9.3 Working at height from fixed or temporary platforms

Question 1

Under the Work at Height Regulations, duty holders (employers, the self-employed, and any person that controls the work of others, such as facilities managers or building owners who may contract others to work at height), must ensure: 5

Answer 1

 all work at height is properly planned and organised  those involved in work at height are competent  the risks from work at height are assessed and appropriate work equipment is selected and used  the risks from fragile surfaces are properly controlled  equipment for work at height is properly inspected and maintained.

Question 2

Duty holders must also adhere to the following hierarchy for managing and selecting equipment for work at height:

Answer 2

 Avoid work at height where possible.  Use work equipment or other measures to prevent falls (where working at height cannot be avoided).  Use work equipment or other measures to minimise the distance and consequences of a fall, should one occur (where the risk of a fall cannot be eliminated).

Question 3

The first step in the risk management hierarchy in the Work at Height Regulations is to consider whether or not the need to work at height could be avoided. Examples of solutions, across a range of industrial sectors include: 6

Answer 3

 Building structures at ground level and lifting them into position on completion, (or in the case of road bridges tunnelling beneath them).  Tilt and turn windows, which can be cleaned from a safe position inside the building.  Use of water fed poles that allow windows to be cleaned from ground level.  Use of long handled tools that can be utilised from ground level, for example, long handled vacuum cleaners to clean dusty surfaces from ground level.  Vacuum filling raised hoppers from ground level.  Shrink-wrapping pallets at ground level can remove the need to sheet vehicles, which requires working at height.

Question 4

Principles of preventing falls and minimising the consequences of falls 3

Answer 4

 prevention takes priority over consequence minimisation (arrest)  collective measures take priority over personal protective measures  passive measures are preferred to active measures.

Question 5

Schedule 6 of the Work at Height Regulations states that a ladder should only be used for work at height if a risk assessment has demonstrated that the use of more suitable work equipment is not justified because of: 4

Answer 5

 The low risk - ‘light work’ (loads

Question 6

Hazards and Precautions When working on a ladder or stepladder care should be taken to avoid:

Answer 6

 Overloading - the maximum load stated on the ladder should not be exceeded.  Overreaching – the workers body should remain between the stiles, and both feet should be planted on the same rung throughout the task.

Question 7

Users should be trained and instructed to use the equipment safely, in accordance with the following rules: 7

Answer 7

(1) Ensure the ladder or stepladder is long enough (2) Ensure the ladder or stepladder rungs or steps are level for use(3) Ensure the weather is suitable(4) Wear robust, sensible footwear(5) Know how to prevent members of the public and unauthorised workers from using them(6) Know that certain medical conditions or medication, alcohol or drug abuse could stop them from using ladders(7) Know how to tie a ladder or stepladder properly

Question 8

Standard

Answer 8

Vertical (upright) tube.

Question 9

Ledger

Answer 9

Horizontal tube - in the direction of the larger dimension of the working scaffold.

Question 10

Transom

Answer 10

Horizontal tube - in the direction of the smaller dimensions of the working scaffold.

Question 11

Raker

Answer 11

Load-bearing tube inclined at 75o and coupled to the second lift. Used where normal ties are inappropriate.

Question 12

Façade (Face) bracing

Answer 12

Diagonal tube parallel to the façade of the building.

Question 13

Ledger bracing

Answer 13

Diagonal tube perpendicular to the face of the building.

Question 14

Base plate

Answer 14

Metal plate used to spread the load from a standard (base plates with vertical adjustment are called base jacks).

Question 15

Sole board

Answer 15

Timber plank positioned beneath two or more base plates to evenly distribute the scaffold load over the ground.

Question 16

Coupler

Answer 16

Device used to connect two tubes.

Question 17

Tie

Answer 17

Means of securing the scaffold to the building

Question 18

Bay

Answer 18

Distance between pairs of standards (parallel to face of building).

Question 19

The main hazards associated with scaffolds are:

Answer 19

 Collapse of the scaffold  People falling from the scaffold  Objects (including components) falling, or being dropped from the scaffold  People walking into the scaffold.

Question 20

Statutory inspection of scaffolds Scaffolding must be regularly inspected by a competent person:

Answer 20

(a) Immediately after it has been constructed (the scaffold contractor should provide a hand-over certificate within 24 hours of completing the scaffold). (b) Before anybody goes on to it (this may be some time after it has been built). (c) After any incident that may have damaged it. For example: after a storm or vehicle impact. (d) Every 7 days (a formal report must be completed and entered into the site register).

Question 21

An independent tied scaffold to a new ten-storey office block has collapsed into a busy street. (a) Outline the factors that may have affected the stability of the scaffold. 8 marks (b) Outline the main principles of scaffold design, erection and use to ensure the stability of such a scaffold. 12 marks

Answer 21

(a) Factors affecting the stability of the scaffold include:  the original erection of the scaffold not following the intended design or the design itself being inadequate  the unsatisfactory bearing capacity of the ground on which the scaffold was sited  the scaffold foundation being undermined either by surface water or by site works such as excavation  the use of incorrect or damaged fittings such as non-load bearing couplers or those affected by corrosion  standards which were out of plumb or bent  a lack of ties  unauthorised alteration of the scaffold  overloading either with materials or because waste chutes became blocked  impact by a load suspended from a crane or by a road vehicle  severe weather conditions including high winds or snow. (b) The main principle to be followed in achieving the stability of the type of scaffold described in the question is to ensure that it is designed to carry all loads, is suitable for its use in accordance with BS EN 12811-1 and is constructed of sound materials and fittings. In practical terms this would involve setting standards on base plates on suitable sole plates taking care to ensure joints are staggered; fitting longitudinal and diagonal bracing and ledger braces at every other pair of standards and fitting vertical and horizontal ties which should be replaced by temporary ties in the event that any have to be removed. If the scaffold is erected in a position where there is likely to be movement of vehicles, protection should be provided to prevent damage from any collision that might occur. The scaffold should be erected only by competent persons and after erection should be used only at the designed and correct level of duty and not overloaded. Inspection by a competent person is necessary at intervals not exceeding seven days and additionally after alterations, damage or after a period of inclement weather.

Question 22

A three-storey building is situated with one side fronting on to a pedestrian walkway. The building is to undergo extensive maintenance to the external fabric which includes a sloping roof. (a) Outline the health and safety issues of the work that will need to be considered before work starts. 11 marks (b) Outline the features of a scaffold designed to provide a safe place of work for working at height during the maintenance activity. 9 marks

Answer 22

(a) Note: The issues relate to the safe management of construction work in an area where the public has access and are concerned with public safety such as the provision of barriers and screening to ensure protection from plant and falling materials, working at height requiring precautions to be taken to prevent falls and to ensure safe access for materials, and the introduction of safe systems of work for operations such as sand blasting and water jetting. Therefore, an outline of issues to consider before work starts would include:  the requirements for suitable plant and equipment including roof ladders bearing in mind the requirements of the Working at Height Regulations  the provision of access for vehicles and the arrangements for the movement and storage of materials on site  the security of the site and the need to ensure the safety of the building’s occupants if they are to remain whilst the work is completed  the likely presence of any hazardous materials such as lead and/or asbestos and those likely to be flammable  the need to consult any existing health and safety files or structural surveys which have been completed  the proximity of any utility supplies and the effect that the proposed work may have on neighbouring buildings  possible health issues arising from exposure to the sun or inclement weather, or to dust from bird or animal droppings  the provision of personal protective equipment such as hard hats, eye protection and fall arrest equipment, such as harnesses and the provision of adequate welfare facilities. (b) An outline of features of a suitably designed scaffold would include:  The correct erection of the scaffold, for example, ensuring the use of upright standards positioned on base plates on stable level ground, horizontal ledgers and tight couplers with adequate bracing and guard rails, and the need to tie it into the structure.  Ensuring the working platforms were wide enough, fully boarded and provided with safe access minimising or plugging the gap between the scaffold and the wall of the building.  The provision of a special working platform below the eaves.  Protecting the scaffold at its base from impact by vehicles.  Using a chute for the disposal of waste materials.

Question 23

A company has been contacted to undertake maintenance work on the roof of a building that is partly constructed of fragile material. (a) Identify the characteristics of the fragile material that may contribute to the risk of falls through the roof. 6 marks (b) Outline the measures to be taken to minimise the risk to persons involved with the work. 14 marks

Answer 23

(a) Characteristics that may contribute include:  the type of material (for example fibre board, asbestos or polycarbonate) and its thickness  the age and condition of the material which might be corroded, rotten, water sodden or weathered  the sheet profile and the design of the supporting structure such as the purlins together with the span between the roof supports  the fact that the fragile material might well be camouflaged by deposits of dirt and other material. (b) An initial reference should have been made to the importance of completing a full risk assessment of the operation to be carried out, and the consequent production of a method statement detailing the safe system of work to be followed. This would describe the proposed means of access to the area of work, such as the provision of scaffolds and crawling boards, and the erection of edge protection comprising guard rails and toe boards to prevent the falls, both of persons and materials from the roof. It would also be necessary to identify areas of the roof containing fragile materials, to mark them with barriers or signs and to prevent falls through them by the use of covers. An additional safeguard would be to provide safety nets and/or air bags under the areas of the roof which contained fragile materials. For certain tasks, the use of safety harnesses with adequate fixing points might also be necessary. Arrangements, such as a hoist, might be needed to transport tools, equipment and materials to the roof, while the use of chutes should be considered for the removal of rubbish. An important factor in carrying out this type of work is to ensure the use of competent personnel fully briefed and aware of the risks involved and the precautions to be observed and to draw up procedures to deal with any emergency that might occur. Finally, measures would have to be taken, such as the erection of barriers and signs, to prevent occupants of the building from passing beneath areas of the roof where work was being carried out, and also members of the public from passing in close proximity to the building.