1Purpose: To establish the minimum safetyrelated technical requirements for temporary elevated work areas, ladders, and scaffolds. 2 I. SCAFFOLD TERMINOLOGY TOP RAIL MID RAIL DROP BAR 0.95m – 1.15 m FALSE UPRIGHT (38”-45”) 36” min. SCAFFOLD PLANKS BEARER (TRANSOM) LONGITUDINAL BRACING LADDER CLAMP TOEBOARD STANDARD SWIVEL COUPLER FIXED COUPLER (90º) RUNNER (LEDGER) TRANSVERSE BRACING BASE LIFT (KICKER LIFT) BASE PLATE SILL (SOLE BOARD) 3 I. SCAFFOLD TERMINOLOGY BIOARD BEARER (INTERMEDIATE TRANSOM) BAY LENGTH RUNNERS (LEDGERS) BEARERS (TRANSOMS) RUNNERS & BEARERS INSTALLED INSIDE POSTS TYP. POST (STANDARD) BASE PLATES SILLS (SOLE BOARDS) BASE LIFT (KICKER LIFT) 4 I. SCAFFOLD TERMINOLOGY BEARERS (TRANSOMS) RUNNERS (LEDGERS) BAY LENGTH BAY SCAFFOLD WIDTH LIFT HEIGHT 6” POST (STANDARD) BASE LIFT (Foot Tie or Kicker Lift) 5 . II.) apart. (38 “) and not more than 1. 3.top edge height of toprails shall not be less than 0. (200 lbs.) It consists: 1. 4. 2. GUARDRAIL SYSTEMS Guardrail system shall be able to withstand a force of at least 90kg.8 m. (1/4”) gap above the working surface and should withstand a force of at least 23 kg (50 lbs). ELEVATED WORK AREAS . Toprails .95 m.15 m.7 m.) shall be protected from falling by means of guardrail systems or personal fall arrest systems. Uprights – shall not be spaced more than 2.GENERAL REQUIREMENTS FALL PROTECTION Each person who could fall more than 1. (45”) above the walking/working surface of a platform. (9 ft. Toeboards – shall have no more than 6 mm. self closing drop bar false upright (puncheon) toprails midrails toeboards 6 . Midrails – installed approximately halfway between the walking/working surface and toprail. (6 ft. It shall conform the ffg. requirements: 1.) or striking any lower level should a fall occur.). (1”) thick. (33 ft. Horizontal and vertical lifelines shall be made from 10 mm.000 lbs.300 kgs. (6 ft.8 m. 2.) above lower levels. No more than 6 mm. diameter wire rope. 7 . 3.) thus it shall be anchored high enough to prevent the worker from free falling more than 6 feet (1. (6 ft. (4”) in height and 25 mm.8 m. (1/4”) above the working surface. and other components of personal fall arrest system shall have a capacity of at least 2. (3/8”) min.) When there is a danger for objects falling through guardrails a protective screen (minimum No.8m. (12”) for every 10 m.II. Should withstand a force of at least 23 kg. (5.) of lifeline length between attachments. mesh) shall be securely fixed to the toeboard. 18 gauge wire with a maximum 13 mm. lanyards. midrail and guardrail. Minimum dimension of 100 mm.. FALLING OBJECT PROTECTION Toeboards shall be installed on all edges of elevated work areas more than 1. (50 lbs. Lanyards shall have a maximum length of 1. Horizontal lifelines shall be maintained with a sag at the center of no greater than 300mm. lifelines or overhead structural anchorage. ELEVATED WORK AREAS .GENERAL REQUIREMENTS PERSONAL FALL ARREST SYSTEMS Full body harnesses. ) • • • 8 . Minimum clear headroom above scaffold platforms shall be 1.6 m (2 feet) above or below a point of access.GENERAL REQUIREMENTS ENTRY AND EXIT A safe means of access shall be provided whenever the scaffold platform is 0. TEMPORARY STAIRWAYS PARTS OF STAIRWAY LANDING REQUIREMENTS • • RISER At least 560 mm. Can withstand a force of at least 90 kg. (200 lbs. Shall be uniform with each flight of stairs.8 meters (6 feet). 80 mm. (9”) to 280 mm.7 m. (30”) long. (11”) wide. TREAD • 220 mm. A means of exit shall be provided at least every 30 m (100 feet). (12’) of vertical distance. ELEVATED WORK AREAS . Shall have landing not more than every 3. STAIR SLOPE • Between 30 to 35 degrees HANDRAIL • 860 mm.II. (34”) to 940 mm. (8”) depth. • 150 mm. (3”) clearance between wall or other object. (22”) wide & 760 mm. (37”) in height. If horizontal travel distance exceeds 15 m (50 feet) each elevated work area shall have at least 2 means of exit. (6”) to 215 mm. Distance on the climbing side to the nearest object on the back side of the ladder shall be no less than 250 mm (10 inches). Shall have a minimum clear distance of 760 mm (30”) to the nearest protruding object on the climbing side. bottom). 9 . If steeper than ratio 1 : 4 the ramp shall have cleats no more than 350 mm (14”) apart.II. HIGH WINDS Personnel shall not be on any scaffold or other temporary elevated work area during storms or high winds – sustained winds more than 65 kph (40 mph). ELEVATED WORK AREAS . LADDERS A slope of 4:1. Rungs uniformly spaced between 250 mm (10”) and 360 mm (14”) although 300 mm (12 inches) is preferred.GENERAL REQUIREMENTS TEMPORARY RAMPS Shall not be inclined more than a ratio of 1 : 3 or 20º above the horizontal although a slope not over 15º is preferred. WORK OVER WATER Personnel working over water shall have floatation ring provided at intervals not greater than 15 meters (50 feet) and a man watch shall also be provided. middle. (4”) shall apply. When unavoidable a minimum vertical toe clearance of 100 mm. side rails rigidly attached to supporting structure (top. This distance maybe reduced to 610 mm (24 inches) if deflector plates are provided. Yield Stress (Sy) Nominal Wall Thickness B 290 N/mm² 42 ksi 30 Kg/mm² 3. 48. SCAFFOLDING COMPONENTS GENERAL Scaffold components manufactured by different manufacturers should not be intermixed unless the components are compatible and the scaffold’s structural integrity is maintained. Sec.1 235 N/mm² 34 ksi 24 Kg/mm² 4.30 mm [1. All defective scaffold component s shall be marked with bright fluorescent orange paint and immediately removed from Saudi Aramco property or project site.III.40 mm 3.90 inch] nominal outside diameter ) Grade Min.00 mm - 320 N/mm² 46 ksi 32 Kg/mm² 3. SCAFFOLD TUBING AND FITTINGS SPECIFICATIONS ( Scaffold tubing. 1.20 mm Type ASTM A500 EN 10129 10 .76 mm ASTM A53 B 240 N/mm² 35 ksi 24 Kg/mm² 3.68 mm BS 1139 Part 1. 740 lbs.75 lbs.190 lbs. (Swivel) Slip along tube A 5. EN 74 class SWL (Min. - 30 KN 6. (Double or load bearing) Slip along tube A 6. SCAFFOLDING COMPONENTS SCAFFOLD TUBING AND FITTINGS SPECIFICATIONS Safe Working Load of Individual Coupler Type of coupler Type of load Min. (per pair) End-end coupler (Sleeve) Bearer coupler (Putlog / Single) Girder coupler (Drop forged) Shear 11 .400 lbs.59 KN-m 435 lbs-ft. Bending B 0.25 KN 1. Tension B 3.53 KN 120 lbs.0 KN 6.3 KN 1. Adjustable coupler.III.) Right angle coupler. Force to pull the tube axially out of the coupler - 0. If height stack exceeds 20 Shall have the word planks. 12 . succeeding layers “PROOF TESTED should be tied or bond. w/ banding •Twist 13mm (1/2”) max. SCAFFOLD PLANK” and “OSHA” or • Shall not stood on end Saudi Aramco unattended accepted equivalent. continuously embossed on both edges. trench shoring.III. Scaffold planks shall not be used as concrete forms. end to end • Shall not be painted treated or coated (except at the ends) • Shall be properly stacked. SCAFFOLDING COMPONENTS PLATFORM UNITS Wood Plank Dimensions Solid Sawn Wood 2x10 inch (nom) Certified / Approved by • 2x9 inch (rough) • 38x25mm or 50x225 mm (basic) Laminated Veneer Lumber 38mm (1-1/2”) by 225mm (9”) wide or larger • • West Coast Lumber Inspection Bureau (WCLB) Southern Pine Inspection Bureau (SPIB) American Lumber Standards Committee Requirements • Shall be certified and bear a grade stamp • Free from defects •Splits 25mm (1”) max. or as sills for scaffolds. w/o banding 300mm (1’)max. IV. The maximum deflection for platform units shall not exceed 1/60th of the span length when supporting any of the unfactored concentrated or uniformly distributed concentrated loads. the platform units own weight and at least four times the most critical maximum intended load as shown. its own weight (dead load) and at least four (4) times the maximum intended load applied or transmitted to it (D + 4*L). without failure. without failure. Scaffolds and scaffold components shall not be loaded in excess of their load rating. The maximum allowable span for planks/platforms shall be the shortest span required to support. 13 . REQUIREMENTS COMMON TO ALL SCAFFOLDS CAPACITY Every scaffold and scaffold component shall be capable of supporting. (1-1/2”) thick • Shall extend under at least two posts (standard). REQUIREMENTS COMMON TO ALL SCAFFOLDS FOUNDATIONS Foundations shall be sound. (9”) wide by 38 mm. rigid. Components Timber Sills (sole boards) Steel Base Plates Screw Jacks Requirements • At least 225 mm. and capable of carrying the scaffold self-weight plus the maximum intended load without settling or displacement. thick (6 x 6 inches & 1/4 inch thick) • For special scaffolds base shall be designed • Shall not be adjusted to more than twothirds (2/3) of the total length of the threaded section 14 . (30”) long • At least 150 x 150mm. & 6mm. if not applicable sills under individual posts shall be at least 765 mm. Scaffolds shall not be hung from or supported by guardrails or handrails.IV. Supported scaffolds with a height to the uppermost planked level that is over four times the minimum base dimension (over a 4:1height-towidth ratio) shall be restrained from tipping by ties. outrigger frames.IV. or equivalent means. Ties and guys shall be installed as follows: 15 . REQUIREMENTS COMMON TO ALL SCAFFOLDS STABILITY Scaffold posts and frames shall be vertically plumb and vertically braced in both directions. guys. (30’) measured from one end toward the other. (26’)(4 lifts) or less.IV. 16 . REQUIREMENTS COMMON TO ALL SCAFFOLDS STABILITY Ties and guys shall be installed as follows: Ties or guys shall be spaced vertically every 8 m. Ties or guys shall be installed on both ends of the scaffold and at horizontal intervals not to exceed 9 m. REQUIREMENTS COMMON TO ALL SCAFFOLDS STABILITY CROSS TUBE 17 .IV. Scaffold materials shall not be thrown or dropped from heights. guardrails do not need to be erected from that edge. Planks & toeboards should not be nailed. (27”) (3planks) wide. The slope of platform units shall not exceed 1 vertical to 4 horizontal. For medium-duty and more heavily loaded scaffolds. dismantling and alteration. and walkways should be at least 675 mm.IV. including during erection. landings. (14”) from the face of the wall or structure. at least one board bearer (intermediate transom) shall be used in every bay at each platform level. clamped toe boards or other equivalent means. 18 . Planks should be secured on both ends by using fiber rope/wire lashing. Scaffold platforms. REQUIREMENTS COMMON TO ALL SCAFFOLDS SCAFFOLD PLATFORM CONSTRUCTION AND USE If the front edge of a working platform is less than 360 mm. If an internal ladder is used. When larger gaps are unavoidable. If an external ladder is used.IV. exterior grade plywood. (2’) in width shall be covered at least 20 mm. o Gaps larger than 600 mm. The slope of scaffold platform units shall not exceed 1 vertical to 4 horizontal. (30”). REQUIREMENTS COMMON TO ALL SCAFFOLDS SCAFFOLD PLATFORM CONSTRUCTION AND USE Gaps between platform units shall be less than 25 mm. (27”) (3 planks) wide & not less than 900mm (36”) deep. on both sides of the opening and held with cleats. (30’) of ladder height. step-through opening width on guardrails shall not be less than 675 mm. (2’) in width shall be covered with properly secured cross planks.. (1”) wide. Plywood covering shall be overlapped with at least the width of the gap. (1”) thick. Safe landings shall be provided at the top of all ladders and at least every 9m. 19 . (27”) or more than 760 mm. 12” min. opening shall be at least 675mm. they shall be covered as follows: o Gaps less than 600 mm. IV. REQUIREMENTS COMMON TO ALL SCAFFOLDS SCAFFOLD PLATFORM CONSTRUCTION AND USE 20 . More than 50 Kv.- 300 Volts to 50 Kv.IV. o Satisfies clearance between scaffold and power lines. CLEARANCES BETWEEN SCAFFOLDS AND POWER LINES: Insulated Minimum Distance Uninsulated Less than 300 Volts. 1 meter (3 feet) . 21 . More than 50 Kv. It should be lockout/tagut. Alternative: 2x the length of the line insulator but never less than 3 meter (10 feet).. or protective coverings installed to prevent accidental contact with the lines. REQUIREMENTS COMMON TO ALL SCAFFOLDS CLEARANCES Scaffold operations adjacent to overhead power lines are prohibited unless one of the following conditions are satisfied: o The power line has been de-energized. 3 meters (10 feet) Less than 50 Kv.. 3 meters (10 feet) + 4 inches per Kv over 50 Kv..5 times the depth of excavation away from the edges of the excavations (including trenches). Bases of scaffold shall be at least 1. relocated. usually 18-mm. the rope shall be of the correct size to suit the gin wheel. REQUIREMENTS COMMON TO ALL SCAFFOLDS RAISING AND LOWERING MATERIALS USING GIN WHEELS The gin wheel shall be mounted on a cantilevered horizontal tube projecting outward from the scaffold and shall be kept to a minimum distance.). Tube shall be fixed with right-angle couplers to two scaffold post (standard). not greater than 750 mm. (30”).IV. (3/4”). Materials to be raised shall not exceed 50 kg. (110 lbs. 22 . (Min. 150 mm. 23 . (6”) Min. (6”) Min.V. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS TYPICAL TUBE & COUPLER SCAFFOLD GUARDRAIL SYSTEM INCLUDING TOEBOARDS PLANKING (BOARDS) TOEBOARD CLIPS RUNNER (LEDGER) BEARER (TRANSOM) RIGHT-ANGLE (DOUBLE) COUPLER POST (STANDARD) 1/4” THK.) BASE PLATE ADJUSTABLE (SWIVEL) COUPLER TRANSVERSE CROSS (“X”) BRACING SILL LONGITUDINAL (FAÇADE) BRACING 150 mm. 24 .V. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS HORIZONTAL MEMBERS No lift height shall exceed 2m. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS HORIZONTAL MEMBERS Bearers (transoms) and board bearers (intermediate transom) shall be installed on top of and not underneath supporting runners. at each lift. Every line of posts (standards) shall have runners (ledgers) installed horizontally in continuous lengths along the entire scaffold length (longitudinally) and bearers (transoms) installed in continuous lengths across the entire scaffold width (transversely).V. 25 . V. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS HORIZONTAL MEMBERS Bridging of scaffolds shall be as conceptually as follows: 26 . REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS HORIZONTAL MEMBERS Bridging of scaffolds 27 .V. V. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS HORIZONTAL MEMBERS Bridging of scaffolds 28 . V. Transverse (sectional) braces shall be connected to either posts (standards) or runners (ledgers) as close as possible to the intersection (node point) of the bearer (transom) and post (standard). Longitudinal (façade) braces shall be connected to posts (standards) as close as possible to the intersection (node point) of the runner (ledger) and post (standard). 29 . REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS Bracing Vertical bracing to prevent excessive sway is necessary in both the transverse and longitudinal direction of all system and tube & coupler scaffolds for the full height of the scaffold. Alternatively. 30 .V. REQUIREMENTS COMMON TO SYSTEM AND TUBE & COUPLER SCAFFOLDS Bracing Brace ends may be joined together with end-to-end (sleeve) couplers. for braces subject to large tension loads. shall be overlapped & joined with at least two adjustable (swivel) couplers. SYSTEM SCAFFOLDS System Scaffolds All system scaffolds shall be erected per manufacturer’s published instructions 31 .VI. Shall be connected by means of one of the following fastening methods: o o o Captive wedge system (such as Saudi (“Kwikstage”) Quick-fix system (such as Layher “All-around”) Cup locking system (such as SGB “Cuplock”) Scaffolding Factory System scaffold components shall not be used to construct underhung scaffolds. all system scaffold shall be vertically braced in both directions with diagonal braces (as close to 45º as possible) to its full height for each 10 m. SYSTEM SCAFFOLDS System Scaffolds Unless otherwise specified in manufacture’s instruction. (33’) of run.VI. tube & coupler scaffold components may be used for bracing of system scaffolds. Where specially designed system bracing cannot be used. Components from different scaffold manufacturers shall not be intermixed (except when needed in bracing). Connections shall be tightened with a single hammer blow to the wedge or cup to provide high degree of rigidity. 32 . Posts (standards) shall be connected by bolted spigots and shall be secured into place using two spigot pins for situations where uplift may occur. The upper post (standard) shall slide over the spigot. 33 .VI. SYSTEM SCAFFOLDS System Scaffolds The locking-pin type of system scaffold shall not be used. ) 2 2 24 m.) 3 3 28 m. Total Number Planked/Platformed Levels Maximum Scaffold Height 1 9 38 m.) 34 .VI. (125 ft. Total Number Planked/Platformed Levels Maximum Scaffold Height 1 7 38 m.) MEDIUM DUTY Maximum Number of Working Levels Max. the maximum number of working levels and total planked levels shall be as follows: LIGHT DUTY Maximum Number of Working Levels Max. (78 ft. (125 ft.) 2 6 38 m. (91 ft. (125 ft. SYSTEM SCAFFOLDS System Scaffolds Unless otherwise justified and stated in writing by the system scaffold manufacturer. TUBE AND COUPLER SCAFFOLDS TYPICAL TUBE & COUPLER SCAFFOLD GUARDRAIL SYSTEM INCLUDING TOEBOARDS PLANKING (BOARDS) TOEBOARD CLIPS RUNNER (LEDGER) BEARER (TRANSOM) RIGHT-ANGLE (DOUBLE) COUPLER POST (STANDARD) 1/4” THK. (6”) Min. 35 . 150 mm. (Min.) BASE PLATE ADJUSTABLE (SWIVEL) COUPLER TRANSVERSE CROSS (“X”) BRACING SILL LONGITUDINAL (FAÇADE) BRACING 150 mm. (6”) Min.VII. joint pins are only designed for compression load. Joints in posts (standards) shall be staggered. end-to-end (sleeve) couplers shall be used for joints in post (standards). End-to-end couplers shall be used where tension (uplift) can be present in a posts (standard) or other scaffold tube. TUBE AND COUPLER SCAFFOLDS POSTS Joint pins or. Joints in adjacent posts shall not occur in the same lift height.VII. preferably. However. 36 . 37 .VII. including board bearers. (4”) beyond the runner centerline. TUBE AND COUPLER SCAFFOLDS RUNNERS (LEDGERS) AND BEARERS (TRANSOMS) Runners (ledgers) and bearers (transoms) shall be securely fixed to the inside of each posts. When bearers (transoms) and board bearers (intermediate transoms) are coupled to runners (ledgers) they shall always be installed on top of the supporting runners Bearers (transoms). (standard). shall extend at least 100 mm. (12”) apart from the post. 38 . When bearers (transoms) are coupled to posts (standards). right-angle couplers should not be used to attach bearers or board bearers to runners. the bearer shall be connected to the posts only with right-angle (load bearing) couplers and the coupler shall rest directly on the runners (ledgers) right-angle couplers. At lifts to be planked. because the coupler bolts may interfere with proper placement of planks.VII. Instead bearer (putlog) couplers shall be used. the coupler shall never be more than 300 mm. When a bearer (transom) is coupled to a supporting runner (ledger). TUBE AND COUPLER SCAFFOLDS RUNNERS (LEDGERS) AND BEARERS (TRANSOMS) Runners (ledgers) shall be connected to posts (standards) only with right-angle (load bearing) couplers. TUBE AND COUPLER SCAFFOLDS RUNNERS (LEDGERS) AND BEARERS (TRANSOMS) Runners (ledger) or bearers (transoms) shall not have more than one joint between adjacent posts. In this case. joints shall be staggered (adjacent joints shall not occur on the same bay). Alternatively. the joint shall not be located in the middle third of the runner or bearer span. 39 . the joint shall not be located more than 300mm. (12”) from a post (standard). End-to-end couplers may be used may be used for joints in runners (ledgers) or bearers (transoms). joints in runners or bearers may be made by abutting the runner or bearer ends together and overlapping this ends with a separate parallel tube.VII. This parallel tube shall be coupled to each abutted runner or bearer end with at least two equally spaced adjustable swivel couplers. TUBE AND COUPLER SCAFFOLDS RUNNERS (LEDGERS) AND BEARERS (TRANSOMS) Right-angle (double) couplers shall be installed such that the load is against the hinge and not against the bolt. as they give greater leverage than proper scaffold spanner wrenches and could damage the coupler. “Cheater bars” or longer handled wrenches shall not be used.-lbs. (30 ft. Scaffold couplers shall be tightened to the torque as indicated by the manufacturer preferably between 40 kg-m.) and 80 kg-m. 40 .VII. (60 ft-lbs.) Only proper scaffold spanner wrenches shall be used. VII. 41 . TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING ( Transverse “Zigzag” Bracing) Transverse (sectional) “zigzag” bracing: The first diagonal brace shall be installed from the base of the first post (standard) diagonally upward to the first lift at whichever post (standard) is required to make the angle of the diagonal brace be between 35 and 55 degrees (may be across two bays in one lift height). Additional diagonal braces shall be installed in alternating directions (“zigzag”) until reaching the top of the scaffold. VII. this transverse “zigzag” bracing shall be shall be repeated across the width of the scaffold such that no more than 3 adjacent bays are open without transverse bracing. This set of transverse “zig-zag” braces shall be installed at both scaffold ends and repeated along the length of the scaffold at least every third line of posts (standards). 42 . TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING ( Transverse “Zigzag” Bracing) For wide scaffolds. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING ( Transverse “Zigzag” Bracing) For wide scaffolds 43 .VII. This “X” bracing should be repeated up to the height of the scaffold at least every third lift (two adjacent open lift heights permitted. the first brace is installed from the base of the first post (standard) diagonally upward to the first lift at the post (standard) required for the base to be between 35 and 55 degrees (may be across two bays in one lift height). Thus.VII. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING (Transverse “X” Bracing) Transverse (sectional) “X” bracing: the first two diagonal braces are installed forming an “X” shape. The second brace is installed from the base of the same post (standard) diagonally upward to the first post (standard). 44 . 45 . This set of transverse “X” braces shall be installed at both scaffold ends and repeated along the length of the scaffold at least every third line of posts (standards). such transverse “X” bracing shall be repeated across the width of the scaffold such that no more than 3 adjacent bays are open without transverse bracing. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING (Transverse “X” Bracing) For wide scaffolds.VII. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING (Longitudinal “Facade” Bracing) Longitudinal (façade) bracing for a scaffold whose length is greater than its height: A diagonal brace shall be installed from the base of the first post (standard) upward. at between 35 and 55 degrees. 46 . This longitudinal (façade) bracing shall be installed in opposite directions.VII. This longitudinal bracing shall be repeated along the length of the scaffold at least every 5th posts (standard). to the extreme top of the scaffold. along the front (inner) and rear (outer) lines of posts (standards). at between 35 and 55 degrees. along the entire length of the scaffold to the last end post. 47 . This longitudinal (façade) bracing shall be installed in opposite directions.VII. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING (Longitudinal “Facade” Bracing) Longitudinal (façade) bracing for a scaffold whose length is less than its height: The first diagonal brace shall be installed from the base of the first end post (standard) upward. along the front (inner) and rear (outer) lines of posts (standards). at between 35 and 55 degrees. in alternating directions (“zigzag”) across the entire scaffold length until reaching the top of the scaffold. Additional diagonal braces shall then be installed. Additional diagonal braces shall then be installed in alternating directions (“zigzag”) until reaching the top of the scaffold. 48 . at between 35 and 55 degrees.VII. Such longitudinal “zig-zag” bracing shall be repeated along the length of the scaffold such that no more than 4 adjacent bays are open without longitudinal braces. This set of longitudinal “zig-zag” braces shall be repeated across the width of the scaffold at least every third line of post. TUBE AND COUPLER SCAFFOLDS VERTICAL BRACING (Interior Longitudinal “Zig-zag” Bracing) Interior longitudinal “zig-zag” bracing for a scaffold with multiple bays across its with (“birdcage” scaffold): The first diagonal brace shall be installed from the base of the first post (standard) diagonally upward. to the second post at the first lift (across one bay in one lift height). VII. TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY SCAFFOLD LOADING 49 . VII. TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS Embossed Light-duty Tube & Coupler Scaffold Post Spacing Emboss ed Tubing Number of 225mm (9”) wide planks per bay width Transverse post Spacing (Bearer/Transom Span) Longitudinal Post Spacing (Runner/Ledger Span) Option 1 OPTION 1 4 1.7 m (9.25 ft.0 ft.) max.0 ft. 50 . Option 2 5 1.) 2.) 2.0 m (3.2 m (4.4 m (8.0 ft.) max. VII. TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS Embossed Light-duty Tube & Coupler Scaffold Post Spacing OPTION 2 51 . ) 1.2 m (4.D. 3.5 ft. TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS Non-Embossed Light-duty Tube & Coupler Scaffold Post Spacing (Based on 48.0 m (3.25 ft.2 mm wall thickness. steel tubing) Emboss ed Tubing Number of 225mm (9”) wide planks per bay width Transverse post Spacing (Bearer/Transom Span) Longitudinal Post Spacing (Runner/Ledger Span) Option 1 OPTION 1 4 1.3 mm O. 52 .) max.0 ft.) 2.) max.VII. Fy = 235 N/mm 2 (34 ksi).8 m (6..0 ft. Option 2 5 1.3 m (7. Fy = 235 N/mm 2 (34 ksi). TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS Non-Embossed Light-duty Tube & Coupler Scaffold Post Spacing (Based on 48.3 mm O.VII.2 mm wall thickness. 3..D. steel tubing) OPTION 2 53 . along with material tensile/yield stress test reports for the specific scaffold tubing to be used.I. shall be classified as a Special Scaffold and shall be properly designed and reviewed per G. (125 ft.2 kN/m2) (25 lb. Maximum Max. All light-duty tube & coupler scaffolds may have a maximum of three working levels in use at any one time only when there are no additional levels where platform units are installed.) Light-duty3tube & coupler scaffolds requiring 3 28 m. (91 ft. Preferably. (125 ft. a properly designed system scaffold should be used instead of tube & coupler construction for scaffolds over 38 m. TUBE AND COUPLER SCAFFOLDS LIGHT-DUTY TUBE AND COUPLER SCAFFOLDS Larger post spacing may be used if justified by structural calculations or load test submitted for review per G.001.) tall 54 . (125 ft.) more than the above working or planked levels. The maximum total number of levels that can be planked at one time depends on the number of working levels simultaneously used by workers. Total Number Number of Maximum Scaffold Planked/Platformed Working Height Levels Levels 1 9 38 m.) 2 6 38 m. 8.I.VII. The maximum uniformly distributed load on each working level shall be 120 kg/m2 (1.001. 8. or over the maximum heights shown in the table./ft2). VII. TUBE AND COUPLER SCAFFOLDS MEDIUM-DUTY TUBE AND COUPLER SCAFFOLDS MEDIUM-DUTY LOADING 55 . Maximum post spacing for medium-duty scaffolds: OPTION 1 56 . TUBE AND COUPLER SCAFFOLDS MEDIUM-DUTY TUBE AND COUPLER SCAFFOLDS All tubing used to construct Medium-duty and more heavily loaded tube & coupler scaffolds shall be embossed.VII. TUBE AND COUPLER SCAFFOLDS MEDIUM-DUTY TUBE AND COUPLER SCAFFOLDS Maximum post spacing for medium-duty scaffolds: OPTION 2 57 .VII. Total Number Planked/Platformed Levels Maximum Scaffold Height 1 7 38 m. Medium-duty tube & coupler scaffolds may have a maximum of two working levels in use at any one time only when there are no additional levels where platform units are installed. Maximum Number of Working Levels Max. (125 ft. 8.I.4 kN/m2) (50 lb.VII. 8. (78 ft./ft2). or over the maximum heights shown in the table. The maximum distributed load on each working level shall not exceed 240 kg/m2 (2. when only one working level is being used.I. a maximum of additional 6 levels may be planked if they are not being used at the same time. (125 ft. along with material tensile/yield stress test reports for the specific scaffold tubing to be used.) tall 58 . Preferably. a properly designed system scaffold should be used instead of tube & coupler construction for scaffolds over 38 m.) or planked levels. TUBE AND COUPLER SCAFFOLDS MEDIUM-DUTY TUBE AND COUPLER SCAFFOLDS Larger post spacing may be used if justified by structural calculations or load test submitted for review per G.001.001.) Light-duty tube & coupler scaffolds requiring more than the above working 2 2 24 m. shall be classified as a Special Scaffold and shall be properly designed and reviewed per G. However. and at least every third lift of all mobile and tower scaffolds to prevent racking (twisting). Plan (horizontal) bracing shall be installed at the base. and square and be horizontally and vertically braced (in both directions) by diagonal braces. level. 59 .VIII. at the top. MOBILE AND TOWER SCAFFOLDS MOBILE AND TOWER SCAFFOLD CONSTRUCTION Mobile and tower scaffolds shall be plumb. MOBILE AND TOWER SCAFFOLDS MOBILE AND TOWER SCAFFOLD CONSTRUCTION Tube & coupler mobile and tower scaffolds that are one bay long and one bay wide (only 4 posts): LOADING Light-duty Light-duty MAX. POST SPACING IN BOTH DIRECTION (only 4 post) 2 m.5ft) STEEL TUBING MANUFACTURE D & EMBOSED AS PER SPECIFICATION S ADD’L REQUIREMENT / CONDITION Yes • Used only for personnel access and inspection • At least two equally spaced board bearers shall be used • Uppermost work platform height shall not exceed 4 times the minimum base dimension No •Uppermost work platform height shall not exceed 4 times the 60 .5ft) 1. (5.VIII. (6.7 m. MOBILE AND TOWER SCAFFOLDS MOBILE AND TOWER SCAFFOLD CONSTRUCTION MOBILE SCAFFOLD 61 .VIII. VIII. (5”) in diameter. Mobile scaffolds rated for Medium-duty shall have heavyduty steel casters not less than 170 mm. 62 . Casters shall be securely fixed to the base of scaffold posts or screwjacks by locking pins. MOBILE AND TOWER SCAFFOLDS MOBILE AND TOWER SCAFFOLD CONSTRUCTION Mobile scaffolds rated for Light-duty shall have steel casters not less than 120 mm. (7”) in diameter. All casters shall be fitted with a positive wheel lock (which cannot be accidentally released) to prevent movement while the mobile scaffold is being used. No men. or materials shall be on the working platform or elsewhere on the scaffold while it is in motion.5 m. equipment. (5’) above the supporting surface. Force shall not be applied at a height greater than 1. The temporary foundation or track shall be level and properly secured.VIII. Where the scaffold is to be used on an elevated floor or roof. A mobile scaffold shall be moved only by manually pushing or pulling at the base. Casters shall be lock at all times except during scaffold movement. Temporary foundations or tracks shall be properly set in place on soft or uneven ground to facilitate movement of the mobile scaffold. it shall be designed to apply loads no greater than the capacity of the floor or roof. MOBILE AND TOWER SCAFFOLDS MOBILE SCAFFOLD OPERATION Mobile scaffold shall only be used and moved on surfaces sufficiently firm level to ensure stability. 63 . shall be erected per It shall not be used for a loading greater than a Light-duty loading of 120 kg/m2 (1. Each frame must have flip-lock fittings. 64 . Scissor (cross) bracing shall be installed on both sides in every bay between each lift. in good condition.IX. FABRICATED TUBULAR FRAME SCAFFOLDS Fabricated Tubular Frame Scaffolds All fabricated tubular frame scaffold manufacturer’s published instructions. The maximum height shall be 6 meters. Components from different scaffold manufacturers shall not be intermixed.2 kN/m2) (25 lb. A complete guardrail system shall be provided at every platform. for the attachment of horizontal members and diagonal members./ft2). 65 .X./ft2). BRACKET SCAFFOLDS Brackets and Straps Bracket scaffolds shall only be used to support a Light-duty loading of 120 kg/m2 (1.2 kN/m2) (25 lb. approval of welding procedures and verification of tank integrity is required from the Proponent’s Engineering Unit. Brackets scaffold shall be inspected prior to installation by scaffold craftsmen and prior to each used by scaffold users. 66 . completed bracket straps shall be inspected and approved by a welding inspector. BRACKET SCAFFOLDS Brackets shall be installed vertically. Only welders certified shall weld bracket straps. Prior to attaching the bracket. Brackets and Straps X. Prior to welding on any tank. Planks shall be overlap in 1 direction only. 230 mm (9”) min. (200 lbs. If the gap on the inside platform edge to the platform exceeds 360 mm (14”) a guardrail system shall be provide. The area below the bracket scaffolds shall be barricaded and warning signs posted. Guardrails shall be constructed using either wire rope [10mm (3/8”) diameter min.] or steel tubing [can withstand a force of at least 90 kg.)]. BRACKET SCAFFOLDS GUARDRAILS AND PLATFORMS FOR BRACKET SCAFFOLDS A continuous guardrail system shall be provided along the outside platform edge. 67 . All working levels shall be fully planked (at least 2 but not more than 3 planks wide).X. Both horizontal tubes shall be attached to the hanger with a right-angle couplers. A guardrail system shall be provided. When a hanger tube is coupled to a horizontal tube that is placed across the top of a supporting beam a second horizontal tube shall be attached underneath the supporting beam with a pair of girder couplers. UNDERHUNG SCAFFOLDS CRITERIA FOR UNDERHUNG SCAFFOLDS All underhung scaffolds shall be hung from structures capable of supporting at least 4 times the load imposed on them by the scaffold. Check coupler shall be installed at top & bottoms of all hanger tubes and beneath trapeze tubes. 68 . Whenever possible vertical hanger tubes should be in one length where joints are necessary. the tubes should be single lapped using at least four couplers. UNDERHUNG SCAFFOLDS SUSPENDED BY TUBES & COUPLRES Suspension points of hanger tubes shall be securely fixed to prevent their being dislodged by all potential forces acting upon them.XI. Runners and bearers shall be coupled to hanger tubes using rightangle couplers.5 m (5”) apart in the longitudinal direction. and also to serve as a secondary support should the runner slip. At least one board bearer shall be installed when the hanger spacing is more than 1.XI. Only drop-forged girder couplers shall used for the support of hanging scaffolds. Pressed girder couplers shall not be used for the support of hanging scaffolds. UNDERHUNG SCAFFOLDS UNDERHUNG SCAFFOLDS SUSPENDED BY TUBES & COUPLRES Trapeze tubes shall be installed approximately 600 mm (2”) below the runners (ledgers) to assist in erection. Hanger tube spacing shall comply with the tube and coupler post spacing requirements for the load duty of scaffold. 69 . modification and dismantling. UNDERHUNG SCAFFOLDS UNDERHUNG SCAFFOLDS SUSPENDED BY TUBES & COUPLRES 70 .XI. Suspension wire ropes shall be shielded from heat producing processes. Spacing of wire ropes used to carry the scaffold shall comply with the post spacing requirements for the duty of the scaffold.XI. 71 . When an underhung scaffold is suspended by wire rope. such rope shall be wrapped at least twice around (softeners shall be used) the supporting members and twice around the bearers of the scaffold. Wire suspension rope shall be minimum 9 mm (3/8”) diameter (splices in wire ropes are not permitted. UNDERHUNG SCAFFOLDS UNDERHUNG SCAFFOLDS SUSPENDED BY WIRE ROPE A working platform shall have at least six (6) suspension points evenly spaced and kept taut. Wire rope cable including connecting hardware shall be capable of supporting at least six (6) times the maximum intended load applied or transmitted without failure. Wire ropes shall be inspected for defects prior to each work shift and after every occurrence. which could affect a ropes integrity. and shall be tied or otherwise secured to prevent it from swaying. XI. UNDERHUNG SCAFFOLDS USE OF WIRE ROPE CLIPS There shall be minimum of 3 clips installed at the load end and 3 clips installed at the attachment end of each rope. Clips installation and retightening after initial loading shall be according to the manufacturer’s recommendation. When wire rope clips are used, the U-bolt shall be placed over the dead end of the rope, and saddle (bridge) shall be placed over the live (loaded) end of the rope. “DON’T SADDLE A DEAD HORSE” 72 XI. UNDERHUNG SCAFFOLDS WELDING FROM UNDERHUNG SCAFFOLDS SUSPENDED BY WIRE ROPES To reduce the possibility of welding current flowing through the suspension wire rope when performing welding from underhung scaffolds, the following precautions shall be taken, as applicable: o An insulated thimble shall be used to attach each suspension wire rope to its support. Additional independent lines to provide grounding shall be insulated. o All suspension wire rope shall be covered with insulating material extending at least 1.2 m (4”) above the working platform. o In addition to work lead attachment required by the welding process, a grounding conductor shall be connected from the scaffold to the structure. The size of this conductor shall be at least the size of the welding process work lead, and this conductor shall not be in series with the welding process or the work piece. o If the scaffold grounding lead is disconnected at any time, the welding machine shall be shut off. o An active welding rod or uninsulated welding lead shall not be allowed to contact the scaffold or its suspension system. 73 MMG SCAFFOLD TAGGING RED SCAFFOLD TAG Indicates the scaffold has not been inspected or is not safe for use (by anyone other than the scaffold erection craftsmen. 74 MMG SCAFFOLD TAGGING GREEN SCAFFOLD TAG Indicates the scaffold is complete, has been inspected, and is safe for use at the time of inspection. 75 76 . Must have engineering design Dancing Scaffold. Must have engineering design Yellow tag – will be used rarely. Full body harness required for scaffolds yellow tagged. high. tags to be revalidated as needs arise Over 20 ft.Safety Tips Competent or trained scaffolder only can erect or dismantle scaffold A trained or competent scaffolding supervisor/foreman must over-see the erection or dismantling 1 week-signing interval (maximum). Safety Tips • Couplers Riveted type prohibited BS 1139. EN74 acceptable 77 . Safe Use of Ladder Extend 1 meter or 3 to 4 rung above the working platform Lashed with rope to prevent movement 4m Stile feet resting on a firm and level surface 1m Ladder set at a 4 to 1 ratio Positioning and securing ladders in scaffold platform 78 . Safe Use of Ladder 79 . Safe Use of Ladder Do not use rebar to replace missing rungs Do not use ladder with broken or damage rungs Do not lash ladders together to extend the reach Use the proper extension ladders – 80 . Safe Use of Ladder 81 .