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Prevention of Falls

Hazard Related Topics


A large proportion of all deaths on construction sites are caused by falls from height. Therefore, prevention of these accidents would have a dramatic influence on total fatal accident numbers. The following legislation, if followed by persons at work and by persons in control of the work and the workplace, would prevent a large number of these accidents.

To be of any value, information provided should be project specific and not generic. The AcoP to the CDM 2007 regs stated about Designers,

"For example, providing generic risk information about the prevention of falls is pointless, because competent contractors will already know what needs to be done, but if the design gives rise to a specific and unusual fall risk which may not be obvious to contractors, designers should provide information about this risk."

Many serious injuries are caused to persons falling from work platforms and ladders where the distance of fall is less than 2 metres. The 2 metre rule has been revoked and protection must be provided for persons working in any place where a fall could cause injury. Risk assessment should identify the reasonably practicable protective measures. The use of a ladder as a place of work should only be allowed if the risk assessment demonstrates that the work is of short duration and does not involve using two hands or excessive force, such that the use of scaffold towers, scaffolding, mobile elevating working platforms (MEWPs) were not reasonably practicable.

Design Considerations

Designers should consider the hierarchy of measures specified within the Working at Height Regulations 2005 (WAHR) e.g.

Hierarchy for safe work at height

AVOID the risk by not working at height. Where it is reasonably practicable to carry out the work safely, other than at a height, then do so.

PREVENT falls. Where it is not reasonable practicable to avoid working at height, you should assess the risks and take measures to allow the work to be done whilst preventing (so far as is reasonably practicable) people or objects falling. This might include ensuring the work is carried out safely from an existing place of work; or choosing the right work equipment to prevent falls.

MITIGATE the consequences of a fall. Where the risk of people or objects falling remains, you should take steps to minimise the falling distance and the consequences of such falls. This also involves the selection and use of work equipment.

Construction Considerations

The WAHR require contractors to:

  • Assess the risk to help you decide how to work safely;
  • Follow the hierarchy for safe work at height - avoid, prevent, mitigate; and give collective measures priority;
  • Plan and organise your work properly taking account of weather conditions and the possibility of emergencies;
  • Make sure those working at height are competent;
  • Make use of appropriate work equipment; Manage the risks from working on, or around, fragile surfaces and from falling objects;
  • Inspect and maintain the work equipment to be used and inspect the place where the work will carried out (including access and egress).

The Working at Height Regulations 2005 (WAHR) are objective based, in that they do not lay down many specific requirements. The following safeguards are recommended.

Construction of Working Platforms, Gangways and Runs

  1. Any working platform shall be of sufficient strength and width to provide for the safe storage of materials and safe passage of personnel. It is recommended that the width of a working platform shall be a minimum of 600 millimetres wide and a scaffold which is used for the deposit of materials shall be a minimum of 800 millimetres wide. A scaffold used for the support of a higher platform should be at least 1.05 metres wide. A scaffold used for stone dressing or stone shaping shall be at least 1.30 metres wide and when it is also used for the support of a higher platform shall be at least 1.50 metres wide.
  2. None of the above apply where it is not practicable because of lack of space to provide a platform of the correct width, provided the platform used is as wide as is reasonably practicable.
  3. The gap between a working platform and the face of the structure must be as small as possible, except in the case where it is necessary for a person to sit on the edge of the platform to work, when the gap should not exceed 300 millimetres.
  4. No gangway or run should be used if its slope is more than 1 vertical to 1.5 horizontal.
  5. Should additional foothold be needed then in every case where the slope exceeds 1 vertical to 4 horizontal stepping laths should be provided at intervals and they must be the full width of the platform, except where a gap of not more than 100 millimetres may be left in each lathe to facilitate the movement of wheel barrows.

Boards and Planks in Working Platforms Gangways & Runs

  1. Boards or planks which exceed 50 millimetres in thickness must be not less than 150 millimetres wide and in every other case not less than 200 millimetres.
  2. No board or plank shall project beyond its end support more than 4 times its thickness, unless it is secured to prevent tipping.
  3. Suitable measures such as the provision of bevelled pieces must be taken to minimise the possibility of tripping and to help the movement of barrows where boards overlap or for any other reason do not have a reasonably even surface. This does not apply where the working platform, gangway or run has one side which is contiguous to a curved surface of any cylindrical or spherical structure.
  4. Every board or plank should rest on three supports unless, taking into account the distance between the supports and the thickness of the board or plank, conditions are such as to prevent undue or unequal sagging.
  5. Working platforms should project beyond the end of a wall or face to a distance of at least 600 millimetres, wherever possible.
  6. Boards or planks placed alongside each other to make a platform must be firmly cleated together using adequate plates and bolts.
  7. Secure handholds shall be provided for persons on a working platform.

Guard Rails, Toe Boards etc.

  1. Toe board height must be sufficient to prevent persons and materials from falling from the working platform. It is recommended that toe boards should not be less than 150 millimetres.
  2. Guard rail heights above any place of work on a working platform, gangway, run or stairway must:
    1. have a top rail not less than 950 millimetres and not more than 1.05 metres.
    2. be constructed so that the maximum vertical gap in the barrier is not more than 470 millimetres. This could be achieved by the erection of an intermediate rail, or some other means of filling in the gap.
  3. Outward movement of guard rails must be prevented by placing them on the inside of uprights or by other equally effective means.
  4. Guard rails and toe boards are not required on the side of a suspended scaffold next to the wall or working face if workers sit at the edge of the face to work and ropes or chains, affording all the workers a safe and secure handhold are provided.

Reference should also be made to:

  • BS EN 12811-1:2003, Temporary works equipment (BSI)
  • TG20:05, Guide to Good Practice for Scaffolding with Tubes and Fittings (National Access & Scaffolding Confederation - NASC)
  • SG4:00, The Use of Fall Arrest Equipment Whilst Erecting, Altering & Dismantling Scaffolding (National Access & Scaffolding Confederation - NASC)

Relevant Legislation