SOP-45
Scaffolding
Table Ta ble of Contents
Page Pa ge
1.0
PURPOSE ............ ....................... ....................... ....................... ....................... ....................... ....................... ....................... ....................... ....................3 ........3
2.0
DEFINITIONS ........... ...................... ....................... ........................ ........................ ....................... ....................... ........................ ....................... .............. ...3 3
3.0
GENERAL GUIDELINES ........... ....................... ....................... ...................... ...................... ....................... ....................... ......................7 ...........7 3.1 Use ........... ...................... ....................... ....................... ....................... ....................... ...................... ....................... ....................... ....................... ................ ....7 7 3.2 Prejob Planning and Work Site Inspection............. Inspection........................ ...................... ...................... ...................... ............. ..7 7 3.3 Responsibilities.............................. Responsibilities.................. ....................... ...................... ....................... ....................... ...................... ...................... .............. ...7 7 4.0 LOCATION....................... LOCATION............ ....................... ....................... ....................... ....................... ....................... ....................... ....................... ....................9 ........9 5.0
ERECTION .......... ...................... ....................... ....................... ....................... ...................... ....................... ....................... ....................... ...................10 .......10 5.1 General........... General ....................... ....................... ....................... ....................... ...................... ....................... ....................... ....................... ...................10 .......10 5.2 Load Design (12.11) ............ ....................... ...................... ....................... ....................... ...................... ...................... ......................10 ...........10 5.3 Height Limitations .......... ...................... ....................... ...................... ...................... ....................... ....................... ...................... ................ .....11 11 5.4 Base Plates (See Figure 12.10 Foundation) ............ ....................... ...................... ....................... ....................11 ........11 5.5 Posts (See 12.3a and 12.3b) ........... ...................... ...................... ....................... ....................... ...................... .....................11 ..........11 5.6 Bearers (Transom) (12.3a and 12.3b) ........... ...................... ...................... ...................... ...................... ...................12 ........12 5.7 Runners (Ledgers, Ribbons) (12.3a and 12.3b)........ 12.3b)................... ...................... ...................... ...................12 ........12 5.8 Bracing, Diagonal and Cross Bracing (12.3a, 12.4a, 12.5a and 12.9) .......... ............... .....12 12 5.9 Board Planking, Overlays Overlays and Working Platforms Platforms (12.8, 12.12a and 12.12b) 12.12b) ... ...13 13 5.10 Securing the Scaffold to a Structure (12.13) .......... ..................... ...................... ....................... ......................14 ..........14 5.11 Guardrails – Top Rails and Midrails (12.3a)..... (12.3a)................ ....................... ....................... ....................... ................ ....14 14 5.12 Toeboards (12.3a) ........... ...................... ....................... ....................... ...................... ...................... ....................... ....................... .............. ...14 14 5.13 Ladder Access Safety Safety........... ....................... ....................... ...................... ...................... ....................... ....................... ....................15 .........15 5.14 Incomplete Walkways .......... ...................... ....................... ....................... ....................... ....................... ....................... ....................16 .........16 5.15 Alterations.............. Alterations......................... ....................... ....................... ....................... ....................... ....................... ....................... .......................16 ............16 5.16 System Scaffolds ........... ...................... ...................... ....................... ....................... ...................... ...................... ....................... ................. .....16 16 5.17 Combination Scaffolding Scaffolding........... ....................... ....................... ....................... ....................... ....................... ....................... ............... ....17 17 6.0 INSPECTIONS...................... INSPECTIONS........... ....................... ....................... ....................... ....................... ....................... ....................... ....................... .............. 17 7.0
SCAFF-TAGS AND HAZARD WARNING TAPE (FIGURE 12.6)........................... 12.6)............................. 18
8.0
DISMANTLING........... DISMANTLING ....................... ....................... ....................... ....................... ....................... ....................... ....................... ....................... ............. 18
9.0
SCAFFOLDING SUSPENDED BY CABLES (CRADLE)........ (CRADLE)................... ...................... ......................19 ...........19
10.0
CRITERIA FOR UNDERHUNG SCAFFOLDS SCAFFOLDS (12.5A) ............ ....................... ....................... ....................19 ........19
11.0
USE OF SCAFFOLDS ........... ...................... ....................... ....................... ...................... ....................... ....................... ...................... ............. ..21 21
12.0
REFERENCES................. REFERENCES...... ....................... ....................... ...................... ....................... ....................... ....................... ....................... ..................22 .......22
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SOP-45 1.0
Scaffolding
PURPOSE
Scaffolding is occasionally needed to perform Company work assignments such as painting, insulating, pipefitting, general maintenance work or new construction from elevated areas. This Standard Operating Procedure (SOP) - applies to all CABGOC departments and contractors who erect, tubular steel scaffolds and ladders providing access to them. This SOP-45, Scaffolding, is CABGOC’s proprietary, internal working guideline intended to facilitate safe and incident-free operations. It is not intended, nor should it be interpreted, as a mandatory regulatory standard. CABGOC does not guarantee accuracy of this guideline or assume any risk or liability for its use. Users of this guideline are solely responsible for the consequences of their actions. 2.0
DEFINITIONS
2.1
Scaffolding is a temporary, elevated, work platform used for supporting workers, materials, or both.
2.2
Post (12.3a) is the vertical tube which acts as a column to transmit the total weight of the scaffold structure and its load down to its base. (Other names include standard, vertical, leg).
2.3
Base Plate (12.2) is a steel pad attached to the bottom of the post in order to distribute the load. The post is centered centered on the base plate. Adjustable screw screw jacks are often often attached attached to base plates. plates.
2.4
Runner (12.3a) (12.3a) is a horizontal tube which runs parallel to the length of the scaffold, the longitudinal direction. (Other names include ledger, ribbon).
2.5
Bearer (12.3a) (12.3a) is a horizontal tube which runs perpendicular to the length of the scaffold, scaffold, (the (the width or transverse transverse direction). direction). (Other names include include transom).
2.6
Right Angle Coupler (12.2) is the rigid load bearing fitting used to attach tubes at a 90 degree angle to each other, such as horizontal tubes to vertical tubes. (Other names names include 90 degree coupler, coupler, double coupler, right angle angle clamp).
2.7
Swivel Coupler (12.2) (12.2) is the non load bearing fitting used for attachment of two tubes to each other at other than a right angle, such as a diagonal tube to a vertical tube.
2.8
Transverse Diagonal Bracing (12.3a) is the diagonal bracing which is installed perpendicular to the length of the scaffold, across the width (transverse direction) of the scaffold. (Other common names include Internal Diagonal Bracing).
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SOP-45 2.9
Scaffolding Longitudinal Diagonal Brace (12.3a) is the diagonal bracing which runs parallel to the the length of the the scaffold. scaffold. (Other common common names names include face, face, façade. Or sway bracing).
2.10
Lift (12.3a) means a unit of height of a completed scaffold. For example, one lift high means one level high, two lifts high means two levels high, etc. A scaffold lift or level is most commonly six feet six inches (two meters) in height.
2.11
Bay (12.4a) means a horizontal unit of scaffold, the distance between two sets of posts. (Other common names include Section).
2.12
Check/Safety Coupling (12.5a) is an additional coupling fitted above or below an existing coupler to give extra strength in the direction of potential slippage. (Other names names include safety safety clamp). clamp).
2.13
Putlog/Half Coupler (12.2) (12.2) is used for attaching an intermediate bearer to a runner allowing a board to lie flat. This clamp is also called a single and is Non Load Bearing
2.14
Sleeve Coupler (12.2) is an external fitting used for joining scaffold tubes end to end.
2.15
Spigot (12.2) is an internal fitting used to join scaffold tubes end to end.
2.16
Guardrail (12.3a) is a horizontal tube placed approximately 42 inches above the platform as part of a fall protection system.
2.17
Midrail (12.3a) is a horizontal tube placed approximately midway in height between the platform and guardrail as part of a fall protection system. system.
2.18
Toe board (12.3a) is a protective barrier board placed around the edge of the platform as part of a falling object protection system. Toeboards must be a minimum of 3 ½ inches in height.
2.19
Red Scaff-Tag (12.6) “DO NOT USE SCAFFOLD” is hung from all ladders and access ways to a scaffold by the “competent person” (Scaffold Erector), indicating that the scaffold is incomplete, being erected, dismantled, or modified, and not to be used.
2.20
Green Scaff-Tag (12.6) is hung from all ladders and access ways to a scaffold by the “competent person” (Scaffold Erector) indicating that the scaffold erection has been completed, inspected, and meets satisfactory safety standards, and the scaffold is ready to be used. Scaffolds shall be inspected a minimum of once every seven days. All Tags automatically expire to Red at the completion of seven days, and remain “Red Tagged” until the scaffold is re-inspecte re-inspected d regardless of whether the scaffold was used or not.
2.21
Person in Charge (PIC) is designated by the department or section that owns/operates owns/operate s the facility. The PIC is responsible for ensuring that conditions
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SOP-45
Scaffolding in the facility or area are safe for the scaffolding work to begin. Personnel who can be the PIC are the Platform Operator, Municipal Projects Supervisor, etc.
2.22
Person Performing the Work (PPW) is the Contractor Supervisor who directly supervises the scaffolding work on the job site. He is a “certified scaffold erector”, experienced with or trained in scaffold erection, dismantling, use, and knowledgeable about the hazards of scaffolding. He is authorized and capable of taking prompt corrective measures.
2.23
CABGOC Representative/Supervisor is responsible for ensuring that the site preparation and permit requirements are completed before work begins and that the work is done safely and in accordance with permit conditions. Personnel who can be the CABGOC Representative/Supervisor are the Facilities Engineering Construction Superintendent, Project Engineering Supervisor, Building & Infrastructure Supervisor or personnel reporting directly to them.
2.24
Certified Scaffold Erector means a person designated by the employer who has the ability to identify existing and predictable hazards associated with an activity, and who has the authority to have such hazards eliminated. Hazard recognition ability for scaffolding should include a thorough knowledge of CABGOC SOP-45 scaffold procedures as well as knowledge of potential hazards of the environment at the location where the scaffold will be installed. Hazard recognition ability should be verified through appropriate training.
2.25
Scaffold Work Team To measure, manage and safely apply the scaffolding function consistently, on or off shore, it is recommended that scaffolding teams be balanced to ensure the minimum skill and safety requirements are met at all times.
The size of the team is determined by each individual job. However, each team must have a Certified Scaffold Erector. The recommended Scaffold Erection and Dismantling Team shall be composed of a minimum Scaffold Erector, Scaffold Fixer, and a trained Scaffold Hand. A Cert if ied Scaf fol d Erec to r will have a minimum of 2 years practical experience and completed 40 hours of formal scaffolding training, either through an industry accredited institute or CABGOC in house training.
The Certified Scaffold Erector shall understand and practice correctly: • SOP 45 directives and required standards Erection and dismantling procedures for types and configurations • of scaffolds • Job planning and communication • Read, understand and apply Engineered Drawings • Fall protection
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SOP-45
Scaffolding Inspection
•
A Cert ifi ed Scaf fo ld Fix er shall have a minimum of one year’s practical experience as a laborer, working in support of scaffolding teams.
The Certified Scaffold Fixer shall support the Certified Scaffold Erector in all scaffold applications, and, under the supervision of the Scaffold Erector, be able to carryout basic scaffolding handling, erection and dismantling procedures, such as: •
• • • •
Erection and dismantling of posts, runners, bearers, braces and ties Erection and dismantling of working platform decking Erection and dismantling of access ladders Safe raising and lowering of scaffolding equipment Have proven knowledge of basic scaffolding theory as described in SOP 45.
The Scaffolder’s Hand shall act as a support for the Trained and Trainee Scaffolders. The Scaffolder’s Hand shall be trained or have proven knowledge and experience of: • Safe ground level equipment handling • Scaffolding parts and pieces identification • Basic rigging knots for raising and lowering equipment.
2.26
Underhung (12.5a) scaffold means a scaffold suspended from I beams or other structural members using tube and coupler components and girder couplers (beam clamps). (Other common names include hanging scaffold).
2.27
PFAS means personal fall arrest system consisting of a full body harness, a sound anchorage point, and a connecting system between the anchorage point and harness such as a shock absorbing lanyard, self retracting lifeline, or some combination of vertical lifeline, horizontal lifeline or other premanufactured combination.
2.28
Dead L oad means the weight of the scaffold components.
2.29
Live Load means the weight that will be placed on the scaffold not including the scaffold components. Examples include of live load include workers, tools, materials, wind, hoists, etc. Live load capacity for scaffold platforms is usually expressed in terms of 25 pounds per square foot (approx 120 kg/m^2, 1200 N/m^2) or 50 PSF.
2.30
Special Scaffold A scaffold that meets any of the following conditions and for which a structural engineering review of the scaffold plan is required: higher than 50 feet (15 meters), or cantilevered by more than 6.5 feet (2 meters), or over 30 sq. meters (320 sq. ft.) total platform area and supported by or hung from an existing structure or building (e.g., roof, pipe rack,
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SOP-45
Scaffolding offshore platform), or supporting loads greater than 240 kg/sq.m. (50 PSF), including piping, equipment, masonry, new or existing structures, or loads other than workers and their materials, or supported by or hung from one or more outrigger beams, or supported by or hung from wind girders or roofs of floating roof tanks.
2.31 3.0
Node point (12.7) means the intersection of vertical, horizontal, and diagonal tubes.
GENERAL GUIDELINES
3.1
Use 3.1.1 If elevated work can not be carried out safely from portable ladders, a mechanical lift or work basket, a building or other permanent structure, or if there is no permanent access to the workplace, or if the job is such that it is safer to do it from scaffolding, then approved scaffolding must be provided, erected and secured such that this work can be performed from an elevated level. 3.1.2 Scaffolding normally shall be 2-inch nominal OD tube steel or other metal of equivalent strength ( 5.2.2 )
3.2
Prejob Planning and Work Site Inspection 3.2.1 When planning the provision of temporary scaffolding access, consideration should be given to Rope Access and Mechanical Access. The feasibility of all types of access should be evaluated. The most practical application that minimizes risk should be used. 3.2.2 A pre-work safety meeting must be held with all workers such that they are completely briefed on the scaffolding job and its safety requirements. 3.2.3 The scaffold users should communicate to the Scaffold Erector the purpose for which the scaffold is to be used. Normal capacity is 25 PSF or less. If the capacity exceeds this threshold it must be communicated to the Scaffold Erector in the planning stage as indicated on the Scaff Tag.
3.3
Responsibilities 3.3.1 All Workforce Personnel Everyone is responsible for scaffold safety regardless of position or areas of authority. Stop the work and take appropriate corrective action when scaffold hazards are observed. 3.3.2 Person In Charge (PIC)
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SOP-45
Scaffolding The CABGOC’s PIC retains overall responsibility for all scaffolding erected, and stored at his facility. The PIC (2.21) should ensure prior to erection of scaffolding that: • •
•
•
Scaffolding is the safest and most efficient and effective means of man access to accomplish the task. (3.2.1) A method of safely providing scaffolding equipment to the facility is in place (3.2.2.) (3.4.3) A Scaffold Erector has been designated to oversee the erection and dismantling, equipment handling and hazard avoidance in compliance with SOP 45 (2.24 – 2.25) General Work Permit is approved and in place before erection/dismantling activities begin.
3.3.3 The Scaffold Erector is responsible to the PIC for: •
•
•
• •
Ensuring the contractor (PPW 2.22) providing the scaffolding has completed all Prejob Planning and Inspection requirements. (3.2.2) (3.2.3.) That the scaffold being provided is not a “special scaffold” requiring technical approval. That the PPW is trained and fully aware of the requirements of SOP 45 Section 5, erection, and completes the work in accordance with SOP 45 requirements. Will establish and perform the Scaffold Inspection and Tagging process as defined in Section 6.0 and 7.0 (Fig. 12.6) Submit request for a General Work Permit.
3.3.4 PPW or Trained Scaffold Erector The PPW or Trained Scaffold Erector is responsible for: •
In addition to being trained in the requirement s of SOP 45 the PPW must have a complete working knowledge of Section 3, Safety Practices, 4.0 Location and 5.0 Erection.
3.3.5 Scaffold User The User of the scaffold has a responsibility to ensure the scaffold is ready for use each shift by visually checking: • • • •
• •
•
Green Scaff-Tagg is in date The base of the scaffold has not shifted All tubes and decking remain fixed Any ties securing the scaffold to the existing structure are in place All hazard precautions and warnings are in effect The scaffold is free of any loose equipment or debris from previous users That they use the scaffold for the purpose it was designed. Page 8 of 40
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SOP-45
3.4
Scaffolding
Safety Practices 3.4.1 No persons other than those involved in the scaffold erection, shall be allowed on scaffolding during its erection or dismantling. 3.4.2 Good housekeeping should be exercised at all times. Loose equipment and materials should not be left on scaffold platforms. Materials such as welding rods, bolts or small-bore piping should not be placed in the open ends of scaffold tube, as this would create a hazard during dismantling. 3.4.3 Scaffolding materials shall be handled carefully to avoid damage. It is prohibited to throw materials or equipment up to scaffold platforms, or down to the ground. Instead, use hand lines or mechanical lifting equipment to lift loads. 3.4.4 Containers or bags capable of preventing tools or small items from falling out shall also be used for lifting or lowering equipment and items from scaffold platforms. 3.4.5 Scaffolding tubes shall not be used as rollers or used as levering devices. 3.4.6 Personnel are prohibited from riding on scaffolding equipped with wheels. 3.4.7 All scaffolding work is to be suspended during diving operations below the platform or jacket 3.4.8 No scaffold work over the side of offshore locations is to be carried out during the hours of darkness.
4.0
LOCATION
4.1
Scaffolding shall be erected as near as possible to the structure, piping, plant process equipment or building involved. Scaffold should be erected to safely suit the purpose of the work and meet SOP45 requirements.
4.2
Care should be taken to not obstruct access to operating equipment, valves, or controls when erecting scaffolds.
4.3
Care must be taken when positioning wooden planking, so that it will not be too close to hot surfaces where ignition of the boards could result. Metal planks shall be used in these areas.
4.4
Scaffolding close to pedestrian and vehicular thoroughfares should be marked with hazard warning tape to identify it as a potential hazard area.
4.5
If scaffolding is erected within 16 feet (5 meters) of power supply conductors or power lines, the conductors shall be de-energized and grounded,
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SOP-45
Scaffolding dismantled or protected by protective insulating materials during erection and dismantling of the scaffolding. In some cases the energized power line may be contained within a specifically designed “cable tray” and protected by adequate insulation to allow closer access. The CABGOC supervisor should be consulted for allowable clearance near cable trays carrying energized circuits.
5.0
ERECTION
5.1
General 5.1.1 The erection and dismantling of approved scaffolding shall be performed only by trained scaffold work crew. 5.1.2 All personnel involved in erection/dismantling of scaffolding must wear appropriate personal protective equipment including a personal fall arrest system. Scaffold erectors should implement a 100% tie off policy. The anchorage point should be a structural member other than the scaffold which will support either 5000 pounds or two times the actual maximum arresting force known to be generated by the brand and type of PFAS connection being employed. If no such structural anchorage is available, the scaffold itself may be used as a last resort. In such cases, the preferred scaffold anchorage should be a post which itself has been braced by horizontal and diagonal bracing as required by the scaffold design. 5.1.3 Personnel working 6 feet (1.8 meters) or more above grade shall be protected by either a guardrail system or a personal fall arrest system if guardrails are not in place. If the facility supervisor suspects that fall hazards present an unusual level of risk, both a guardrail system and a personal fall arrest system may be required. An example of this would be work from an underhung scaffold.
5.2
Load Design (12.11) 5.2.1 Scaffolds and their components must be capable of supporting without failure its own weight plus at least four times the maximum intended load. Loads on scaffolding shall not exceed the design load. For guidance on recommended scaffold standard spacing, load concentration, number of working platforms and applications, refer to Appendix 1. 5.2.2 Materials, other than those designed and manufactured for the purpose of scaffolding, shall not be permitted for use. All tubing and couplers shall meet the requirements of BS1139, EN74, or US MIL-S29108A. Alloy and steel tubes should never be mixed unless specifically designed to be assembled in that manner. 5.2.3 The scaffold loads shall be transmitted to a structurally sound foundation. The foundation which supports the scaffolds shall be designed and verified to be able to support the loads imposed by the
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Scaffolding scaffold. Guardrails shall not be used as a support or foundation for scaffolds. 5.2.4 Scaffold work level decks shall be able to carry a minimum of 25 pounds per square foot (approx 120kg/m^2 or 1200 N/m^2). If the scaffold user determines that more weight than 25 PSF must be placed on the deck, then the user must communicate this to the Scaffold Erector and the scaffold must be designed to carry the appropriate loading.
5.3
Height Limitations 5.3.1 If the height of scaffolding exceeds three (3) times its minimum base dimension, it shall be secured per the requirements in Section 5.10 5.3.2 Intermediate rest platforms should be provided for climbing to levels where the change in elevation is greater than 35 feet. The Intermediate rest platforms shall be fully planked, equipped with guardrail/handrail and toe boards, and shall not be used for storage of material or as an additional working platform.
5.4
Base Plates (See Figure 12.10 Foundation) 5.4.1 The footing or anchorage for scaffolds shall be sound, rigid, and capable of carrying the maximum anticipated load without settling or displacement. Unstable objects such as boxes, loose bricks, concrete blocks, or scrap lumber shall not be used to support or level scaffolds. 5.4.2 Typical scaffolding footing connections on soil or gravel consists of a steel base plate and a wooden pad of scaffold grade lumber large enough to distribute the load. Scaffold grade 2” X 10” by 18” long pads are typical for small scaffolds. Larger scaffolds may require the calculation of the actual post load to determine the size of pad required. 5.4.3 Any existing steelwork to be used as support for scaffolding shall be inspected prior to being used, to ensure its suitability, and condition. Typical scaffolding footing connections on an offshore platform steel grating or metal plate decking should have suitable thickness timber or steel positioned across support steel, to spread the load applied by standards and base plates. Permanent guardrails shall not be used as a footing for scaffolds. In no cases should an unsupported post be placed upon grating without a base plate and / or timber support.
5.5
Posts (See 12.3a and 12.3b) 5.5.1 All posts must be plumb and rigidly braced by horizontal and diagonal bracing. Maximum spacing between posts in the transverse direction (width) is 8 feet (2.4 meters) and in length 10 feet (3 meters). Note: the span on the bearer is limited to 4 feet (1.2 meters) by section 5.6.
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SOP-45 5.6
Scaffolding Bearers (Transom) (12.3a and 12.3b) 5.6.1 Bearers (Transoms) shall be long enough to fully seat into their support couplers. 5.6.2 Bearer spans shall not be longer than 4 feet (1.2 meters) without additional midspan support. Support can be accomplished be attachment of a diagonal brace from the midspan of the bearer down to the nearest node point. 5.6.3 Metal or wooden planking may be used for the elevated work area. However, both ends of the planking must be tied down or clamped to the bearer.
5.7
Runners (Ledgers, Ribbons) (12.3a and 12.3b) 5.7.1 Runners shall be installed using right angle couplers along the length of the scaffold located on both the inside and outside rows of posts at level heights, and coupled to each post. Runners shall be installed on the inner side of the post instead of the outer side whenever possible. 5.7.2 Maximum vertical spacing between runners is 6.5 feet (2 meters). 5.7.3 The lowest runner shall not be installed more than 30 inches (0.75 meters) from the bottom, unless it creates a hazard. Where they are above 30 inches (0.75 meters) as in some offshore applications, adequate bracing shall be provided, to prevent lateral movement.
5.8
Bracing, Diagonal and Cross Bracing (12.3a, 12.4a, 12.5a and 12.9) 5.8.1 Longitudinal Diagonal bracing shall be installed at approximately a 45° angle from near the base (within 12 inches) of the first post upward to the extreme top of the scaffold. On scaffolds which are taller than they are long, this diagonal will reach the last post before it reaches the extreme top. In this event, the diagonal shall be restarted in the opposite direction and shall continue up in an alternating direction or “zig-zag” pattern. In a similar manner, longitudinal bracing shall be installed beginning from the bottom of the last post back to the first post, and repeated as above. On scaffolds that are longer than five sets of posts, a new line of bracing shall be begun at every fifth post, and installed per the instructions above. This will create a diamond shaped appearance on the longitudinal face. This bracing shall be installed on both the inner and outer rows of posts. 5.8.2 An alternative method of longitudinal diagonal bracing is to install alternating diagonal bracing in the first bay (between the first and second sets of posts) all the way to the top. This bracing should be repeated every fifth post (e.g. between the fifth and sixth sets of posts, the tenth and eleventh sets of posts, etc.), and at both end bays.
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Scaffolding 5.8.3 Bracing should clamp to an exterior post as close to the intersection of the posts and horizontals as possible, within 12 inches (0.3 meters). 5.8.4 Transverse diagonal bracing shall be installed across the width of the scaffold. An alternating direction or “zig-zag” pattern all the way to the top of the scaffold. The transverse diagonal bracing must be repeated along the length of the scaffold every third set of posts. On large area scaffolds where the scaffold is several bays wide, a new line of transverse bracing shall be started every sixth post in width, in both directions. 5.8.5 Plan bracing should be installed all rolling scaffolds, at the base and every three levels in height.
5.9
Board Planking, Overlays and Working Platforms (12.8, 12.12a and 12.12b) 5.9.1 All scaffold boarding and wooden planks shall be “selected scaffold grade as recognized by lumber industry standards” and have at least a minimum size 1.5 inches x 9 inches. 5.9.2 All scaffold metal and wooden planking shall be inspected before use, during erection, and as part of the workshift inspection. 5.9.3 Scaffold metal or wooden planking used on working platforms, should cover the complete space between posts. Gaps up to one inch between planks are allowed. If the post spacing is such that a gap of more than one inch would occur between the last plank and post, the last plank shall be positioned as close as possible to the post. 5.9.4 All metal or wooden planking shall be tied in place at both ends, using a tie down bar or other secure means. 5.9.5 Where wooden planking is lapped, each board shall lap its end supports (bearers) by a minimum of 12 inches (0.3 meter), and be secured from movement. 5.9.6 To prevent tripping where the ends of scaffold planks abut each other to form a flush floor, the abutted ends should be butted closely together and shall be secured to separate bearers. At corners, boarding should preferably be butted and not overlapped to minimize tripping hazards. 5.9.7 Where scaffold planking rests on bearers, ends shall extend a minimum of 6 inches (15 cm.), but no more than a maximum of 18 inches (45 cm.) over end supports. 5.9.8 Damaged boards (split, burned, chemical contaminated) will be replaced when found. Boards are the most “at risk” components for misuse and damage on any scaffold.
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Scaffolding 5.9.9 The maximum span on wood planks shall be 4 feet (1.2 meters). Intermediate bearers shall be used to limit the span of wood planks. 5.9.10 Loads on individual wood planks shall be limited to 250 pounds maximum. 5.9.11 The maximum span on manufactured planks such as aluminum or steel shall be as recommended by the plank manufacturer, based upon the capacity to carry a minimum load of 250 pounds at the center.
5.10
Securing the Scaffold to a Structure (12.13) 5.10.1 Scaffolding shall be braced or guyed to an adjacent building, structure or equipment to prevent it from swaying or tipping over. Ties shall be at least doubled 12 gauge iron wire or equivalent. The first tie-in in shall be at a height of three times the narrowest base dimension. Tieins must be repeated at least every 30 feet (9.1 meters) horizontally and 26 feet (7.9 meters) vertically. The ties should be within three times the narrowest base dimension to the top working platform. 5.10.2 Tie-ins should be constructed from scaffold tubes creating box ties with load bearing right angle couplers or girder couplers (beam clamps) whenever possible. If wire tie-ins are used, number 9 gauge wire or double wrapped number 12 gauge wire should be used.
5.11
Guardrails – Top Rails and Midrails (12.3a) 5.11.1 Open sides and ends of all working levels shall be guarded by top rails, midrails, and toeboards. The top rail shall not be less than 42 inches (1.07 meters) nor more than 45 inches (1.14 meters above the platform. 5.11.2 A mid rail shall be not less than 20 inches (0.5 meters) or more than 24 inches (0.6 meters) above the platform. The mid rail shall not be used as a support for boards to aid working.
5.12
Toeboards (12.3a) Open sides and ends of all working levels shall have toeboards to prevent objects laying on the platform from falling over the sides or ends. A half coupler may be used to secure the toeboards. 5.12.1 Side toe boards should be secured to upright standards, preferably using a half coupler. 5.12.2 End toeboards should be installed across the whole width of the scaffolding platform. 5.12.3 Toeboards should be at a minimum of 3.5 inches (9 cm.) high with the clearance between the toeboard and the platform to be a maximum of Page 14 of 40
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Scaffolding ¼-inch (0.6 cm.) A standard scaffold board may be used as a toe board. 5.12.4 Where barricading cannot be effective, such as where personnel are required to work or pass under a scaffold platform, or where sensitive equipment is subject to falling object hazards, a screen (18 gage, ½inch mesh or equivalent synthetic) shall be installed between the top guardrail and toeboard of the platform and extend horizontally the length of the opening.
5.13
Ladder Access Safety A safe means of access such as a walkway, stairway, or fixed ladder must be provided to all scaffold platforms. A portable ladder may be used if securely attached to the scaffold to provide unobstructed access and egress to scaffold platforms. 5.13.1 Scaffold ladder systems manufactured specifically for use as scaffold ladders by scaffolding manufacturers are recommended. These systems typically come with “U-shaped brackets with built on couplers for attachment to the scaffold. The brackets shall be attached to a separate post adjacent to the main posts so that the ladder is beside and perpendicular to the guardrails. 5.13.2 When used, portable Ladders must be set-up at a safe angle and secured to the scaffold to prevent slippage. The distance from the base of the ladder to the scaffold should be a quarter of the working height (75 degrees), or four units up to each unit out from the base. 5.13.3 All scaffolding ladders must extend a minimum of 3 feet (1 meter) above the platform deck, if guardrails and handrails are not required, otherwise 12 inches (0.3 meter) above top rail to provide a handhold during mounting and dismounting. 5.13.4 Ladders must be placed on a firm footing to avoid slipping or tipping. 5.13.5 Ladders should always be erected so they are the correct way up, i.e. extending ladders, so that the extending section is on top. 5.13.6 Ladders must be of the correct length for the job and shall not be lashed or spliced together, or placed on boxes or other loose packing to gain extra height. 5.13.7 Ladders shall be inspected prior to each use and as part of the work shift inspection. Workers should report faulty ladders to their supervisor without delay. Damaged or defective ladders shall not be used and should be marked "DO NOT USE.” If repairs cannot be made to a damaged ladder, the ladder must be removed from service immediately.
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Scaffolding 5.13.8 A person climbing a ladder shall face the ladder and use both hands for climbing. The carrying of tools and materials shall minimized when traveling up and down ladders. The preferred method is the use of a hand line for the raising or lowering tools/materials. 5.13.9 A person working on a ladder should not over-reach. The ladder should be re-positioned to a more convenient site to allow safer access. It is essential that the position of the ladder is safe and that it is secured at the top or held firmly at the base to prevent movement before the ladder is ascended. 5.13.10 Ladders should be removed as soon as a job is complete and stored in a horizontal position. 5.13.11 Care should be taken when carrying ladders, especially at doorways or around corners. 5.13.12 Ladders shall be installed such that adequate foot clearance is maintained above and behind each rung. 5.13.13 Drop bars shall be installed at the point of ladder access whenever possible. 5.13.14 Ladder rest platforms shall be installed at a minimum of every 35 feet vertically up the ladder. These rest platforms shall incorporate a mandatory break in the ladder, and subsequent continuation with a new ladder. (See Diagram 12.4(a)).
5.14
Incomplete Walkways If there are any incomplete walkways during erection or dismantling, a “ RED Scaff-Tag” (indicating the red prohibitive circle and slash across it with the words “DO NOT USE SCAFFOLD”) must be attached to all ladders and access ways to that scaffold. (See Section 7.0 on Scaff-Tags and Hazard Warning Tape). If grating or deck plate is removed, a “RED Scaff-Tag” must be attached to all ladders and access ways to that scaffold. Also a scaffold barrier should be erected around the hazardous area.
5.15
Alterations Scaffolds and their foundations shall only be altered by trained erectors working under the supervision of the Scaffold Erector responsible for the scaffold.
5.16
System Scaffolds All system scaffolds shall be erected per the manufacturer’s published instructions and the requirements of this Manual. Since assembly instructions on system scaffolds can vary from tube and coupler and from Page 16 of 40
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Scaffolding system to system, the manufacturer’s assembly and loading instructions shall be made generally available to all persons responsible for inspecting the scaffold.
5.17
Combination Scaffolding At the discretion of the Scaffold Erector the combination of both, system and conventional tube and clamp may be used.
6.0
INSPECTIONS
Scaffolding should be inspected as follows: 6.1
Completed scaffolds shall be inspected by a Scaffold Erector every seven days, and after any occurrence which could have caused damage to the scaffold.
6.2
In addition to ensuring that the scaffold is constructed in accordance with SOP-45, the inspection shall encompass the following items which may have occurred prior to or during usage.
6.3
All boarding and wooden planking shall be inspected to ensure the following: a) No splits, distortions (warping), damage or decay. b) Notches do not exceed 1/3rd of the width of the board/plank. c) No chemicals/contamination spilled on the planking such that personnel at a later date using the scaffolding could get on their bodies while working or sitting on the scaffolding. d) Hot welding slag or other burning operations have not damaged the planking. e) Secured on platforms, and re-laid if found untied or loose.
6.4
Tubes and couplers shall be inspected and removed from service for the following: a) Tubes that are bent more than 1/2 inch (1.3 cm) out of plumb over the length of the member. Bent tubes are not to be straightened. b) Tubes that have a visible defect, such as dents, cracks or been subjected to excessive heat. Cracks on tubes shall not be welded. c) Couplers that do not tighten securely, have stripped threads, or are loose when applied to tubes. d) Couplers that are distorted, loose, or have worn pins. Corrosion, both internal and external on scaffolding tubing is the foremost danger in this environment. e) Couplers shall not be soaked in oil based products. Threads may be lubricated, but all other areas of the couplers shall be free from contaminants.
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8.0
Scaffolding
SCAFF-TAGS AND HAZARD WARNING TAPE (FIGURE 12.6)
7.1
If the scaffold is incomplete, being erected, dismantled or modified the Scaffold Erector supervising the work, should ensure " RED" Scaff-tags with the words “DO NOT USE SCAFFOLD” must be attached to all ladders and access ways to that scaffold.
7.2
Once a scaffold erection has been completed, inspected and meets a satisfactory standard, the Scaffold Erector who supervised the erection, should ensure "GREEN" Scaff-tags (indicating Erection and Inspection Record information) must be attached to all ladders and access ways to that scaffold.
7.3
If it is impossible to completely eliminate all hazards from a scaffold or to meet the intent of SOP45, and the scaffold must be used in that condition, the scaffold shall be tagged by the Scaffold Erector with a Yellow warning tag. The nature of the unavoidable hazard should be explained on the tag. An example might be if plywood decking had to be used to cover a gap between planks, a small tripping hazard is created. It is presumed the vast majority of scaffolds can be erected to comply with SOP-45, and that the need to yellow tag a scaffold would be extremely rare.
7.4
During erection or dismantling where personnel can walk close to and past scaffolds and staging, hazard warning tape or signs should be used to barricade off the area.
DISMANTLING
Scaffolding shall be removed upon completion of the scope of work. If the work is incomplete or suspended, access to the work areas should be prevented by attaching "RED" Scaff-tags to all ladders and access ways to that scaffold. If a project is placed on hold: the scaffolding can be left in good working order, green tagged and inspected in line with the company’s procedures. If the scaffolding is to be isolated then the ladders should be removed and the structure red tagged. 8.1
Do not remove any ties until the scaffold is dismantled to their particular level.
8.2
Do not remove any of the bracing’s, bearers, and guardrails other than progressively as the work proceeds.
8.3
Do not leave a partly dismantled scaffold in an unstable condition.
8.4
Do not leave a scaffold component partially attached to the rest of the scaffold structure.
8.5
Do not overload the scaffold by the temporary storage of dismantled material.
8.6
All materials should be lowered to the ground immediately upon being disassembled.
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8.7 9.0
Scaffolding
Do not allow scaffold components to drop freely.
SCAFFOLDING SUSPENDED BY CABLES (CRADLE)
Occasionally work assignments such as sandblasting, painting, pipefitting, insulating, general maintenance or new construction is best performed on scaffolding suspended from a tank roof, “I” beam of an offshore platform or other fixed structure to reach the desired elevated area. 9.1
Ensure the suspended scaffolding anchors are secured to the tank roof, “I” beam of the offshore platform or fixed structure.
9.2
Ensure the suspended scaffolding safety devices, electric mechanism and rollers of the scaffold are functioning properly.
9.3
Ensure personnel on the suspended scaffolding wear a full body safety harness having a “D-ring” on the back, secured by a lanyard to a lifeline, drop line or fixed anchor. The lanyard should not be attached to the railing of the suspended scaffolding.
9.4
If personnel on the suspended scaffolding are working over water, each person should wear a work vest.
hoisting
When possible, it is advisable to have the rollers on the suspended scaffolding be in contact with the tank wall or vertical structure as the scaffolding is lowered or raised rather than the scaffolding hanging several feet away from the tank wall or vertical structure. Having the scaffolding rollers in contact with the tank wall or structure prevents the scaffolding from swaying creating an “off-balance” working condition for the personnel on the scaffold. 10.0
CRITERIA FOR UNDERHUNG SCAFFOLDS (12.5A)
10.1
All underhung scaffolds shall be hung from structures capable of supporting at least 4 times the load imposed on them by the scaffold.
10.2
Suspension points of hanger tubes shall be securely fixed to prevent their being dislodged by all potential forces acting upon them.
10.3
Horizontal tubes shall be affixed to the underneath of existing steel I beams by the use of a pair of girder couplers (beam clamps) designed for such purpose. A girder coupler shall be attached on both flanges of the beam two beam clamps per connection) everywhere a horizontal intersects a beam. Horizontal tubes shall continue across and be attached to at least two structural steel I beams.
10.4
Hanger tubes shall be coupled to the horizontal tube that is placed across the bottom of the supporting beam. Hanger tubes shall be attached using load bearing right angle couplers.
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Scaffolding Check (safety) couplers shall be installed above the load bearing coupler which connects the hanger tube to the support horizontal. Bearers shall be installed on top of runners as customary and additional check couplers shall be placed under the runners. Check (safety) couplers shall also be installed directly beneath all trapeze tubes.
10.6
Whenever possible vertical hanger tubes should of one length. Where joints are necessary, the tubes should be parallel spliced using a minimum of four couplers.
10.7
The preferred method of underhung scaffold erection is to begin by erecting a supported scaffold from a lower deck as close as possible to the area where the underhung scaffold is needed, then build the supported scaffold up to the underhung beams, attaching to the underhung beams. Temporary cantilevered erector platforms can be constructed from the supported scaffold following the underhung beams by pre-placing a swivel coupler onto the ends of two tubes, then extending the two tubes outward with one serving as a horizontal and the other as a diagonal, upward and back to the already constructed portion of the scaffold. Girder couplers connected by short tubes can be placed under the deck beams as an anchorage point for 100% fall protection. An alternate erection technique is to install trapeze tubes approximately 2 feet (600 millimeters) below the runners (ledgers) to assist in erection, modification and dismantling, and also to serve as a secondary support should the runner slip.
10.8
Runners (ledgers) and bearers (transoms) shall be coupled to hanger tubes using right-angle couplers.
10.9
Hanger tube spacing shall comply with the same tube and coupler post spacing requirements for supported scaffolds.
10.10 Bearers or intermediate bearers shall be spaced no more than 1.2 meters on center under scaffold planks, consistent with supported scaffolds. 10.11 Drop-forged girder couplers shall be used for the support of hanging scaffolds. 10.12 Diagonal bracing on underhung scaffolds shall be installed in the same manner as diagonal bracing on conventional base supported scaffolds. Diagonal bracing shall originate within 12 inches of a node point. See section 5.8. 10.13 Diagonal plan bracing shall be installed in each end bay and every fourth bay along the length. 10.14 An additional (third) guardrail shall be installed above the normal guardrail on all underhung scaffold on offshore facilities. The vertical spacing to the third Page 20 of 40
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Scaffolding guardrail shall be approximately equal distance to the normal midrail and guardrail.
10.15 Under no circumstances should a half coupler be used to support a horizontal tube to the underside of an “I” beam. 11.0
USE OF SCAFFOLDS
Scaffold Users should abide by the following common sense guidelines: 11.1
Do not work from a scaffold if it has not been inspected that workshift and tagged as “Approved, Ready to Use”. In addition, do a visual inspection for the obvious requirements such as ladder access, full planking, guardrails, plumbness, rigidity, etc.
11.2
Do not use a scaffold if it does not have a proper ladder or other equivalent safe means of access. Do not climb the scaffold itself.
11.3
Do not use a scaffold if the working platform is not planked all the way across. Do not use a scaffold if only one or two planks are placed where there should be more.
11.4
Do not use a scaffold if the planks are not scaffold grade. If the planks are man made, make sure they are in good condition.
11.5
Do not use a scaffold if the planks are bowing more than 1/60 of their span.
11.6
Do not use a scaffold if it is not plumb, square and rigid.
11.7
Do not use a scaffold taller than 3 times its minimum base unless it is tied, guyed, or braced to prevent tipping ( 5.3.1).
11.8
Do not climb the scaffold other than by the safe means of access provided. Never climb guardrails.
11.9
Do not work if you feel weak, sick or dizzy. Never use drugs or alcohol on a scaffold.
11.10 Do not climb with slippery shoes. 11.11 Do not carry materials as you climb. Keep both hands on the ladder side rails. 11.12 Do not jump on to planks or platforms. 11.13 Do not use scaffolds during storms, rain or high wind. 11.14 Do not allow tools, material or debris to accumulate on the platforms and cause a hazard.
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11.15 Do not alter the scaffold . Scaffold alterations may only be performed by a trained crew under the supervision of a Scaffold Erector. 11.16 Do not use heat producing equipment such as welding or burning equipment without taking precautions to protect the scaffold members or boards. 11.17 Do not work if you notice any components which are damaged. 11.18 Do not attempt to extend working heights by planking guardrails or by the use of boxes or ladders on scaffold platforms. 11.19 Do not use scaffold as material hoist towers or for mounting derricks unless the scaffold is designed for such use. 11.20 Do not bridge between towers with planks or stages unless the scaffold assembly has been designed for this use by a qualified person. 11.21 Do not violate clearances from electrical power lines. 11.22 Do not overload the platform by more than its intended uniform loading. 11.23 Do not overload the scaffold by point loading a plank above its capacity. 11.24 Do not ride scaffolds constructed on fork lifts, truck trailers, or other moving vehicles. 11.25 Do not use the scaffold unless the proper falling object protection for the users and workers below has been provided. 11.26 Do not use rolling towers unless the wheels are locked. 11.27 Do not ride rolling towers while they are being moved. 12.0
REFERENCES
Scafftag Products, Ltd. Chevron Safety in Designs Manual Section 8, "Scaffolds" (Section 7 in some earlier editions of SID) Gaviota Oil and Gas Plant Safety Manual U.S. OSHA 29 CFR Subpart L "Scaffolding" U.K. Health and Safety Executive Guidance Note GS15 “General Access Scaffolds” Scaffold Training Institute “Competent Person Manual” 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8
Drawings Diagrams of scaffold components Two Level Tube & Coupler scaffold Multiple Section Independent Scaffold Typical underhung Tube & coupler scaffolds Scaffold Tags Node point Plank detail
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12.9 12.10 12.11 12.12 12.13
Bracing detail Foundations Table of loadings and allowable platforms Diagrams of typical scaffold grade planks Diagrams of Typical Tie In Details
12.1
Drawings The followings drawings are intended to supplement SOP45 as illustrative and educational material. Site conditions may vary so the drawings below are not intended as detailed plans or solutions for every field condition. When modifications are necessary, the requirements of SOP45 must be followed.
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FIGURE 12.2 SCAFFOLD TUBE & COUPLER COMPONENTS
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4’-0” [1.2m] 7’-0” [2.1m]
TOE BOARD GUARDRAIL WIRE TOE BOARD TO BEARER SLEEVE COUPLER
ADD EXTRA BEARERS IN BETWEEN POSTS AS REQ’D. 4’-0” [1.2m] MAX. SPACING BETWEEN BEARERS
1’-9” [0.5m] 1’-9” [0.5m]
6’-6” [2.0m]
PUTLOG COUPLER FULLY PLANKED PLATFORM MAX. 1” GAP
SCAFFOLD LADDER
SWIVEL CLAMP AT DIAGONALS EXTENSION OF BEARER OR SEPARATE POST RIGHT ANGLE CLAMP AT BEARERS & RUNNERS
6’-6” [2.0m]
POST RUNNER 10’-0” LG. MAX
BEARER TRANSVERSE DIAG. BRACE 9’-0” [2.7m] ± TUBING SOLID FOUNDATION STEEL BASE PLATE
LONGITUDINAL DIAGONAL BRACE WOODEN PAD
FIGURE 12.3a Two Level Tube & Coupler Scaffold Less than 4 feet in Width
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10’-0” [3.0m]
8’-0” [2.4m]
FULLY PLANKED PLATFORM MAX. 1” GAP
TOE BOARD
GUARDRAIL
WIRE TOE BOARD TO BEARER SLEEVE COUPLER
1’-9” [0.5m]
ADD EXTRA BEARERS IN BETWEEN POSTS AS REQ’D. 4’-0”[1.2m] MAX. SPACING BETWEEN
1’-9” [0.5m] BEARERS WIDER THAN 4’-0” ON SPAN MUST BE SUPPORTED IN 6’-6” THE MIDDLE (SEE [2.0m] DETAILS OPTION 1 & OPTION 2)
EXTENSION OF BEARER OR SEPARATE POST
SWIVEL CLAMP AT DIAGONALS 6’-6” [2.0m]
RIGHT ANGLE CLAMP AT BEARERS & RUNNERS
SCAFFOLD LADDER
BEARER TRANSVERSE DIAG. BRACE 11’-0” [3.4m] ± TUBING
RUNNER 10’-0” LG. MAX
POST
SOLID FOUNDATION STEEL BASE PLATE
LONGITUDINAL DIAGONAL BRACE WOODEN PAD
FIGURE 12.3b Two Level Tube & Coupler scaffold More than 4 feet in Width
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Figure 12.3 c Details of intermediate bearer support
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FULLY PLANKED PLATFORM MAX 1” GAP
GUARDRAIL
TOE BOARD
POST
SLEEVE COUPLER (STAGGERED) BEARER 4’-0” SPAN MAX.
SCAFFOLD LADDER EXTENSION OF BEARER OR SEPARATE POST
POSITIVE TIES SEE FIG. 12.13
NODE POINT RUNNER 10’-0” SPACING MAX.
TRANSVERSE DIAG. BRACING (ZIG-ZAG)
LADDER REST PLATFORM EVERY 35’-0” MAX.
LONGITUDINAL DIAGONAL BRACING (ZIG-ZAG)
FIGURE 12.4a Multiple Section Independent Scaffold
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FULLY PLANKED PLATFORM MAX 1” GAP
GUARDRAIL
TOE BOARD
POST BEARER 4’-0” SPAN MAX. LADDER NOT SHOWN FOR CLARITY
SLEEVE COUPLER (STAGGERED)
RUNNER 10’-0” SPACING MAX. LONGITUDINAL DIAGONAL BRACING (ZIG-ZAG) TRANSVERSE DIAGONAL BRACING (ZIG-ZAG)
FIGURE 12.4b Multiple Section Independent Scaffold Wider than 4 feet.
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FIGURE 12.5a Typical Underhung Tube & Coupler Scaffold
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FIGURE 12.5a Details Above
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FIGURE 12.6 SCAFFOLD TAGS
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DIAGONAL POST
BEARER RUNNER
DIAGONAL
FIGURE 12.7 NODE POINT
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Figure 12.8 Plank Detail
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LONGITUDINAL DIAGONAL BRACING (ZIG-ZAG) th EVERY 4 SET OF POST
TRANSVERSE DIAGONAL BRACING (ZIG-ZAG) rd EVERY 3 SET OF POST
FIGURE 12.9 Bracing Detail
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FIGURE 12.10 Foundation
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TABLE 12.11 ALLOWABLE LOADINGS Note: The above limits are from OSHA based on a light duty scaffold 4 feet wide by 10 feet long, or a medium duty scaffold 4 feet wide by seven feet, or a heavy duty using 2.5 inch OD bearer tubing. For other sizes a leg load calculation must be done by a qualified person.
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FIGURE 12.12(a) View of scaffold grade stamp
FIGURE 12.12(b) Platform with scaffold grade stamps visible
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FIGURE 12.12 (c) Examples of scaffold grade stamps
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