Falls are among the most common causes of serious work related injuries and deaths. Employers must set up the work place to prevent employees from falling off of overhead platforms, elevated work stations or into holes in the floor and walls.
A Personal Fall Arrest System is comprised of three (3) key components – anchorage connector; body wear; and connecting device.
While a lot of focus has been given to anchorage connectors and body wear (full-body harnesses), when discussing fall protection, the connecting device (a shock-absorbing lanyard or self-retracting lifeline) between these two components actually bears the greatest fall forces during a fall.
about 28% of the scaffold accidents that occur are the result of construction deficiencies. These deficiencies include using substandard components, omitting essential components, or failing to complete the assembly.
Of the fatalities that occurred, 23% occurred as a result of construction deficiencies. About 14% occurred while climbing. Another 8% occurred while assembling/disassembling the scaffolding. About 10% of the fatalities occurred where the result of the scaffolding structurally failing. Another 18% of the fatalities happened as a result of electrocutions. Approximately 10% of the fatalities were from falling objects, while 17% happened because of falls while working on the platform.
Metal scaffolding can be used for different purposes in different construction activities. In Iran, it is commonly used as the supporting scaffolding in a falsework system. Collapse of falsework due to reasons such as insufficient strength to carry the imposed loads or inadequacy in design and construction frequently occurs and has inflicted heavy casualties to workers working on it. In order to prevent collapse of falsework on construction sites,
A trained workman in respect of metal scaffolding refers to a scaffolder who is responsible for on-site erection, addition, alteration and dismantling of metal scaffold under the immediate supervision of a competent person, and has satisfactorily completed a formal training in metal scaffolding works at least 1 year of experience in metal scaffolding works (inclusive of experience under the formal training period).
‘scaffold’ means any temporarily provided structure on or from which persons perform work in connection with operations and any temporarily provided structure which enables persons to obtain access to or which enables materials to be taken to any place at which such work is performed, and includes any working platform, gangway, run, ladder together with any guard rail, toe board or and all fixings.
Scaffolding can provide an efficient and safe means to perform work. However, unsafe scaffolding procedures can lead to accidents, serious injuries and death. This guide makes clear that planning ahead for the erection, use and dismantling of scaffolding can substantially reduce scaffold-related accidents and injuries. Compliance with the manufacturer’s instructions, the use of this guide and compliance with all scaffolding standards will help ensure a safer workplace for employees.
Safety and health in the workplace is everyone’s responsibility. Employers must be aware of workplace hazards facing their workers, and they must take appropriate action to minimize or eliminate exposure to these hazards. Workers are responsible for following the policies, procedures and training requirements established by their employers. A Guide to Safe Scaffolding discusses precautions that can prevent serious accidents and protect workers against fall injuries and fatalities.
Scaffolding has a variety of applications. It is used in construction, alteration, routine maintenance and renovation. Scaffolding offers a safer and more comfortable work arrangement compared to leaning over edges, stretching overhead and working from ladders. Suitable and sufficient scaffolding must be supplied for work at elevations that cannot be accomplished safely by other means. Properly erected and maintained, scaffolding provides workers safe access to work locations, level and stable working platforms, and temporary storage for tools and materials for performing immediate tasks.
Accidents involving scaffolding mainly involve people falling, incorrect operating procedures, environmental conditions and falling materials caused by equipment failure. The causes of scaffolding accidents include failures at attachment points, parts failure, inadequate fall protection, improper construction or work rules, and changing environmental conditions (high winds, temperature extremes or the presence of toxic gases). Additionally, overloading of scaffolding is a frequent cause of major scaffold failure.
Safe scaffold erection and use should begin by developing policy and work rules. Policy and work rules should concentrate on:
The scaffold should be capable of supporting its own weight and at least four times the maximum intended load to be applied or transmitted to the scaffold and components. On complex systems, the services of an engineer may be needed to determine the loads at particu- lar points.
Factor these considerations into your policy:
Assign a competent person to oversee the scaffold selection, erection, use, movement, alteration, dismantling, mainte- nance and inspection. Only assign trained and experienced personnel to work on scaffolding. Be certain they are knowl- edgeable about the type of scaffolding to be used and about the proper selection, care and use of fall protection equipment (perimeter protection, fall protection, lifelines, etc.).
Employees should receive instruction on the particular types of scaffolds that they are to use. Training should focus on proper erection, handling, use, inspection, removal and care of the scaffolds. Training must also include the installation of fall protection, particularly guardrails, and the proper selection, use and care of fall arrest equipment.
The competent person(s) should receive additional training regarding the selection of scaffolds, recognition of site conditions, scaffold hazard recognition, protection of exposed personnel and the public, repair and replacement options, and requirements of standards.
Site management personnel should also be familiar with correct scaffolding procedures so they can better determine needs and identify deficiencies.
Accidents and injuries can be reduced when the guidelines in this section are followed.
Supervise the erection of scaffolding. This must be done by a person competent by skill, experience and training to ensure safe installation according to the manufacturer’s specifications and other requirements.
Know the voltage of energized power lines. Ensure increased awareness of location of energized power lines; maintain safe clearance between scaffolds and power lines (i.e., minimum distance of 3 feet for insulated lines less than 300 volts; 10 feet for insulated lines 300 volts or more). Identify heat sources like steam pipes. Anticipate the presence of hazards before erecting scaffolds and keep a safe distance from them.
Be sure that fall protection equipment is available before beginning erection and use it as needed. 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.
Ensure the availability of material hoisting and rigging equipment to lift components to the erection point and elimi- nate the need to climb with components. Examine all scaffold components prior to erection. Return and tag “Do Not Use” or destroy defective components.
Prohibit or restrict the intermixing of manufactured scaffold components, unless: (1) the components fit together prop- erly, without force, (2) the use of dissimilar metals will not reduce strength, and (3) the design load capacities are main- tained.
Require that scaffolds be altered, moved and dismantled under the supervision of a competent person.
Alteration and dismantling activities should be planned and performed with the same care as with erection.Tag any incomplete scaffold or damaged component out of service.
Inspect all scaffolds and components upon receipt at the erection location. Return, tag “Do Not Use” or destroy defec- tive components. Inspect scaffolds before use and attach a tag stating the time and date of inspection.
Inspect scaffolds before each workshift and especially after changing weather conditions and prolonged interruptions of work. Check for such items as solid foundations, stable conditions, complete working and rest platforms, suitable anchorage points, required guardrails, loose connections, tie-off points, damaged components, proper access, and the use of fall protection equipment.
Maintain scaffolds in good repair. Only replacement components from the original manufacturer should be used. Intermixing scaffold components from different manufacturers should be avoided. Fabricated scaffolds should be repaired according to the manufacturer’s specifications and guidance. Job-built scaffolds should not be repaired without the super- vision of a competent person.
Store all scaffolding parts in an organized manner in a dry and protected environment. Examine all parts and clean, repair or dispose of them as necessary.
A tube and coupler scaffold is a supported scaffold consisting of platforms supported by individual pieces of tubing, erected with coupling devices connecting uprights, braces, bearers and runners (see Figure 3). A registered professional engineer may need to be consulted about the design, construction, and loading of the scaffold. Tube and coupler scaffolds over 125 feet high must be designed by a registered professional engineer and be constructed and loaded consistent with the design.
Transverse bracing forming an “X” across the width of the scaffold must be installed at the scaffold ends and at least at every third set of posts horizontally (measured from only one end) and every fourth runner vertically. Bracing must extend diagonally from the inner or outer posts or runners upward to the next outer or inner posts or runners. Building ties must be installed at the bearer levels between the transverse bracing and must conform to the requirements of This bracing must be placed for each section of six levels between the fourth and sixth levels. The brac- ing must extend diagonally from the inner or outer posts or runners at the bottom of the fourth level, upward to the inner or outer posts or runners at the bottom of the fifth level, and likewise to the sixth level. If this technique is used, the scaffold should be tied at the “k” function level.
On straight run scaffolds, longitudinal bracing across the inner and outer rows of posts must be installed diagonally in both directions and must extend from the base of the end posts upward to the top of the scaffold at approximately a 45 degree angle. When the length of the scaffold is greater than the height, such bracing must be repeated starting at least with every fifth post. When the length is shorter than the height, such bracing must be installed from the base of end posts upward to the opposite end posts and then in alternating directions until the top of the scaffold is reached.
In situations where the attachment of bracing to posts is precluded, the bracing must be attached to the runners. Bearers must be installed transversely between the posts, and when coupled to the posts, the inboard coupler must bear directly on the runner coupler. When the bearers are coupled to the runners, the couplers must be as close to the posts as possible. Bearers must extend beyond the posts and runners and provide full contact with the coupler.
The scaffold must have runners installed along its length along both the inside and outside posts at the various level heights. Runners must be interlocked on straight runs to create continuous lengths and be coupled to each post. Bottom runners should be located as close to the base as possible. Couplers must be made of structural metal. When platforms are being moved to the next level, the existing platform must be left undisturbed until new bearers have been set in place and braced prior to receiving the new platforms.