TYPES OF SCAFFOLDING

Some common types of scaffolding are as follows:

Single pole (standard) type scaffolding (Putlog Scaffold)
Double pole (standard) type scaffolding (Independent Scaffold)
Rolling Scaffolding, Trestle, Mobile Towers, Patented Scaffolding (Mobile Scaffold)
Outrigger Scaffolding
Swinging (Hanging) Scaffolding
Suspended Scaffolding
Boatswain’s Chair

Single pole type scaffolding (Putlog Scaffold)

The upright (vertical poles/Standard) should rest on a strong foundation to support the load without a settlement. They should not be kept more than 3 meters apart.

Tubular uprights have steel base plates placed on wooden/steel sole plates. Soft ground should be well rammed and leveled.

Fixing like steel bolts, nails of fiber rope of approved size, joint pins and couplers should be properly fitted. For load-bearing right-angled or swivel, couplers must be used.

Putlog couplers are useful for putlog members only. Putlog members (horizontal, ledger) must be at least 10-20 cm be inserted in the wall. Bracing (diagonal connection) must be tied to ensure structural stability and prevent buckling.

To prevent overturning the scaffold should be secured at intervals not greater than 7.6 m vertically and horizontally.

Double pole (standard) type scaffolding (Independent Scaffold)

This is an independent scaffold without any support of other structures/walls.

Rolling Scaffolding, Trestle, Mobile Towers, Patented Scaffolding (Mobile Scaffold)

Such scaffolds move on rollers (wheels) or castors with wheel locking device. They are portable and most useful for maintenance.

To prevent overturning, height should not be more than three times the minimum width of the base. The minimum base length should be 4 feet.

While pushing or pulling the tower, persons should not ride/work on it. Tools and materials should be removed before moving.

The top working platform must have handrails and toe guard/board. It should support a 30 lbs/ft2 distributed the load.

The rigidity of the tower is secured by diagonal bracing on all four sides and on the plan. Moving the tower scaffolding by pulling at the top or leaning sideways should be avoided.

Outrigger Scaffolding

It is a balcony type cantilever scaffold resting on the wall. If other types of the scaffold are possible, this type should not be used.

The outriggers should be passed right through the wall and be secured on the inner side. Supporting hook between brick joints is dangerous.

The platform should not project beyond 2 meters from the wall. Guard rail and toe board should be provided.

Swinging (Hanging) Scaffolding

Here the platform is hanging by two chain pully blokes, ropes and hooks on supporting beam. The suspended platform can be raised or lowered as per need.

The movement of both ends should be simultaneous. The anchorage and the suspension gear should be strong enough to withstand the load with good factors of safety.

Suspension ropes should withstand 6 times (safety factor 6) the intended load. Rope diameter shall be more than 0.75 inches.

A safety rope shall be provided in addition to the suspension ropes.

The width of the platform must have more than 50 cm and less than 90 cm. Guard rails and toe boards/guard necessary on all t sides open. The platform must be lashed or secured while in use to prevent swaying.

Each person working on a swinging scaffold should wear Full body safety harness with a lifeline attached to an anchorage other than the scaffold itself.

Lifeline must be able to carry a minimum weight of 2268 kg.

Suspended Scaffolds

Two or more platforms are suspended by ropes from overhead outriggers anchored to the building.

Such scaffolds are designed with a factor of safety 4 and shall never be overloaded. Anchor plates should be tied with U bolts. Counterweights are used to prevent overturning. Wire ropes (FS 6) are used to support scaffold.

Hoisting drum (like winch) is used with at least 2 dead turns. The gap between the handrail and toe board should be covered by a wire mesh of 38 mm and 16 gauge wire. Overhead protection should be provided if the risk of falling objects is possible.

Boatswain’s Chair

Boatswain’s Chair is used for supporting and hoisting a single person in a sitting position. General Chair (seat) size is 60 cm × 30 cm, with 25 mm thick timber. Cleats extending in front to at least 23 cm should be securely fixed under the chair at both ends.

The chair is supported by a suitable sling passing through the four corner holes in the chair for proper stability. The suspension rope is fixed to overhead support or passed through a pully block fastened to such support.

The free end is secured to a conveniently accessible anchorage and the person in the chair must wear a safety belt, the lifeline of which is secured to the tackle supporting the chair, Fiber rope slings should not be used if the person in the chair has to do welding or cutting work.