Wednesday, November 22, 2006

Working at height - scaffolding

Scaffolding provides a means of working at height. However, erecting scaffolding can be hazardous in its own right, and the safety of the people using it depends on how it is design , erected and maintained whilst in place.

There are codes of practice that cover scaffolding, including use of fall arrest equipment whilst it is being erected or altered.

Key requirements for safe use of scaffolding include:* It must only be erected or modified by competent people;* It must be designed for the intended use by competent people* Handling various components (poles etc.) can cause hazard due to weight, dropped items or knocking people over.

* It must be inspected by a competent person before first use, after modification, after an event that may have affected its integrity (e.g. adverse weather) and at 7 day intervals
* Scaffolding must be erected on firm, level ground of foundations (beware of hidden voids, drains etc.)
* Beware of overhead cables
* Protect against vehicle impact
* If intended to take loads, it must be designed and constructed accordingly
* If intended to be sheeted, it must be design and constructed to withstand wind load
* Working platforms must be properly supported and large enough for people to work (minimum width 600mm)
* Guardrails should be provided at working platforms to prevent people falling (approximately 1m high, with intermediate guard rails provided so gaps are less than 470mm)
* Toe boards should be provided on working platforms to prevent materials falling (minimum height 150 mm)
* Safe ladder or other access must be provided
* Arrangements need to be made for raising and lowering of materials
* Make sure ends and other parts are easy to see so people do not walk into them
* Mark incomplete sections so that they are not use
* Prevent unauthorised access by removing ladders or covering rungs

For stability, the scaffold should usually be tied in to the structure being built or worked on. There are different types of tie:

* Through tie - scaffold pole is extended through an opening (e.g. window) and then arrangements are made so that pressure is applied to the wall opposite to the scaffolding (i.e. on the inside of the building if the scaffold in on the outside)
* Reveal tie - again in an opening, but pole is wedged horizontally into the opening and screw devices used to tighten the gap so that friction is used stop the pole moving
* Box tie - attached around a pillar or similar structure
* Eye bolts - screwed into the wall onto which scaffold is attached
* Putlog - poles with flattened ends which are inserted into gaps between brick courses

Where ties are not possible, angled supports can be used to support the scaffold.


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