Scaffold safety requirements: The fall of people from work at height, as well as materials and objects, represents the most dangerous in the construction industry. Falls cause a large proportion of deaths. Many are produced from an unsafe working platform or unsafe means of access to the work location. In this blog, we will discuss the type of temporary working platform (scaffolding), ladders and their hazards and safe erecting, modification and dismantling procedures.
Scaffolding can be defined as a temporary structure that supports one or more platforms and is used as a working platform or to store materials in any type of construction work, including maintenance and demolition work. This is the sense in which the term is used here Scaffold safety requirements. Scaffold safety requirements
When work cannot be carried out safely on the ground or the building or structure, suitable scaffolding must always be available. It must be properly assembled from solid materials that are strong enough to simultaneously provide workers with equally safe means of access and a working platform. Scaffold safety requirements
Scaffold safety requirements overview
Scaffolds should only be erected, modified or dismantled by competent persons (certified by a third party) under supervision, and this manual describes the general principles of the most common types of scaffolds. These are Scaffold safety requirements that after erection, the scaffold must be inspected at least once a week, keeping a written record (Tagging system) of each inspection including:
- The Scaffold safety requirements are that the Scaffold load rating, corresponding to the maximum intended load of light duty is 120 kg/m² (1.2 N/m²) (25 lb/ft², medium-duty – 240 kg/m² (2.4 N/m²) (50 lb/ft²), and heavy scaffold is designed for more than 240 kg/m² (2.4 N/m²) (50 lb/ft²).
- Base plate: dimensions for all scaffolds post shall be 150 mm (6 inches) * 150 mm (6 inches) and 6 mm thick.
- Guard rail system: the height of the top rail is not less than 0.95 m (38 in) and not more than 1.15 m (45 in). Mid rail should be installed between the working surface and the top rail. The guard rail system should be able to withstand at least 90 kg. (200 lb). Toe boards should be at least 100 mm (4 in) and capable of withstanding 23 kg. (50 lb).
- Tagging system: green tag no need full-body harness means complete scaffold, yellow tag means need full-body harness due to some interference in scaffold erection, red tag for scaffold erection, dismantling and modification.
- High wind: The Scaffold safety requirements are that Scaffold erection, dismantling and modification is not permitted if the wind speed is more than 65 Kph (40 mph).
- The scaffold bay has two sides, one side is called the transverse side and another one is called the longitudinal side. Medium-duty scaffolds, the maximum transverse post spacing (bearer/transom span) is 1.2 m (4 ft) and the maximum longitudinal post spacing (runner/ledger span) is 1.8 m (6 ft).
Scaffold Tube Fittings
Scaffold tubing should be an outside diameter of 48.3 mm (1.9 in), and a wall thickness of 3.76 mm (0.15 in). Scaffold couplers shall be marked as conforming to EN 74. The scaffold component should be capable of supporting its weight (dead load) and at least four
times the maximum intended load (live load) (i.e., D+4L).
The Scaffold safety requirements are that the scaffold structure must be tied vertically every 8 m (26 ft) (4 lifts) or less and at horizontal intervals not to exceed 9 m (30 ft). Bases of scaffolds should be at least 1.5 times the depth of excavation away from the edge of the excavation.
The Scaffold safety requirements are that the Gin wheels shall be mounted on a cantilever tube projecting outward from the scaffold and shall be kept to a minimum distance, not greater than 750 mm (30 in). The horizontal tube holding the gin wheel shall be fixed with right-angle couplers to two scaffold posts (standards). Materials to be raised should be firmly attached to the gin wheel rope and shall not exceed 50 kg (110 lb). Gin wheel ropes shall be of the correct size to suit the gin wheel, usually 18 mm (3/4 in).
The Scaffold safety requirements are that the maximum lift height should be 2 metres. Vertical bracing to prevent excessive sway in both the transverse and longitudinal directions must be installed at an angle of between 35 degrees and 55 degrees above the horizontal. Runners (ledgers) and bearers (transoms) shall be securely attached to the inside of each post (standard) only with right-angle couplers.
The runners and bearers (base lift) should be located approximately 150 mm (6 in) above the scaffold base.
Reference: Scaffold safety requirements
What are the hazards and potential risks associated with scaffolds?Scaffold safety requirements
In any work, we must always be attentive to safety, but the risks on scaffolding represent one of the weakest and most critical points of that safety plan. We can designate the following essential points to which we must pay special attention:
- Remote falls from different levels. It can be at the time of assembly or disassembly, due to the absence of railings, platform deficiencies, misuse of stairs… etc.
- The possible collapse of the structure. Whether due to a softening or sinking of the support surface, incorrect support to the ground, improper use of the platform, incorrect assembly… etc.
- Fall of materials on goods or the operators themselves. Due to an overturning of the scaffolding, due to an unprotected platform, due to not adequately marking the material hoisting area… etc.
- The operator falls to the same level. It is mainly caused by a lack of cleanliness and order on the surfaces of the platforms, the existence of inadequate holes, deficiencies in the fastening of the work platforms to the structure that can cause displacement or movement, etc.
- Indirect or direct electrical contacts with special attention to overhead power lines.
- Entrapment of the extremities of the operators in their work functions.
- Overexertion in the assembly and disassembly work. It is due to the operators or the components themselves.
What are the safety precautions for scaffolding?
- Design, assemble and maintain in such a way as to prevent accidental, collapse or movement.
- Keep Scaffold working platforms and ladders free from falling objects and obstructions.
- The dimensions, shape and arrangement of the platforms of a scaffold must be appropriate for the type of work to be carried out. The platform must be adequate for the loads they have to support and allow safe work and movement on them.
- Free from a dangerous gap between platform components.
- Holding a red tag during erection, dismantling or modification that prevents access to the danger zone.
- Scaffolds may only be erection, dismantled or modified under the direction of a person with professional training. Workers who have received adequate and specific training, allow for the planned operations.
- The understanding of the assembly, disassembly or transformation plan of the scaffold.
- The measures to prevent the risks of falling people or objects.
- Safety measures in the event of changes in weather conditions that could negatively affect the safety of the scaffolder.
- Any other risk involved in the erection, dismantling or modification operations.
- Scaffolds inspection by a professionally trained person before in-service.
- After any modification, period of non-use, exposure to rain, seismic shocks, or any other circumstance that could have affected its resistance or stability.
What is the most commonly used type of scaffold?
Many different types of scaffolds are used to build but the safety principles remain the same:
- That the structure has the necessary strength to support the weight and stresses that workers and processes will have to exert on it;
- That it has a safe and stable anchorage, and that it is designed to prevent the fall of workers and materials.
- Tower Scaffold
- Independent Scaffold
- Birdcage Scaffold
- Cantilever Scaffold
- Suspended Scaffold
- Mobile Scaffold
What are the two types of tower scaffolds?Scaffold safety requirements
A tower scaffold consists of a platform resting on horizontal ledgers connected to four uprights post by base plates if the structure is fixed, or by wheels if it is mobile (see below detail about mobile tower Scaffold). It is used by painters and other labourers who do light, limited-duration work or used for access to independent Scaffolds. The stationary tower scaffolds height shall not exceed four times the minimum base dimension
Hazards of Tower Scaffold
Accidents can occur when the tower tips over, which is likely when:
- The ratio between the height and width of the base is excessively large.
- The upper work platform is overloaded and makes the structure unstable.
- A mobile tower is moved by people with materials or men on the platform.
- The tower is not secured to the building or structures.
The Scaffold safety requirements are that the tower scaffolds must be upright and used only on a firm, level with fixed tower uprights supported on suitable base plates. The dimensions can vary according to the needs, but the ledgers must never be less than 1.2 m apart from each other. The work platform will require railings and toeboards on the edges.
An independent scaffolding consists of two rows of standards in only one direction running parallel to the wall of a building or structure. Although freestanding scaffolds have to be tied to the building or structure. The braces are essential to give rigidity to the scaffold and prevent lateral displacements; they must run diagonally from one post to another, or from one stud to another. The braces can be parallel or zigzag up.
Scaffold safety requirements are the placement of safety rails and toe boards in all places where falls of more than 1.8m can occur. It is of fundamental importance in the prevention of fall mishaps. Both must be fixed on the inside of the uprights. The railings must be between 90 cm and 1.15 m high above the platform, to prevent easy falls from above or below.
The toe-boards, which are also intended to prevent material from being pushed over the edge of the platform, must be raised at least 4 inches above the platform to achieve their purpose, and if materials are stored higher such It may be necessary to add planks or fill the space with wire mesh.
Birdcage scaffolding is typically used in buildings where access is required, to high levels, for example, roofs. A birdcage is a freestanding scaffold consisting of more than two rows of standards in both directions connected by a brace at each platform height.
- Only use cage-type scaffolding to support formwork if it has been specifically designed for this purpose.
- Provide longitudinal bracing or a tied face on every third longitudinal row of standards.
- Reinforce the outer row of standards on each face and every third row internally with longitudinal bracing.
- Provide cross-bracing at every fourth run at the ends of the scaffold.
- Consider the use of elevating work platforms to help erect or dismantle birdcage scaffolds.
Cantilever scaffolding, also known as needle scaffolding, is a type of scaffolding that is a separate scaffold that is built to form an angle outside of a structure. Generally, this scaffolding is placed near balconies to facilitate access. This scaffold is specifically used when there are obstacles on the ground or narrow paths that prevent the scaffold from being supported on the ground.
One of the main benefits of cantilever scaffolding is that it is cost-effective and cost-effective in situations where the surface does not allow for a regular scaffolding system. Cantilever scaffolds are relatively easy to erect and this can support both the average worker and supplies. This scaffolding eliminates the need for posts and frames erected in front of a building.
- Also known as “single frame scaffold”.
- It requires several revisions before its installation.
- Its use requires a lot of attention and care.
- It can be used for the construction of a high wall or when the ground is close to the wall and has no obstacles.
They are generally used on tall structures or buildings located on busy streets, or in other circumstances where it is not feasible or economical to erect scaffolding from the ground. They are suspended from the building or structure using cantilevers and rails. The work platform should be inspected every time it is to be used, and at least once a week. The maximum workload will be marked on it.
All suspended scaffolds require the services of a suitable person, capable of supervising their construction and subsequent use. Assembly should only be done by someone experienced. Only people who have been trained in the use of safety equipment and devices, and have emergency procedures should work on suspended scaffolds. Remember that to work on suspended scaffolds you must wear a safety belt with a lifeline securely attached to the building.
The Scaffold safety requirements are that the hanger tubes should be attached to the supporting beam using a box-type connection made up of two horizontal tubes, with each horizontal tube attached to the top and bottom flanges of the supporting beam with a pair of girder couplers. Check (safety) couplers shall be installed at the top and bottom of all hanger tubes. Scaffold safety requirements
Check (safety) couplers shall also be installed directly beneath all trapeze tubes. Trapeze tubes shall be installed approximately 600 mm (2 ft) below the lowest platform level to assist in erection, alteration and dismantling.
Mobile scaffolding Tower
A mobile scaffold assembly is supported by casters and therefore moved along manually. A mobile scaffolding tower consists of four posts. And connected longitudinally with runners and bearers at right angles to the runners and forming a square or rectangular tower subsequently.
The Scaffold safety requirements are that the height from the base to the working platform of a mobile tower scaffold certainly shall not exceed 3 times the minimum base dimension. Therefore the working platform may be used up to a maximum height of 12 meters (40 feet). A mobile tower scaffold has a single working platform and is a common form of access scaffolding for painters and others who do work of a light nature and short duration likewise.
What must you ensure when working on a mobile tower scaffold?
Mobile towers height (from the ground to the last platform): 3 times of minimum dimension and a maximum of 12.2 meters (40 feet). The access ladder to the work platform must be placed inside the tower, as a precaution so as not to tip it over. The work platform will require railings and toeboards on the edges, similar to freestanding scaffolds.
Light-duty tube and coupler mobile tower scaffold: It has only four posts and shall have a maximum post spacing of 2 meters in both directions.
Medium-duty tube and coupler mobile tower scaffold: It has also only four posts and shall have a maximum post spacing of 1.5 meters in both directions.
The Scaffold safety requirements are that the wheels of the mobile towers must have a device for blocking rotation. The correct operation of the brakes must be verified. These towers should only be moved manually on firm, solid, level and unobstructed ground. Wheels or casters are not less than 12.7 centimetres (5 inches) in diameter for light-duty, and 18 c.m (7 inches) for medium or heavy-duty mobile tower scaffolds.
To prevent tipping, it is forbidden to move them with personnel or materials and tools on them. A mobile tower scaffold shall be moved only by pushing or pulling at the base. Force must not be applied at a height greater than 1.4 meters (4 feet, 6 inches).
That is to say, it is not authorized to install pulleys or other lifting devices on these types of scaffolding. Meanwhile, access to the platform of this type of scaffolding must be done from the inside with an integrated ladder.
The Scaffold safety requirements are that It certainly is protected on the four perimeter sides by a railing with a minimum height of 90 cm. It would be recommended 1 m ± 50 mm, an intermediate bar at a minimum height of 0.45 m and a skirting board at a minimum height of 0.15 m.
However, the access must not rest on the ground. The distance from the ground to the first step will be 400 mm maximum. Do not jump between a mobile work tower and any fixed element of the work or building.
Scaffolding ladder with a working platform
Every year many workers are killed or seriously injured while working with ladders of all kinds. The fact that ladders are so readily available and cheap sometimes makes their limitations seem obvious. So, the first thing to ask is whether it is not safer to carry out the work in question with another type of equipment. For example, a suitable work platform often ensures that the task is carried out more quickly and efficiently.
- If you are going to use a ladder, remember that:
- It only allows the ascent or descent of one person at a time;
- It only allows one person to work from it at a time;
- If it is not tied at the top, it will require a worker to hold it;
- Climbing a ladder with tools or loads is difficult and dangerous. There is also the danger of dropping things on top of other people;
- It has to be well-located and fastened;
- It is limited in how high it can reach.
More than half of ladder accidents are caused by the ladder slipping at the bottom or top, so be sure to set it on firm, level ground. Never jack up one side of the base with a wedge if the ground is uneven. Whenever you can tie off the top of the ladder another person must hold it on the base while operating. If this is not feasible, support the foot of the ladder by tying it to stakes in the ground or using sandbags.
If that is not possible either, another worker should stand at the foot of the ladder to prevent it from slipping while you work, but this precaution is effective only if the ladder is less than 5 m long. Your partner should face the ladder holding a crossbar in each hand, with one foot on the first rung.
What is the safety rule when using a ladder?
Safe use means taking the following precautions:
- Check that there are no overhead power lines that the ladder could come into contact with;
- When wooden ladders have metal-reinforced stringers, you should use them with the metal part to the rear. Metal crossbars must be below the rungs and not above;
- The ladder must extend at least 1 m above the place to be accessed. This avoids the risk of losing balance when entering and exiting from the top.
- Never use a ladder that is too short, and never support the base on a box, a pile of bricks, a fuel drum or the like to lengthen it;
- Support the ladder at a safe angle of about 75° to the horizontal, i.e. leave a span of about 1m at the base for every 4m of height;
- Go up or down facing the ladder;
- Make sure there is enough space behind the rungs to support your feet;
- On extension ladders, leave at least two rungs overlapping if the sections are 5 m long, and three rungs if they are longer than 5 m.
- Check that your shoes are clean of mud or grease before climbing a ladder;
- Whenever possible, carry tools in your pockets or bag when climbing a ladder, leaving your hands free to grab the rails. Use a rope to lift them.
- A common cause of accidents is overreaching; don’t try to reach too far and move the ladder when necessary.
Base Plate – A metal plate with a screwjack for distributing the load from a post.
Bearer (Transom) – A horizontal tube connects the outer posts to the inner posts.
Brace – A tube placed diagonally to give stability to the scaffold.
Coupler – A fitting for locking together components of the scaffold.
Design Load – The maximum intended load, including the worker(s), material and equipment.
Guardrail System – A rail system erected along open sides. The rail system consists of a top rail and a mid-rail.
How much weight can a scaffold coupler hold?
Scaffold couplers are essentially the fundamental component used to assemble tube and coupler scaffolds. A tube and coupler scaffold is defined as “a scaffold in which individual circular tubes serving as standards, clamps, or ties are joined by specifically designed couplers.”
This basic accessory that is designed to join two scaffold tubes can be used to create a wide range of scaffold structures or can be used as an accessory for prefabricated scaffold systems.
This manual includes basic types of scaffold couplers that join two tubes together, as well as special couplers that are used to connect scaffold tubes to other components, equipment, or structures. scaffold clamp load capacity.
Safe working loads (SWL) for couplers in ponds
|Type of coupler||EN 74 class||Rated SWL|
|Swivel||A – B||1190|
|Sleeve||B – B||675|
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