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Work at Heights and DemolitionBob Todd

The largest cause of accidents every year in the construction industry is from falls and collapse of structures duringdemolition. Working at height will always be potentially hazardous due to the temporary nature of the workplace in mostinstances. The majority of these accidents are avoidable. This section will cover scaffolding, guardrails, elevated workequipment, fall arrest equipment, all of which can be used to prevent falls, irrespective of the activity.

Latest Updates

17/ 10/ 2003Information is given on new guidance from the HSE on Power Operated Mobile Work Platforms (MEWPS), morecommonly called cherry pickers.

08/ 07/ 2003Research identifying the underlying factors for falls from height in the workplace and the most effective ways of controllingthem, based on analysis of RIDDOR data, has been published by the Health and Safety Executive (HSE), which can forma significant art of employers' Considerations when Working at Height.

08/ 07/ 2003A case illustrating General Principles when Working at Height, particularly the need for proper planning, is given by aserious injury on a construction site. A site foreman was fined £1,500 after he pleaded guilty at the City of LondonMagistrates' Court on Wednesday 25 June 2003, to a breach of Section 7(a) of the Health and Safety at Work etc. Act1974.

20/ 06/ 2003An Introduction to the legal requirements upon an employer with employees working at height is given by the case ofDecorative Specialists Ltd who were fined a total of £15,000 and ordered to pay £1,070.20 in costs as a result of anincident where a worker fell from height and sustained head injuries.

02/ 06/ 2003The HSE is pursuing a more rigorous policy of inspection of work at heights - particularly during June 2003, as a move toprioritise their actions to reduce the greatest cause of death, disability and injuries in construction, falls from height, andalso to prepare the way for the future work at heights regulations arising from the European Directive on Temporary Workat Heights (2001/45/EC) which must be implemented into UK law by 16 June 2004, as indicated in the Introduction.

23/ 05/ 2003When considering the General Principles when Working at Height, employers would be advised to consider the caseof a construction company that did not properly protect its workforce, and thus caused a fatality. One of UK's largest steelerection companies, William Hare Limited, was fined a total of £75,000 following an incident when two workers fell fromheight, resulting in the death of one of them, while undertaking construction work at the Imperial War Museum in London.

19/ 03/ 2003The Health & Safety Executive (HSE) is alerting owners of Power Operated Mobile Work Platforms, also known asMobile Elevating Work Platforms (MEWP), to an incident in which a work basket became detached from its supportingboom.

20/ 02/ 2003The Health and Safety Executive has released a Discussion Paper on the safe design, manufacture, assembly, use andmaintenance of climbing frames on tower cranes, that reinforces the General Principles when Working at Height.

12/ 04/ 2002An indication of the dangers of Demolition is given by case relating to a fatal incident involving a father and son teamwhen a kiln they were demolishing collapsed because their employer did not take enough safety precautions.

29/ 10/ 2001When undertaking Roofwork, it is important that both the client and the contractor take note of the special dangers asshown by a recent case as a result of an injury.

Work at Heights and Demolition(Printed 10/3/2004)

Copyright © GEE Publishing Ltd 2004 1 Contents

23/ 10/ 2001When undertaking the risk assessment for Roofwork, care must be taken to use the correct guidance publication todetermine the fragility of the material of the roof.

17/ 10/ 2000In General Principles when Working at Height information is included about a guidance publication issued by the HSEregarding the advice with which their inspectors are issued when inspecting mobile elevating working platforms and safetyharnesses. This will be of interest to employers and representatives of employees who use this type of equipment to workat heights.

Table of Contents

• Quick View ................................................................... 5• 1. Introduction ................................................................... 6

• 1.1 Interpretation ................................................................... 7• 2. General Principles when Working at Height ................................................................... 8

• 2.1 Guardrails and Toeboards ................................................................... 10• 2.2 Considerations when Working at Height ................................................................... 10• 2.3 Selection of a Means of Access ................................................................... 11• 2.4 Working Platforms ................................................................... 12

• 3. General Access Scaffolds ................................................................... 13• 3.1 Reports ................................................................... 13• 3.2 Foundations ................................................................... 14• 3.3 Independent Tied Scaffolds ................................................................... 14• 3.4 Bridle ................................................................... 15• 3.5 Bracing ................................................................... 16

• 3.5.1 Ledger Bracing ................................................................... 16• 3.5.2 Facade Bracing ................................................................... 16

• 3.6 Ties ................................................................... 16• 3.6.1 Movable Ties ................................................................... 17• 3.6.2 Non-movable Ties ................................................................... 17

• 3.7 Buttresses ................................................................... 18• 3.8 Anchor Ties ................................................................... 18• 3.9 Working Platforms ................................................................... 19

• 3.9.1 Platform Widths ................................................................... 20• 3.10 Loadings ................................................................... 20

• 3.10.1 Loads on Scaffolds ................................................................... 20• 3.11 Edge Protection ................................................................... 21

• 3.11.1 Loading Bays ................................................................... 21• 3.12 Incomplete Scaffolds ................................................................... 22

• 3.12.1 Handing Over ................................................................... 22• 3.13 Trestle Scaffold ................................................................... 22

• 4. Aluminium Towers ................................................................... 23• 5. Mobile and Suspended Access Equipment ................................................................... 25• 6. Power Operated Mobile Work Platforms ................................................................... 26• 7. Mast-elevated Work Platforms ................................................................... 28• 8. Suspended Access (Cradles) ................................................................... 29• 9. Personal Suspension Equipment (Boatswains Chairs and

Abseiling Equipment) ................................................................... 30• 10. Roofwork ................................................................... 31

• 10.1 Planning ................................................................... 31



• 10.1.1 Method of Work ................................................................... 32• 10.2 Safe Access ................................................................... 32

• 10.2.1 Ladders ................................................................... 32• 10.2.2 Tower Scaffolds ................................................................... 33• 10.2.3 Independent Scaffolds ................................................................... 33• 10.2.4 Mobile Work Platforms ................................................................... 33

• 10.3 Types of Roofs ................................................................... 33• 10.3.1 Flat Roofs ................................................................... 33• 10.3.2 Sloping Roof ................................................................... 34• 10.3.3 Crawling Boards ................................................................... 34• 10.3.4 Chimneys ................................................................... 35• 10.3.5 Roof Trusses ................................................................... 35• 10.3.6 Fragile Roofs ................................................................... 35• 10.3.7 Industrial Roofs ................................................................... 36• 10.3.8 High Level Work ................................................................... 36• 10.3.9 Other Situations ................................................................... 37

• 11. Demolition ................................................................... 38• 11.1 Survey ................................................................... 38• 11.2 Notifications ................................................................... 38• 11.3 Method of Work Statement ................................................................... 39

• 11.3.1 Method Statement ................................................................... 39• 11.4 Precautions ................................................................... 39

• 11.4.1 Protection of the Public ................................................................... 39• 11.4.2 Overhead and Underground Services ................................................................... 39• 11.4.3 Removal of Plant ................................................................... 39• 11.4.4 Falls ................................................................... 39• 11.4.5 Safe Areas ................................................................... 40• 11.4.6 Health Hazards ................................................................... 40

• 11.5 Demolition Technique ................................................................... 40• 11.5.1 Piecemeal Demolition ................................................................... 40• 11.5.2 Controlled Collapse Demolition ................................................................... 40• 11.5.3 Demolition by Explosives ................................................................... 40• 11.5.4 Demolition by Pre-weakening ................................................................... 41• 11.5.5 Demolition by Overturning ................................................................... 41• 11.5.6 Demolition of Special Structures ................................................................... 41• 11.5.7 Training and Competence for Demolition ................................................................... 41

• Key Questions ................................................................... 42• Troubleshooter ................................................................... 43

• Adequate Edge Protection ................................................................... 43• Only Competent Persons to Erect and Dismantle

Scaffolds ................................................................... 43• Operatives not Competent or Trained in Demolition Work ................................................................... 43

• Checklists ................................................................... 44• Considerations when Working at Height ................................................................... 44• Selection of a Means of Access ................................................................... 44• Statutory Requirements for an Inspection Report ................................................................... 45• General Guidelines for Erecting and Using Tower

Scaffolding ................................................................... 45• General Guidelines for Power Operated Mobile Work

Platforms and their Use ................................................................... 46



• General Guidelines for Erecting and Using Mast-elevatedWork Platforms ................................................................... 46

• General Guidelines for Erecting and Using a SuspendedAccess System ................................................................... 47

• Key Principles to be Observed when Using PersonalSuspension Equipment ................................................................... 48

• Requirements for Crawling Boards/Ladders ................................................................... 48• Requirements for Tile Battens ................................................................... 48• General Guidelines for mobile elevating work platforms ................................................................... 48• Elements to Consider for Demolition Hazard Identification ................................................................... 49• Items for Inclusion in the Method Statement ................................................................... 49

• Addresses ................................................................... 50



Quick View

1. Work at heights should only be undertaken where essential and then only using safe secure working platforms withadequate prevention of falls. See General Principles when Working at Height.

2. Scaffolding is the most common workplace on a construction site and has specific requirements to ensure a safe placeof work concerning its erection, alteration and dismantling, the materials used for its construction, being left partiallyerected and its inspection. See General Access Scaffolds.

3. For safe work at height there are other means of providing a workplace, particularly if for short periods of time, such asmobile elevating working platforms, cradles, mast platforms, boatswain's chairs and rope access equipment. SeeMobile and Suspended Access Equipment.

4. There are times when safe work at height cannot be achieved by mechanical means, such as glazed areas on a highbuilding or roof, when a boatswain's chair or abseiling equipment is the only reasonably practicable means - but onlyfor short periods of time. See Personal Suspension Equipment (Boatswains Chairs and Abseiling Equipment).

5. Safety during roofwork can be achieved by a variety of methods or systems that can be grouped into two types, thosegiving general protection, such as safety nets, and those giving individual protection, such as safety harnesses. SeeRoofwork.

6. A safe system of work is essential during demolition work. See Demolition.


Copyright © GEE Publishing Ltd 2004 5 Quick View

1. Introduction

Within the construction industry approximately half of fatalities can be attributed to falls. The majority of these are falls ofpersons from height with most of the others being persons struck by falling objects. It is imperative that the hazards andrisks of falls are recognised and safe systems of work implemented to eliminate and reduce accidents. In this sectionconsideration is given to a safe place of work at height.

The HSE is pursuing a more rigorous policy of inspection of work at heights, particularly during June 2003, as a move toprioritise their actions to reduce the greatest cause of death, disability and injuries in construction, falls from height, andalso to prepare the way for the future work at heights regulations arising from the European Directive on Temporary Workat Heights (2001/45/EC) which must be implemented into UK law by 16 June 2004.

The blitz will be focusing on making sure that where work at height is taking place or planned a proper assessment of therisks has been carried out and the hierarchy of controls have been considered.

For instance, inspectors will be looking to see that:

1. Work at height has been eliminated where possible

2. Where elimination is not possible, the correct equipment has been selected

3. Work platforms have been installed with adequate access

4. If using mobile elevating work platforms (MEWPs), they are used correctly

5. If using tower scaffolds, they are correctly erected with edge protection and toeboards as necessary

6. Ladders or step ladders are only being used for short duration work and that they are the correct type, secure,inspected and maintained

7. If using safety harnesses, they have suitable anchorages and adequate fall distances and are inspected

8. All work at height equipment has been inspected, examined and maintained as necessary

In addition, inspectors will look to ensure that only competent contractors are used for work at height and that all jobshave been properly planned and thought through.

An introduction to the legal requirements upon an employer with employees working at height is given by the case ofDecorative Specialists Ltd who were fined a total of £15,000 and ordered to pay £1,070.20 in costs as a result of anincident where a worker fell from height and sustained head injuries.

The incident occurred on 11 October 2002 when a worker was undertaking painting and minor repair work at The Holme,Regents Park, London. Mr Bryan Blackmore, employed by Decorative Specialists Ltd as Project Manager and SafetyAdvisor for the job to repaint and repair The Holme, fell almost three metres while attempting to climb from an unsecuredladder onto a scaffold platform.

Mr Blackmore landed face down with the ladder underneath him, sustaining head injuries that have impaired the cognitivefunctioning of his brain. Decorative Specialists Ltd pleaded guilty to breaching three separate regulations of theConstruction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) (CHSW) at the London MagistratesCourt on Wednesday 4 June 2003.

The Regulations breached were the:

1. Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) , reg. 6(3), for failing to ensure thatthe scaffold being used was provided with suitable and sufficient guard rails

2. Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) , reg. 6(6), for failing to ensure thatthe ladder used was fit for purpose and correctly tied off

3. Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) , reg. 29, for failing to ensure thatthe scaffold used as a place of work at the Holme was inspected by a competent person as required by the


Copyright © GEE Publishing Ltd 2004 6 Introduction

Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) , reg. 29, Sch. 7

Decorative Specialists Ltd were fined the maximum £5,000 for each of these breaches of the CHSW Regulations totalling£15,000, and ordered to pay £1,070.20 at the City of London Magistrates' Court.

1.1 Interpretation

The requirement to provide a 'safe place of work' is fundamental to all health and safety legislation.

Where 'construction work' is being undertaken the Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996,No. 1592) provide legislative requirement.

'Construction work' means the carrying out of any building, civil engineering or engineering construction work. This justabout covers all aspects of construction, repair, upkeep, decoration, maintenance, demolition and dismantling andinstallation. A fuller definition can be found in the regulations.

'Loading bay' means any facility for loading or unloading equipment or materials for use in construction work.

'Place of work' means any place which is used by any person at work for the purpose of construction work or for thepurpose of an activity arising out of or in connection with construction work.

'Working platform' means any platform used as a place of work or as a means of access or egress from that place andincludes any scaffold, suspended scaffold, cradle, mobile platform, trestle, gangway, run, gantry, stairway and crawlingladder.


Copyright © GEE Publishing Ltd 2004 7 Introduction

2. General Principles when Working at Height

One of the key sections of the Construction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592) coversthe prevention of falls.

If it not possible to operate from a safe place of work on a structure then consideration should be given to the following:

1. Only work at height if it is essential

2. Ensure that any working platform is safe and secure whether static or mobile

3. Ensure that where any person could fall from an open edge that adequate guardrails, barriers or any other means ofprotection are provided

When considering how this will be achieved the principles of risk assessment must be applied. This may be influenced bythe nature and duration of the work. Matters to be considered include:

1. How long the work will last

2. How many people will need to work there

3. Whether the permanent structure can be used at an early stage

4. What risks there will be when erecting and dismantling the platform

The majority of work at height is done from scaffolding. However modern building design does require a greater degree offlexibility in providing other means of access. Alternatives could include mobile elevating work platforms, mast platforms,tower scaffolds, personal suspension equipment and man riding cages. The requirements of the Construction (Designand Management) Regulations 1994 (S.I. 1994, No. 3140) may have an influence when undertaking maintenance,cleaning, repair, renovation and demolition.

It is useful to be aware of the points that HSE inspectors will be specifically looking for when inspecting equipment usedfor working at heights. To assist this, the HSE has made available free to the public, copies of the advice given to itsinspectors in an operational circular OC314/19 Mobile Elevating Platforms and the Use of Safety Harnesses, which isavailable from:

HSE infolineTel: 0870 154 5500

The document gives information and guidance on how the inspectors will inspect mobile elevating work platforms(MEWPs) - some of which are known as 'cherry pickers' - and safety harnesses.

The advice includes:

1. Precautions to be taken for using the equipment safely

2. How to adopt a safe system of work

3. How best to plan the job

4. Ensuring the use of trained and experienced operators

5. The use of safety harnesses in high risk situations in MEWPs

The guidance also includes situations when the use of fall restraint equipment is preferred to the use of fall arrestequipment.

The Health and Safety Executive (HSE) has released a discussion paper (available atwww.hse.gov.uk/construction/index.htm) on the safe design, manufacture, assembly, use and maintenance of climbingframes on tower cranes. This paper identifies issues for discussion by the industry to feed into the development ofimproved standards for this type of work.


Copyright © GEE Publishing Ltd 2004 8 General Principles when Working at Height

http://www.hse.gov.uk/construction/index.htm

The paper arises from the HSE's wider consideration of climbing frames prompted by the investigation into the collapse ofthe tower crane at Canary Wharf in 2000. However, nothing in the paper should be read as being directly relevant to anyone incident.

The discussion paper identifies the following potentially critical factors:

1. Establishing and maintaining the balance of the crane during changing environmental conditions

2. Correct location of the climbing frame on the climbing lugs or other support points during the climb

3. Prevention of slewing - either deliberate or inadvertent

4. Wind loading, should conditions change during a climb

The discussion paper suggests that:

1. Designers need to take into account all the relevant forces

2. Consideration could be given to improving the information available to the erection supervisor during climbing

3. Effective measures are needed to avoid deliberate or inadvertent slewing of the crane jib during a climb

4. Prevention of falls from walkways, platforms and access ladders needs some thought

5. Operating instructions should be easily understood and cover all the critical steps

6. Consideration should be given to the certification of erection crews by manufacturers or suppliers of climbing frames

7. Detailed risk assessments taking account of local conditions should be carried out

8. Consideration should be given to how the overall climbing operation is to be supervised

9. A systematic approach to the examination, test and maintenance of climbing frames is needed

When considering the general principles when working at height, employers would be advised to consider the case of aconstruction company that did not properly protect its workforce, and thus caused a fatality. One of UK's largest steelerection companies, William Hare Limited, was fined a total of £75,000 following an incident when two workers fell fromheight, resulting in the death of one of them, while undertaking construction work at the Imperial War Museum in London.The Health and Safety Executive (HSE) prosecution followed the accident which occurred on 2 April 1998 during theconstruction of an extension to the Imperial War Museum at Lambeth Road, London.

On 12 March 2003 at the City of London Magistrates' Court, William Hare Limited pleaded guilty to a breach of the Healthand Safety at Work etc. Act 1974 , s. 2(1) for failing to ensure the safety of its employees, and were fined a total of£75,000 and ordered to pay costs of £9,162.80 at the Old Bailey on 8 May 2003. Norwich man Mr Brian Knights - a steelerector employed by William Hare Limited, fell from the steelwork of the new extension to the ground outside the structureand was killed.

Mr Richard Bartram, another steel erector, also fell in the same incident but landed on the decked-out floor below andescaped serious injury. Mr Knights and Mr Bartram had been standing on a wooden staging board that was resting ontwo horizontal steel beams, at a height of 13 metres above the ground. They were retrieving a ladder that was footed onthe staging board, and giving access to the top of a column, where steel channels had been bolted into position a fewdays earlier. The board became unbalanced and tipped both men off.

Another case illustrating the need to properly plan working at height is given by a serious injury on a construction site. Asite foreman was fined £1,500 after he pleaded guilty at the City of London Magistrates' Court on Wednesday 25 June2003, to a breach of the Health and Safety at Work etc. Act 1974 , s. 7(a). The prosecution resulted from a Health andSafety Executive (HSE) investigation following an accident at the new Sutton Police Station project in Surrey, on 12November 2001, when another employee suffered two badly broken legs. It is unlikely that he will be able to work again.

The site foreman, Mr John Cullen, was employed by O'Rourke Civil and Structural Engineering Limited, the principalcontractors for the Sutton Police Station project. He was given the task of establishing the site, which included the



erection of a site hoarding around the perimeter. Several large advertising billboards were in place around the site, andhad to be removed to accommodate the hoarding.

The client had agreed to remove the billboards, but there were several delays in this being carried out. Mr Cullen hadalready arranged for some of the advertising billboards to be removed by having them lifted into the site with an excavatorand a lifting sling. However, the project manager told him to stop, as arrangements were made for the client to remove thebillboards, and it was not part of the O'Rourke method statement.

On Monday 12 November 2001, Mr Ron Given began work on the site as a joiner, employed to help make sections of thesite hoarding. That afternoon it was decided to remove a large advertising billboard. This required access at height, toremove the frame of the billboard. Under the supervision of Mr Cullen, an excavator assisted them. The bucket wasturned around on the machine, and Mr Given climbed into the bucket to be lifted to the top of the billboard, a height ofapproximately five metres. The bucket fell from the machine, tipping out Mr Given who fell to the ground with theexcavator bucket falling onto his legs.

As a result he can still only walk a short distance with the aid of sticks. The HSE investigation revealed that the safety pinhad not been inserted in the quick-hitch, and that the warning buzzer on the quick-hitch switch was not working.Nevertheless, Mr Given would not have been injured if Mr Cullen had intervened to prevent this highly unsafe system ofwork. Mr Cullen was fined £1,500 and ordered to pay HSE costs of £1,380.

2.1 Guardrails and Toeboards

When any work is undertaken whereby a person could fall 2 m or more then guardrails, toeboards or other similar barriersmust be provided. Where a person could fall less than 2 m but could be injured by the fall then guardrails, toeboards orother similar barriers must be provided.

Any guardrail or barrier must be a minimum height of 910 mm to prevent falls of persons.

Much of the work undertaken at height involves persons bending, stooping and kneeling, therefore an intermediateguardrail must be provided to protect the gap. The distance between any guardrail, intermediate guardrail or toeboardmust not exceed 470 mm.

To ensure no loose material or debris falls off, a toeboard must be provided which is at least 150 mm high.

Where material is stacked or stored above the level of the toeboard then a brickguard or similar barrier must be provided.Any brickguard or similar barrier may act as an alternative to the intermediate guardrail.

Any guardrail or toeboard may be made from any material providing it is strong and rigid enough to prevent people fallingand to be able to withstand other loads likely to be placed on it.

Where the risk of falling is through openings in the floor or fragile material, e.g. rooflights, then a cover can be provided tothe opening or material as an alternative to guardrails and toeboards.

2.2 Considerations when Working at Height

Considerations when Working at Height

• Make sure there is a safe route or method to and from the work area.

• Ensure that any equipment will be suitable for the job and the conditions on site.

• Make sure that any equipment needed is delivered to site in good time and that the site hasbeen prepared for it.

• Any work platforms and any edges from which people are likely to fall must have guardrails andtoe boards or other barriers.

• Check that any equipment is in good condition.



• Make sure that whoever puts the equipment together is trained and competent and knows whatthey are doing, e.g. making scaffolders erect and dismantle scaffolding or supplying trainedpersonnel to erect mobile towers.

• Ensure those who use the equipment are supervised so that they use it properly and arecompetent and trained, e.g. have attended a scaffold awareness training. Where the equipmentis more specialised (i.e. boatswain's chairs and rope access equipment), the greater the degreeof training and supervision required to ensure safety.

• Where another company provides equipment on site, check it is safe before using it.

• Where any defects are found ensure they are corrected immediately.

Research identifying the underlying factors for falls from height in the workplace and the most effective ways of controllingthem, based on analysis of RIDDOR data, has been published by the Health and Safety Executive (HSE).

The research report RR116 Falls from height - Prevention and risk control effectiveness (available from HSE Books, price£50.00, ISBN 0 7176 2221 5, or online at www.hse.gov.uk/research/index.htm) provides a:

The research identifies and compares the effectiveness of alternative measures to prevent and control the risk of fallsfrom height in order that effort can be targeted most appropriately.

Some of the key issues highlighted are:

1. The importance of design and designers in eliminating work at height hazards.

2. Enough guidance and information is available but people need to be aware of risks and actually use the guidanceavailable.

3. The importance and large number of 'low falls', especially on stairs. The report states around 60 per cent of non-fatalaccidents and injuries over the past five years have been due to low (under 2m) falls.

4. The economic benefits of good health and safety performance need to be better understood and publicised.

2.3 Selection of a Means of Access

Selection of a Means of Access

• Wherever possible a working platform with guardrails and toeboards should be provided. Thismay form part of the structure or an elevated work platform.

• When it is not practicable to provide a work platform, consider whether other means of access(for example, boatswain's chairs or rope access techniques) should be used.

• Only when no other method is practicable or when work platforms cannot comply with allrequirements for safe work (e.g. a guard rail has to be removed to land materials or roofsheeting is being laid), should a means of arresting falls be relied upon, e.g. a safety harnessand lines or nets.

• Safety harnesses, lines and nets only provide protection for the person using the equipment inthe event of a fall - they do not prevent falls.

• Those persons employed put up guard rails or other protection to the workplace shall alsorequire the protection of safety harnesses and lines and nets.

• For short-term work the use of tower scaffolds or mobile elevating work platforms (MEWPs)may be suitable. Ladders should only be used as workplaces for short periods and then only if itis safe to do so.



http://www.hse.gov.uk/research/index.htm

• Checks need to be made to ensure that there is adequate clearance for equipment, e.g. contactwith overhead power lines can be a risk when erecting scaffolds or using MEWPs. When mobileaccess platforms are manoeuvered there can be a risk of crushing against nearby structures.

2.4 Working Platforms

A working platform may be a variety of places where people work which can include parts of the structure, scaffolding,trestles, MEWPs, cradles or any other place people stand whilst working.

The working platform must be a minimum of 600 mm wide (subject to available space between fixed structures) to provideenough space for people to pass back and forth. When any equipment or materials are stored or placed on the workingplatform then it must increase in size accordingly to accommodate adequate passing space.

Any working platform must be free of tripping and slipping hazards. There must not be any holes or openings which couldcause a person to trip or fall. Openings must be provided with guardrails and toeboards, holes securely covered and awarning sign in place.

Any working platform must not allow material or objects to fall through. For scaffolds, a close-boarded platform would besufficient. Where members of the public pass below, a higher standard would be required, e.g. two layers of boards withpolythene or some similar sheet material between. On a MEWP or cradle, there is often a mesh platform floor. This meshshould be fine enough to prevent small objects falling through, e.g. nails.

Any platform must be kept clean and tidy.



3. General Access Scaffolds

Scaffolding must only be erected, altered and dismantled by a competent person and under the directions of competentsupervision.

Scaffolding must be constructed of sound strong material. Tubes must not be rusty, bent or distorted and timber forboards must be of the right type.

No defective materials and parts may be used and the scaffolding must be properly stored when not in use.

No scaffold shall be left partly erected or dismantled unless adequate notices are displayed and access blocked.

Once erected the scaffold must be inspected before being put into use.

All scaffolds must be inspected after erection, substantial alteration or when adverse weather is likely to have affected thestability and otherwise at regular intervals not exceeding seven days and the result of the inspections recorded on theappropriate form. This report must be completed before the end of the day or working period.

3.1 Reports

Statutory Requirements for an Inspection Report

There is a requirement for specific information to be included in the report as identified in Construction (Health, Safety andWelfare) Regulations 1996 (S.I. 1996, No. 1592) > reg. 20 & Sch. 8. The report should contain the following information:

• Name and address for whom the inspection was carried out

• Location of the workplace inspected

• Description of the workplace or part of workplace inspected (including any plant, equipment andmaterials, if any)

• Date and time of the inspection

• Detail of any matter identified that could lead to a risk to the health and safety of anyone

• Details of any action taken as a result of any matter identified in the last point

• Details of any more action considered necessary

• The name and position of the person making the report

Any report must be kept on the site where the work is being carried out and then retained for a further three months.

An inspection of a place of work shall include an inspection of any plant and equipment and any materials which affect thesafety of that place of work, e.g. a hoist or stacked bricks.

If the competent person carrying out the inspection is not satisfied that work can be carried out safely, they must advisethe person for whom the inspection was carried out as soon as possible. Any report on the scaffold inspection must bepassed onto the person for whom the inspection was carried out within 24 hours, e.g. a foreman undertaking theinspection passing the report onto the site manager.

The workplace should not be used until the defects are put right.

Any scaffold must be properly maintained and inspected at frequent intervals to check all parts are serviceable andsecured to prevent accidental displacement, e.g. ongoing monitoring of the use the scaffold by the various contractors.

If the scaffold is erected by other persons, it is the duty of the user to check the adequacy of the scaffold to suit the workrequirement, e.g. that the scaffold platform is at the correct level to complete the work.

Further information on the format of a report and a scaffold inspection checklist may be found in HS(G) 150 booklet


Copyright © GEE Publishing Ltd 2004 13 General Access Scaffolds

available from HSE Books.

3.2 Foundations

Erect scaffolding on a firm and level foundation. The foundation or ground should be capable of supporting the weight ofthe scaffold and any loads likely to be placed on it. Care must be taken not to position the scaffold over voids or softground, e.g. previous excavations.

A suitable sole plate must be used on the ground, which is normally a timber scaffold board 38 mm thick × 219 mm wide.The sole plate area should not be less than 1,000 cm², or 1,700 cm² on soft ground. Often a sole board will support twostandards which gives a greater load distribution. Bricks, blocks or other material that may shatter must not be used.

Standards should be placed on metal base plates 150 mm × 150 mm to prevent splitting the sole board.

3.3 Independent Tied Scaffolds

An independent scaffold consists of a double row of standards, with each row parallel to the building. The inner row is setas close to the building as is practicable. The distance between the lines of standards should be the minimum necessaryto accommodate the required number of boards and toe boards.

A variation may be adopted in which the row of standards nearest to the building can be set back about 300 mm from thebuilding face so that one of the boards of the platform can be laid between the inside row of the standards and thebuilding.

Standards must be erected vertically or leaning slightly into the structure.

Ledgers must be level and fitted to standards with right angle couplers.

Transom tubes should be secured to ledgers or standards with putlog clips or right angle couplers.

Putlogs are tubes, either with one end flattened or fitted with a putlog adaptor. They are fitted into the brickwork, andserve a similar purpose to a transom whereby they both support the working platform.

Putlogs should rest on and be coupled to the ledgers or standards with right angle or putlog couplers.

A putlog adaptor must be at least 75 mm long and 50 mm wide, and it should rest flat on the brickwork to allow amaximum area of bearing surface.



3.4 Bridle

Where a putlog is required for a board support and it is opposite an opening in the building, such as a window ordoorway, the inside end of the putlog should be supported on an underslung bridle tube which is connected to adjacentputlogs.

It should be fixed with right angle couplers at the minimum to main putlogs on each side of the opening.

A right angle coupler should be used for fixing the intermediate putlog to the bridle.

No ledger or transom should protrude more than is necessary beyond the general outline of the scaffold, i.e. a maximumof 300 mm. At lower levels this could be a hazard to pedestrians or vehicles.

The use of tube safety caps reduces the potential injury and identifies the hazard. At higher levels they protect againstcollision by crane handled loads or hoisted material i.e. dislodged materials on gin wheels.



On the inside of a scaffold the transom should extend to the building face where possible to prevent inward movement.The use of tube safety caps reduces the potential for damage to the building face.

Any joints in ledgers and standards must be staggered (i.e. not in the same bay) to provide greater strength and stability.

3.5 Bracing

Bracing stiffens the structure and should preferably be connected to the scaffold with right angled couplers or failing thatswivel couplers. Bracing comes in two forms:

1. Ledger or diagonal bracing runs between ledger to ledger through the scaffold and must be fitted at every other bay.

2. Facade or longitudinal bracing runs along the face of the scaffold at an angle of 45° to full height and must bepositioned on each end and then at least every 30 m.

3.5.1 Ledger Bracing

Independent tied access scaffolding should contain ledger bracing which should generally be on alternate pairs ofstandards. Any pair of standards which are ledger braced should be made into a complete series of triangles.

When the bay length is 1.5 m or less, the ledger bracing may be fixed to every third pair of standards.

The ledger bracing should preferably be fixed from ledger to ledger with right angle couplers when the lift is not to beboarded, but may be fixed to the standards using swivel couplers.

The bracing on boarded lifts should be from under the outside ledger of a boarded lift down to the inside ledger of the liftbelow so as to avoid the toeboards. This arrangement may require an extra width on the scaffold to accommodate thebrace.

The direction of ledger bracing is immaterial for the structural stability of the scaffold but it should be pre-planned to takeaccount of the intended use of the scaffold.

3.5.2 Facade Bracing

Longitudinal bracing should be provided to all scaffolds in which the movement along the facade of the building is notprevented by other means. It need not be fixed where the scaffold is securely butted between opposing outside or insidefaces of returns or recesses, provided that no length greater than 10 m is so fixed against movement in both directions.

The two principal forms of longitudinal arrangements are where the bracing takes the form of either a zigzag from thebottom to top or a continuous sloping tube from bottom to top. In either case the bracing tubes should be connectedeither:

1. To every lift on to extended transoms with right angle couplers

2. To every standard with swivel couplers

One such brace assembly should be provided at intervals along the scaffold not exceeding 30 m.

The longitudinal bracing should be fixed as near to the standards as possible. When the brace is fixed to extendedtransoms, the latter should be fixed to the outside ledgers with right angle couplers.

3.6 Ties

The prevention of outward primarily and inward movement of the scaffold is normally achieved by the use of ties to thefacade of the structure. All ties must be connected with right angled couplers. Irrespective of the type of tie it is essentialto establish that the structure is of adequate strength to sustain the loads transferred onto it. This applies particularly toany proposed use of parapets or architectural features (e.g. rain water pipes, balustrades, railings) as it is frequently



found that the strength of such features is negligible.

There are two classes of ties.

3.6.1 Movable Ties

Ties which may be temporarily moved for the execution of work include:

1. Through ties - A tie assembly through a window or other opening in a wall.

2. Reveal ties - The assembly of a reveal tube with wedges or screwed fittings and pads, if required, fixed betweenopposing faces of an opening in a wall together with the tie tube.

3.6.2 Non-movable Ties

Where the face of the building or structure is strong enough for their use, various kinds of built-in or non-movable ties maybe incorporated. These can be secured into the structural concrete by a nut cast specifically for scaffolding ties, with boltholes drilled right through into the building, or by drilled anchors with expanding bolts.

The spacing of lines should not exceed 8.5 m horizontally or vertically. Ties should be reasonably evenly distributed overthe scaffold surface area (see table below) at the following minimum frequency:

Unsheetedscaffold

Sheetedscaffold

Heightlimitation

Movable ties 32 m² - 50 m

- 25 m² 25 m

Non-movableties

40 m² - 50 m

- 32 m² 25 m

Ties, where practicable, should be left undisturbed until the scaffold is dismantled. Sometimes it may be necessary toremove the ties during the building process, e.g. to fit a window frame. Note: there may be limitations on thesemeasurements for ties depending on other factors, e.g. wind effect.

Through ties are the most commonly used which consist of a scaffold tube connected at right angles to the scaffold andpassing through a window or other opening and then a further tube lipped at right angles to the structure thus preventingoutward movement.



Where it is not possible for the tube to pass through an opening, a reveal tie can be used. This consists of a butt tubebeing fixed between the reveals of an opening with wedges or screwed fittings. As this relies solely on friction it doesconsiderably reduce its efficiency. Only 50% of ties may be reveal ties on any facade.

3.7 Buttresses

The stability of a scaffold may be achieved by means other than ties fixed to the surface of the building. A buttress maybe used which consists of raking tubes set at an angle of 75° to the scaffold thus giving stability against overturning.

A single unjointed raking of up to 6 m in length, coupled at the top to the ledger at the second lift and tied back to thescaffold at the foot, may be considered as equal to one tie. The raking tube should be external to the scaffold and at anangle of not more than 4 vertical to 1 horizontal.

The friction of the foundation of a scaffold may be regarded as providing adequate attachment for the lower 3 m of thescaffold.

Buttresses, either inside or outside of a scaffold providing they are of a width greater than that of the scaffold and areledger braced, may be regarded as providing adequate attachment for a 3 m length of the scaffold on either side of thebuttress.

Returns of scaffolds which are themselves effectively tied round the ends of building facades may be regarded asproviding an adequate attachment of the scaffold to the facade for a 3 m length of the scaffold, measured from therelevant corner.

Rakers are angled tubes placed along the length of the scaffold and connected to the ledgers with right angled couplers.Usually rakers only extend up to 6 m high.

On taller structures a buttress is required. This would require special design. Note: a buttress may also be used to supportstructures during structural alteration work where their stability may be affected.

3.8 Anchor Ties



These can be used where there is no opening to take a scaffolding tie, as in a gable end or in stone or concrete faces,and where use of existing openings would be impracticable because of other operations.

Wherever possible, the bolt should be fixed in reinforced concrete, or in bricks in cement mortar.

There are several proprietary makes available.

They can be left in permanently, for use in later operations and for maintenance.

See also Requirements for the Designer (Regulation 13)

When using anchor bolts or similar fixings, a pull out test should be undertaken to test the integrity of the fixing.

3.9 Working Platforms

Any scaffold boards should rest firmly and evenly on any transoms. Any scaffold board should have a minimum of threesupports unless its thickness or span is sufficient to prevent any sagging under load. If the board has only two supports itmust be safe from dislodgment by position or secured in place, e.g. use of single scaffold clip.

The majority of scaffold boards are 38 mm thick and require support every 1.2 m. If the boards conform to BS 2482 1981'Specification for Timber Scaffold Boards' they may have a maximum span of 1.5 m.

The overhang at the end of the scaffold board should not exceed 4 × the thickness of the board (to prevent tipping) andnot less than 50 mm (to prevent dislodgment).

Generally all boards are supported at 1.2 m centres and allowing for 150 mm overhang this means 4 support tubes to astandard 3.9 m scaffold board. All boards should be marked with their maximum span.

The following section gives a table of spans for boards.

Nominalthickness ofboard (mm)

Maximumspanbetweentransoms(m)

Minimumoverhang(mm)

Maximumoverhang(mm)



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38 1.5 50 150

50 2.6 50 200

63 3.25 50 250

The surface of the working platform should be even to prevent tripping. There is always the risk that in windy conditionsthe boards may lift. In this situation the boards will require securing, e.g. wire ties or straps. NB: care should be taken notto create a tripping hazard.

3.9.1 Platform Widths

The width of a working platform should always allow for the free movement of people and materials.

Platform widths as follows:

1. 3 boards (600 mm) - when used as footing only

2. 4 boards (800 mm) - when used as footing and for stacking of material

3. 5 boards (1.05 m) - when working with stacked materials to allow 600 mm clear for barrow

4. 6 boards (1.3 m) - when used by masons for dressing and shaping stone

5. 7 boards (1.55 m) - when used by masons and to support their trestle platforms

A minimum width of 600 mm must be maintained for both working space and access and egress.

The space between the scaffold platform and structure must be as small as possible.

3.10 Loadings

No working platform should be overloaded.

3.10.1 Loads on Scaffolds

Loads, bricks etc. on scaffold platforms must be evenly distributed and must not be too heavy for the platform. The bestplace for the main load is as near the standards as possible. 250 kg/m² is the maximum for a bricklayer's scaffold.

Loads must always be moved carefully and impact loads avoided. Loose or unwanted material must be cleared away asquickly as is practicable.

The following section gives details on access and working platforms.

Duty Use ofplatform

Distributedload onplatforms(kg/m²)

Maximumnumber ofplatforms

Commonlyusedwidthswith 225mmboards

Maximumbay length(m)

Inspectionand very lightduty

Inspection,painting,stonecleaning,lightcleaningandaccess

0.75 1 workingplatform

3 boards 2.7



Light duty Plastering,painting,stonecleaning,glazingandpointing

1.50 2 workingplatforms

4 boards 2.4

Generalpurpose

Generalbuildingwork,includingbrickwork,windowandmullion,fixing,rendering,plastering

2.00 2 workingplatforms +1 at verylight duty

5 boardsor 4boards + 1inside

2.1

Heavy duty Blockwork,brickwork,heavycladding

2.50 2 workingplatforms +1 at verylight duty

5 boardsor 5boards + 1inside or 4boards + 1inside

2.0

Masonry orspecial duty

Masonrywork,concreteblockworkand veryheavycladding

3.00 1 workingplatform +1 at verylight duty

6 to 8boards

1.8

3.11 Edge Protection

Where a person can fall more than 2 m, platforms and access ways must be fitted with guardrails and toeboards.Guardrails are a minimum of 910 mm above the platform. Toeboards are at least 150 mm high. Any unprotected gapsbetween any guardrails and toeboards must not exceed 470 mm. NB: brickguards may be used as an alternative tointermediate guardrails.

Where material is stacked above the height of a toeboard, brickguards must be used.

Any working platform where a person can fall more than 2 m must be fitted with toeboard and double guardrail or othersuitable material of sufficient rigidity.

On a working platform below 2 m high, there may be a requirement for edge protection depending on the degree of risk ofinjury from falling, e.g. landing on reinforced starter bars protruding from concrete.

3.11.1 Loading Bays

Where the placing of material on a scaffold would cause overloading a designated loading bay must be provided. Thesemust be designed and have the safe working loads clearly marked including distribution of loadings.

Where the edge protection requires removing for the access of materials, a suitable integrated gate system must be usedto prevent persons falling. There are several proprietary systems available.



3.12 Incomplete Scaffolds

Incomplete scaffolds must have suitable warning signs and access barred. Proprietary systems are available, e.g.'scaff-tag'.

3.12.1 Handing Over

Before any scaffold is handed over by the scaffolding contractor, they usually undertake their own inspection of thescaffold and issue a 'handing over' certificate. This confirms that the scaffold is safe and complies with the Construction(Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592). All scaffolding should also comply with BS 5973:1993 Code of practice for temporarily installed suspended scaffolds and access equipment.

It is the responsibility of the person accepting the scaffold to inspect it and ensure it is safe and suitable for use. SeeReports.

3.13 Trestle Scaffold

Trestles or bandstands are commonly used on site to provide a low level work platform. These should only be used forlight work and only extended approximately 1/3 of their height. NB: trestles are not suitable for using to lay 140 mm blocksat a platform height of 1.8 m or above.

The platform must be a minimum of 600 mm wide and the boards supported no more than 1.2 m apart.

A proper access must be provided, e.g. a ladder.



4. Aluminium Towers

There are a several different types of towers available which are comparatively easy to erect and offer an excellentalternative to traditional scaffolding.

These towers are also mobile and will normally be prefabricated aluminium. The lightness of the material makes themeasier to erect, rather than traditional steel scaffolding. In either form, competent and trained personnel are required toerect the tower.

Most scaffolding is usually erected by a trained scaffolder who will normally have a CITB (Construction Industry TrainingBoard) certificate as evidence of competency and training. With aluminium towers, there is a tendency for them to beerected by untrained personnel. This is because their pre-fabrication and relative ease of construction means everybodythinks they can put them up, which leads to many accidents.

As the towers are scaffolding by definition, it is a requirement that they conform to the legal standards set out in theConstruction (Health, Safety and Welfare) Regulations 1996 (S.I. 1996, No. 1592).

Any persons who erect a mobile tower must be competent and trained.

Before commencement of the erection of the tower, a copy of the manufacturers' erection instruction must be availableand the recommendations followed. Remember it is the duty of the supplier to provide this information.

General Guidelines for Erecting and Using Tower Scaffolding

• All the components must be in good condition, work correctly and be compatible. Checks shouldbe made for cracks, broken welds, crushed or bruised tube or any other damage.

• Mobile towers should only be erected on firm and level ground and with the castors locked.

• The maximum height of a mobile tower should be no more than three times the minimum widthwhen used outside. This can increase to three and a half times inside. However, themanufacturers' recommendations should be followed.

• Out riggers or stabilisers may be used to gain extra height, but within the limitations of themanufacturers' recommendations.

• Double guardrails and toeboards must be fitted as with normal scaffold.

• Before climbing the tower any movement must be prevented by locking the wheels.

• Any outriggers or stabilisers must be securely fastened and braced.

• Steps or ladders should not be placed on the platform to gain extra height.

• Towers should only be moved by pushing at the base and there should be no persons ormaterials on the platform. When moving towers they must be dismantled to a platform level of2.5 times the effective least base dimension. Care should be taken that there are no overheadobstructions or power lines.

• Adequate means of access to the working platform should be provided. This may be in the formof angled steps, an inclined ladder within the tower, a vertical ladder attached to the narrow sideor a built-in vertical ladder integral within a frame section, climbing the outside cross supports orbracing sections is not permitted.

• There should be a platform provided at distances not exceeding 4 m.

• The recommended load should never be exceeded.

• If a mobile tower is left erected in the same place in excess of seven days, then an inspectionand report must be undertaken similar to the requirements for scaffolding (see Reports).


Copyright © GEE Publishing Ltd 2004 23 Aluminium Towers

When using a tower, consideration has to be given to activity being undertaken. For work of very light nature, wherebyany tools and material can be carried up in holsters or shoulder bags, then an inclined or vertical ladder would beadequate for access, e.g. replacing light bulbs. In some situations it may be necessary for tools, etc. to be carried up orthe tower may be used as a common access. Then the provision of angled steps would be recommended. This wouldgive the same effect as stairs.

Although a tower is generally used as a temporary work platform for short-term work there are limitations to its suitabilityand efficiency. If the tower has to be moved frequently the height of the tower may need to be reduced many times. Thisputs the personnel undertaking the task at greater risk of falling during the activity. There may also be other plant ormachinery obstructing the area where access is required. There could also be a cost saving benefit to consider.

In this situation, the findings of a risk assessment may indicate the provision of a higher standard of safe access isrequired.


Copyright © GEE Publishing Ltd 2004 24 Aluminium Towers

5. Mobile and Suspended Access Equipment

Where access for a working platform cannot be gained using traditional scaffolding there is a range of other alternativeswhich include mobile elevating work platforms (MEWPs), cradles, mast platforms, boatswain's chairs or seats, and ropeaccess equipment.

All persons using this type of equipment must be competent, experienced and trained. A higher standard of training isrequired which includes both emergency procedures and depending upon location, evacuation procedure, e.g. reacting toa mechanical failure to the platform or a fire which breaks out in the building being worked on.


Copyright © GEE Publishing Ltd 2004 25 Mobile and Suspended Access Equipment

6. Power Operated Mobile Work Platforms

Power operated mobile work platforms provide a safe means of access and place of work when working at height,particularly if the work is of short nature.

The common name for this equipment is generally mobile elevating work platforms (MEWPs) and they are available in avariety of different types which include scissor, telescopic or articulating. It is important that the correct type of machine isselected to suit the task.

General Guidelines for Power Operated Mobile Work Platforms and their Use

• The ground must be firm and level

• An indicator for levelling or a self-levelling device fitted to the chassis to ensure verticality in use

• Stability in use must be ensured, including the provision of outriggers on some machines, whichmust be fully extended and locked in place before the equipment is used/raised, in accordancewith the manufacturer's instructions

• The platform is provided with guardrails and toeboards and a safe means of access onto theplatform

• A safety harness should be worn and connected to the MEWP

• Care should be taken not to come into contact with overhead obstructions including electriccables

• Consideration must be given to the effects of wind or other side forces

• The safe working load must be clearly marked and adhered to

• The area below must be kept clear of personnel and appropriate barriers and signs used

• Only authorised and competent persons may operate the equipment. The operator must be inpossession of an approved training certificate appropriate to the type of machine, e.g. a CITB(Construction Industry Training Board) CTA (Certificate of Training Achievement) card or note.Familiarisation training given by hire companies may not be considered sufficient.

A MEWP is primarily a work platform and although the equipment is used as a means of access to height it is notpermissible for persons to leave the platform at an elevated position, nor transfer materials to another place. If thissituation arose then a hoist would be appropriate.

The Health & Safety Executive (HSE) is alerting owners of Mobile Elevating Work Platforms (MEWP) to an incident inwhich a work basket became detached from its supporting boom. No one was injured during this incident, but it has raisedconcerns about the safety of other MEWPs of the same construction and make. The MEWP was made by AccessMachines Ltd. It was a Micro 95 trailer mount, class A1, made in 1998, with a Safe Working Load of 120 Kg. The basketof the MEWP that failed was bolted to a round plate by four bolts and in turn the plate was welded to a pin or stub axle onthe main boom. In this instance the pin to plate weld failed allowing the basket to fall off the end of the boom. There wassome evidence of fatigue in the weld but HSE is concerned that poor quality welding may have contributed to the failure.This is possibly a one off incident nevertheless HSE strongly recommends that owners/operators of these and similarmachines have this pin/plate connection thoroughly examined by a competent person at the earliest possible opportunity.

The HSE has issued new guidance on preventing falls from 'cherry pickers', MISC614 Preventing falls from boom-typemobile elevating work platforms. It is available from HSE Books or on the HSE website atwww.hse.gov.uk/pubns/misc614.pdf. The information sheet explains how to prevent falls, not just mitigate the effectsonce a fall occurs. It also explains how to select suitable fall protection equipment where the risk cannot be adequatelycontrolled.

All types of boom (articulated and telescopic) mobile elevating work platforms (MEWPs), commonly known as 'cherrypickers', are covered in the guidance, including ones that are:


Copyright © GEE Publishing Ltd 2004 26 Power Operated Mobile Work Platforms

1. Vehicle-mounted

2. Self-propelled

3. Trailer-mounted


Copyright © GEE Publishing Ltd 2004 27 Power Operated Mobile Work Platforms

7. Mast-elevated Work Platforms

Generally this type of equipment is used on high rise structures or buildings. It provides access to working areas for bothrefurbishment and repairs or external cladding. There are three types of equipment which consist of:

1. A mast(s) or tower(s) which support(s) a platform or cage

2. A platform which is capable of supporting persons and/or equipment

3. A chassis supporting the tower/mast section

General Guidelines for Erecting and Using Mast-elevated Work Platforms

• Only trained personnel should erect, operate or dismantle the equipment.

• The manufacturer's instructions on inspection, maintenance and servicing should be followed.

• The equipment should be erected on firm and level surfaces. Where outriggers are providedthey must be extended before use or testing.

• The safe working load of the equipment should be clearly marked on it, be readily visible to theoperator and never be exceeded.

• Raising and lowering sequences should only be initiated if adequate clearance is available.

• The platform should be protected with edge guardrails, toeboards and provided with adequatemeans of access.

• Any potential crushing area at ground level must be guarded.

• Unauthorised access into the work area should be prevented using ground barriers.

• Contact with overhead power cables should be prevented by preliminary site inspection and bynot approaching closer than a given distance. This distance can be obtained in respect of theparticular power lines, from the power supply company.

• Emergency systems must not be used for normal lowering.

• Repairs and adjustments should only be carried out by qualified people.


Copyright © GEE Publishing Ltd 2004 28 Mast-elevated Work Platforms

8. Suspended Access (Cradles)

A suspended access system includes a working platform or cradle, equipped with the means of raising or lowering whensuspended from a roof rig.

General Guidelines for Erecting and Using a Suspended Access System

• The safe working loads must be clearly marked and the cradle must be capable of taking theloads to be imposed on it.

• Experienced erectors only should be used for the installation.

• Supervisors and operators should be trained and competent in the safe use of the equipmentand in emergency procedures.

• Inspections and maintenance are to be carried out regularly.

• Suspension arrangements must be installed as designed and calculated.

• All safety equipment, including brakes and stops, must be operational.

• The marked safe working load must not be exceeded, and the effects of wind should beconsidered.

• Platforms should be free from obstruction, and fitted with edge protection. It is recommendedthat safety harnesses are worn and secured.

• Any tools or equipment are secured to the platform where practicable.

• The route of the platform must be clear and care should be taken that occupants of the buildingdo not open windows or create other obstructions.

• The electrical supply is not to be capable of inadvertent isolation, and should be properlymaintained.

• Adverse weather conditions should be defined so that supervisors and operators know what isnot considered acceptable.

• All defects noted are to be reported and rectified before further use of the equipment.

• Safe access is required for the operators at either ground level or other safe place, andunauthorised access is prevented.

• Necessary protective measures for the public and those working below should be in placebefore work begins.

• Checks of the suspended roof beams, counterweights and fixings must be made before everyentry.

• Access to this area should be prohibited.

• Between periods of work the platform must be left at a safe position and secured.

• A suspended platform must not be used to transfer persons from one place to another.

• Do remember that objects may fall from a higher level and therefore safety helmets need to beworn. Be aware of persons maliciously 'bombing' operatives in cradles.


Copyright © GEE Publishing Ltd 2004 29 Suspended Access (Cradles)

9. Personal Suspension Equipment (Boatswains Chairs and Abseiling Equipment)

A boatswain's (or bosun's) chair is a seating arrangement provided with a means of being raised or lowered with asuspension system and it should only be used in positions where access by other means is impossible, or for very shortduration work.

Abseiling equipment is used by specialists to gain access where the provision of more conventional means of accesswould be difficult or prohibitively expensive, the duration of work is likely to be very short indeed and the nature of thework lends itself to this approach.

The following section gives details of main requirements.

Key Principles to be Observed when Using Personal Suspension Equipment

• The equipment must be suitable and of sufficient strength for the purpose it is to be used for,and the loads which are anticipated.

• All equipment must be checked before use.

• The equipment must be securely attached to plant or a structure strong and stable enough forthe circumstances.

• Suitable and sufficient steps must be taken to prevent falls or slips from the equipment.

• The equipment must be installed or attached to prevent uncontrolled movement, e.g.anti-spinning devices fitted.

• A means of rescuing persons is in place.

A specific risk assessment should be made in every case.


Copyright © GEE Publishing Ltd 2004 30 Personal Suspension Equipment (Boatswains Chairs and Abseiling Equipment)

10. Roofwork

Several of the fatal construction accidents every year occur when roofwork is being undertaken. There are also manyserious injuries resulting in permanent disabilities.

Many of these accidents involve specialist roofers, however other workers who are carrying out maintenance andcleaning operations also suffer the same accidents.

Sometimes the accidents are from falling off the edge of flat or sloping roofs. Others from falling through fragile materials,e.g. rooflights, asbestos sheeting, roofsheets. Some materials like asbestos cement sheets, fibreglass and plastic are notobviously fragile, but may deteriorate with age. Metal sheeting which is not fragile originally may suffer from rust. Equallymetal roof supports may rust or timber supports suffer from dry rot or similar. Or there may have been repairs ormodifications that have been poorly carried out.

Potentially any roof is unsafe and could give way without warning. Do not trust any sheeted roof or stand on it. On afragile roof, many people think that 'walking the bolts' or along the ridge is acceptable. The sheets could crack at anymoment and give way, causing a fall.

Rooflights can be more dangerous with age, as they become difficult to see in certain light conditions due to dirt or havingbeen covered by bituminous paint to reduce glare in the building.

The Health and Safety Executive (HSE) has changed the guidance publication classifying the fragility of sheet materialsused in roofing. The HSE's report, Fragile and Non-fragile Sheeting Materials, SIR 30, is no longer valid and has beenwithdrawn. The only current test accepted by the HSE to classify non-fragile materials (contained in ACR[M]001:2000(second edition)) is Test for Fragility of Roofing Assemblies (Second Edition), also known as the Red Book. This isavailable from:

National Federation of Roofing Contractors24 Weymouth StreetLondonW1N 4LXTel: 020 7436 0387

When undertaking roofwork, it is important that both the client and the contractor take note of the special dangers asshown by the case in which McDonald's Insulation and Maintenance Limited and The London Borough of Havering werefined more than £10,000 between them, at Havering Magistrates' Court for breaching health and safety regulations.

The prosecution by the Health and Safety Executive (HSE) followed an accident on 20 February 2000 in which TerryUpton, an employee of McDonald's Insulation and Maintenance Limited, fell three metres through a fragile roof of adisused building. He was removing an asbestos cement roof at Clockhouse Primary School, Romford on behalf of thecouncil. Asbestos cement sheeting is well known to be fragile, and there are several recognised safe methods of workingon such material. However, Mr Upton and his colleagues were working under an unsafe system of work, with a ladder thatdid not cover the length of the roof. He sustained severe head injuries as a result of the fall and was in a coma for severalweeks. Mr Upton still has speech and memory problems and has been told that he may not be able to return to work.

The London Borough of Havering, as the clients, were fined £4,500 and paid £5,043 costs for a breach of theConstruction (Design and Management) Regulations 1994 (S.I. 1994, No. 3140) and McDonald's Insulation andMaintenance Limited, contracted by the council, were fined £6,000 with £1,485 costs for a breach of the Health andSafety at Work etc. Act 1974 , s. 2(1).

10.1 Planning

Due to the high risk nature of roofwork it is essential it is pre-planned. A risk assessment must be completed which willidentify the risk of falling. A safe system of work must be developed which identifies the control measures for the variousactivities. Consideration should be given not only to those persons involved in the work but to others who may beaffected, such as employees of other contractors, occupiers of the building and the general public. Generally a writtenprocedure or method statement should be prepared.

The hazard of roofwork is ever present whether undertaking new construction or maintenance work. For those carrying


Copyright © GEE Publishing Ltd 2004 31 Roofwork

out new work, the hazards are well known and not following the agreed method, bad work practices or familiarity can leadto an accident. With maintenance-type operations, they may be done by inexperienced workers who are not aware of thehazards.

10.1.1 Method of Work

The method of work for all roofwork, whatever its nature or extent, should provide a safe place of work.

The method statement should identify the safe working positions, access routes, movement of materials, falling materials,protection of public, other risks, e.g. fire, equipment to be used, competency, supervision, changes, control measures,etc.

To achieve this there is a hierarchy of risk safeguards. The provision of physical safeguards such as guardrails, toeboardsand barriers is preferable. However depending on the type of work activity this high standard cannot always be achieved.

Ensuring the safety of the workers at height then relies on fall arrest systems, which do not prevent falls but reduce theinjury once a fall has happened. There are two basic types:

1. Those that give general protection, e.g. safety nets

2. Those giving individual protection, e.g. safety harnesses connected to a suitable anchorage point

Safety nets provide protection to everyone in the work area and allow freedom of movement. They need to be installed asclose as possible beneath the work area to reduce the potential fall area, i.e. no more than 2 m. They are probably moresuited to open span areas such as portal frame buildings.

Safety harnesses protect the individual when they are worn and fitted correctly and whilst attached to a suitable anchorpoint. They do rely upon the self-discipline of the wearer and are therefore not an easy option. Means of rescue also needto be considered, particularly regarding the maximum time suspended in a harness. Often there is not a suitable anchorpoint available, although proprietary mobile systems can be obtained. When undertaking maintenance work a suitableanchor point may be available.


10.2 Safe Access

A safe means of access must be provided to any roof. This may be by ladder, tower scaffolds, independent scaffolds,mobile work platforms or the existing permanent access route for maintenance.

10.2.1 Ladders

Always ensure that any ladder stands on a firm level base and is supported by both stiles. If the surface is smooth or of aslippery nature, non-slip pads or caps are available.

Set the ladder at an angle of 75° to the horizontal to obtain optimum balance - i.e. 1 m out for every 4 m of height.

Secure the ladder at the top. The provision of permanent securing points can improve ladder safety. It may also avoid theneed for the ladder to be untied and rely on someone supporting the foot of the ladder to prevent it from slipping.

No ladder must extend beyond 9 m high. The longer the ladder, the more difficulty there is in handling and moving it. Thelanding place must be safe with suitable edge protection to prevent falls.

All ladders must extend about 1 m above the stepping off point to provide suitable hand hold. At the stepping off point asuitable access must be provided and kept clear.

Should it be necessary to carry tools, materials or small components a ladder may not provide a safe access andalternative means of access should be considered.











10.2.2 Tower Scaffolds

Traditionally ladder access up a tall structure would have been by a ladder tower which was purpose built and attached tothe main scaffold. This is still a system commonly used, however modern materials and building techniques and fasterwork methods mean aluminium towers are now more often used.

There are a several different types of towers available which are comparatively easy to erect and offer an excellentmeans of access.

These towers are also mobile and will normally be made of prefabricated aluminium. The lightness of the material makesthem easier to erect, rather than traditional steel scaffolding. In either form, competent and trained personnel are requiredto erect the tower.

These towers can be 'stairway' designs and are preferable to the ladder type when tools, small components, etc. need tobe carried.

10.2.3 Independent Scaffolds

An independent scaffold can provide safe access to and around a roof with the benefit of space for material storage.Loading bays can also be provided for material transfer. The scaffold needs to be suitable for the work being undertaken,e.g. the work platform at roof height level.

10.2.4 Mobile Work Platforms

Power operated mobile work platforms provide a safe means of access and place of work when working at height,particularly if the work is of short nature. The appropriate type of equipment needs to be selected. The ground conditionsand access at ground level may affect selection.

10.3 Types of Roofs

If a person could fall more than 2 m, then suitable edge protection must be provided, similar to the requirements forscaffolding, e.g. guardrails at least 910 mm above platform. Toeboards must be at least 150 mm high. Gaps between anyguardrails and toeboards must not exceed 470 mm. NB: brickguards may be used as an alternative to intermediateguardrails.

10.3.1 Flat Roofs

A roof of a pitch of less than 10° is classified as a flat roof. Safe access must be provided and maintained.

On flat roofs falls may occur:

1. From the edge of a completed roof

2. From the edge where work is being carried out

3. Through openings or gaps

4. Through fragile material

When planning any roof work, the system of work should be organised to prevent anyone falling. The use of a birdcagescaffold, safety nets or other systems should be adopted. The wearing of safety harnesses is a last resort.

When working to a leading edge then guardrails may be removed subject to:

1. A maintained safe system of working which prevents falls (e.g. birdcage scaffold, safety nets, youngmans' boards,etc.)



2. Barriers being erected or re-erected as soon as the work ceases

3. Safety harnesses are used and connected to a suitable anchor point. NB: a retractable line may be used in somesituations

Any openings, gaps or fragile material such as skylights would require guardrails or barriers, or secure covering, plus awarning sign.

Should the whole roof be made of a fragile material such as asbestos cement sheeting, then the system of work shouldnegate the need to be on the roof or provide suitable walkways with guardrails.

10.3.2 Sloping Roof

A roof of a pitch more than 10° is classified as a sloping roof.

On traditional pitched roofs, most falls occur:

1. From the eaves

2. From the roof, i.e. slipping down the roof and then falling from the eaves

3. Through the roof, i.e. falling internally during roof truss erection or stripping of a roof during demolition

4. From gable ends

A scaffold at the eaves level gives a good standard of protection at roof edges and should be provided unless the work isof a short nature.

On steeply sloping roofs the working platform needs to be wide enough to accommodate any eaves overhang andprovide a minimum of 600 mm-wide effective working platform.

Depending upon the height of the roof eaves to the scaffold guardrails it may be necessary to raise the height of theguardrails. Extra guardrails may be introduced subject to maintaining a maximum gap of 470 mm.

The step down from a roof to a working platform should be kept to a minimum, i.e. 300 mm.

10.3.3 Crawling Boards

Suitable crawling boards or ladders should be provided for access.

Requirements for Crawling Boards/Ladders

Crawling boards/ladders must be:

• Of good construction, strong enough and properly maintained

• Properly supported

• Securely fixed to the roof over the ridge with hooks, which must not bear on the ridge or cappingtiles

Requirements for Tile Battens

As an alternative to roof ladders, the tile battens may be used for access provided they:

• Offer a secure foothold

• Are of good quality

• Are fixed to rafters not more than 450 mm apart



• Meet the current minimum standard to BS 5534 1997, Pt. 1 'Code of Practice for Slating andTiling - Design'

• Are no less than 19 mm thick by 32 mm wide

Greater care is required on re-roofing work where the battens may have deteriorated or be to a lesser standard.

Roofs of more than 50° are classed as steep roofs and a higher standard of safety is required.

10.3.4 Chimneys

For work on chimneys, a properly designed scaffold should be used.

10.3.5 Roof Trusses

When roof trusses are being erected the hazard is from falling through the trusses.

Pre-fabrication at ground level and lifting the completed roof would considerably reduce the risk. Due to lack of space atground level this is not always possible.

To prevent falls, the provision of a birdcage scaffold beneath the soffit of the trusses would reduce the distance of fall butnot prevent it. Traditional scaffolds can be used but are often impracticable on housing work. Proprietary systems areavailable as an alternative.

Other methods available are safety nets which span from one wall plate to another. Consideration should be given to thesag distance if a person falls onto a net. An alternative to safety nets is the provision of airbags which fill the void.

Where a person has to access a higher point within the roof truss, e.g. to fix a ridge board, then the birdcage or safety netmay be more than 2 m below and therefore not provide adequate protection from a fall.

In this situation it may be necessary to provide an intermediate platform within the roof trusses. The designer should havean involvement.


10.3.6 Fragile Roofs

Fragile roofing material includes asbestos, glass, plastic, cement sheet and other similar brittle surfaces.

Substantial-looking metal roof cladding can be dangerously corroded. Surface coatings or dirt may conceal the fragilenature of the material, giving an appearance of solidity to glass, plastic, asbestos etc.

When working or passing across fragile materials, crawling or staging boards must be used so that a person's weight ison the board, never on the fragile roofing sheet. Guardrails or coverings are required to prevent a person who is passingor working near fragile material from falling through. These sheets can be brittle and shatter without warning.

Where it is not practicable to maintain guardrails, then safety harnesses, securely anchored, may be used.

'Walking the bolts' is dangerous and should not be permitted. A safe system of work should be adopted, as describedabove.

Work must cease when windy. The sheet may act as a sail, causing a person to be blown off the roof. All materials shouldbe secured down.

Any walkway near fragile materials (valleys, parapets, gutters or channels) must be provided with guardrails or adjacentmaterial must be covered to prevent any persons falling through.

All fragile roofs should have suitable warning signs.











10.3.7 Industrial Roofs

The roofing of industrial buildings accounts for many accidents and injuries.

Falls during industrial roofing often occur:

1. Through fragile roof lights

2. Through gaps in the partially completed roof

3. Through the liner panels that are not fully fixed

4. From the leading edge

5. From the edge of the roof or gutter

6. From the frame when loading out

Where fragile roof lights are used, the design should prescribe other safeguards. This may be in the form of a reinforcedmetal mesh built into the roof thereby preventing any person falling through. Other precautions could be in the form ofguardrails, barriers or temporary covers which are clearly marked, indicating the hazard.

Any gaps in the roof must have guardrails, barriers or temporary covers, with the nature of the hazard clearly written onthem.

The majority of lining panels rely on the correct number and quality of the fixings to prevent persons falling through.Because of their relatively flimsy nature and tendency to damage easily, the roofers avoid standing on them, more from aquality angle. However too often the roofers inadvertently stand on them and fall through.

There are temporary leading edge roofing trolley systems available which provide platforms for the work. Often theinstallation and moving of the platform is hazardous in itself.

The hazard of the leading edge is ever present because there has to be a space to place the next sheet over. Relianceon safety harnesses is never satisfactory there; the provision of safety nets is essential.

Because of the need to move freely on the roof or having laid the liner sheets, return over the roof again laying the topsheet, the provision of safety nets gives the best protection.

Accessing the roofing sheets from the storage area to the work area presents its own risks of falling from the roof edge orthe gutter during movement. Although running lines may be provided to which the harness is attached, the restriction ofmovement is prohibitive. Again safety nets provide the best protection. When planning the work, stored material shouldideally be positioned behind the leading edge.

Positioning the roofing sheets onto the purlins before work commences presents its own hazard as there is usuallynowhere for the unloading gang to stand and access is difficult. Although cranes have been used for many years, thetechnological advancement of telescopic handlers, with greater lifting capability and reach, means that materials can belifted to designated loading areas close to the actual roofing activity.

10.3.8 High Level Work

Often high level work is undertaken in a factory or warehouse. A suitable scaffold should be erected below the work area.This could be a mobile scaffold tower. However, because of the height involved, this is not always practical. Above 6 mhigh, a mobile elevating work platform (MEWP) is more appropriate.

General Guidelines for mobile elevating work platforms

• The type of machine should be appropriate to the work, i.e. telescopic, scissors, or articulating

• The MEWP should be placed on level ground



• The operator must be suitably trained on that type of machine

• In most MEWPs it is recommended that a safety harness is worn and connected to the machine

• Care should be taken when operating, that there is a clear head space and no overheadobstructions, including electric cables

10.3.9 Other Situations

This section has not covered all work at height activities. There are sometimes situations whereby a safe place of workcannot be provided, such as for window cleaning or for small remedial work in a part of the building not accessible to thetypes of working platform mentioned earlier. If this occurs, then a safety harness must be worn and connected to thebuilding structure, but only as a last resort, subject to a risk assessment.



11. Demolition

The main causes of accidents in the demolition industry is the premature collapse of buildings and structures, and fallsfrom working places and access routes. It is not only the workers who are at risk but possibly the public or personspassing by. The effects of dust, noise and other contaminates present significant problems. Failure to adequately planoperations is the common cause, thus leaving operatives to devise their own methods of work. It is important thateverybody knows what the safe system of work is.

An indication of the dangers of demolition is given by a case relating to a fatal incident involving a father and son teamwhen a kiln they were demolishing collapsed because their employer did not take enough safety precautions, a jury heardat Staffordshire Crown Court, 8 April 2002, as reported by Construction News (9 April 2002).

Michael Redgate, 46, and Carl Redgate, 18, were crushed to death buried in the rubble and masonry following thecollapse in July 2000. Brian Dean, 59, the boss of tile-makers Daniel Platt Ltd of Stoke-on-Trent denies manslaughter andfailing to provide safety at work for employees. The two men were employed to cut and remove pipe work, wiring andducting at the side of the kiln in preparation for its demolition on the weekend of their deaths. The cutting and removal ofinternal metal frameworks that held the structure in place is alleged to be the cause of the collapse.

11.1 Survey

Elements to Consider for Demolition Hazard Identification

Before any demolition works commence there should be a survey of the site to identify all the potential hazards.Consideration should be given to the following:

• The site in general including location and access

• The presence of adjoining or adjacent properties, e.g. hospitals whereby the system of workmay be restricted

• The type of structure and its key elements

• The condition of the structural members and their effect on the overall stability, there may be arequirement for temporary support

• Cellars or confined spaces, e.g. old tanks

• Health hazards, such as asbestos, residues from previous processes or contaminated land

• Waste removal

• Presence of services, e.g. underground electrics

11.2 Notifications

Depending upon the nature of the demolition work there is a requirement to notify certain bodies.

1. The Health and Safety Executive (HSE) if the works are notifiable.

See also Notification of Project (Regulation 7)

2. The Environmental Health Officer (EHO) if there is likely to be pollution, e.g. noise

3. The Health and Safety Executive (HSE) if work on asbestos is required

4. The utilities for location of services, isolation or diversion, or arrangements for temporary supplies

It is important to remember that all demolition work is covered by the Construction (Design and Management) Regulations1994 (S.I. 1994, No. 3140).


Copyright © GEE Publishing Ltd 2004 38 Demolition

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11.3 Method of Work Statement

With the knowledge gained from the survey, a preferred method of work can be identified. Methods that reduce oreliminate the need to work at heights should be employed. If this is not possible then adequate safe work places need tobe planned.

11.3.1 Method Statement

Items for Inclusion in the Method Statement

A detailed method statement must be prepared. It should be agreed by the site management and any employeesinvolved. It should include such matters as:

• The sequence of work including means of access, working platforms and plant and equipmentrequirements

• The protection of persons including the general public

• The details on any pre-weakening or use of explosives

• The making safe of any services

• The method of dealing with any flammable materials and gases

• The identification of any hazardous substances, the means of their disposal and therequirements of protective equipment

• The adequate arrangement for the removal of waste

• Appointment of a competent supervisor to control the demolition

11.4 Precautions

11.4.1 Protection of the Public

Demolition is frequently carried out in well-populated areas. Suitable fencing, at least 2 m high, should be provided andfixed with warning signs and the site made secure out of working hours.

The site should always be left safe and tidy out of working hours including immobilising plant, isolating services andremoving ladders. Debris, netting and facade fence may be used to reduce the risk from falling objects hitting personsbelow.

11.4.2 Overhead and Underground Services

A survey should be undertaken to identify the presence of any services. These must be made safe by disconnection andin any case all overhead services should have the safe distance marked with bunting 'goalposts' and all groundwork nearunderground services undertaken in an appropriate manner taking their possible presence into account.

11.4.3 Removal of Plant

When removing existing plant, tanks, etc., care needs to be taken to ensure there is no residue of flammable materials. Ifit is necessary to enter any tank, etc. then the requirements for confined space working need to be followed.

11.4.4 Falls



The method of work should always minimise the risk of persons falling. Many items of plant are available which enableremote working methods, e.g. hydraulic excavators with scissor/shear jaws attached to the dipper arm. They often have afacility for attaching hoses and are able to spray water as the demolition progresses. Other systems available have ballingmachines, impact hammers and hydraulic pusher arms.

Whenever any person is working at height edge protection must be provided. Guardrails at a minimum of 910 mm aboveplatform. Toeboards are at least 150 mm high. Any unprotected gaps between any guardrails and toeboards must notexceed 470 mm. NB: brickguards may be used as an alternative to intermediate guardrails.

Where material is stacked above height of toeboard, brickguards must be used, e.g. saved materials such as slates orbricks.

Other means of access can be used such as scaffolding, elevated work platforms, man-riding cages attached to plant.

In some situations a safety harness may be worn and connected to the building structure, e.g. removal of roof slates on asteep pitched roof.

Any working platform where a person can fall more than 2 m must be fitted with toeboard and double guardrail or othersuitable material of sufficient rigidity.

11.4.5 Safe Areas

Areas affected by the demolition work must be restricted or made safe. If debris is being dropped then a clear radius of 6m should be maintained, and similarly if mechanical plant is used. On tall structures an area of one and a half times thetotal height should be kept clear.

11.4.6 Health Hazards

During demolition certain substances will be encountered which can cause health risks:

1. Lead can be encountered as a toxic fume when cutting and burning steelwork covered with lead-based paints orhandling old petrol tanks from filling stations.

2. Asbestos dust will be generated whenever demolition work involves the removal of any asbestos-based material. NB:the removal of asbestos roof sheeting usually involves working at height where the risk of operatives falling isconsidered more dangerous than the health risk from asbestos dust. In these circumstances controlled collapse maybe a safer alternative; however, strict control needs to be taken to reduce the level of asbestos dust emitted into theair. Dampening down and good housekeeping will normally be adequate.

3. The use of mechanical plant, etc. during demolition usually creates noise above the permitted levels.

11.5 Demolition Technique

11.5.1 Piecemeal Demolition

With masonry and brick buildings this is usually undertaken by hand. The building should be demolished in the reverseorder of building erection, using the same safety elements. NB: the removal of the roof covering may present specialproblems (see Sloping Roof).

Steel-framed buildings should be demolished by competent specialist contractors.

11.5.2 Controlled Collapse Demolition

This is normally undertaken by the use of explosives, pre-weakening or overturning.

11.5.3 Demolition by Explosives



When explosives are being used very careful planning and control is required by persons experienced in this type of work.Blast protection is necessary in order to minimise damage. Exclusion zones must be set up, including a buffer zone. Noperson may enter the area until the 'all clear' is given.

11.5.4 Demolition by Pre-weakening

As the name suggests this involves the weakening or removal of certain structural elements.

11.5.5 Demolition by Overturning

This usually means the attachment of wire ropes to a structure and then pulling it over using winches or vehicles.

11.5.6 Demolition of Special Structures

Pre-stressed concrete has its own unique hazards due to the unpredictable nature on the release of the potential storedenergy. Information obtained from 'as-built' drawings are of great benefit.

See also Client to Ensure a Health and Safety File is Available for Inspection (Regulation 12)

Chimneys present their own problems dependent upon their location, e.g. densely populated sites. This will usuallydetermine the demolition technique.

Brick or masonry arches are often inter-dependent on each other for stability. Careful analysis and planning is necessary,including any temporary shoring.

All of these types of demolition should only be undertaken by specialist contractors.

11.5.7 Training and Competence for Demolition

Only trained and competent operatives should undertake demolition works.



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Key Questions

• What is the maximum height that a mobile aluminum tower can be erected?

See Aluminium Towers.

• Does every scaffold platform have to have an intermediate guardrail?

See General Access Scaffolds and Edge Protection.

• Can my roof sheet workers use safety harnesses?

See Roofwork and Method of Work.

• What should I be looking for in a demolition method statement?

See Demolition, Method of Work Statement and Method Statement.

• We only need to work at height for short periods. Do we have to provide a scaffold every time?

See Mobile and Suspended Access Equipment.


Copyright © GEE Publishing Ltd 2004 42 Key Questions

Troubleshooter

Adequate Edge Protection

Q. We are having some work done near to a service riser shaft to which access is not normally possible and so it hasno edge protection. What should we do to ensure the safety of the operatives?

A. It is important to ensure that service shafts which are near to areas where work is being carried out are suitablyprotected, both from people falling and from tools and materials falling. To this end the edge protectionrequirements are the same as for the scaffolding. There should be a guard rail at a minimum height of 910 mm andif the work requires much bending or stopping then there must be an intermediate guard rail at a distance from thetoeboard or the top guardrail of no more than 470 mm. The toeboard is to prevent tools or materials from fallingand should be at least 150 mm high. If the work is carried out on more than one level through which the serviceshaft passes, then these guardrails and toeboards should be provided at all levels throughout the duration of thework.

See Working Platforms.

Only Competent Persons to Erect and Dismantle Scaffolds

Q. We intend to refurbish one of our office blocks. During this work we will have scaffolding on the side of the buildingwith an inclined hoist through it to supply materials to the roof workers. After the roof work is completed we need toremove the hoist to complete the exterior decorating which will leave a gap in the scaffolding. We have some sparescaffolding around. The site manager has attended a scaffold awareness course. Can he alter the scaffold?

A. Whilst altering a section of scaffolding is fairly straightforward, it is important that it is undertaken properly. Whenanyone alters an existing scaffold erection it is a possibility that not all the scaffold tubes and clips are properlyreplaced and correctly tightened. The site manager may have attended a scaffold awareness course, but this willnot have provided sufficient skill to alter a scaffold. There is a risk of them falling because of not being aware of, ornot following the correct sequences and their potential lack of familiarity with handling the scaffold components.Only properly trained and competent people should be permitted to erect, alter or dismantle scaffolding.

See General Access Scaffolds.

Operatives not Competent or Trained in Demolition Work

Q. We have to remove two non-loadbearing adjacent brickwork walls during some demolition work and we originallyintended to use unskilled labourers with sledge hammers to do this. On the other side of these walls is a restaurantwhich is open for lunchtime business and so we are considering the use of specialist equipment to enable the jobto be done outside of the restaurant's business hours and still keep to the schedule. Is this OK?

A. Although early indications are that the two walls were separate, once exposed it may be that the walls are abuttingeach other, and when the restaurant was built later, the mortar from the brick joints may be squeezed out and nowsticking to the wall awaiting demolition. The wall will have to be removed piecemeal, by hand rather than withmachines due to excessive noise and vibration in the restaurant.

Due to the location of the wall to be removed, which is attached to an occupied building, it is essential that anyperson undertaking demolition work must be competent and fully appreciate the consequences of their actions.There is a likelihood that the casual labourers will not have an appreciation of the potential hazards of not workingin a safe and systematic manner. If specialist hydraulic expansion tools are to be used then the two labourerswould not have sufficient skills to use them even if they received some training. Too often this type of equipmentarrives and untrained persons are told to get on with it. See Demolition and Survey.


Copyright © GEE Publishing Ltd 2004 43 Troubleshooter

Checklists

Considerations when Working at Height

• Make sure there is a safe route or method to and from the work area.

• Ensure that any equipment will be suitable for the job and the conditions on site.

• Make sure that any equipment needed is delivered to site in good time and that the site hasbeen prepared for it.

• Any work platforms and any edges from which people are likely to fall must have guardrails andtoe boards or other barriers.

• Check that any equipment is in good condition.

• Make sure that whoever puts the equipment together is trained and competent and knows whatthey are doing, e.g. making scaffolders erect and dismantle scaffolding or supplying trainedpersonnel to erect mobile towers.

• Ensure those who use the equipment are supervised so that they use it properly and arecompetent and trained, e.g. have attended a scaffold awareness training. Where the equipmentis more specialised (i.e. boatswain's chairs and rope access equipment), the greater the degreeof training and supervision required to ensure safety.

• Where another company provides equipment on site, check it is safe before using it.

• Where any defects are found ensure they are corrected immediately.

For further information on using this checklist see 2. General Principles when Working at Height

Selection of a Means of Access

• Wherever possible a working platform with guardrails and toeboards should be provided. Thismay form part of the structure or an elevated work platform.

• When it is not practicable to provide a work platform, consider whether other means of access(for example, boatswain's chairs or rope access techniques) should be used.

• Only when no other method is practicable or when work platforms cannot comply with allrequirements for safe work (e.g. a guard rail has to be removed to land materials or roofsheeting is being laid), should a means of arresting falls be relied upon, e.g. a safety harnessand lines or nets.

• Safety harnesses, lines and nets only provide protection for the person using the equipment inthe event of a fall - they do not prevent falls.

• Those persons employed put up guard rails or other protection to the workplace shall alsorequire the protection of safety harnesses and lines and nets.

• For short-term work the use of tower scaffolds or mobile elevating work platforms (MEWPs)may be suitable. Ladders should only be used as workplaces for short periods and then only if itis safe to do so.

• Checks need to be made to ensure that there is adequate clearance for equipment, e.g. contactwith overhead power lines can be a risk when erecting scaffolds or using MEWPs. When mobileaccess platforms are manoeuvered there can be a risk of crushing against nearby structures.

For further information on using this checklist see 2. General Principles when Working at Height


Copyright © GEE Publishing Ltd 2004 44 Checklists

Statutory Requirements for an Inspection Report

There is a requirement for specific information to be included in the report as identified in Construction (Health, Safety andWelfare) Regulations 1996 (S.I. 1996, No. 1592) > reg. 20 & Sch. 8. The report should contain the following information:

• Name and address for whom the inspection was carried out

• Location of the workplace inspected

• Description of the workplace or part of workplace inspected (including any plant, equipment andmaterials, if any)

• Date and time of the inspection

• Detail of any matter identified that could lead to a risk to the health and safety of anyone

• Details of any action taken as a result of any matter identified in the last point

• Details of any more action considered necessary

• The name and position of the person making the report

For further information on using this checklist see 3. General Access Scaffolds

General Guidelines for Erecting and Using Tower Scaffolding

• All the components must be in good condition, work correctly and be compatible. Checks shouldbe made for cracks, broken welds, crushed or bruised tube or any other damage.

• Mobile towers should only be erected on firm and level ground and with the castors locked.

• The maximum height of a mobile tower should be no more than three times the minimum widthwhen used outside. This can increase to three and a half times inside. However, themanufacturers' recommendations should be followed.

• Out riggers or stabilisers may be used to gain extra height, but within the limitations of themanufacturers' recommendations.

• Double guardrails and toeboards must be fitted as with normal scaffold.

• Before climbing the tower any movement must be prevented by locking the wheels.

• Any outriggers or stabilisers must be securely fastened and braced.

• Steps or ladders should not be placed on the platform to gain extra height.

• Towers should only be moved by pushing at the base and there should be no persons ormaterials on the platform. When moving towers they must be dismantled to a platform level of2.5 times the effective least base dimension. Care should be taken that there are no overheadobstructions or power lines.

• Adequate means of access to the working platform should be provided. This may be in the formof angled steps, an inclined ladder within the tower, a vertical ladder attached to the narrow sideor a built-in vertical ladder integral within a frame section, climbing the outside cross supports orbracing sections is not permitted.

• There should be a platform provided at distances not exceeding 4 m.

• The recommended load should never be exceeded.

• If a mobile tower is left erected in the same place in excess of seven days, then an inspection



and report must be undertaken similar to the requirements for scaffolding (see Reports).

For further information on using this checklist see 4. Aluminium Towers

General Guidelines for Power Operated Mobile Work Platforms and their Use

• The ground must be firm and level

• An indicator for levelling or a self-levelling device fitted to the chassis to ensure verticality in use

• Stability in use must be ensured, including the provision of outriggers on some machines, whichmust be fully extended and locked in place before the equipment is used/raised, in accordancewith the manufacturer's instructions

• The platform is provided with guardrails and toeboards and a safe means of access onto theplatform

• A safety harness should be worn and connected to the MEWP

• Care should be taken not to come into contact with overhead obstructions including electriccables

• Consideration must be given to the effects of wind or other side forces

• The safe working load must be clearly marked and adhered to

• The area below must be kept clear of personnel and appropriate barriers and signs used

• Only authorised and competent persons may operate the equipment. The operator must be inpossession of an approved training certificate appropriate to the type of machine, e.g. a CITB(Construction Industry Training Board) CTA (Certificate of Training Achievement) card or note.Familiarisation training given by hire companies may not be considered sufficient.

For further information on using this checklist see 6. Power Operated Mobile Work Platforms

General Guidelines for Erecting and Using Mast-elevated Work Platforms

• Only trained personnel should erect, operate or dismantle the equipment.

• The manufacturer's instructions on inspection, maintenance and servicing should be followed.

• The equipment should be erected on firm and level surfaces. Where outriggers are providedthey must be extended before use or testing.

• The safe working load of the equipment should be clearly marked on it, be readily visible to theoperator and never be exceeded.

• Raising and lowering sequences should only be initiated if adequate clearance is available.

• The platform should be protected with edge guardrails, toeboards and provided with adequatemeans of access.

• Any potential crushing area at ground level must be guarded.

• Unauthorised access into the work area should be prevented using ground barriers.

• Contact with overhead power cables should be prevented by preliminary site inspection and bynot approaching closer than a given distance. This distance can be obtained in respect of theparticular power lines, from the power supply company.



• Emergency systems must not be used for normal lowering.

• Repairs and adjustments should only be carried out by qualified people.

For further information on using this checklist see 7. Mast-elevated Work Platforms

General Guidelines for Erecting and Using a Suspended Access System

• The safe working loads must be clearly marked and the cradle must be capable of taking theloads to be imposed on it.

• Experienced erectors only should be used for the installation.

• Supervisors and operators should be trained and competent in the safe use of the equipmentand in emergency procedures.

• Inspections and maintenance are to be carried out regularly.

• Suspension arrangements must be installed as designed and calculated.

• All safety equipment, including brakes and stops, must be operational.

• The marked safe working load must not be exceeded, and the effects of wind should beconsidered.

• Platforms should be free from obstruction, and fitted with edge protection. It is recommendedthat safety harnesses are worn and secured.

• Any tools or equipment are secured to the platform where practicable.

• The route of the platform must be clear and care should be taken that occupants of the buildingdo not open windows or create other obstructions.

• The electrical supply is not to be capable of inadvertent isolation, and should be properlymaintained.

• Adverse weather conditions should be defined so that supervisors and operators know what isnot considered acceptable.

• All defects noted are to be reported and rectified before further use of the equipment.

• Safe access is required for the operators at either ground level or other safe place, andunauthorised access is prevented.

• Necessary protective measures for the public and those working below should be in placebefore work begins.

• Checks of the suspended roof beams, counterweights and fixings must be made before everyentry.

• Access to this area should be prohibited.

• Between periods of work the platform must be left at a safe position and secured.

• A suspended platform must not be used to transfer persons from one place to another.

• Do remember that objects may fall from a higher level and therefore safety helmets need to beworn. Be aware of persons maliciously 'bombing' operatives in cradles.

For further information on using this checklist see 8. Suspended Access (Cradles)



Key Principles to be Observed when Using Personal Suspension Equipment

• The equipment must be suitable and of sufficient strength for the purpose it is to be used for,and the loads which are anticipated.

• All equipment must be checked before use.

• The equipment must be securely attached to plant or a structure strong and stable enough forthe circumstances.

• Suitable and sufficient steps must be taken to prevent falls or slips from the equipment.

• The equipment must be installed or attached to prevent uncontrolled movement, e.g.anti-spinning devices fitted.

• A means of rescuing persons is in place.

For further information on using this checklist see 9. Personal Suspension Equipment (Boatswains Chairs andAbseiling Equipment)

Requirements for Crawling Boards/Ladders

Crawling boards/ladders must be:

• Of good construction, strong enough and properly maintained

• Properly supported

• Securely fixed to the roof over the ridge with hooks, which must not bear on the ridge or cappingtiles

For further information on using this checklist see 10. Roofwork

Requirements for Tile Battens

As an alternative to roof ladders, the tile battens may be used for access provided they:

• Offer a secure foothold

• Are of good quality

• Are fixed to rafters not more than 450 mm apart

• Meet the current minimum standard to BS 5534 1997, Pt. 1 'Code of Practice for Slating andTiling - Design'

• Are no less than 19 mm thick by 32 mm wide


General Guidelines for mobile elevating work platforms

• The type of machine should be appropriate to the work, i.e. telescopic, scissors, or articulating

• The MEWP should be placed on level ground

• The operator must be suitably trained on that type of machine

• In most MEWPs it is recommended that a safety harness is worn and connected to the machine



• Care should be taken when operating, that there is a clear head space and no overheadobstructions, including electric cables


Elements to Consider for Demolition Hazard Identification

Before any demolition works commence there should be a survey of the site to identify all the potential hazards.Consideration should be given to the following:

• The site in general including location and access

• The presence of adjoining or adjacent properties, e.g. hospitals whereby the system of workmay be restricted

• The type of structure and its key elements

• The condition of the structural members and their effect on the overall stability, there may be arequirement for temporary support

• Cellars or confined spaces, e.g. old tanks

• Health hazards, such as asbestos, residues from previous processes or contaminated land

• Waste removal

• Presence of services, e.g. underground electrics

For further information on using this checklist see 11. Demolition

Items for Inclusion in the Method Statement

A detailed method statement must be prepared. It should be agreed by the site management and any employeesinvolved. It should include such matters as:

• The sequence of work including means of access, working platforms and plant and equipmentrequirements

• The protection of persons including the general public

• The details on any pre-weakening or use of explosives

• The making safe of any services

• The method of dealing with any flammable materials and gases

• The identification of any hazardous substances, the means of their disposal and therequirements of protective equipment

• The adequate arrangement for the removal of waste

• Appointment of a competent supervisor to control the demolition

For further information on using this checklist see 11. Demolition



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