixtures in storage areas, or within 25 feet (7.62 m) of underground areas where oil, grease, or diesel fuel are stored, shall be approved for Class I, Division 2 locations, in accordance with subpart K of this part.
(10) Leaks and spills of flammable or combustible fluids shall be cleaned up immediately.
(11) A fire extinguisher of at least 4A:40B:C rating or other equivalent extinguishing means shall be provided at the head pulley and at the tail pulley of underground belt conveyors.
(12) Any structure located underground or within 100 feet (30.48 m) of an opening to the underground shall be constructed of material having a fire-resistance rating of at least one hour.
(n) Welding, cutting, and other hot work. In addition to the requirements of subpart J of this part, the following requirements shall apply to underground welding, cutting, and other hot work.
(1) No more than the amount of fuel gas and oxygen cylinders necessary to perform welding, cutting, or other hot work during the next 24-hour period shall be permitted underground.
(2) Noncombustible barriers shall be installed below welding, cutting, or other hot work being done in or over a shaft or raise.
(o) Ground support —(1) Portal areas. Portal openings and access areas shall be guarded by shoring, fencing, head walls, shotcreting or other equivalent protection to ensure safe access of employees and equipment. Adjacent areas shall be scaled or otherwise secured to prevent loose soil, rock, or fractured materials from endangering the portal and access area.
(2) Subsidence areas. The employer shall ensure ground stability in hazardous subsidence areas by shoring, by filling in, or by erecting barricades and posting warning signs to prevent entry.
(3) Underground areas. (i)(A) A competent person shall inspect the roof, face, and walls of the work area at the start of each shift and as often as necessary to determine ground stability.
(B) Competent persons conducting such inspections shall be protected from loose ground by location, ground support or equivalent means.
(ii) Ground conditions along haulageways and travelways shall be inspected as frequently as necessary to ensure safe passage.
(iii) Loose ground that might be hazardous to employees shall be taken down, scaled or supported.
(iv) (A) Torque wrenches shall be used wherever bolts that depend on torsionally applied force are used for ground support.
(B) A competent person shall determine whether rock bolts meet the necessary torque, and shall determine the testing frequency in light of the bolt system, ground conditions and the distance from vibration sources.
(v) Suitable protection shall be provided for employees exposed to the hazard of loose ground while installing ground support systems.
(vi) Support sets shall be installed so that the bottoms have sufficient anchorage to prevent ground pressures from dislodging the support base of the sets. Lateral bracing (collar bracing, tie rods, or spreaders) shall be provided between immediately adjacent sets to ensure added stability.
(vii) Damaged or dislodged ground supports that create a hazardous condition shall be promptly repaired or replaced. When replacing supports, the new supports shall be installed before the damaged supports are removed.
(viii) A shield or other type of support shall be used to maintain a safe travelway for employees working in dead-end areas ahead of any support replacement operation.
(4) Shafts. (i) Shafts and wells over 5 feet (1.53 m) in depth that employees must enter shall be supported by a steel casing, concrete pipe, timber, solid rock or other suitable material.
(ii) (A) The full depth of the shaft shall be supported by casing or bracing except where the shaft penetrates into solid rock having characteristics that will not change as a result of exposure. Where the shaft passes through earth into solid rock, or through solid rock into earth, and where there is potential for shear, the casing or bracing shall extend at least 5 feet (1.53 m) into the solid rock. When the shaft terminates in solid rock, the casing or bracing shall extend to the end of the shaft or 5 feet (1.53 m) into the solid rock, whichever is less.
(B) The casing or bracing shall extend 42 inches (1.07 m) plus or minus 3 inches (8 cm) above ground level, except that the minimum casing height may be reduced to 12 inches (0.3 m), provided that a standard railing is installed; that the ground adjacent to the top of the shaft is sloped away from the shaft collar to prevent entry of liquids; and that effective barriers are used to prevent mobile equipment operating near the shaft from jumping over the 12 inch (0.3 m) barrier.
(iii) After blasting operations in shafts, a competent person shall determine if the walls, ladders, timbers, blocking, or wedges have loosened. If so, necessary repairs shall be made before employees other than those assigned to make the repairs are allowed in or below the affected areas.
(p) Blasting. This paragraph applies in addition to the requirements for blasting and explosives operations, including handling of misfires, which are found in subpart U of this part.
(1) Blasting wires shall be kept clear of electrical lines, pipes, rails, and other conductive material, excluding earth, to prevent explosives initiation or employee exposure to electric current.
(2) Following blasting, an employee shall not enter a work area until the air quality meets the requirements of paragraph (j) of this section.
(q) Drilling. (1) A competent person shall inspect all drilling and associated equipment prior to each use. Equipment defects affecting safety shall be corrected before the equipment is used.
(2) The drilling area shall be inspected for hazards before the drilling operation is started.
(3) Employees shall not be allowed on a drill mast while the drill bit is in operation or the drill machine is being moved.
(4) When a drill machine is being moved from one drilling area to another, drill steel, tools, and other equipment shall be secured and the mast shall be placed in a safe position.
(5) Receptacles or racks shall be provided for storing drill steel located on jumbos.
(6) Employees working below jumbo decks shall be warned whenever drilling is about to begin.
(7) Drills on columns shall be anchored firmly before starting drilling, and shall be retightened as necessary thereafter.
(8) (i) The employer shall provide mechanical means on the top deck of a jumbo for lifing unwieldy or heavy material.
(ii) When jumbo decks are over 10 feet (3.05 m) in height, the employer shall install stairs wide enough for two persons.
(iii) Jumbo decks more than 10 feet (3.05 m) in height shall be equipped with guardrails on all open sides, excluding access openings of platforms, unless an adjacent surface provides equivalent fall protection.
(iv) (A) Only employees assisting the operator shall be allowed to ride on jumbos, unless the jumbo meets the requirements of paragraph (r)(6)(ii) of this section.
(B) Jumbos shall be chocked to prevent movement while employees are working on them.
(v) (A) Walking and working surfaces of jumbos shall be maintained to prevent the hazards of slipping, tripping and falling.
(B) Jumbo decks and stair treads shall be designed to be slip-resistent and secured to prevent accidental displacement.
(9) Scaling bars shall be available at scaling operations and shall be maintained in good condition at all times. Blunted or severely worn bars shall not be used.
(10)(i) Blasting holes shall not be drilled through blasted rock (muck) or water.
(ii) Employees in a shaft shall be protected either by location or by suitable barrier(s) if powered mechanical loading equipment is used to remove muck containing unfired explosives.
(11) A caution sign reading “Buried Line,” or similar wording shall be posted where air lines are buried or otherwise hidden by water or debris.
(r) Haulage. (1)(i) A competent person shall inspect haulage equipment before each shift.
(ii) Equipment defects affecting safety and health shall be corrected before the equipment is used.
(2) Powered mobile haulage equipment shall have suitable means of stopping.
(3)(i) Power mobile haulage equipment, including trains, shall have audible warning devices to warn employees to stay clear. The operator shall sound the warning device before moving the equipment and whenever necessary during travel.
(ii) The operator shall assure that lights which are visible to employees at both ends of any mobile equipment, including a train, are turned on whenever the equipment is operating.
(4) In those cabs where glazing is used, the glass shall be safety glass, or its equivalent, and shall be maintained and cleaned so that vision is not obstructed.
(5) Anti-roll back devices or brakes shall be installed on inclined conveyor drive units to prevent conveyors from inadvertently running in reverse.
(6)(i) (A) Employees shall not be permitted to ride a power-driven chain, belt, or bucket conveyor unless the conveyor is specifically designed for the transportation of persons.
(B) Endless belt-type manlifts are prohibited in underground construction.
(C) General requirements also applicable to underground construction for use of conveyors in construction are found in § 1926.555 of this part.
(ii) No employee shall ride haulage equipment unless it is equipped with seating for each passenger and protects passengers from being struck, crushed, or caught between other equipment or surfaces. Members of train crews may ride on a locomotive if it is equipped with handholds and nonslip steps or footboards. Requirements applicable to Underground Construction for motor vehicle transportation of employees are found in § 1926.601 of this part.
(7) Powered mobile haulage equipment, including trains, shall not be left unattended unless the master switch or motor is turned off; operating controls are in neutral or park position; and the brakes are set, or equivalent precautions are taken to prevent rolling.
(8) Whenever rails serve as a return for a trolley circuit, both rails shall be bonded at every joint and crossbonded every 200 feet (60.96 m).
(9) When dumping cars by hand, the car dumps shall have tiedown chains, bumper blocks, or other locking or holding devices to prevent the cars from overturning.
(10) Rocker-bottom or bottom-dump cars shall be equipped with positive locking devices to prevent unintended dumping.
(11) Equipment to be hauled shall be loaded and secured to prevent sliding or dislodgement.
(12)(i) Mobile equipment, including rail-mounted equipment, shall be stopped for manual connecting or service work.
(ii) Employees shall not reach between moving cars during coupling operations.
(iii) Couplings shall not be aligned, shifted or cleaned on moving cars or locomotives.
(13)(i) Safety chains or other connections shall be used in addition to couplers to connect man cars or powder cars whenever the locomotive is uphill of the cars.
(ii) When the grade exceeds one percent and there is a potential for runaway cars, safety chains or other connections shall be used in addition to couplers to connect haulage cars or, as an alternative, the locomotive must be downhill of the train.
(iii) Such safety chains or other connections shall be capable of maintaining connection between cars in the event of either coupler disconnect, failure or breakage.
(14) Parked rail equipment shall be chocked, blocked, or have brakes set to prevent inadvertent movement.
(15) Berms, bumper blocks, safety hooks, or equivalent means shall be provided to prevent overtravel and overturning of haulage equipment at dumping locations.
(16) Bumper blocks or equivalent stopping devices shall be provided at all track dead ends.
(17)(i) Only small handtools, lunch pails or similar small items may be transported with employees in man-cars, or on top of a locomotive.
(ii) When small hand tools or other small items are carried on top of a locomotive, the top shall be designed or modified to retain them while traveling.
(18)(i) Where switching facilities are available, occupied personnel-cars shall be pulled, not pushed. If personnel-cars must be pushed and visibility of the track ahead is hampered, then a qualified person shall be stationed in the lead car to give signals to the locomotive operator.
(ii) Crew trips shall consist of personnel-loads only.
(s) Electrical safety. This paragraph applies in addition to the general requirements for electrical safety which are found in subpart K of this part.
(1) Electric power lines shall be insulated or located away from water lines, telephone lines, air lines, or other conductive materials so that a damaged circuit will not energize the other systems.
(2) Lighting circuits shall be located so that movement of personnel or equipment will not damage the circuits or disrupt service.
(3) Oil-filled transformers shall not be used underground unless they are located in a fire-resistant enclosure suitably vented to the outside and surrounded by a dike to retain the contents of the transformers in the event of rupture.
(t) Hoisting unique to underground construction. Except as modified by this paragraph (t), employers must: Comply with the requirements of subpart CC of this part, except that the limitation in § 1926.1431(a) does not apply to the routine access of employees to an underground worksite via a shaft; ensure that material hoists comply with § 1926.552(a) and (b) of this part; and ensure that personnel hoists comply with the personnel-hoists requirements of § 1926.552(a) and (c) of this part and the elevator requirements of § 1926.552(a) and (d) of this part.
(1) General requirements for cranes and hoists. (i) Materials, tools, and supplies being raised or lowered, whether within a cage or otherwise, shall be secured or stacked in a manner to prevent the load from shifting, snagging or falling into the shaft.
(ii) A warning light suitably located to warn employees at the shaft bottom and subsurface shaft entrances shall flash whenever a load is above the shaft bottom or subsurface entrances, or the load is being moved in the shaft. This paragraph does not apply to fully enclosed hoistways.
(iii) Whenever a hoistway is not fully enclosed and employees are at the shaft bottom, conveyances or equipment shall be stopped at least 15 feet (4.57 m) above the bottom of the shaft and held there until the signalman at the bottom of the shaft directs the operator to continue lowering the load, except that the load may be lowered without stopping if the load or conveyance is within full view of a bottom signalman who is in constant voice communication with the operator.
(iv)(A) Before maintenance, repairs, or other work is commenced in the shaft served by a cage, skip, or bucket, the operator and other employees in the area shall be informed and given suitable instructions.
(B) A sign warning that work is being done in the shaft shall be installed at the shaft collar, at the operator's station, and at each underground landing.
(v) Any connection between the hoisting rope and the cage or skip shall be compatible with the type of wire rope used for hoisting.
(vi) Spin-type connections, where used, shall be maintained in a clean condition and protected from foreign matter that could affect their operation.
(vii) Cage, skip, and load connections to the hoist rope shall be made so that the force of the hoist pull, vibration, misalignment, release of lift force, or impact will not disengage the connection. Moused or latched openthroat hooks do not meet this requirement.
(viii) When using wire rope wedge sockets, means shall be provided to prevent wedge escapement and to ensure that the wedge is properly seated.
(2) Additional requirements for cranes. Cranes shall be equipped with a limit switch to prevent overtravel at the boom tip. Limit switches are to be used only to limit travel of loads when operational controls malfunction and shall not be used as a substitute for other operational controls.
(3) Additional requirements for hoists. (i) Hoists shall be designed so that the load hoist drum is powered in both directions of rotation, and so that brakes are automatically applied upon power release or failure.
(ii) Control levers shall be of the “deadman type” which return automatically to their center (neutral) position upon release.
(iii) When a hoist is used for both personnel hoisting and material hoisting, load and speed ratings for personnel and for materials shall be assigned to the equipment.
(iv) Material hoisting may be performed at speeds higher than the rated speed for personnel hoisting if the hoist and components have been designed for such higher speeds and if shaft conditions permit.
(v) Employees shall not ride on top of any cage, skip or bucket except when necessary to perform inspection or maintenance of the hoisting system, in which case they shall be protected by a body belt/harness system to prevent falling.
(vi) Personnel and materials (other than small tools and supplies secured in a manner that will not create a hazard to employees) shall not be hoisted together in the same conveyance. However, if the operator is protected from the shifting of materials, then the operator may ride with materials in cages or skips which are designed to be controlled by an operator within the cage or skip.
(vii) Line speed shall not exceed the design limitations of the systems.
(viii) Hoists shall be equipped with landing level indicators at the operator's station. Marking the hoist rope does not satisfy this requirement.
(ix) Whenever glazing is used in the hoist house, it shall be safety glass, or its equivalent, and be free of distortions and obstructions.
(x) A fire extinguisher that is rated at least 2A:10B:C (multi-purpose, dry chemical) shall be mounted in each hoist house.
(xi) Hoist controls shall be arranged so that the operator can perform all operating cycle functions and reach the emergency power cutoff without having to reach beyond the operator's normal operating position.
(xii) Hoists shall be equipped with limit switches to prevent overtravel at the top and bottom of the hoistway.
(xiii) Limit switches are to be used only to limit travel of loads when operational controls malfunction and shall not be used as a substitute for other operational controls.
(xiv) Hoist operators shall be provided with a closed-circuit voice communication system to each landing station, with speaker microphones so located that the operator can communicate with individual landing stations during hoist use.
(xv) When sinking shafts 75 feet (22.86 m) or less in depth, cages, skips, and buckets that may swing, bump, or snag against shaft sides or other structural protrusions shall be guided by fenders, rails, ropes, or a combination of those means.
(xvi) When sinking shafts more than 75 feet (22.86 m) in depth, all cages, skips, and buckets shall be rope or rail guided to within a rail length from the sinking operation.
(xvii) Cages, skips, and buckets in all completed shafts, or in all shafts being used as completed shafts, shall be rope or rail-guided for the full length of their travel.
(xviii) Wire rope used in load lines of material hoists shall be capable of supporting, without failure, at least five times the maximum intended load or the factor recommended by the rope manufacturer, whichever is greater. Refer to § 1926.552(c)(14)(iii) of this part for design factors for wire rope used in personnel hoists. The design factor shall be calculated by dividing the breaking strength of wire rope, as reported in the manufacturer's rating tables, by the total static load, including the weight of the wire rope in the shaft when fully extended.
(xix) A competent person shall visually check all hoisting machinery, equipment, anchorages, and hoisting rope at the beginning of each shift and during hoist use, as necessary.
(xx) Each safety device shall be checked by a competent person at least weekly during hoist use to ensure suitable operation and safe condition.
(xxi) In order to ensure suitable operation and safe condition of all functions and safety devices, each hoist assembly shall be inspected and load-tested to 100 percent of its rated capacity: at the time of installation; after any repairs or alterations affecting its structural integrity; after the operation of any safety device; and annually when in use. The employer shall prepare a certification record which includes the date each inspection and load-test was performed; the signature of the person who performed the inspection and test; and a serial number or other identifier for the hoist that was inspected and tested. The most recent certification record shall be maintained on file until completion of the project.
(xxii) Before hoisting personnel or material, the operator shall perform a test run of any cage or skip whenever it has been out of service for one complete shift, and whenever the assembly or components have been repaired or adjusted.
(xxiii) Unsafe conditions shall be corrected before using the equipment.
(4) Additional requirements for personnel hoists. (i) Hoist drum systems shall be equipped with at least two means of stopping the load, each of which shall be capable of stopping and holding 150 percent of the hoist's rated line pull. A broken-rope safety, safety catch, or arrestment device is not a permissible means of stopping under this paragraph (t).
(ii) The operator shall remain within sight and sound of the signals at the operator's station.
(iii) All sides of personnel cages shall be enclosed by one-half inch (12.70 mm) wire mesh (not less than No. 14 gauge or equivalent) to a height of not less than 6 feet (1.83 m). However, when the cage or skip is being used as a work platform, its sides may be reduced in height to 42 inches (1.07 m) when the conveyance is not in motion.
(iv) All personnel cages shall be provided with a positive locking door that does not open outward.
(v) All personnel cages shall be provided with a protective canopy. The canopy shall be made of steel plate, at least 3/16-inch (4.763 mm) in thickness, or material of equivalent strength and impact resistance. The canopy shall be sloped to the outside, and so designed that a section may be readily pushed upward to afford emergency egress. The canopy shall cover the top in such a manner as to protect those inside from objects falling in the shaft.
(vi) Personnel platforms operating on guide rails or guide ropes shall be equipped with broken-rope safety devices, safety catches or arrestment devices that will stop and hold 150 percent of the weight of the personnel platform and its maximum rated load.
(vii) During sinking operations in shafts where guides and safeties are not yet used, the travel speed of the personnel platform shall not exceed 200 feet (60.96 m) per minute. Governor controls set for 200 feet (60.96 m) per minute shall be installed in the control system and shall be used during personnel hoisting.
(viii) The personnel platform may travel over the controlled length of the hoistway at rated speeds up to 600 feet (182.88 m) per minute during sinking operations in shafts where guides and safeties are used.
(ix) The personnel platform may travel at rated speeds greater than 600 feet (182.88 m) per minute in completed shafts.
(u) Definitions. “Accept”—Any device, equipment, or appliance that is either approved by MSHA and maintained in permissible condition, or is listed or labeled for the class and location under subpart K of this part.
“Rapid Excavation Machine”—Tunnel boring machines, shields, roadheaders, or any other similar excavation machine.
[54 FR 23850, June 2, 1989; 58 FR 35311, June 30, 1993, as amended at 61 FR 5510, Feb. 13, 1996; 63 FR 1297, Jan. 8, 1998; 71 FR 16674, Apr. 3, 2006; 75 FR 48135, Aug. 9, 2010; 77 FR 49728, Aug. 17, 2012; 78 FR 23841, Apr. 24, 2013; 84 FR 21577, May 14, 2019]


§ 1926.801 Caissons.

(a) Wherever, in caisson work in which compressed air is used, and the working chamber is less than 11 feet in length, and when such caissons are at any time suspended or hung while work is in progress so that the bottom of the excavation is more than 9 feet below the deck of the working chamber, a shield shall be erected therein for the protection of the employees.
(b) Shafts shall be subjected to a hydrostatic or air-pressure test, at which pressure they shall be tight. The shaft shall be stamped on the outside shell about 12 inches from each flange to show the pressure to which they have been subjected.
(c) Whenever a shaft is used, it shall be provided, where space permits, with a safe, proper, and suitable staircase for its entire length, including landing platforms, not more than 20 feet apart. Where this is impracticable, suitable ladders shall be installed with landing platforms located about 20 feet apart to break the climb.
(d) All caissons having a diameter or side greater than 10 feet shall be provided with a man lock and shaft for the exclusive use of employees.
(e) In addition to the gauge in the locks, an accurate gauge shall be maintained on the outer and inner side of each bulkhead. These gauges shall be accessible at all times and kept in accurate working order.
(f) In caisson operations where employees are exposed to compressed air working environments, the requirements contained in § 1926.803 shall be complied with.