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(d) Bracket Scaffolds. The use of bracket scaffolds shall be permitted only when through-bolted to walls, with at least 5/8-inch diameter bolts; welded to steel tanks; secured with a metal stud attachment device; or, hooked over a well-secured and adequately strong supporting member.
Note: This Order does not prohibit the use of bracket scaffolds that are an integral part of movable form panels or similar construction. (See Plates B-20 and B-21, Appendix.)
All form scaffolds shall be designed and erected with a minimum safety factor of 4, computed on the basis of the maximum rated load; i.e., the total of all loads including the working load, the weight of the scaffold, and such other loads as may be reasonably anticipated.
(1) Spacing of brackets shall be such that they are not more than 10 feet apart horizontally.
(2) If brackets are secured to walers held by snap-tie or she-bolts, they must extend through both wall forms and be properlysecured.
(3) Railings shall be installed on bracket scaffolds for all heights 7 1/2 feet or more above the ground.
(4) The platform shall consist of two or more 2-inch by 10-inch planks, laid closely together, and shall be of such length that they overlap the ledgers at each end by at least 6 inches. Unsupported projecting ends of planks shall be limited to an overhang of 18 inches or less.
(5) Wooden bracket form scaffolds shall be an integral part of the form panel and shall not be used to support loads exceeding 25 pounds per square foot, unless specifically designed for a heavier loading. Ledgers shall be made from 2-inch by 6-inch or heavier material and shall not project more than 3 feet 6 inches from the form panel. Uprights shall consist of 2-inch by 4-inch or heavier material. Scaffold planks shall be either nailed, wired or bolted to the ledgers. Planks shall overlap the ledgers at each end by at least 6 inches. Unsupported projecting ends of platform planks shall be limited to a maximum overhang of 18 inches. Ledgers shall not be spaced more than 8 feet on centers. (See Appendix Plate B-20.)
(6) Bracket scaffolds installed on metal tanks larger than 40 feet in diameter for the use of those engaged in tank erection operations, shall have platforms that are at least 30 inches wide, with the open ends and sides protected by a substantial railing, with midrail, which may be altered by the substitution of 3/8-inch wire rope for the top and middle rails. Platforms on 40-foot or smaller diameter tanks will be acceptable if not less than 24 inches in width, consisting normally of two 2-inch by 12-inch planks side by side, protected by railings as described above.
Note: For railing requirements, see Section 1620.
(e) Carpenters' Bracket Scaffolds.
(1) The brackets shall consist of a triangular wood frame not less than 2 x 3 inches in cross section, or of metal of equivalent strength. Each member shall be properly fitted and securely joined.
(2) Each bracket shall be attached to the structure by means of one of the following:
(A) A bolt, no less than 5/8-inch in diameter, which shall extend through to the inside of the building wall;
(B) A metal stud attachment device;
(C) Welding to steel tanks;
(D) Hooking over a well-secured and adequately strong supporting member.
(3) The brackets shall be spaced no more than 10 feet apart.
(4) No more than two employees shall occupy any given 10 feet of a bracket scaffold at any one time. Tools and materials shall not exceed 75 pounds in addition to the occupancy.
(5) The platform shall consist of not less than two 2- x 10-inch nominal size planks extending not more than 18 inches or less than 6 inches beyond each end support.
Note: For railings see Section 1620.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1646. Tower Scaffolds and Rolling Scaffolds, Wood or Metal.
(a) The minimum dimension of the base of any free-standing tower or rolling scaffold shall not be less than 1/3 the height of the scaffold unless such scaffold is securely guyed or tied. For restrictions when worker rides scaffold see paragraph (f) following.
(b) Construction and Erection.
(1) The uprights, ledgers, ribbons, braces, and splices shall be equivalent to the standards specified in other applicable Sections of these Orders. Railings are required if the platform is 7 1/2 feet or more above grade. Railings shall be installed in accordance with the provisions of Section 1644(a)(6).
Note: Toeboards or side screens may also be required. (See Section 1621.)
(2) The screw jack shall extend into its leg tube at least 1/3 its length, but in no case shall the exposed thread exceed 12 inches.
(3) The uprights (legs of rolling scaffolds) shall not exceed 24 inches without being braced according to the manufacturer's specifications.
(c) Wheels or casters of rolling scaffolds shall be provided with an effective locking device, and kept locked when workers are climbing or working on the scaffold. At least 2 of the 4 casters or wheels shall be a swivel type. All wheels or casters shall be properly designed for strength and dimension to support at least 4 times the maximum intended load.
(d) Joints of metal scaffolds shall be locked together with lock pins, bolts or equivalent fastening, including caster joints. Lock pins used must be of a locking type.
Exception: Screw jacks and guardrail posts.
(e) Platform planks on rolling or tower scaffolds shall not project farther than 18 inches past supports at the edges of the scaffold. An effective method of preventing platform planks on rolling scaffolds from slipping off must be provided. The nailing of cleats of 1-inch material on the underside of each projecting end, or other equivalent means, will be acceptable. Platforms shall be tightly planked for the full width of the scaffold except for any necessary entrance openings.
Note: Refer to Orders 1621 and 1637(f) for regulations on required plank and platform sizes.
(f) Riding. Employees may ride on rolling scaffold moved by others below if the following conditions exist:
(1) The floor or surface is within 3 degrees of level, and free from pits, holes, or obstructions.
(2) The minimum dimension of the scaffold base, when ready for rolling, is at least 1/2 of the height. Outriggers, if used, shall be installed on both sides of staging.
(3) The wheels are equipped with rubber or similar resilient tires. For towers 50 feet or over metal wheels may be used.
(g) Ladders. Ladders or other unstable objects shall not be placed on top of rolling scaffolds to gain greater height.
(h) Scaffolds on Vehicles. When scaffolds are built on motor trucks or vehicles, they must be rigidly attached to the truck or vehicle. The attachment must be made in a manner that will develop the full strength of the scaffold in resisting an overturning force.
(i) Trucks or vehicles that have scaffolds attached to them shall have a device in use whenever employees are on the scaffold that prevents swaying or listing of the platforms.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1647. Horse Scaffolds.
(a) General. (1) Lumber for construction of scaffolded horses shall be of "selected lumber" grade.
Note: The lumber sizes specified are nominal sizes for which standard finished sizes may be substituted. (See Plate B-41, Appendix.)
(2) The members of horses used for scaffolds shall be securely nailed or bolted together, and well braced to prevent collapse.
(3) The distance between the bottoms of adjacent legs measured perpendicular to the ledger shall be approximately 1/2 the horse height.
(4) The shimming of horse ledgers to obtain added height is prohibited.
(5) Horses or parts which have become weak or defective shall not be used.
(6) When horse legs are extended by splicing, the joints must be butt-ended, and scabs not less than 18 inches long and of the same cross section as the leg shall be nailed on each side of the joint. As an alternative, new legs of adequate length may be installed, provided that they completely overlap the original legs and are well secured to them from top to bottom. Vertical extensions shall not be used to extend height of metal folding horses if the stability of the horse is impaired.
(7) When arranged in tiers, each horse shall be placed directly over the horse in the tier below.
(8) On all scaffolds arranged in tiers, the legs shall be nailed down or otherwise secured to the planks to prevent displacement or thrust and each tier shall be substantially cross braced.
(9) Railings meeting the requirements of Section 1620 shall be installed on all open sides and ends of work platforms 7 1/2 feet or more above the ground, floor or level underneath.
(b) Light Trades.
(1) Horses for light-trade scaffolds shall have top horizontal members or ledgers of 2-inch by 4-inch lumber or material of equivalent strength, if the distance between the leg connections is 4 feet or less. Ledgers of 2-inch by 6- inch lumber or material of equivalent strength are required if the distance between the leg connections is greater than 4 feet but does not exceed 8 feet.
If the distance between leg connections exceeds 8 feet, the ledger strength must be increased in proportion to the amount by which the 8-foot distance is exceeded.
(2) The legs of horses for light-trade scaffolds shall be 1-inch by 6-inch lumber or material of equivalent strength for horses not exceeding 4 feet in height and 2-inch by 4-inch lumber or material of equivalent strength for horses between 4 feet and 10 feet in height. Horse scaffolds shall not be constructed or arranged more than two tiers or 10 feet in height.
(c) Heavy Trades.
(1) Horses for heavy-trade scaffolds shall have top horizontal members or ledgers of 3-inch by 4-inch lumber or material of equivalent strength, if the distance between the leg connections is 4 feet or less. Ledgers of 2-inch by 6- inch lumber or material of equivalent strength are required if the distance between the leg connections is greater than 4 feet but does not exceed 8 feet. If the distance between leg connections exceeds 8 feet, the ledger strength must be increased in proportion to the amount by which the 8-foot distance is exceeded.
(2) The legs of horses for heavy-trade scaffolds shall be 1-inch by 8-inch lumber or material of equivalent strength, for horses not exceeding 4 feet in height, and 2-inch by 4-inch lumber or material of equivalent strength, for horses between 4 feet and 10 feet in height.
(d) Collapsible Types.
(1) Collapsible horses constructed of well-braced frames hinged at the top may be used in place of the specified rigid horses, if construction is such that equivalent strength is provided.
(2) Adjacent legs of a collapsible horse shall be connected near the bottom with securely attached chains, hinged brackets, or other suitable links to prevent the legs from spreading beyond the distance intended. The height of collapsible horse scaffolds shall not exceed 6 feet.
(e) Platforms.
(1) Scaffold platforms shall not be supported by single horses having a total height exceeding 10 feet. Tiered horse scaffolds shall be limited to 10 feet in height made from no more than 2 tiers of horses. All horse scaffolds shall be substantially constructed and braced both transversely and laterally.
(2) Platforms shall be not less than 20 inches wide for light trades, and 4 feet wide for bricklayers, stonemasons, stone cutters, or concrete workers. Platforms used primarily by bricklayers or stonemasons shall extend to within 5 inches of the building face upon which the work is being performed. A single 2- inch by 10-inch plank may be used for light trades work up to a height of 4 feet.
(3) Planks used for platforms shall not be less than 2 inches by 10 inches, and the distance between supports shall not exceed 10 feet for light trades and 7 feet 6 inches for heavy trades.
(4) For horse scaffolds up to a height of 6 feet, platform planks shall not be more than 2 inches apart. Platform planks on higher scaffolds shall be laid closely together. Planks shall be of such length that they overlap the supports at each end by at least 6 inches. A plank shall not overlap an unsupported end of another plank. Unsupported projecting ends of planks shall be limited to an overhang of 18 inches or less.
(5) Douglas fir plywood that is 3/4 inch thick or thicker may be used for platforms if the panels are 4 feet wide or wider and are supported on cross members at 4-foot or closer intervals for light trades and 2-foot intervals for heavy trades.
(6) Provide standard ladder or other safe, unobstructed means of access to all work platforms.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1648. Ladder-Jack Scaffolds.
(a) Ladder-jack scaffolds shall not be used when the platform is over 16 feet above the ground. Not more than two employees shall be allowed on a scaffold of this type. The ladders shall be secured against displacement. (See Plate B-34, Appendix.)
(b) The platform shall be at least 14 inches wide consisting of ladder staging, "structural plank" or equivalent, free from damage that affects the strength. The ladders shall not be placed over 16 feet center to center, and where the platform consists of a single-dressed 2-inch by 14-inch plank, the spacing shall not be greater than 12 feet. Both metal and wood platform planks shall overlap the bearing surface by at least 12 inches.
(c) Drop lines of at least 3/4-inch diameter Manila rope or other rope of equivalent diameter and strength shall hang from secure overhead anchorages where the working platform is 7 1/2 feet high or more. An independently anchored line shall be provided for and used by each employee in accordance with the provisions of Article 24 of the Construction Safety Orders.
(d) All ladders used in connection with ladder jack scaffolds shall be heavy-duty ladders and shall be designed and constructed in accordance with the General Industry Safety Orders, Sections 3278 and 3279. Job-built ladders shall not be used for this purpose.
(e) The ladder jack shall be so designed and constructed that it will bear on the side rails in addition to the ladder rungs, or if bearing on rungs only, the bearing area shall be at least 10 incheson each rung.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1649. Float Scaffolds.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1650. Needle-Beam Scaffold.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1651. Boatswains' Chairs.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1652. Staging Supported by Catenary or Horizontal Wire Ropes.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1653. Bricklayers' Square Scaffolds.
(a) The squares shall not exceed 5 feet in width and 5 feet in height.
(b) Members shall be not less than those specified in the Schedule below: (See Plate B-32, Appendix)
Minimum Dimensions for
Bricklayers' Square Scaffold Members
Members .................................. Dimensions
Ledgers or horizontal members............. 2 x 6 in.
Legs...................................... 2 x 6 in.
Braces at corners......................... 1 x 6 in.
Braces diagonally from center frame....... 1 x 8 in.
(c) The squares shall be reinforced on both sides of each corner with 1- x 6- inch gusset pieces. They shall also have diagonal braces 1 x 8 inches on both sides running from center to center of each member, or other means to secure equivalent strength and rigidity.
(d) The squares shall be set not more than 5 feet apart for medium duty scaffolds, and not more than 8 feet apart for light duty scaffolds. Bracing, 1 x 8 inches, extending from the bottom of each square to the top of the next square, shall be provided on both front and rear sides of the scaffold.
(e) Platform planks shall be at least 2- x 10-inch nominal size. The ends of the planks shall overlap the ledgers of the squares and each plank shall be supported by not less than three squares.
(f) Bricklayers' square scaffolds shall not exceed three tiers in height and shall be so constructed and arranged that one square shall rest directly above the other. The upper tiers shall stand on a continuous row of planks laid across the next lower tier and be nailed down or otherwise secured to prevent displacement.
(g) Scaffolds shall be level and set upon a firm foundation.
(h) For guardrailing requirements see Section 1621.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1654. Window Jack Scaffolds.
(a) Window jack scaffolds shall be used only for the purpose of working at the window opening through which the jack is placed. (See Plate B-35)
(b) Window jacks shall not be used to support planks placed between one window jack and another or for other elements of scaffolding.
(c) Window jack scaffolds shall be provided with guardrails unless safety belts and lanyards are provided for and used by employees. (See Section 1670.)
(d) Not more than one employee shall occupy a window jack scaffold at any one time.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1655. Pump Jack Scaffolds.
(a) Pump jack scaffolds shall:
(1) Be limited to a maximum working load of 500 pounds; and
(2) Have a Safety Factor of at least four times the maximum intended load.
(3) The manufactured components shall not be loaded in excess of the manufacturer's recommended limits. (See Plate B-33, Appendix)
(b) Pump jack brackets, braces, and accessories shall be fabricated from metal plates and angles. Each pump jack bracket shall have two positive gripping mechanisms to prevent any failure or slippage.
(c) The platform bracket shall be fully decked and the planking secured. Planking, or equivalent, shall conform with Section 1637.
(1) When wood scaffold planks are used as platforms, poles used for pump jacks shall not be spaced more than 10 feet center to center. When fabricated platforms are used that fully comply with all other provisions of this Order, pole spacing may exceed 10 feet center to center.
(2) Poles shall not exceed 30 feet in height.
(3) Poles shall be secured to the work wall by rigid triangular bracing, or equivalent, at the bottom, top, and other points as necessary, to provide a maximum vertical spacing of not more than 10 feet between braces. Each brace shall be capable of supporting a minimum of 225 pounds tension or compression.
(4) For the pump jack bracket to pass bracing already installed, an extra brace shall be used approximately 4 feet above the one to be passed until the original brace is reinstalled.
(d) All poles shall bear on mud sill or other adequate firm foundations.
(e) Pole lumber shall be two 2 x 4's, of Douglas fir, or equivalent, straight-grained, clear, free of cross-grain, shakes, large loose or dead knots, and other defects which might impair strength.
(f) When poles are constructed of two continuous lengths, they shall be 2 x 4's, spiked together with the seam parallel to the bracket, and with 10d common nails, no more than 12 inches center to center, staggered uniformly from opposite outside edges.
(g) If 2 x 4's are spliced to make up the pole, the splices shall be so constructed as to develop the full strength of the member.
(h) Not more than two employees shall be permitted at one time upon a pump jack scaffold between any two supports.
(i) Pump jacks scaffolds shall be provided with standard guardrails as described in Article 16 but no guardrail is required when safety belts with lanyards are provided for and used by employees.
(j) When a work bench is used at an approximate height of 42 inches, the top guardrail may be eliminated, if the work bench is fully decked, the planking secured, and is capable of withstanding 200 pounds load in any direction.
(k) Employees shall not be permitted to use a work bench as a scaffold platform.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1658. Suspended Scaffolds -General.
(a) Hoisting machines or winches that are a part of a suspended scaffold, and are used in raising or lowering that scaffold, shall be approved.
(b) All scaffolds shall be fastened or hung so as to avoid swaying from the building or structure. Window cleaners' anchors shall not be used for this purpose. Supporting cables shall be vertical for their entire length, unless otherwise designed by a currently registered civil engineer in California. The baskets of single-unit, power-driven suspended scaffolds shall not be swayed nor shall support cables be fixed to intermediate points to change the original paths of travel.
(c) Design. All scaffold members, including related parts and rigging, shall be of adequate strength to support intended loads to which they will be subjected, without exceeding stresses established by factors of safety specified in these Orders; or if no safety factors are given, those generally accepted by the engineering profession.
(d) Ladders shall not be used as scaffold platforms, even if a horizontal working surface has been placed over the rungs. Other Orders in this Article call for the use of stage ladders, planking, or specially designed platforms for such service.
(e) Supporting Ropes. Ropes supporting scaffolds shall have a factor of safety of at least 6. They shall be inspected on each job before being used to determine if they are unsafe because of damage, wear, chemical action or similar defects. The use of repaired wire rope as suspension rope is prohibited.
(f) Manila, or other fiber or synthetic ropes shall not be used to support scaffolds upon which workers are using welding or burning equipment of any type, sandblasting equipment, or any chemical substance which may damage the rope by chemical action if splashed or spilled on the rope. Wire rope is required for the above uses. Further, the wire shall be protected against burning or a welding arc to a height of 8 feet above the platform with a rubber hose or equivalent protection.
(g) Inspection. Suspended scaffolds that are in service shall be inspected by a qualified person daily and tested as frequently as is necessary in order to provide proper maintenance. Special attention shall be given to ropes and other rigging.
(h) Suspended scaffolds shall be hung so as to avoid overlap or possible interference with movement from a scaffold above or below.
(i) When suspended scaffolds are supported by a second wire rope, employees shall fasten their lanyards to the work platform trolley line or droplines hanging from secure overhead anchorages between each pair of hangers or falls. One line shall be provided for each employee. It shall be a continuous rope in good condition and free of imperfections, serious wear, or fraying.
(j) Outrigger beams used as supports for suspended scaffold shall be tied back or secured in place and placed in saddles or otherwise positively secured against the possibility of turning or twisting. The attachments on these beams for support of suspended loads shall consist of well-anchored L-hooks fitted with 1/2 inch shackle bolts, or equivalent. See Plate B-24, Appendix.
(1) The outrigger beams and supporting system shall be capable of safely sustaining 4 times the rated load of the platform or hoist whichever is greater.
(2) When a counterweight system is used, the counterweights shall consist of solid materials such as steel or concrete (See Plate B-39, Appendix) and the tiebacks shall be at least equivalent in strength to the suspension ropes and anchored securely.
(k) Unless otherwise designed by a currently registered civil engineer in California, each suspended stage or plank-type platform shall be supported at two or more places by rigging that receives its load from only that one platform. Thus, two or more suspended scaffolds, suspended stage, or plank type platforms shall not be combined into one by bridging the distance between them with planks or similar connecting platforms.
( l ) Metal hangers for suspended scaffolds shall be made of mild steel or equivalent material, capable of sustaining 4 times the maximum rated load.
(m) Except where overhead protection is required and which would result in a greater hazard, employees working in single or two-point suspended scaffolds, shall be required to use safety belts and lanyards attached to independently anchored droplines.
(n) Where the use of independently anchored drop line is not possible, alternate safety measures shall be used.
(o) Railing. All scaffolds or staging referred to in this Article suspended more than 7 1/2 feet from the ground or floor below shall have a standard guardrail of 2-inch by 4-inch of selected structural grade lumber, free of knots or defects, not less than finished size of 1 7/8 inches by 3 1/2 inches, or of other equally rigid materials of equivalent strength. This railing shall be not less than 36 inches nor more than 42 inches above the platform with midrails attached at half the distance from the platform floor to the top rail. All wood members shall not contain any splices that fail to provide full strength and rigidity to the wood member. When railing is longer than 10 feet between stirrups, it shall have a vertical support near the midpoint of the span.
(p) Unattended Scaffold. When a suspended scaffold is left unattended in an elevation position, it shall be securely lashed to the building and be cleared of all tools, buckets, or other moveable materials.
(q) When employees on the scaffolds are exposed to the hazards of falling objects, overhead protection not more than 9 feet above the platform shall be installed.
(r) Hooks used as a part of rigging for scaffold support shall be closed or "moused" (See Plate C-4, Appendix).
(s) Where a single outrigger beam is used, the steel shackles or clevises with which the wire ropes are attached to the outrigger beams shall be placed directly over the hoisting machines.
(t) The free end of the suspension wire ropes shall be equipped with proper size thimbles and secured by splicing or other equivalent means. Where applicable, the running ends shall be securely attached to the hoisting machines and at least four turns of wire rope shall at all times remain on the drum.
(u) Multi-level platforms and suspended scaffolds with overhead protection shall be equipped with additional independent lines equivalent in strength to the suspension ropes to support the units if the primary suspension system fails. These additional independent lines shall be tied to a structural member other than the primary suspension member, capable of supporting the resulting suspended load imposed. (See Plate B-42, Appendix.)
(v) Gasoline-powered equipment and hoists shall not be located on suspension scaffolds.
(w) Devices whose sole function is to provide emergency escape and rescue shall not be used as working platforms. This provision does not preclude the use of systems which are designed to function both as suspension scaffolds and emergency systems.
Note: Authority cited: Section 142.3, Labor Code. Reference: Sections 142.3 and 7152, Labor Code.
s 1659. Bricklayers' or Masons' Suspended Scaffolds.
Note: Stone setters' adjustable multiple-point suspended scaffolds shall also be constructed in accordance with this Order. See Plate B-26, Appendix.
(a) Each outrigger shall be equal in strength to at least a standard 7-inch, 15.3-pound steel at least 15 feet long. It shall not project more than 6 feet 6 inches beyond the bearing point and it shall be supported laterally at or near its fulcrum point. Where the overhang exceeds 6 feet 6 inches, thrustouts shall be composed of stronger beams or multiple beams and be installed under the supervision of a person who is capable of securing a safe installation. Outriggers shall be securely fastened to the structure by the equivalent of "U" bolts and anchor plates, washers, and nuts. All beams shall be set with their webs vertical, and they shall rest on wood bearing blocks. A stop bolt shall be placed at the outer end of the outrigger to prevent suspension rope from slipping off.
(b) The platform shall be suspended by wire ropes capable of supporting at least 6 times the intended load, properly secured to the outriggers and to each end of the bolster (putlog), or to hoisting machines.
(c) Bolsters not more than 4 1/2 feet long between supports may be of wood, provided they are equal in strength to 4-inch by 6-inch "selected lumber" grade, free from damage that affects the strength.
(d) The bolsters and outriggers shall be spaced not more than 8 feet center to center.
(e) Platform Width. The platform shall be not less than 4 feet wide and made of 2-inch by 10-inch or larger "selected lumber" laid closely together and adequately secured to prevent them from slipping, tipping, or collapsing.
(f) The scaffold shall be as close to the wall as reasonably possible, but not more than 6 inches from the wall.
(g) When employees are at work on the scaffold and an overhead hazard exists, overhead protection shall be provided on the scaffold, not more than 9 feet above the platform, consisting of 2-inch planking, or material of equivalent strength, laid tight, and extending not less than the width of the scaffold.
(h) The scaffold shall be capable of sustaining a working load of 50 pounds per square foot and shall not be loaded in excess of that figure.
Exception: When the scaffold is designed for loads in excess of 50 pounds per square foot by a Civil Engineer currently registered in California.
(i) The use of fiber rope is prohibited.
(j) Toeboards and side screens shall be installed in accordance with the applicable Sections of Article 16.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1660. Suspended Scaffolds for Loads of 425 Pounds or Less.
(a) Only one employee for each fall or hanger shall be allowed on this type of suspended scaffold. (See Plates B-24, B-26, B-26-a and B-27-a, Appendix).
Exception: Single, power-driven units described in Section 1667.
(b) Stirrups or slings shall be made of wire rope of at least 9,000 pounds breaking strength, or of solid round or square mild steel (reinforcing steel shall not be used) not less than 3/4 inch dimension, forged or welded into one piece. Loops in wire rope slings for the use of bolsters shall be spliced. The top loop shall have a galvanized thimble fastened in place with a clip.
(c) Bolsters shall be 2-inch by 4-inch "selected lumber," or stronger material, placed so that the 4-inch sides are vertical. An iron or steel bolt 6 inches long and 3/4 inch in diameter shall be fastened through wooden bolsters at right angles to same not nearer than 3 inches to the end to prevent sling from accidentally slipping off the end of bolster.
(d) Scaffold platforms shall be at least 14 inches wide. Planks of dressed 2- inch lumber shall consist of "structural plank" free from damage affecting its strength. Where platforms are composed of two 2-inch by 10-inch or two 2-inch by 12-inch dressed planks, side by side, they shall be firmly cleated together so as to act as a unit. Maximum platform width shall be 36 inches.
(e) The span between hangers or falls shall not be more than 10 feet when the planks are composed of two 2-inch by 10-inch planks or more than 12 feet when composed of two 2-inch by 12-inch planks as permitted in Subsection 1660 (d). The span between hangers or falls when being used with patented-type planks shall not exceed the manufacturer's specifications. The platform shall not extend beyond the hangers more than 18 inches. A bar or other effective means shall be securely fastened at each end of the platform to prevent it from slipping off the hanger.
(f) Ladder-Type and Needle Beam-Type Platforms.
(1) Platforms placed in service after April 18, 1999 shall comply with the American National Standard (ANSI) Scaffolding-Safety Requirements, A10.8-1988, which is hereby incorporated by reference. Platforms placed in service on or before April 18, 1999 shall comply with ANSI A10.8-1977, Safety Requirements for Scaffolding, which is hereby incorporated by reference.
(2) Light metal-type platforms shall be approved.
(g) Each employee shall be provided with and use personal fall protection in accordance with the requirements of Article 24. Lanyards shall be securely attached to substantial members of the structure (not scaffold), or to securely rigged lines, which will safely suspend the employee in case of a fall. In order to keep the lanyard continuously attached, with a minimum of slack, to a fixed structure, the attachment point of the lanyard shall be appropriately changed as the work progresses.
(h) Hooks supporting scaffolds or stagings shall be made of mild steel (reinforcing steel shall not be used), free from flaws or other imperfections. Each hook shall, if loaded to point of failure, be capable of supporting a load 4 times that to which it will be subjected in service. The expected load per hook in service shall include its share (normally half) of the total scaffold and rigging weight plus the total weight of employees and movable tools or equipment, which shall never be considered as less than 500 pounds. All hooks shall be provided with rings for tie-back ser-vice. The ring should be fitted through a hole in the hook not more than 5 inches from the hook point. Hooks shall be kept clean at all times.Each hook shall be tied back to a substantial object on the roof with at least a 3/4-inch diameter Manila rope or equivalent. (i) Where the rope blocks supporting scaffolds or boatswains' chairs are not attached directly to hooks, the extension from the top block to the support shall be wire rope at least 1/2-inch in diameter, or equivalent, and sufficient protection shall be provided to prevent this wire rope from chafing.The sheaves of all blocks, consisting of at least one double and one single block, shall fit the size and type of rope used.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1661. Suspended Scaffolds for Loads Between 425 and 1000 Pounds.
(a) Suspended scaffolds providing all of the safety features required by Orders 1658 and 1660 may be used to support as much as 1,000 pounds if the platform and other components are designed and constructed to carry such a live load without exceeding allowable working stresses.
(b) Suspended scaffolds in this load range which are used by cement masons shall have platforms at least 24 inches wide.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1662. Boatswains' Chairs.
(a) Persons shall be trained and/or experienced in the use of boatswains' chairs before being permitted to use such equipment.
(b) When a boatswains' chair is suspended over an area traversed by employees, pedestrians or vehicular traffic, the ground area immediately below shall be effectively blocked by barricades, or an attendant shall be stationed to keep the area clear. Warnings signs shall also be posted below.
(c) An employee using a boatswains' chair shall wear a safety belt with attached lanyard secured to a separate drop line or other means affording equivalent safety.
(d) Rope attachment to a block shall be by a thimble and splice.
(e) Hooks shall be provided with a means to prevent accidental disengagement or a shackle shall be used in place of a hook.
(f) Each double block of luff (or watch) tackle shall be branded or otherwise clearly marked so as to indicate the fully extended length in feet from block to block. A knot or splice shall be made in the end of the line to prevent it from running through the block.
(g) Thimbles shall not be used where the chair connects to the hook.
(h) Tackle shall consist of rope equivalent in strength to at least 5/8 inch rope of first grade Manila as well as properly-sized blocks.
(i) The chair shall be suspended from its four corners by means of rope slings. It shall have a seat not less than 24 inches long by 10 inches wide and, if of soft wood, 2 inches thick (1 1/8 inches if of oak or ash). It shall be reinforced across the full width by cleats securely fastened to each end. The seat may be constructed of material other than wood, provided the material used is equivalent in strength to 2 inches of soft wood or 1 1/8 inches of oak or ash. If constructed of material of equivalent strength, cleats across the full width of the seat shall be provided unless structural analysis indicates that they are not necessary. Other design and construction of equivalent safety and strength may be substituted.
(j) Boatswains' chairs with fiber rope slings shall not be used to support an employee with welding, burning torch, sandblasting equipment, or chemicals harmful to fiber rope. In such cases, the slings shall be at least 3/8 inch wire rope, or equivalent. Further, the wire rope shall be protected against burning or welding arc by covering with a rubber hose or other equally effective means.
(k) Fiber rope seat slings shall be of 5/8 inch Manila rope, or equivalent, reeved through the four seat holes so as to cross each other on the underside of the seat.
(l ) Boatswains' chairs, their supports and all accessories shall be capable of supporting, without failure, at least 4 times the maximum load.
(m) Parapet or cornice hooks or clamps used to support chairs shall be provided with rings for tie-back use.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1663. Float Scaffolds.
(a) Scaffolds of this type are to support not more than three employees and light tools, such as those needed for riveting, bolting, and welding. They shall be constructed as follows, unless substitute designs and materials provide equivalent strength, stability, and safety (See B-38, Appendix).
(1) The platform shall be not less then 3 feet wide and 6 feet long, made of 3/4 inch plywood, equivalent to Douglas Fir Plywood Association Grade A-A Exterior.
(2) Under the platform, there shall be 2 supporting bearers made from 2-inch by 4-inch "selected lumber," or better. They shall be free of knots or other flaws and project 6 inches beyond the platform on both sides. The ends of the platform shall extend about 6 inches beyond the outer edges of the bearers. Each bearer shall be fastened to the platform by at least two 1/2 inch-diameter bolts.
(3) An edging of wood not less than 3/4 inch by 1 1/2 inches, or equivalent, shall be placed around all sides of the platform to prevent tools from rolling off.
(4) Supporting ropes shall be 1-inch-diameter Manila rope, or equivalent, free from deterioration, chemical damage, flaws, or other imperfections. Rope connections shall be such that the platform cannot shift or slip. If two ropes are used with each float, they shall be arranged so as to provide four ends which are to be securely fastened to an overhead support. Each of the two supporting ropes shall be hitched around one end of a bearer and pass under the platforms to the other end of the bearer where it is hitched again, leaving sufficient rope at each end for the supporting ties.
(5) Each employee working from a float scaffold shall be provided with and use fall protection in accordance with the requirements of Article 24.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1664. Needle-Beam Scaffold.
(a) Needle-beam scaffolds shall be designed with a factor of safety of at least 4, to support the loads to be imposed, but in no case shall the strength or quality be less than required by the following specifications. (See B-37, Appendix)
(1) Wood needle beams shall be not less than 4 inches by 6 inches in cross section, if the distance between supports does not exceed 10 feet. Larger beams are required for spans in excess of 10 feet, and in all cases they shall be placed with the greater dimension vertical. They shall be "selected lumber," or equivalent, straight-grained, and free of knots or other defects. Other materials or types may be used if of equivalent strength and rigidity.
(2) Wood needle beams shall be made from one piece of material without splices or laminated joints. Laminated wood beams, manufactured of good quality, glued members, subjected to proper bonding pressure, may along with other materials be used if of equivalent strength.
(3) Wood needle beams shall not be painted in such a manner as to hide the grain structure. They may be coated with linseed oil or other transparent coating.
(4) Ropes used for the support of needle beams shall be not less than 1 1/4- inch diameter Manila rope, or equivalent, free from flaws, deterioration, chemical damage, or other imperfections. C-clamps or open hooks shall not be used for support of needle beams or needle-beam ropes.
(5) The ropes shall be attached to the needle beams by a scaffold hitch, or some other equally effective method, at a point not less than 1 foot from the end of the beam. Ropes shall be so secured to the beams or girders as to prevent tipping or slipping of either the beam or the scaffold. When the rope attachment is within 2 feet of beam end, bolt or cleat shall be attached or other means taken to prevent rope from coming off beam.
(6) Planks making up platforms on needle beams shall not be less than 2 inches by 10 inches and not have more than a 10 foot span. All planks shall be secured by suitable cleats or drop bolts to prevent slipping, tipping, or collapsing, with special attention for those planks that are on the beam overhang outside the rope attachment. When planks are in an inclined position of 5 percent or more, they shall be provided with cleats on the working surface at least 1 3/4 inches by 2 inches in cross section, spaced not more than 16 inches apart.
(7) Platforms used for riveting or other work requiring similar tools shall be not less than 36 inches wide when used on exterior of structures, and not less than 30 inches wide for interior work.
(8) Needle-beam platforms that are used for rivet heaters shall be not less than 6 feet wide and 10 feet long, with planks laid close together, and some provision shall be made to prevent materials or tools from rolling off edges.
(9) Where the supports for needle beams are fixed members rather than suspension ropes, positive means shall be taken to prevent the beams from turning or rotating to a position where the strength is reduced.
(10) All unattached tools, bolts, and nuts used on needle beam scaffolds shall be kept in suitable containers, properly secured.
(11) If one end of a needle beam scaffold platform rests on a permanent structural section, all applicable sections of this Article and Article 23 shall be observed.
(12) Each employee working on a needle beam scaffold shall be provided with and use personal fall protection in accordance with the requirements of Article 24 or by a safety net rigged as provided in Section 1671.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1665. Interior Hung Scaffolds.
(a) An interior hung scaffold shall be hung or suspended from the roof structure or ceiling beams.
(b) The suspension rope shall be wrapped at least twice around the supporting members and twice around the ledgers of the scaffold, with each end of the wire rope secured by at least three standard wire-rope clips properly installed.
(c) For hanging wood scaffolds, the following minimum nominal size material shall be used:
(1) Supporting ledgers 2 x 10 inches on edge;
(2) Planking 2 x 10 inches, with maximum span 7 feet for heavy duty and 10 feet for light duty or medium duty.
(d) Steel tube and coupler members may be used for hanging scaffolds with both types of scaffold designed to sustain a uniform distributed working load up to heavy duty scaffold loads with a safety factor of four.
(e) When a hanging scaffold is supported by means of wire rope, it shall be attached with a thimble to a 1/2-inch shackle or bolt of not less than 1/2-inch diameter. The shackle shall be secured by means of a stop bolt 4 inches from the end of the beam or ledger. Wire rope shall not be wrapped around either member. See Plate C-2, Appendix.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1666. Staging Supported by Catenary or Horizontal Wire Ropes.
(a) Staging supported by wire rope shall have hook-shaped stops on each end of staging members so as to prevent them from slipping off the wire ropes. These hooks shall be so placed that they will also tend to prevent the staging members from falling if one wire rope breaks. Planks shall be at least 14 inches wide and consist of "structural plank" or the equivalent.
(b) Wire ropes shall not be tightened to the extent that the application of a scaffold load may overstress them.
Note: It is suggested that a hanger or set of falls be used every 50 feet to pick up the sag of the wire rope. Cables shall be continuous without splices between anchors.
(c) A safety factor of at least 6 shall be used in determining the size of wire rope to be used.
(d) The wire rope manufacturer's recommendations with respect to the number and spacing of clamps shall be followed. The clamps shall be placed with the "U" on the dead end. See Plate C-2, Appendix.
(e) Standard guardrail shall be installed to protect all open sides and ends of staging or safety nets shall be installed.
In lieu of guardrails or safety nets, safety belts and lanyards shall be used, provided the lanyard is tied off to the structure or to a separate cable for this purpose. (See Article 24 of the Construction Safety Orders.)
(f) A safe means of access and egress shall be provided to the stage at all times.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1667. Suspended, Power-Driven Scaffolds.
Note: For additional details relating to exterior building maintenance and window cleaning operations see Articles 5 and 6 of the General Industry Safety Orders.
(a) Powered scaffold platforms, not required to be completely railed, such as those supported by 2 or more hoisting units, shall at least have a protective railing, or equivalent, on all open sides and ends. The railing shall be not less than 36 inches nor more than 42 inches high, and it shall be capable of supporting a 200-pound concentrated load without permanent deflection.
(b) Loading. The total load on any 1 power unit shall not exceed the rated working capacity. If a unit is to support 500 pounds or more, special attention shall be given in advance to eliminate the possibility that the staging, hooks, shackles, parapet walls, and other load-carrying items will be overstressed. The total allowable load on stage ladders of the type described in Section 1660(f) shall not exceed 425 pounds.
(c) Wire Rope. Powered scaffolds shall be supported by wire rope providing a safety factor of 6 or more. It shall be 6 by 19 or 6 by 37 hemp center construction or better, not less than 5/16 inch in diameter, or with a breaking strength of not less than 6,000 pounds.
(d) Platforms shall not be less than 20 inches wide and shall be provided with a guardrail as specified in Section 1658(o). Platforms shall be designed to support the loads to be imposed without exceeding allowable working stresses established by recognized engineering practice.
(e) Safety Devices for Electric-Powered Unit.
(1) Wiring. All wiring including supply cords shall conform to the Electrical Safety Orders.
(2) Electrical Devices. All electrical devices, such as control switches, shall conform to the Electrical Safety Orders.
(3) Load Release. A hand-operated release mechanism to allow unit to descend faster than normal speed is prohibited.
(f) Safety Devices for Air-Powered Unit.
(1) Control Valve. Control valve shall be a nonlocking dead-man-control type. A shutoff valve shall be installed ahead of the control valve for the purpose of shutting off air when employees leave the stage.
(2) Load Release. A hand-operated release mechanism to allow unit to descend faster than normal speed is prohibited.
Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.
s 1669. General.
(a) When work is performed from thrustouts or similar locations, such as trusses, beams, purlins, or plates of 4-inch nominal width, or greater, at elevations exceeding 15 feet above ground, water surface, or floor level below and where temporary guardrail protection is impracticable, employees shall be required to use approved personal fall protection system in accordance with Section 1670.
(b) When requirements in subsection (a) are impractical, approved safety nets shall be used in accordance with Section 1671.
(c) When the work is of short duration (i.e., non-repetitive) and limited exposure and the hazards involved in rigging and installing the safety devices required by this Article equals or exceeds the hazards involved in the actual construction, these provisions may be temporarily suspended, provided adequate risk control is recognized and maintained under immediate, competent supervision. (continued)