Scaffolding is widely used on construction project. The quality and durability
are the main essential parts of it because it supports the workers.Scaffolding platforms help all kinds of workers reach places difficult to reach
even on ladders. Carpenters and construction workers, painters, maintenance
workers and electricians all use scaffolding. There are many different types of
scaffold platforms with different support systems to accommodate the various job
requirements. Now, if we take closer look, we will find that there are three different types of scaffolding. Each type serves for different function as well. Let’s take a look.
What Are the Different Types of Scaffolding?
Access Scaffolding, Aluminium Scaffolding, Chimney
Scaffolding, Commercial Scaffolding, Domestic Scaffolding, Exterior Scaffolding,
Facade Access, Facade Scaffolding, Guttering Scaffolds, Independent Scaffolding,
Industrial Scaffolding, Inside Scaffolding, Putlog Scaffolding, Roofing
Scaffolds, Scaffolding, Span Deck, Stage Scaffolding, Support Scaffolding,
System Scaffolding, new builds, Roofs, Call outs, Home owners.
Types Of Scaffolding And its Uses..
There is a surprising range of scaffolding types that can be used in construction and for other purposes. The general principle of a scaffolding construction, whether it is a static, rolling, or any other type of construction, remains the same – to provide a platform for workers and materials while work takes place.Most often seen in construction projects, scaffolding structures and other constructs can be used for a variety of purposes. It is common to see scaffolding being used for repair work, to access high objects, for window cleaning tall buildings, and more. Choosing the most appropriate form of scaffold structure is an important stage in the project that you are undertaking.
1,Supported Scaffolding
This is the most commonly used form of scaffolding and is the type that you will see being used in construction work and on most other forms of work where elevation is required. Extra support may be required if the scaffolding will be long or required to take a lot of weight.Supported scaffolding is built from the base upwards, and will normally be used wherever possible. It is considered the easiest, most convenient, safest, and most cost effective form of scaffolding construct. Different forms of supported scaffolding are available, and each will serve a very specific purpose and used in specific circumstances.
2,Suspended Scaffolding
Suspended scaffolding is typically suspended from a roof or other tall construct. It is most commonly used when it is not possible to construct a base, or where access to upper levels may be required, and the building of scaffolding from floor to the required level would be impractical.This type of scaffolding is commonly used by window cleaners on tall buildings, but may also be seen where repairs are needed to the exterior of upper levels of similarly tall buildings. Supported scaffolding is usually preferred where possible.
3,Rolling Scaffolding
Rolling scaffolding is a similar type of construct to supported scaffolding, but rather than offering a stable base, it uses castor style wheels that enable the base to be moved. This is a useful form of scaffolding when you need to complete work over a longer distance than a single scaffolding construction would permit.The wheels should be locked when workers or materials are on the scaffolding, in order to ensure the safety of those using it, and those around it.
4,Mobile Scaffolding
There are a number of factors to consider when deciding whether to use static or mobile scaffolding. Ease of access is one such consideration, along with the amount of movement on the scaffolding itself. Where possible, you should rely on the use of a single scaffolding structure, or a number of structures, because mobile units, while perfectly safe when well-constructed and used properly, do pose more of a hazard than mobile constructs.Most scaffolding is considered semi-permanent. Once used, it can be taken apart and moved to another location before it is constructed again. Fixed scaffolding can be left in position for longer periods of time, making it especially useful in those situations where permanent access may be needed to elevated positions.
5,Aerial Lifts
Aerial lifts should be used where workers need to be able to access a number of levels in order to be able to complete a construction. For example, if building work is being completed on the outside of a multi-storey property and both workers and materials will be needed to work outside two or more floors, at different times, then an aerial lift will make it easier and safer to lift even large amounts of material, and multiple workers to the levels required.Scaffold components cannot be mixed if they are from different manufacturers unless they fit together without force. Scaffold components of dissimilar metals should not be used together, unless the competent person has determined that galvanic action will not reduce the strength of any component.
Supported scaffold poles, legs, posts, frames, and uprights shall bear on base plates and mud sills (or other adequate firm foundation). The size of the mud sill shall be based on the type of soil the scaffold will be erected upon.
Scaffolds 4 levels or less in height
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2" x 10" pad, 12" - 18" long
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Scaffolds > 4 levels on Type A Soil
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2" x 10" pad, 18" long
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Scaffolds > 4 levels on Type B Soil
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2" x 18" x 18" pad
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Scaffolds > 4 levels on Type C Soil
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2" x 36" x 36" pad
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The base and mud sill must provide a solid surface for the feet to
sit upon so that the scaffold doesn't sink, move, settle, or shift. Unstable
objects, such as bricks, cinder blocks, buckets, scrap lumber, etc., shall not
be used to support or level scaffolds. Screw jacks must be used to level
scaffolding on uneven surfaces. The maximum extension for a screw jack is 18
inches high. Most screw jacks will have a built-in stop so that the maximum
height cannot be exceeded. (For mobile scaffolds, the maximum height of the
screw jack is 12 inches.) Plumb/Level/Square..
Supported scaffold poles, legs, posts, frames, and uprights shall be plumb (i.e.
perfectly vertical) and braced to prevent swaying and
displacement. Cross bracing is required on both front and back sides of each
scaffold buck or frame. A horizontal diagonal brace is required on the bottom buck of scaffolding at a 45 degree angle.
To check a scaffold for being plumb, use a level on two opposite uprights. To make sure the scaffold is level, use a level on a horizontal support or bearer. To ensure the scaffold is "square", use a tape measure and measure the distance between opposite corners. The two measurements should be equal.
Securing..
Scaffold frames (i.e. bucks) must be joined together vertically by coupling or stacking pins (or equivalent means).
Scaffolds with a height-to-base width ratio of more than
four to one shall be restrained from tipping over by guying, tying, bracing, or
equivalent means. Guys, ties and braces shall be installed where horizontal
members support both inner and outer legs. Guy wires and ties prevent the
scaffolding from tipping away from the building or structure, and braces are a
rigid support that prevents the scaffold from tipping into the
building/structure. Vertical Securing
If the base width is wider than three feet, the first tie will be a vertical distance of four times the base width and every 26 feet vertically thereafter. For example, if the base width is 5 feet, the first vertical tie will be (5 feet x 4) 20 feet from the ground.
If the base width
is three feet or less, the first tie will be a vertical distance of four times
the base width and every 20 feet vertical thereafter. For
example, if the base width is three feet, the first vertical tie will be (3 feet
x 4) 12 feet from the ground. Horizontal Securing
For long (running) scaffolds, guys, ties, and braces shall be installed at each end of the scaffold and at horizontal intervals not to exceed 30 feet.Platforms/Decking
Platform/decking planks may be made of solid sawn wood, manufactured wood, manufactured steel, or manufactured aluminum. If solid sawn wood is used, it must be scaffold grade.- Note: Once a plank has been used as a mud sill, it cannot be used as decking again.
Where the platform will not be more than 14 inches from the face of
the work (18 inches for plastering and lathing operations), fall protection is
not required. The face of the work (ex. the side of a building) basically serves
as the fall protection system. The ends of each platform must be cleated or restrained by hooks (or equivalent) to prevent accidental displacement, or must extend at least 6 inches over the centerline of the support.
- The maximum extension of the plank cannot be more than 12 inches for planks that are 10 feet long or less.
- For planks that are greater than 10 feet long, the maximum extension past
the
centerline of the support is 18 inches.
- Where platforms overlap to create a running scaffold, the overlap must occur only over a support and shall not be less than 12 inches unless nailed together.
Wooden platforms (i.e. decking, planks) must not be painted to hide defects. They may, however, be treated periodically with clear preservatives, fire-retardants, and/or slip-resistant finishes.
Access..
Proper access must be provided to access the work platform of the scaffold.- Ladders that are a part of the scaffolding system, such as hook-on and attachable ladders, shall be positioned so that the bottom rung is not more than 24 inches above the supporting level.
- Portable extension ladders used to access the work platform must meet OSHA design and use criteria, which includes securing the ladder to the scaffold at the top and bottom and having the ladder extend at least three feet past the landing surface. Ladders must also be positioned so as not to tip the scaffold.
Stairtowers must have hand and midrails on each side of the stairway. Stairs must be at least 18 inches wide and have a landing platform at least 18 inches long at each level. Stair treads must be of slip-resistant design. The riser height must be uniform, and the stair angle must be between 40 and 60 degrees from the horizontal.
- Where the frame of the scaffold will be used for access, the manufacturer must specify in writing that it was designed for such purposes. Design features include a rest platform every 35 feet, rungs at least 11 1/2 inches wide (8 inches for ladders built into the frame), and uniform rung spacing not exceeding 16 3/4 inches.
Fall Protection..
1,Guardrail Systems...
At Virginia Tech, a fall protection system (i.e. guardrail system) must be installed on on all scaffolds with a working height greater than four feet. The guardrail system shall be installed along all open sides and ends of the platform before being used as a work platform by employees. One exception is when the scaffold platform is within 14 inches of the face of the work.
Top rails (manufactured after 1/1/2000) must be between 38 - 45
inches above the platform surface. (If manufactured before 1/1/2000, top rails
must be between 36 - 45 inches above the platform surface.) Top rails must be
capable of supporting at least 200 pounds applied in a downward or outward
direction. - Note: Crossbracing is acceptable in place of a top rail when the crossing point of the two braces is between 38 - 48 inches above the work platform. It cannot serve as both a midrail and a top rail.
Note: Crossbracing is acceptable in place of a midrail when the crossing point of the two braces is between 20 - 30 inches above the work platform. It cannot serve as both a midrail and a top rail (as incorrectly done in this picture).
2.Personal Fall Arrest Systems...
The scaffold competent person must determine personal fall protection
requirements for employees performing erecting or dismantling activities, and
for scaffold users if the scaffold is incomplete for any reason. Personal fall
protection must be required and provided by the employer where the
installation and use of such protection is feasible and does not create a
greater hazard. Personal fall arrest systems used on scaffolds are required when the guardrail system is incomplete or does not provide adequate protection. Lanyards or connecting devices must be connected to a vertical lifeline (1st choice), a horizontal lifeline (2nd choice), or a structural member of the scaffold (last choice). 3.Toeboards
Toeboards must be installed on work platforms where materials or tools will be in use. Toeboards must be installed not more than 1/4 inch above the platform and securely fastened. They may be made of solid material or mesh with openings no greater than 1 inch. Toeboards must be capable of withstanding at least 50 pounds applied in a downward or outward direction.
4.Nets and Platforms..
Additional protection from falling debris and other small objects must be provided in areas where personnel will be in the vicinity of scaffolds. Such protection may be in the form of:
- Barricades to keep personnel out of a hazardous area,
- Screens which are erected between the toe board and hand rail of the work platform,
- Debris nets to catch materials before they hit the ground, or
- Canopy structures made of solid materials.
Scaffolding Basic Components...
Intelligent design based on Layher’s unique connection technology provides verified high load-bearing capacity and reduces the required material to a minimum.A few basic components form the basis for almost limitless uses. There are many additional parts for special solutions, such as console brackets, stairs, aluminium beams, and edge protection. Layher Allround scaffolding is available in steel or aluminium. All steel components are manufactured in Germany from high grade steel with superior hot dipped galvanising, and so are durable and virtually maintenance free.
7 basic components
» Adjustable base plate
» Base collar
» Standards
» Ledger
» Diagonal brace
» Deck
» Toeboard
» Base collar
» Standards
» Ledger
» Diagonal brace
» Deck
» Toeboard
Adjustable base plates (screw jacks)
Supported scaffold poles, legs, posts, frames, and uprights shall bear on base plates and mud sills (or other adequate firm foundation). Choose between different height-adjustable base plates with sturdy and self-cleaning round threads, with colour and notch markings to provide protection against overwinding. The size of the mud sill shall be based on the type of soil the scaffold will be erected upon.Swivelling base plates are available for sloping ground or uneven surfaces, e.g. in combustion chambers or ship hulls.
Supported scaffold poles, legs, posts, frames, and uprights shall bear on base plates and mud sills (or other adequate firm foundation). Choose between different height-adjustable base plates with sturdy and self-cleaning round threads, with colour and notch markings to provide protection against overwinding. The size of the mud sill shall be based on the type of soil the scaffold will be erected upon.Swivelling base plates are available for sloping ground or uneven surfaces, e.g. in combustion chambers or ship hulls.
Base collars..
The base collar with rosette
together with the height-adjustable base plate form the scaffolding base. The
vertical standard is then placed into the base collar for further
construction.
Standards..
Standards are available in hot-dip
galvanized steel, dia. 48.3 x 3.2 mm, or aluminium, dia. 48.3 x 4.0 mm, with
rosettes at every 50 cm for a maximum of eight connections. Four small openings
in the rosette determine right-angled connections, four larger openings permit
connections at any angles.
Ledgers..
Ledgers are available in different
lengths, depending on the scaffolding bay length, deck type and load. Ledgers
are both guardrails and bracing elements - no ledgers are required at deck
level, which reduces the number of components required compared with other
systems, saving weight and cost. U transverse ledgers and U bridging ledgers,
with lock against lift-off (LALOs), reinforced ledgers, are also available.
Diagonal braces..
The diagonal braces with
wedge brace the basic system together thanks to their high connection
values.
Toe boards..
Toe boards are positioned between
vertical standards, and are available in steel, aluminium or wood (which can be
branded). The steel toe board reduces fire risk and is longer lasting. Due to design, there are gaps will be differ or no gap between the to board and
deck.
Decks..
Choose from decks made of hot-dip
galvanized steel, aluminium, wood or an aluminium frame with plywood board. Or
choose the latest technology in deck construction with the strong yet
lightweight FIPRO deck (glass-fibre reinforced plastic). Decks provide
bracing so ledgers are not required at deck level, saving cost and weight. Hatch
decks are available, providing internal access via integrated drop down
ladders.
Steel decks (planks)
Steel decks are Perforated, non-slip steel decks are available in two
widths, 0.32m and 0.19m, and lengths from 0.73m to 4.14m.
Lapping decks (planks)
The lapping plank is a safe bridging element capable of
bearing high loads. Planks are available in two widths, 0.30m and 0.19m, and
lengths from 1.00m to 2.50m. Lapping planks are available with 1 or 2 locking
pins.
FIPRO decks (planks)
Deck of glass-fibre-reinforced plastic with steel caps,
3 steel claws and steel edge guard. Non-slip, lightweight, strong and sturdy.
Measuring 0.61m wide, and lengths of 2.57m and
3.07m.
Robust decks (planks)
Aluminium stile section, 3 plywood panel BFU 100 G 3
Phenolic resin coating and rot protection; 3 lightweight, non-slip, easily
stackable. Measuring 0.61m wide and 0.32m wide, and lengths of 0.73m to
3.07m.
Hatch decks (planks)
Internal accesses can be built into the scaffolding
with the hatch-type access decks. These decks are available with or without an
integrated ladder for internal access.
The Leaders must have training..
There are also requirements that relate to the work of erecting, altering and dismantling scaffolds, i.e. they must be led by a competent person with sufficient knowledge and experience of such work. The foreman must have undergone general or special training. The foreman must also have access to the plan before the work is started.The theoretical knowledge must at least include:
- An understanding of plans for the erection, dismantling or alteration of scaffolds
- Safety in the erection, dismantling or alteration of scaffolds
- Measures to prevent the risk of people or objects falling
- Safety measures that need to be taken when the weather changes in a way which adversely affects safety
- Conditions as regards permissible loads
- Any other risk which the above mentioned work of erection, alteration or dismantling may entail.
... and also those who erect
The person doing the work must have adequate training for the work to be done and the specific risks involved, according to one of the following alternatives:
- General training is suitable for those working with scaffolds at a maximum height of 9 metre (four lifts) to the working level and where the design is indicated by a general instruction manual.
- Special training is appropriate for those working with more complex scaffolds than those listed above.
- if a scaffold is manufactured abroad and is used in Sweden by people other than those employed by the company, such as subcontractors or companies carrying out work at the same work site, the scaffolding must be type examined by an accredited body.
- There must always be instructions on how to erect, use and dismantle along with instructions on how the scaffold should be maintained. The instructions must be available in the languages used by the workers at the workplace.
- There must be documentation showing that the scaffold is sufficiently strong and stable at the maximum intended load.
- There must be documentation showing that the scaffolding has been checked before it was delivered to be used. These checks are often made jointly by the erector of the scaffold and the person who has ordered it.
2. Take the time for prep work. Before using scaffolding, make sure the base is sound, level and adjusted; that the legs are plumb and all braces in place; that locking devices and ties are secured; that cross members are level; and that planks, decks and guardrails are installed and secure. Check the location for ground conditions, such as slopes, and stay clear away from hazards such as overhead wires, obstructions and changes in surface elevation.
3. Keep it legal. Samsung standard committees have identified “rogue employers” as a significant obstacle to scaffold safety. “These are employers who fly under the radar and operate without a license,” says Mr.Kathikeyan, Samsung Scaffolding Inspector. “They get some pick-up truck, rent a unit and hope they don’t get caught. They might import material from offshore and put it together without having it surveyed or reviewed by a professional engineer.”
4. Know and respect the load capacity. According to the Ministry of Labour, failure to consider all the loads to which the scaffold may be subjected is one of the top things that go wrong at the design stage. The scaffold must be strong enough and capable of holding the desired weight, otherwise it could collapse. Don’t try to fit more workers on the platform than it can handle; don’t overload it with equipment and materials; and don’t rest anything on the guardrails.
5. Ensure the scaffold is properly secured.All types of scaffolding must support, or have the ability to support four times their intended load plus their own weight, according to the North Carolina Department of Labor. Any guardrails need to withstand 100 pounds at the mid rail and 200 or more pounds at the top rail. Suspension ropes on suspension scaffolding must successfully support six times the intended load.
6. Use guardrails. The design of the scaffold must incorporate guardrails on at least the three sides facing away from the building if the scaffold is more than 10 feet above ground. There should be a top rail, a mid rail and a bottom rail (toe board). If you must remove any guardrails while hoisting materials, replace them promptly. Wear fall protection at all times.
7. Inspect and maintain. Scaffolding must be routinely inspected by the supervisor and by a competent person — ideally a professional engineer or a person designated in writing by a professional engineer. In the case of a suspended platform, inspect and test all components including welds, stirrups, connecting pins, connecting plates, trusses, beams and working surface. Check that the lumber is of good quality. If any pieces get broken or damaged, replace them right away. Inspect frames, braces and other components for damage, bends and excessive rust or wear. Also check motors, platforms or wire ropes for damage from chemicals or corrosive material.
8. Good housekeeping. There isn’t much room on a scaffold, so it’s important to store tools and materials in an orderly fashion. Keep the platform free of obstructions. Place debris and waste material in a container or remove it from the platform immediately.
9. Keep your balance. A scaffold and its platform must be perfectly level (CSA standard says it mustn’t deviate from the vertical by more than 12 millimeters per three meters of height) to minimize the risk of workers losing balance and falling off. Particularly on swing stages, there must be an adequately weighted counterweight. Pay attention when working on a scaffold. Any sudden movements, or reaching too far from the platform, can cause a loss of balance.
10. Use appropriate PPE. This includes head protection, non-slip protective footwear and fall protection as required, in the form of a safety harness tied off to a solid structure, such as the building. Ontario’s construction safety regulations indicate that the harness can be tied off to the suspended platform or scaffold only “if all or part of the platform or scaffold has more than one independent means of support and the platform or scaffold is so designed, constructed and maintained that the failure of one means of support will not cause the collapse of all or part of the platform or scaffold.”
With all of these safety practices in place, working on a scaffold can be a high without the dangerous lows.
Great post. Thanks for sharing this blog.
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