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Scaffolding Safety Training Working Safely on Construction Scaffoldings 29 CFR 1926 450 -452 Requirements of Scaffolding
Objectives Understand the training requirements for working on scaffolding. Understand the general structural requirements for scaffolding. Understand the access and working requirements for scaffolding. Understand the requirements for specialty scaffolding.
The Importance of Scaffolding Safety The National Census of Fatal Occupational Injuries reports that an average of 88 fatalities a year occur from working on scaffolding. 72% of scaffolding injuries are a direct result of supports collapsing, workers slipping, or being struck by a falling object. On January 19 th, 2008 an entire block of scaffolding was overturned by high winds. Fortunately, only one person was injured.
Part I Training Requirements
Scaffolding Training Requirements All employees who perform work on scaffolding must be trained by a person qualified in the subject matter. The training must include: 1. The requirements of the OSHA Scaffolding subpart. 2. Electrical hazards, fall hazards, and falling object hazards in the area. 3. The correct procedures for dealing with electrical hazards and for erecting, maintaining, and disassembling fall protection and fall object protection systems. 4. Proper use of the scaffold, and proper handling of materials on the scaffold. 5. Maximum loads and load carrying capacities of the scaffold.
Scaffolding Training Requirements All employees who erect, disassemble, move, operate, repair, inspect or maintain scaffolding must by a competent person. The training must include: 1. The requirements of the OSHA Scaffolding subpart. 2. The nature of scaffold hazards. 3. The correct procedures for erecting, disassembling, moving, operating, inspecting and maintain scaffolding. 4. Design criteria, maximum load capacity, and intended use of the scaffold.
Scaffolding Certification Employees need to be trained on the specific hazards and requirements of the scaffolding in their work area. After completing this training, they should complete a certification specific to their work area.
Part II General Scaffolding Requirements
Scaffolding Design Scaffolding systems must be designed by a qualified person and constructed in accordance with that design. A qualified person is one who by possession of a recognized degree, certificate, or professional standing, or who by extensive knowledge, training and experience, has successfully demonstrated his ability to solve or resolve problems relating to the subject matter, the work, or the project.
Scaffolding Capacity Non-Adjustable Scaffolding Must be capable of supporting its weight and at least 4 times the max load. 2. 1. Suspension ropes and connecting hardware must support its weight and at least six times the max load. Adjustable Scaffolding 1. Stall load on hoist must not exceed 3 times the rated load. 2. Suspension ropes and connecting hardware must support its weight and at least six times the max load. The result of an overloading scaffolding. Do you know the rating of the scaffolding you are working on?
Scaffold Platform Construction The space between adjacent platform units must be less than 1 inch. The space between the platform and the uprights may not exceed 9. 5 inches. Platforms and walkways must be at least 18 inches wide. ◦ If this is not possible, must be protected by guardrails and a fall arrest system. An example of bad planking. Look at all the space between platform planking.
Scaffold Platform Construction Each end of a platform must extend at least 6 inches over the centerline of its support. Platforms that are 10 feet or less cannot extend more than 12 inches over its support Platforms that are longer than 10 feet cannot extend more than 18 inches over its support. An example of poor planking and unsafe loading.
Scaffold Platform Construction When scaffold planks are abutted to make longer platforms, each end must rest on a separate support surface. Overlapping platforms must occur over supports, and must overlap for at least 12 inches, unless the platforms are nailed together. Platforms that rest on a support at an angle other than a right angle must be laid first. Platforms that rest a right angle on the support must be laid second. Note that the connecting platform is not laid first, as required when it does not form a right angle. (It should be on the bottom) This scaffolding also has dangerous guardrails, with no mid rail and a top rail of wire.
Platform Working Faces The front edge of all platforms must be no more than 14 inches from the face of the work. ◦ Faces may be greater than 14 inched if a guardrail is erected along the face side and personal fall arrest systems are used. Outrigger scaffolds must be within 3 inches of the working face. Plastering and lathing operations must be within 18 inches of the working face. This platform is greater than 14 inches from the working face.
Scaffolding Platform Components Wood platforms may not be covered with opaque finishes. Scaffolding components from different manufacturers cannot be mixed unless the pieces fit together without force and structural integrity is maintained. Scaffolding components made of different metals may not be used together unless authorized by a competent person.
Supported Scaffolds Supported scaffolds with a height to base width ratio of more than 4: 1 must be restrained from tipping by guying, tying, or bracing. First fastening device should be attached at the closed horizontal member to the 4: 1 height. Every 20 feet after for scaffolds less than 3 feet wide, 26 feet for ones wider than 3 feet. The top must be secured no greater than the 4: 1 height from the top.
Scaffolding Supports Poles, legs, frames and uprights must bear on base plates and mud sills, or other adequate foundations. The footings must be level, and capable of supporting the scaffolding load. Unstable objects cannot be used as supports or working platforms. Forklifts may not be used to support scaffold platforms unless the entire platform is attached to the fork and the forklift is not being moved horizontally while it is occupied. Supports should be plumbed and braced to prevent swaying.
Suspended Scaffolding All suspension scaffold support devices must be able to support at least: ◦ 4 times the weight of the scaffold operating at the rated load of the hoist. ◦ 1. 5 times the load of the scaffold at the stall capacity of the hoist. Whichever is greater. Outrigger beams must be made of metal or an equivalent, and be restrained to prevent movement.
Securing Suspension Scaffolding Before use, the scaffolding support and connections must be evaluated by a competent person who can confirm the surfaces are capable of bearing the load. Outrigger beams should be stabilized by bolts or direct connections. The should be stabilized by solid counterweights. Sand gravel is not acceptable. Counter weights must be designed for the purpose. Outriggers not stabilized by direct connections should be secured with tiebacks. Outriggers should be perpendicular to the bearing support.
Suspension Scaffold Support Devices All support devices such as roof hooks and clamps must be: ◦ Steel, wrought iron, or equivalent material. ◦ Supported by bearing blocks. ◦ Secured from moving by tiebacks installed at right angles and attached to a sound anchorage. Tiebacks be equivalent in strength to hoisting ropes. Repaired wire rope may not be used as suspension rope. Remember that vents, piping, and electrical conduits are not proper anchorage points.
Wire Ropes for Suspension Scaffolding Wire suspension ropes may not be joined unless eye splice thimbles and connected with shackles are used. The load end must be equipped with proper sized thimbles and secured by eye splicing. Ropes must be inspected by a competent person prior to each work shift. The wire rope eye splice.
Wire Rope Inspection Requirements Wire ropes should be replaced if there is: 1. Physical damage that reduces strength. 2. Kinks that impair strength or operation. 3. 6 randomly distributed broken wires in a rope lay. 4. 3 broken wires in a strand of rope lay. 5. Abrasion, corrosion or flattening that reduces the original diameter by one third or more. 6. Evidence of heat damage. 7. Evidence that the secondary brake has been applied during an over speed condition.
Suspension Scaffolding Hoist Requirements Hoists must be tested by a qualified testing laboratory. Gasoline powered equipment and hoists may not be used on suspension scaffolds. Gears and brakes of power operated hoists must be enclosed. Suspension scaffolding hoists must have a secondary brake that engages in an emergency. The same equipment cannot be used for both hoisting and emergency use.
Part III Accessing and Working on Scaffolding
Accessing Scaffolding Systems When scaffolds are greater than 2 feet above a point of access, ladders, stairways, ramps or similar means must be used. Hook-on or attachable ladders must not tip the scaffold. The bottom rung of ladders or first step of stairs may be no more than 2 feet above the scaffold supporting level. Rest platforms required at 35 foot intervals. Slip resistant tread required on all steps and landings. Never access scaffolding by climbing on cross beams.
Proper Use of Scaffolding Never overload scaffolding! Do not use shore or lean-to scaffolds. Scaffolds and components must be inspected by a competent person before every work shift, and after any event where the scaffolding may have been damaged. Scaffolds may not be moved horizontally while employees are on them. OSHA Case Report Six boilermakers had just left a suspension scaffold when it fell about 392 feet along with the foreman, who was killed. The superintendent had ordered the scaffold's main support be disassembled before the scaffold was lowered to ground level. Rigging, welding machines, materials and supplies, etc. , were placed on the scaffold, and two 1 -inch wire rope hoist lines were cut free. This put the load on a single 3/4 inch wire rope hoist line, which was overloaded by 255 percent, and on the diesel hoist located outside the chimney, which was overloaded by 167 percent.
Electrical Clearance Scaffolding must be kept clear of electrical lines. Insulated Lines Voltage Minimum Distance Less than 300 v 3 Feet 300 v to 50 Kv 10 Feet 50 Kv+ 10 Feet +. 4 inches for 1 Kv over 50 Kv Non Insulated Lines Voltage Minimum Distance Less than 50 Kv 10 Feet More than 50 Kv 10 Feet +. 4 inches for 1 Kv over 50 Kv
Portable Electric Tools Metal scaffolding conducts electricity. An insulation failure in a power tool can electrify the whole structure. All portable electric equipment must be protected by a ground fault current interrupter (GFCI) or a company Assured Equipment Grounding Conductor Program. A ground fault current interrupter is a critical safety device.
Working on Scaffolds Never work on scaffolding that is covered with ice, snow or other slippery materials. Employees may not work on scaffolding during high winds or storms unless: ◦ A competent person determines it is safe. ◦ Employees are protected by wind screens or fall arrest systems. Debris should not be allowed to accumulate on platforms. Scaffolding should be kept clear of clutter. This scaffolding is full of trip hazards.
Working on Scaffolds Makeshift devices, such as boxes and barrels, cannot be used to increase the working level height of employees. Ladders cannot be used on scaffolds, unless it is a large area scaffold and the arrangement meets the requirements of 1926. 451(f)(15)(i). The use of ladders on scaffolding is not allowed.
Scaffolding Fall Protection Requirements Employees on a scaffold greater than 10 feet above a lower level must have fall protection. Employees on a scaffolding walkway must be protected by guardrails that: ◦ Have a minimum 200 lbs top rail capacity. ◦ Have a top rail height of 38 inches to 45 inches. Personal fall arrest systems used on scaffolds must be attached to a vertical lifeline, horizontal lifeline, or to a scaffold structural member. 1926. 451(g) has special fall protection requirements for all types of scaffolding.
Protection from Falling Objects Employees must wear hard hats. If there is a danger of falling objects from the scaffolding, the area below must be barricaded and employees prevented from entering. If employees need to access the areas beneath scaffolding, toe boards, screens and canopies must be used to protect employees from the falling object hazards. What work behaviors lead to falling object hazards? How can they be avoided?
Part IV Specific Scaffolding Requirements
Pole Scaffolding A pole scaffold is a scaffold that is entirely made of wood. When platforms are moved to the next level, the existing platform must remain undisturbed until the new bearers have been set and braced. Pole scaffolds over 60 feet must be designed by a professional engineer. Diagonal bracing (The X shaped supports) is required on both sides of double pole scaffolding and on the outside of single pole scaffolding.
Tube and Coupler Scaffolds These are supported or suspended scaffold consisting of a platform(s) supported by tubing, erected with coupling devices connecting uprights, braces, bearers, and runners. When platforms are moved to the next level, the existing platform must remain undisturbed until the new bearers have been set and braced. Couplers must be made of a structural metal. Grey cast iron is prohibited. Tube and coupler scaffolds over 125 feet must be designed by a Professional Engineer. Transverse bracing forming an X across the width of the scaffold must be installed at the scaffold end of every 3 rd set of posts.
Fabricated Frame Scaffolds These are scaffolds supported on fabricated end frames. When platforms are moved to the next level, the existing platform must remain undisturbed until the new bearers have been set and braced. Fabricated frame scaffolds over 125 feet must be designed by a Professional Engineer. Fabricated frame scaffolds should only be used to support workers, unless specifically designed to bear loads and prevent tipping.
Carpenters Bracket Scaffold Each bracket must be connected to the supporting structure by nails, a metal stud attachment device, or welding. Folding type metal brackets, when extended for use, must be bolted or secured with a locking pin.
Outrigger Scaffolding An outrigger scaffold is one with a platform resting on outrigger beams that extent out beyond the Inboard End wall or structure. Outrigger beams must be secured against movement, and must be braced at the fulcrum point to prevent tipping. Inboard ends of outrigger beams Outboard End must be anchored by braced struts in contact with overhead beams or The inboard beams must the ceiling, or secured to the floor. Outrigger scaffolds must be designed by a Professional Engineer. be at least 1. 5 times the length of the outboard beams.
Pump Jack Scaffolding A pump jack scaffold is a platform supported by vertical poles and movable support brackets. Must be fabricated from metal plates and angles, and have two positive gripping mechanisms. Poles must be secured to the structure by rigid triangular bracing. Pump jack scaffolding is common because it is easy to adjust the working height.
Ladder Jack Scaffolding A ladder jack scaffold is made by resting a working platform on brackets attached to a ladder. Platform may not exceed a 20 foot height. The ladders must be placed, fastened, or equipped to prevent slippage. The weight from the platform must bear on the side rails and ladder rungs, or ladder rungs alone. Ladder Jack Scaffolds should be used for light work only. The ladders must be compliant with Subpart X, Stairways and Ladders.
Single Point Adjustable Scaffolding Single point adjustable scaffolding is one that is suspended from a single rope and has adjustable height. The support rope must be vertical unless the rigging is designed by a qualified person and meets the requirements of 1926. 452(o). The maximum intended load for single point adjustable scaffolding is 250 lbs. Window washers commonly use this type of scaffolding.
Two Point Adjustable Scaffolding Also known as swing stage scaffolds, these scaffolds are suspended from two ropes. Workers on these scaffolds must be protected by both guardrails and personal fall arrest systems. Platforms on this type should not be wider than 36 inches.
Multi Level Suspended Scaffolds Must have additional independent support lines that are: 1. 2. Equal in strength to the suspension ropes. 3. Equal in number to the points supported. Rigged to support the scaffold if the suspension ropes fail. Independent support lines and suspension ropes may not be connected to the same anchorage. Support for platforms must be attached directly to support stirrups and not other platforms.
Mobile Scaffolding Mobile scaffolds must be plumb, level, and squared. Must be braced with cross, horizontal and diagonal braces to support vertical members and prevent collapse. To prevent moving, wheels must be locked. Platforms may not extend beyond the base supports.
Moving Mobile Scaffolding Must be stabilized to prevent tipping during movement. Power systems used to move scaffolding must be designed for that purpose. Employees may not ride on scaffolds while moved unless they are made aware of the move and the scaffold meets the requirements of 1926. 452(w)(6). When moving, the force used to move should be applied as close to the base as possible.
Summary Scaffolding systems must be designed by a qualified person. Scaffolding must be able to support its weight and four times the max load. Stall load on hoists for adjustable scaffolding must not exceed 3 times the rated load. Employees working on scaffolding above 10 feet require fall protection. Portable electric equipment must have GFCIs.