Working on fragile roofs and surfaces

What is considered fragile?

A fragile material or surface is one that does not safely support the weight of a person and any load they are carrying.

workman's tools on a shed roof

The fragility of a surface does not depend solely on the composition of the material in it. The following factors are also important:

  • Thickness of the material
  • The span between supports
  • Sheet profile
  • The type, number, position and quality of fixings
  • The design of the supporting structure, e.g. the purlins
  • The age of the material

Sometimes the entire roof surface is fragile, such as many fibre cement roofs. Sometimes part of the roof is fragile, e.g. when fragile roof lights are contained in an otherwise non-fragile roof. Sometimes a roof is temporarily fragile, such as during ‘built up’ roof construction when only the liner is installed or sheets have not been secured. Sometimes the fragility of a roof can be disguised, for instance when old roofs have been painted over.

The fragility, or otherwise, of a roof should be confirmed before work starts. If there is any doubt, the roof should be treated as fragile unless, or until, confirmed that it is not. It is positively dangerous to assume that a roof is non-fragile without checking this out beforehand. A survey prior to the work commencing is therefore vital.

Prevention of unauthorised access

Make sure that unauthorised access to the roof is prevented by, for instance, implementing a permit-to-work regime or blocking off roof access ladders. Make sure that appropriate warning signs are displayed on existing roofs, particularly at roof access points.

Working on fragile materials

At no time may anyone work on, from or pass over fragile material, unless platforms, coverings, guard rails or similar means are provided that adequately support them.

Properly installed safety netting beneath the roof surface will provide collective fall protection within the protected area. Harnesses can also be an effective solution, but if used they require adequate attachment points which may be difficult to arrange in work on fragile roofs.

They also rely on user discipline, training and constant supervision to ensure that they are consistently and correctly used.  Support platforms should be at least 600mm wide and more when the work requires it.

Make sure that support platforms are long enough to provide adequate support across roof members. They should span across at least two purlins. Using a platform may spread the load, but that will not provide enough support if the only thing supporting it is the fragile material. Walking on the lines of purlin bolts gives no protection whatsoever. It is like walking a tightrope and must never be allowed or condoned.

Workers should not have to constantly move platforms about the roof. It is not acceptable to rely on using a pair of boards to ‘leap-frog’ across a fragile roof. Make sure there are enough platforms provided to avoid this.

Precautions are needed to prevent a person falling from the platform. If possible provide the platform with edge protection comprising of a top rail, intermediate rail (or equivalent protection) and toe board - the dimensions of these have been stated previously in the notes.

Working near fragile material

As a reasonable guide, protection is needed when anyone passes by or works nearer than 2m to fragile materials or surfaces, e.g.:

  • During access along valley gutters in a fragile roof
  • Where fragile roof lights or smoke vents are contained in an otherwise non-fragile roof
  • During access to working areas on a fragile roof or other fragile surface

Wherever possible make sure that all fragile materials, 2m or closer to the people at risk, are securely covered. Alternatively, provide full edge protection, i.e. top rail, intermediate guard rail or equivalent and toe board, around or along the fragile material to prevent access to it. Make sure that appropriate precautions are taken when installing such protection, e.g. the use of netting or safety harnesses.

Sometimes it will not be reasonably practicable to provide such protection, usually if the proximity to fragile material is irregular and short duration, i.e. a matter of minutes.

Safety harnesses will usually be the appropriate solution and may be used in conjunction with any permanently installed running line systems.

Boundaries can be established identifying ‘safe’ areas containing the workplace and routes to and from it. If these are used:

  • The boundary should be at least 2m from the nearest fragile material.
  • The boundary does not need to comply with full edge protection standards, but there should be a physical barrier (a painted line or bunting is not acceptable).
  • Tight discipline is essential to ensure everyone stays inside the safe area at all times.

 

Post date: 23 May 2016

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