Introduction to Scaffolding Safety and Health
Scaffolding and causes accidents
Types of scaffolds
Scaffolding components
General requirements and requirements
Means of protection
Scaffolding rules
Stages of installation of scaffolding
It means connecting the scaffolding
The platform base
Guidelines for Scaffold Erection
What is the most visible sign that a scaffold has not been erected properly? The photo to the right will give you a clue. It’s vitally important to make sure that everyone who is involved in the scaffold erection and use is properly trained, and a scaffold erection process has been developed. Let’s take a look at the key best practices associated with scaffold erection and use.
Pre-planning
The first step in the scaffold erection process is effective pre-planning. A qualified person should do adequate pre-planning to make sure a plan has been develop to make sure the scaffold is erected properly.
Successful pre-planning activities include the following:
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- determine the type of scaffold necessary for the job
- determine the maximum load of the scaffold
- assure a good foundation
- avoid electrical hazards
Click here for a sample Scaffold Erection/Dismantling Checklist.
Supervision
Supervise the erection of scaffolding. This should be done by a person competent by skill, experience and training to ensure safe installation according to the manufacturer’s specifications and other requirements.
Where
Footing
Support scaffold footings must be level and capable of supporting the loaded scaffold. The legs, poles, frames, and uprights must bear on base plates and mud sills.
- Keep the scaffold level, plumb, and square.
- Don’t use bricks, blocks, barrels, or other unstable objects to level a scaffold.
Power Lines
Working around high voltage (HV) power lines can be extremely dangerous. As work is being completed, it’s easy to forget the HV lines are overhead. When working around electrical power lines, make sure you now the voltage of energized power lines and ensure everyone is aware of the location of energized power lines.
Maintain, at a minimum, these clearance distances from power lines:
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- 3 feet for insulated lines less than 300 volts
- 10 feet for insulated lines 300 volts or more
Note: Take the above subject very seriously. Take a look at this short graphic video that demonstrates what happens when a mobile scaffold contacts HV electrical power lines.
Fall Protection
Be sure fall protection equipment is available before beginning erection and use it as needed. Employers must provide fall protection for each employee on a scaffold more than 10 feet (3.1 meters) above a lower level.
A competent person must determine the feasibility and safety of providing fall protection for employees erecting or dismantling supported scaffolds.
See the chart below for a summary of the types of fall protection required for specific scaffolds.
Heat Sources
Identify heat sources like steam pipes. Anticipate the presence of hazards before erecting scaffolds and keep a safe distance from them.
Material Handling
Have scaffolding material delivered as close to the erection site as possible to minimize the need for manual handling. Arrange components in the order of erection.
Storage of Materials
Materials must not be stored on scaffolds or runways in excess of supplies needed for immediate operations.
Condition of Materials
Remove all slippery material from platforms and other scaffold components. Working on a scaffold coated with snow, ice, or other slippery material is prohibited.
Hoisting and Rigging
Ensure hoisting and rigging equipment is available to lift components to the erection point and eliminate the need to climb with components. Examine all scaffold components prior to erection and do the following:
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- Return and tag “Do Not Use” or destroy defective components.
- Prohibit or restrict the intermixing of manufactured scaffold components, unless:
- the components fit together properly, without force
- the use of dissimilar metals will not reduce strength
- the design load capacities are maintained
Crossbracing
When the crosspoint of crossbracing is used as a toprail, it must be between 38 inches (0.97 m) and 48 inches (1.3 meters) above the work platform.
Shore or Lean-to Scaffolds
Shore or lean-to scaffolds are prohibited. They are not properly designed and are a potential safety hazard for anyone who works on them.
Storms and High Winds
Working on a scaffold is prohibited during storms or high winds, unless a competent person has determined that it is safe to be on the scaffold and workers are protected by personal fall-arrest systems or wind screens.
Suspension Ropes
Suspension ropes should be protected from heat and acids or other corrosive substances or be made from material that will not be damaged by corrosive substances.
Tag Lines
When a scaffold might be struck by a swinging load, tag lines or equivalent means should be used to control the load.
Planking
Plank scaffold platforms fully as possible (beginning at the work surface face) with gaps between planks no more than 1 inch wide (to account for plank warp and wane).
See types of planking.
The remaining space on bearer member (between the last plank and guardrail) cannot exceed 9 1⁄2 inches (the space required to install an additional plank).
Platform and Walkway Widths
Platforms and walkways should generally be at least 18 inches wide. If work areas are too narrow for 18-inch platforms or walkways, workers can use narrower platforms, but they should be protected from fall hazards by guardrails and/or personal fall-arrest systems. Some states allow 12-inch widths for ladder jack, top-plate bracket, roof bracket, and pump-jack scaffolds.
Guardrails on Building Side
Guardrail systems are generally not required on the building side when the platform is less than 16 inches from the building, except for suspended scaffolds where the maximum distance is 12 inches. In addition, scaffold setbacks will depend upon the needs of the trade. As an example, masons require the scaffold platform to be as close to the wall as possible (within 6 inches), while lathers and plasterers using spraying apparatus should stand back (and prefer a set-back distance of at least 18 inches).
Overlap
Platform planks overlapped to create a long platform should overlap at least 12 inches over supports, unless the planks are nailed together or otherwise restrained so they do not move.
Abutted Planks
When platform units are abutted together or overlapped to make a long platform, ensure each end rests on a separate support or equivalent support.
Platform Lengths
A platform 10 feet or less in length should generally extend at least 6 inches, but no more than 12 inches, beyond its support, unless the excess length is guarded or can support workers and material without tipping.
A platform longer than 10 feet should generally extend no more than 18 inches beyond a support unless the excess length is guarded or can support workers and material without tipping.
Mixed or Modified Components
Scaffold components made by different manufacturers cannot be mixed unless they fit together easily and do not change the scaffold’s integrity. Components made by different manufacturers cannot be modified to intermix unless a competent person approves.
Components Made from Different Metals
Scaffold components made from different metals cannot be used together unless a competent person approves. If a competent person determines that mixing components made from different metals could reduce their strength, the employer should take corrective action. If a competent person can’t make the determination, then different metals should not be used.
Chemical Treatment
Wood platforms cannot be covered with opaque finishes that might cover defects in wood. Wood platform edges, however, may be marked for identified chemicals. Preservatives or slip-resistant and fire-retardant finishes are acceptable as long as the finish does not cover structural defects or make them hard to spot.
Requirements for Access to Scaffolds
Employers should provide all workers with safe access to scaffolds and scaffold platforms. Workers should use ladders or stairways to reach scaffold platforms that are more than 2 feet above or below the access point.
Do not use crossbraces as a means of access. Note that permanent stairways or portable ladders should meet the requirements of Subdivision 3/X (stairways and ladders) of the construction safety and health standards.
When direct access is used, spacing between scaffold and another surface should be no more than 14 inches horizontally and 2 feet vertically. Access can be provided by:
- portable ladders
- hook-on ladders
- attachable ladders
- stairway-type ladders
- integral prefabricated scaffold rungs
- direct passage from another scaffold
- structure or personnel hoist
- ramps
- runways
- similar adequate means
Ladders and Rest Platforms
Many accidents happen because employees to not access platforms safely. Crossbraces and scaffold frames should not be used to access scaffold platforms unless they are equipped with a built-in ladder specifically designed for that purpose.
- All ladders in use should meet OSHA specifications, designed according to standards and secured against displacement.
- The bottom steps of ladders should not be more than 2 feet from the supporting level.
- Hook-on and attachable ladders on supported scaffolds more than 35 feet high should have rest platforms at 35-foot intervals.
- Stairway-type ladders should have rest platforms every 12 feet.
- Integral prefabricated scaffold-access frames should have rest platforms every 35 feet.
Additional recommendations for the erection of supported scaffolds, suspension scaffolds, fabricated frame scaffolds, outrigger scaffolds, etc., are also described in this course.
