review of cause of construction accidents - hse rr218.pdf

8/14/2019 Review of Cause of Construction Accidents - HSE rr218.pdf

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HSEHealth & Safety

Executive

Peer review of analysis of specialist groupreports on causes of construction accidents

Prepared by Habilis Ltd for the

Health and Safety Executive 2004

RESEARCH REPORT 218


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HSEHealth & Safety

Executive

Peer review of analysis of specialist groupreports on causes of construction accidents

Liz Bennett BSc PGCE CEng MICE MIOSH FRSAHabilis Ltd

3 Market PlaceShipston on Stour

Warwickshire

CV36 4AG

The Construction (Design and Management) Regulations 1994 have introduced new duties for

designers. It is argued that early intervention by designers and indeed clients can have a significant

impact on construction safety during the main building phase and also during maintenance and

demolition of structures.

Until the advent of these Regulations the principal blame for any construction site incident was

generally laid at the door of the main contractor. The industry has found the cultural changes

necessary for proper designer integration difficult to embrace and various projects have been initiated

by the Health and Safety Executive to remedy this.

It was believed that an analysis of a series of randomly selected incidents might give evidence, or at

least an indication, to a reluctant industry that designers can do more to improve safety and health in

construction. The initial stage was to develop a methodology for carrying out this analysis. The

secondary stage was to peer review and iteratively agree on those findings. This report is a summary

of that review.

The findings very thoroughly underline the fact that the thinking behind the Regulations is sound and

that designers can and so arguably should do more.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Itscontents, including any opinions and/or conclusions expressed, are those of the authors alone and do

not necessarily reflect HSE policy.

HSE BOOKS


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Crown copyright 2004

First published 2004

ISBN 0 7176 2836 1

All rights reserved. No part of this publication may bereproduced, stored in a retrieval system, or transmitted inany form or by any means (electronic, mechanical,photocopying, recording or otherwise) without the priorwritten permission of the copyright owner.

Applications for reproduction should be made in writing to:Licensing Division, Her Majesty's Stationery Office,St Clements House, 2-16 Colegate, Norwich NR3 1BQor by e-mail to [email protected]


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ACKNOWLEDGEMENTS

Acknowledgements are made to Malcolm James whose innovative approach to the analysis of

the accidents reviewed in this study was both stimulating and illuminating.


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CONTENTS

1 BACKGROUND.....11.1 Accident Rates..1

1.2 Construction (Design and Management) Regulations 1994 CDM...1

1.3 CDM Regulation 13 Difficulties for Industry...2

1.4 CDM Difficulties for the Health and Safety Executive2

1.5 Industry Wide Initiatives3

2 PROJECT OBJECTIVES AND WORK PHASES.52.1 Project Objectives

2.2 Work Phases

3 SOURCE DOCUMENTS..73.1 Accident Reports 73.2 Original Research Reports.7

4 AUTHORS REMARKS...94.1 Author Entry View..9

4.2 Impact Of Fatal Accident Reports.9

5 ASSUMPTIONS AND PROCESSES.115.1 Processes and Iterations11

5.2 Agreed Assumptions..11

6 FINDINGS13

7 COMMENTARY.21

8 RECOMMENDATIONS.25

APPENDIX 1 CATEGORIES27

APPENDIX 2- ACCIDENT ANALYSIS SHEETS.29


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EXECUTIVE SUMMARY

The Health and Safety Executive is committed to making a fundamental reduction in the

number of deaths, injuries and cases of ill health in construction. There is a view held bysome of the industry and underpinned by Regulations that designers could make a significantdifference. The key changes required are for designers to design structures that are safer andhealthier to build, maintain and demolish. Clearly operational issues must be considered aswell since they have a major effect on maintenance capability.

There are many in the industry, and in particular in the design community, who remainunconvinced by the arguments that designers can and should make a difference to the waythey work. The purpose of this research package was to analyse actual incidents with respect

to designer involvement.

As the research evolved various other potentially useful indicators emerged and additionalrequirements for information collection were identified. This research must therefore be seenas part of an unfolding investigation into the best way to identify some of the key changepoints for the industry.

The author has chosen to track personal views of the research for the reader as this wasjudged helpful. In particular a certain amount of cynicism towards the arguments for realintervention by designers was in place at the beginning of the programme. Long before the

end the author became completely convinced of the enormous importance of the need forradical change amongst the design community.

The original research was modified after discussions between the author and the originator of

the incident summaries. It is recognised that further improvements could be made to thecollection of data and its analysis that could provide significant material for industry.

The original review of the incidents was conducted by Malcolm James, who did thedevelopment of the methodology for the study and also summarised and analysed theincidents in the first instance. The peer review that is the subject of this report acknowledgesthe importance of Malcolms work but takes complete responsibility for statements within thereport.

The Report concludes that almost half of all accidents in construction could have beenprevented by designer intervention and that at least 1 in 6 of all incidents are at least partiallythe responsibility of the lead designer in that opportunities to prevent incidents were not

taken.

The Report makes no commentary on culpability or the moral and ethical dimensions of

designer failings. These must be decided in other places.


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1 BACKGROUND

1.1 ACCIDENT RATES

The United Kingdom construction industry has one of the lowest accident rates in the worldfollowing generally declining rates over recent decades. Latterly, however, a levelling off hasbeen observed and there remain various categories of seemingly intractable accidents. In 2002there where 80 fatal accidents in construction, which is nearly seven each month. The cost ofthese deaths to the families and friends of those killed is incalculable. The cost to the industryand the UK at large can more easily be quantified but never accurately assessed. In any case

this price is always too high for all concerned.

1.2 CONSTRUCTION (DESIGN AND MANAGEMENT) REGULATIONS 1994

CDM

For some years there has been a belief that early contributions to the construction andbuilding processes from both clients and designers could make a radical improvement to theconstruction processes during the whole life of a structure. Anecdotal evidence from industryshowed that the construction and building industry is capable of delivering safe constructionbut that it regularly fails to do so. Changing the emphasis of responsibility towards those whocommission, scope and design works so that the end result is seen as a team approach to lifelong safety and health management was expected to deliver benefits.

The Temporary and mobile construction sites Directive 89/391/EEC was introduced acrossthe European Economic Community to change the way construction health and safety ismanaged. In the UK this Directive was implemented as two sets of construction regulations:the Construction (Design and Management) Regulations 1994 CDM - and the Construction(Health, Safety and Welfare) Regulations 1996 - CHSW.

CDM put new duties on clients and designers and introduced a new statutory appointment ofPlanning Supervisor. The concept behind CDM was one of teams of competent appointeesproviding appropriate information throughout the life of the project for use by those who hadthe capacity to influence health and safety for good or ill. There was also a requirement toallow for adequate resources in all senses to achieve the same ends.

The opportunities presented by CDM would seem to be clearly apparent, based as they are on

sound project management philosophy and holistic risk management.

The regulations were, however, generally considered by consultants and advisors in their

narrowest sense and frequently not read or applied in conjunction with the CHSW or otherrelevant regulations, without which their application becomes meaningless.

Further, the Regulations were not so ordered as to make duty holders duties easily apparentto the vast numbers of those who were obliged to wrestle with legal terminology for the firsttime.

Designers duties are generally encapsulated in Regulation 13, which is often considered asstand alone, though there are significant implied duties for designers embedded in other

regulations, mainly to do with competence, communication, co-ordination and co-operation.Regulation 13 has two key aspects to it. Regulation 13 (i) essentially requires designers to


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ensure that clients are aware of their duties, allowing the non-expert client to be keptinformed by professionals. Regulation 13(ii) can be summarised as a requirement to

contribute to the designing out of hazards and risks of downstream contractor processes.

1.3 CDM REGULATION 13 DIFFICULTIES FOR INDUSTRY

The requirements of CDM Regulation 13 have not been effectively managed by some parts ofindustry. Various reasons for this may exist.

The wording of the regulation is insufficiently precise to set standards in relation tolegal duties.

There has been an assumption that CDM could stand alone without an understandingof building, construction and maintenance processes, including demolition, and ofother requirements such as operational constraints. These other factors are oftenoverlooked to the detriment of decision making.

Many designers are either unaware of, or not up to date in, modern construction andbuilding processes. For them to make any real contribution to safety and health theyclearly need to understand where the challenges are that face those who will

construct. There has been an assumption that the regulation demanded risk assessment now

commonly referred to asDRA orDesign Risk Assessment. Generally the teaching ofCDM to the industry has been conducted by health and safety professionals withexperience in contractor risk assessments. They have tended to translate this across tothe design community. In fact the Regulation makes no reference to risk assessment

nor is the Regulation 13 (2) duty best approached by the same methods as contractorrisk assessments, being rather a design process. Most DRAs are poorly conducted,retro-fitted, contractor risk assessments.

Many of the procurement routes, particularly those facing architects, make earlyintervention difficult from a commercial perspective.

Civil law is at odds with CDM in that case law exists that states that responsibility forsafety and health on site is the responsibility for the constructor alone. Such civil law

is in place at every contract while the criminal law of health and safety may onlypresent as a challenge to this where there is, for whatever reason, enforcerintervention.

The fear of criminal action has resulted in production of excessive paperwork as anattempt to manage liability. In fact such paper trails are generally of poor quality anddo little other than add to costs. They do not reduce liability unless they are effective.

1.4 CDM DIFFICULTIES FOR THE HEALTH AND SAFETY EXECUTIVE

The HSE cannot visit every site and must select those most appropriate to deliver

cultural change to a diverse industry. While large projects are an obvious target thesmaller projects, frequently under resourced in terms of competent advice, continue tobe the places where many of the accidents happen.

HSE field inspectors are experts in the law of health and safety and its enforcement.Design is, however, a complex professional discipline requiring years of training andexperience. For inspectors to challenge decisions taken by designers or to ask whyalternatives have not been considered is not possible except for those inspectors witha specialist background in the appropriate discipline. Even within the industry there isa considerable range of specialist disciplines at work and the provision of competentinspectors to match every such situation is not tenable.

Many of the difficulties that exist for industry also exist for inspectors.

A ten year fatal accident high set challenges to the thinking behind CDM. Many

questioned whether CDM had done anything but add costs to industry.


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1.5 INDUSTRY WIDE INITIATIVES

The Deputy Prime Minister, John Prescott, held a construction health and safety summitwhere he challenged industry to make commitment to improvement. Several strategicinitiatives were launched to bring the construction industry together and improve performanceacross all aspects of the construction process.

Rethinking Construction and its daughter report, Rethinking Health and Safety inConstruction were produced.

Designers were challenged to make a more positive contribution to health and safety inconstruction.


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2 PROJECT OBJECTIVES AND WORK PHASES

2.1 PROJECT OBJECTIVES

The objectives of the whole project were to examine a randomly selected sample of specialistinspector reports to establish:

Whether the case for CDM can be supported

Whether designers are really missing opportunities to contribute to health and safetyin construction

How HSE can best engage in driving change at field enforcement level

2.2 WORK PHASES

2.2.1 Phase 1: Initial research by Malcolm James

A random selection of 91 construction specialist inspectors reports were taken and analysed.Those that were clearly not to do with design were set aside but included in the finalnumerical computations. The categories selected for this analysis were in the first instance

iteratively developed by Malcolm James, who also assigned scores to most categories. Thesecategories are listed in Appendix 1.

Each report was summarised, assessed according to categories and notes made in relation tosuch matters as design failings.

A table was developed that set the opportunity presented to the designer against the

opportunity taken by that designer in relation to intervention to prevent realisation of anincident. Colour coding was used for ease of recognition at the request of the HSE.

2.2.2 Phase 2: Peer review of research by Liz Bennett of Habilis

Each report was reassessed without reference to the initial summaries but using the same

categories. The two results were then compared. Where differences occurred the secondassessment reconsidered the data and original assessors remarks to gain clearerunderstanding of the reasons for disparity.

Outstanding differences were discussed at a meeting between the two reviewers. One of thedifficulties encountered was that in some examples different assumptions had been made. In

others more than one designer could have had an influence. Unless reviewers had selected thesame designer the opportunity assessment could easily differ.

Keywords were a further area of difficulty since these depended on a range of variables. Theiruse to facilitate later search was however agreed.

2.2.3 Phase 2: Amended review and agreed forward strategy

An agreed forward strategy was developed as follows:

A list of standard keywords would be established for selection by assessors. This is seen asimportant for future analysis of findings in relation to particular work activities or commonfailings as it will facilitate a general search enquiry.


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Almost all the reports predate CDM and focus largely on construction processes. This meansthat Temporary Works Designers feature in a way that is likely to be disproportionate to the

potential contribution to be made by other designers. It was agreed that a separate analysis ofeach designer should also be made so that temporary works may be selected out to considerother designer aspects or included in if that is more pertinent to the point being made.

The analysis was to consider the current project only and not any design or construction forthe original works. From time to time where the original design had been a clear contributingfactor, say to later maintenance, this would be noted but not scored.

It was agreed that in areas of doubt assessors should err in favour of the designer.

In certain instances assumption would need to be made and stated about stakeholdercompetence ie the competence of the designer in specialist design areas. This would allowclearer understanding by readers of the reviewer thought processes.

The designer effort assessment can be taken as a rough indicator of designer costs. It was

noted that designer effort is frequently a cost centre for designers even when economicbenefits accrue to the project. These benefits are generally delivered to the contractor and/orthe client unless contractual arrangements also deliver economic benefit to designers.

It was agreed that for the third iteration the forms would be redesigned, slightly reordering theexisting sections and providing opportunity to assess separately the different designerscontributing to a project. It was anticipated that this would be particularly useful for futureanalysis.

It was recognised that what the designer should have doneencompasses moral, professional,economic and statutory obligations. It was agreed that the review should concentrate on whatthe designer could have done set against what was done, without making judgements about

duty and responsibility, which, in relation to statutory duties, would be a matter for the courtsto decide.

It was agreed that while a ten point separation was useful during the analysis phase thisshould be grouped for the final table into five double sections. The final table is thuspresented as 5x5 rather than 10x10

It was agreed that the scales should be more closely prescribed in the introduction to reducethe variation amongst assessors. This is to echo the level of detail given in the accidentseverity scale.

It was accepted that neither assessor had been entirely consistent in considering industry

today and had from time to time included industry opportunities. Such comment adds valuebut assumptions need to be clearly identified.

Some of the reports assessed advisory visits. It was agreed that where there was a report therewas a potential for harm and inclusion of such reports was thus valid as they describedopportunities for all parties to a project.

All of the incidents were reassessed in light of the above decisions.

Only the final iteratively agreed results are included in the Appendix 1 to avoid confusion.

The text describing the incidents is almost entirely that of the original assessor, MalcolmJames, with occasional additional remarks by Liz Bennett of Habilis, where it was felt thatthese added greater clarity or useful comment.


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3 SOURCE DOCUMENTS

3.1 ACCIDENT REPORTS

When an accident occurs it is usually the local HSE Enforcement Officer who attends in thefirst instance. If it is likely that specialist construction expertise is required the case orelements of the case may be passed to the construction specialist for additional input to theenquiry. Where the report relates to request for specialist advice, this is referred to aninspector with the necessary competence.

All construction specialist reports are stored together, being sorted by type of activity anddate. Thus roof work incidents are kept in sequential order. Ground works are similarlysorted.

For the purposes of this research handfuls of specialist inspector reports were removed from

the store ensuring that there were examples from each general category but otherwise makinga random selection of bundles of reports.

At first review those reports that clearly did not have anything to do with design were siftedout and set aside. The iterative process described in section 2 above were then applied to the

residual majority. It is important to recognise that these incident reports relate to realhappenings affecting the lives of many people. Because the documents must remainconfidential for legal reasons they are not included in this report except in sanitised summary.Similar incidents to those described happen regularly in construction and readers will often beable to recognise from their own experience incidents that relate closely to those reported.

3.2 ORIGINAL RESEARCH REPORT

The original research conducted by Malcolm James did not reach publication prior to thisadditional work being conducted because it clearly needed external validation. His

preliminary work, however, set the scene for the whole of this report.

Malcolm James experience of the construction industry and of the law of health and safety inthat industry is clear and his comments and notes form a critical part of the completeddocument. His development of some ways to assess incidents in a structured manner is veryhelpful to both industry and enforcer alike as it provides a framework and breakdown of thecritical elements to be considered by stakeholders in the design process.

Notwithstanding the above, the results presented are only those of the combined iteration as it

was agreed that this would be most helpful for industry. Consequently neither of the mainsource document sets is available for public scrutiny.


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4 AUTHORS REMARKS

4.1 AUTHOR ENTRY VIEW

The following remarks are provided to give the reader an indication of the mindset of thereviewer and author of this report throughout the process. They are personal commentary andprovided to give background information to those who may wish to accept or refute thefindings.

Construction industry design professionals are generally taught to be backward focussed,dependent on codes, standards and experience of similar projects undertaken successfully.Clearly there are some exceptions to this retrospective approach.

Innovation in itself introduces risk and many clients prefer tried and tested methodology.

The construction industry spans across a great many levels of competence and a range ofsectors and types of activity, some of which have little synergy. No single solution to the

continuing high levels of accident and ill health problem suffered as a result of industryactivity can fit all work.

The author is passionate about reducing harm to at risk groups of people and while convincedthat designers can make a contribution to the process of safe and healthy construction was lesspersuaded that this change was worth seeking given the costs to individuals, industry andsociety at large. Further, industry wide problems with CDM compliance already experiencedseemed to indicate that the chance of delivering significant added value change to the cultureof a diverse industry was small.

The author was and is also concerned that health and safety professionals still hold the mainpower base in terms of delivering advice, training and proposing solutions. While theircontribution to construction health and safety is clearly essential, the special nature of design

means that their lead in this area is likely to devalue the potential contribution designers canmake.

Standards of training and competence for designers have not been established across industryby those experts in design who could be demonstrating best practice and the added value ofthis additional effort. Steps are being taken through the Construction Industry Council and itsmember bodies to remedy this.

University courses have not responded to the requirements for educational change in

construction and building design to a sufficient level. There are well rehearsed argumentsrelating to this problem and in any case change is also afoot here. It is clear, however, thatundergraduate courses already impose extremely high workloads on staff and students alike.

In summary the entry frame of mind was that the research was likely to be interesting butarguably only able to deliver skewed results, set out as a politically correct sop to therequirements of a European Directive.

4.2 IMPACT OF FATAL ACCIDENT REPORTS

Many of the incidents reported were technically interesting. Some did not provide sufficient

information to take any but an overview. Most could have resulted in multiple fatalities,including multiple fatalities to members of the public. Some of the projects would have


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required highly competent designers to provide creative solutions or the spending ofconsiderable time and therefore cost to deliver solutions.

Some of the accidents were simply avoidable. Some of these were fatal or resulted in seriousinjury. Reading of incidents that have destroyed lives and had a knock on effect to manyothers associated with the victim in whatever way had a very sobering effect.

None of the incidents should have happened. Many could have been prevented very easily.Many could have been prevented by small actions by someone involved.

Every attempt was made to absolve designers of responsibility. In particular TemporaryWorks designers and manufacturers were removed from the main quoted statistics.

The final numbers are not just persuasive but absolutely convincing. Designers can do more.Designers need to learn how to do better or else be made to do so by whatever means. Theclear message should be one of warning and challenge for the whole design community.


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5 ASSUMPTIONS AND PROCESSES

5.1 PROCESSES AND ITERATIONS

The process for the research was driven by Malcolm James original work, which was slightlymodified in the third iteration.

Each incident was sanitised as a summary description from the report. Various measures weregiven quantitative values from what it is agreed must be inadequate information in manyinstances. These assessments were validated, however, by peer review and comparison andthe close fit gives confidence to the author of the values placed on the findings.

Many of the assessments made were not of primary interest to the objectives of the report.These additional values provide some commentary on matters such as design effort/cost, levelof specialist knowledge required etc which enrich the central debate. There is also an

assessment made of whether a Planning Supervisor appointment could have made adifference to the outcome and likewise whether a site safety supervisor could have prevented

the incident. This was done to provide a minor commentary on the future of the coordinationrole at design and site supervision stages.

5.2 AGREED ASSUMPTIONS

The reports used for the research related to incidents prior to CDM and thus generally madereference to construction products and processes with little reference within those reports todesign and planning aspects of construction. Certain assumptions were made for the purposesof the research and are listed here for clarification.

Designers were given the benefit of any doubt. The aspects of design considered related to the project in hand. Thus maintenance

work referred to designer contribution to that maintenance but not to the originaldesign of the structure. Where poor design had led to difficulties with maintenancethis was pointed out in the notes but not given any value in the overall quantitativeassessment.

Where assumptions about designer competence were critical to the assessment theseare stated.

Designer effort is judged to be roughly equivalent to designer costs. It should berecognised that no indication of the procurement route or contract arrangements isgiven in the reports and this can have a significant effect on the ability of designers tocontribute effectively.

It is here assumed that the designer is appointed prior to any design. In someinstances some designers are required to make speculative outline design as part ofthe tender process. No allowance is made for such factors.

No assumptions are made about designer culpability in law, which assessment mustbe a matter for the courts.

Apportionment of responsibility to architects or consulting engineers is in most casesarbitrary since most reports are silent on the nature of the design professionalsinvolved. For the final commentary these two groups have been assessed together as

principal designers.


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6 FINDINGS

6.1 Prior to CDM data collection by HSE specialist inspectors concentrated on the factsat the scene and did not generally detail any significant designer issues except where

these related to temporary works or the design of construction products.

6.2 Identification of procurement routes and contractual relationships was not consideredpart of the investigation protocol in any the reports considered.

6.3 The results can only give a general indication of the potential for change but it mustbe remembered that the assumption was that any doubts should be resolved in thedesigners favour. In other words, the results are indicative of the level of potentialchange that could be achieved.

6.4 The summary table below collects results from all incidents.

6.5 Tables 2 to 6 select out different groupings that the author judged would add value to

the final output so that new targets can be set for activity by the whole industry toeffect improvements.


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Table 1Summary chart

Architect Consultant TW Other

1. 8G Contractor

2. 4J

3. 4G M

4. 6G M

5. 6J M

6. 6G

7. 2E

8. 4J

9. 6J

10. 6J

11. 6J

12. 8E

13. 10J

14. 4E 8E15. 8J 10E 10J M

16. 6J 8J M

17. 4E 4E 4G M

18. 6E 10J

19. 10J 10J Contractor

20. 4C

21. 6E

22. 8J M

23. 6J 8J M

24. 6G M

25. 4E

26. 4E27. 10J

28. 2C 10J

29. 10J Scaffolder

30. 10J 10J

31. 10J Scaffolder

32. 10J

33. 10J

34. 6E

35. 8G Contractor

36. 10J

37. 4J Subcontractor

38. 4C 10J

39. 10J

40. 6E

41. 4C

42. 4E

43. 8E 8J

44. 10G

45. 6E M

46. 2C

47. 4E 10J

48. 8G

49. 6G 10J

50. 2C 8E 6C

51. 4C52. 2C


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53.

54. 4C M

55. 10G

56.

57.

58. 4E

59. 4E60.

61. 10J

62. 8J M

63. 6C M

64. 8G

65. 8G

66. 8G

67. 6E 10J

68. -

69. 2A

70. -

71. 8G72. 4E M/Transport

73. -

TOTALS

TOTAL 10 5 14 13 41

TOTAL 2 5 4 3 13

TOTAL 7 5 5 7 24

TOTAL 2 3 1 0 6

TOTAL 21 18 22 23 84

Notes:

1. There are 73 reports analysed above. In some cases there can be seen to be more than one party withresponsibility for design issues.

2. The summary diagram takes several views of the data. It considers the reports and is the source for thefollowing tables:Table 2 All design: worst case only included;Table 3 All design: all contributions to each incident;

Table 4 Main design only: worst case only included;Table 5 Temporary works only; andTable 6 Supplier/Manufacturer only.

3. It should be pointed out that it was not always easy to decide who the designer was, an architect orengineer.


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Table 2 Summary of designer intervention

All design: Worst case result only taken in each incident

What designers could have done

Very little A bit more Major

contribution

A lot more Critically

significant

0-2 4 6 8 10

What was

necessary

A 1 0 0 0 0

Something C 2 4 1 0 0

Not enough E 1 6 5 3 0

Not nearly

enough

G 0 2 3 7 2

Whatdesignerdid

Nothing J 0 3 4 5 18

Summary by category

Rating & total number Recommended consideration

5 Designer not implicated

18 Designer could improve

9 Designer may be implicated

39 Designer prosecution supportable

Notes

1 Total incidents considered in detail 73

2 Total incidents reported 91

3 The balance were clearly not to do with design but must be taken into sample for comparisons

4 Percentage of incidents likely to be the subject of further investigation of a designer because thedesigner has failed to take enough action when such action could have made a major contribution toaccident prevention is 39/91 x 100 = 43% or almost half of all cases reported.

5 A further 9/91 x 100 = 10% may well be asked to make improvements to their systems and be subject tocriticism for taking inadequate steps at the design stage of a project.


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All design: All contributions to each incident



contribution


significant

0-2 4 6 8 10

What was

necessary

A 1 0 0 0 0



Not nearly

enough

G 0 2 4 7 2

Wh

atdesignerdid


Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of one or more designers becausethe designer has failed to take enough action when such action could have made a major contribution to

accident prevention expressed as a function of the number of incidents is 42/91 x 100 = 46% or almosthalf of all cases reported.

5 A further 11/91 x 100 = 12% may well be asked to make improvements to their systems and be subject to

criticism for taking inadequate steps at the design stage of a project.


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Main design only: Worst case result only taken in each incident



contribution


significant

0-2 4 6 8 10

What was

necessary

A 0 0 0 0 0



Not nearly

enough

G 0 0 2 4 1

Wh

atdesignerdid

Nothing J 0 2 5 1 4

Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of lead designer because thatdesigner has failed to take enough action when such action could have made a major contribution to

accident prevention is 15/91 x 100 = 16% or about 1 in 6 cases.



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Temporary works design



contribution


significant

0-2 4 6 8 10

What was

necessary

A 1 0 0 0 0



Not nearly

enough

G 0 0 0 0 1

Wh

atdesignerdid


Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of a temporary works designerbecause the designer has failed to take enough action when such action could have made a major

contribution to accident prevention is 15/91 x 100 = 16% or about one in six of all cases reported.



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Supplier or manufacturer



contribution


significant

0-2 4 6 8 10

What was

necessary

A 0 0 0 0 0



Not nearly

enough

G 0 2 2 1 0

Wh

atdesignerdid

Nothing J 0 0 1 4 2

Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of a manufacturing designerbecause the designer has failed to take enough action when such action could have made a major

contribution to accident prevention is 8/91 x 100 = 9% or almost 1 in 10 of all cases reported.

5 A further2/91 x 100 = 2% may well be asked to make improvements to their systems and be subject tocriticism for taking inadequate steps at the design stage of a manufacturing project.


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7 COMMENTARY

7.1 It must be remembered that the figures relate not to all projects but only to those thatwere investigated. This means that the statistics quoted do not indicate that 1 in 6 of

initial designs show designer failure to intervene to prevent accidents but that 1 in 6of those investigated showed this lack.

7.2 Case law exists that states that consultant engineers and architects should have noinvolvement in the construction processes even when the methods chosen by theconstructor threaten safety. There will need to be greater clarity in relation tolegislative changes before designers would be advised to be prescriptive in any greatmanner. This attitude of separation of responsibilities clearly pervaded the industrythroughout the period during which the reported incidents took place.

7.3 There were some key themes to the incidents themselves. In particular poorcommunication between parties to a contract was often cited as a root cause of an

incident.

7.4 There would seem to be many incidents where a designer had not taken sufficient

notice of existing or adjacent structures nor the likely impact their existence wouldhave on operator behaviour or ability to access the site with plant and materials.

7.5 In a great many cases the designer had not understood the construction processes nor

taken any account of them in the final design. This was standard practice (See 7.2)across the industry and remains so to this day for most projects.

7.6 It is to be expected that in an industry where the main duties and liabilities rest withthe principal contractor that the majority of accident reports would reflect this in their

findings. It was for this reason that the incidents that are the responsibility of theTemporary Works designer or manufacturer have been separated out and dealt withas a different industry issue.

7.7 Table 2 shows that in almost half of reported cases a designer could have taken stepsto prevent realisation of an accident but failed to take such steps. There is a clearmessage here for all of those involved in design, specification and communication ofcritical information.

7.8 Table 3 shows much the same as Table 2. It includes multiple responsibility forincident avoidance but does not give results that are very different from Table 2.

7.9 Table 4 shows the results that are at the heart of this research. It is the number ofmain designers who could have, but failed to, intervene to prevent accidentrealisation. In approximately 1 in 6 cases the original designer could have donesomething to prevent an accident happening but failed to take that opportunity. If thisfigure is translated across to the annual accident statistics this means that 1/6x80 = 13deaths a year could be prevented by designer action. Proportionate savings in injuryand ill health could presumably be made. This clearly is a significant difference byany measure and well worth setting out a change agenda to achieve. It is particularlytelling when it is remembered that this peer review chose to err in favour of thedesigner in the event of doubt and also the fact that the reports did not generallycomment on the original designer activity. Further, maintenance accidents included

did not blame the original designer because it was decided to consider only thecurrent project. There are, however, several incidents where the original design made


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22

maintenance activities difficult and unsafe. It is the view of the author that, becauseof the reasons cited above, this figure of 1 in 6 is very conservative.

7.10 Table 5 shows the number of incidents where temporary works designers alone failedto take the opportunities presented to intervene effectively to prevent accidents. It isjudged likely that this statistic is more accurate since at the time of the reportstemporary works design involvement was more often considered by the investigatinginspector than principal design. In any case there clearly need to be improvementsmade by the temporary works community. Common mistakes here included incorrect

assumptions, poor communication and not involving expert designers at theappropriate time, even when they were available.

7.11 Table 6 shows that a significant number of incidents could have been prevented, butwere not, by better intervention from the construction products design community. Inparticular systems scaffolding incorrectly used, systems building units poorly handledor inadequately seated and access systems with inferior failure modes or emergencycontrols were found to be root causes. Generally the product design community did

not give adequate information about the suitability or otherwise of their products forparticular situations.

7.12 Information collection by the Health and Safety Executive (HSE) inspectors rarelyenquired about designer involvement in buildability. This was appropriate to theprevailing culture and to the civil law of the time. For the effective delivery of closerunderstanding of the potential for designer contribution to accident prevention it willbe necessary for this strategy to change and for enquiry methodologies to incorporateinvestigation of complex design processes and decision making. It is likely that thiswill need a considerable amount of additional research to be carried out as many frontline HSE inspectors do not have the technical competence in design to makeappropriate enquiry without additional guidance and support.

7.13 Designers rarely provided adequate information to contractors about significant

aspects of their design. There are several reasons for this. Civil law argues that wherea contractor takes on a contract to construct a particular design he is making astatement about his capability to do so. An integral part of this capability is hiscompetence and presumably his competence to manage the risks to the safety andhealth of his workforce. Designers need clearer advice about the relationship betweencompetence of contractors and their own increased liability if they instructcontractors, or may be seen so to do, in methods of building. Clearer information isneeded too about the kind of information that would be of use to a contractor. Theindustry has evolved a methodology for this process usually called design riskassessment.In fact designers usually retrofit poor quality contractor risk assessments

to their final design. Many do engage in design decisions that take account ofbuildability and maintainability but do not recognise these for what they are, which isa correct response to statutory duty.

7.14 Designers often did not obtain adequate information about existing site conditions orthe fabric and condition of existing structures. Their duty to obtain clearerinformation of sufficient quality to be of use in decision making needs clearer

expression in legal and industry standard documents.

7.15 Designers often did not consider the operational aspects of a structure and the

requirement to maintain that structure during user activity. Not to consider suchmatters where information is available is a failure to provide proper design serviceseven without consideration of the safety aspects of those who will be affected. Inparticular access to lighting, services and minor fixtures and fittings continues to


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cause real problems. Designers need to develop creative solutions to thoserequirements.

7.16 The Planning Supervisor potential contribution to accident prevention was alsoconsidered. In every case where the Planning Supervisor could have intervened forgood it would only have been possible if that Planning Supervisor was highlycompetent in both design and construction processes and also had the character,authority and opportunity to intervene at the correct time in the project delivery. Nogeneral electronic or paper based system frequently used by Planning Supervisors

would have been able to pick up on the technical or other potential defectsadequately.

7.17 The Site Safety Supervisor could in some instances have intervened, for examplewhen system scaffold or building units were not being safely used or installed. Inmany cases, however, technical knowledge beyond that of the general site safetysupervisor was needed to make adequate intervention.

7.18 Procurement routes and the costs to the design community are seen as a real barrier toeffective delivery of change. Where health and safety is an early contract requirementdesigners and constructors alike can deliver high standards. Where designers wouldneed to spend considerable sums of unrecoverable money to deliver change it is nosurprise that they fail to take that opportunity. This must be a matter for regulatorsand government.

7.19 In many instances contractor design incompetence was a major contributor to anaccident. No designer had been involved at all. It may be necessary to put arequirement on certain types of project for such specialist intervention in somemanner.

7.20 It is the Authors very strong conclusion that the case for CDM is made by thisanalysis and that the design community can do more to reduce the number of deaths

and injuries in construction. While health could not be considered in this analysis it isthe view of the Author that the case for improvement, through designer intervention,in workforce health is implicit in these findings.

7.21 There are several opportunities for HSE to improve construction safety throughintervention in the design phase of projects. Methodologies for enforcementintervention need to be developed.


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8 RECOMMENDATIONS

8.1 The design community needs to learn more about modern methods of construction.How this is achieved is complex and is likely to be a mixture of reward, through

clearly better project delivery or reduced Professional Indemnity costs, and penaltythrough enforcement action. To achieve the latter the revised Regulations orApproved Code of Practice will need to emphasis the requirements on designers inthis respect and the HSE will need to develop enquiry methodologies that probe thedesign process.

8.2 The manner in which designers can intervene effectively needs to be more clearlyexpressed in industry standard documentation and training. The culture of acceptanceof poor quality design needs to change.

8.3 It could be extremely helpful to refine this research methodology in the light of newunderstanding about barriers to change and opportunities for improvement. The best

means of making proper enquiry of designers by enforcers without the appropriatedepth of technical skills needs to be developed. Engagement with IT datamanagement could begin to generate systems that can provide a rich source of

downstream information that can readily be searched for a variety of purposes.

8.4 The key words need to be further discussed. The purpose of the selection criteria andthe impact on the data management capabilities need further development. Significant

information could be delivered to the industry, including HSE, through a closerunderstanding of what initiating factors tend to cause later incidents. For instanceprocurement routes, time for planning, nature of the client, size of design house,

competence of design house etc could be useful to future analysis.

8.5 Every opportunity needs to be explored to engage Clients. Where Clients demandhigh qualities of health and safety then procure competent and well resourcedsuppliers of design and construction, the industry can deliver radical improvement.

8.6 The issue of designer liability with respect to instructions to contractors to build in acertain manner needs to be further explored. In particular the tension between thecivil and criminal law in this matter needs to be resolved.

8.7 HSE needs to develop better methodologies for inspector investigation and enquiry,not just following an accident but also when making routine site visits. Theinformation so gathered can serve several purposes. It can encourage and requireimprovement from the design community; it can provide a better source of data forfuture incident review such as this; it can provide better data for appropriateenforcement action.


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APPENDIX 1 CATEGORIES

Key to categories of incident data and other contributory factors detailed in FCG

reports where a design fault may have led to a failure of some description.

Jobrefers to the location or nature of the work being done, where:

F Steelwork and steel frame erectionO RoofingG General construction including scaffoldingR RefurbishmentA Falsework, formwork etcE Excavations and foundations etcC Cleaning and maintenanceW Window cleaning

D Demolition

Incident ratingrefers in sequential rows topotentialfor incident then for actual harmdone,where:

10 Most severe. Major disaster with members of the public affected as well.8 Multiple fatalities to workers on site6 Single fatality to worker4 Serious injury to worker2 Minor injury0 Non injury report or event

Note that property damage almost always has potential to cause harm to people, so will bepicked up in the first listing of incident rating.

Could the designer have done more? This refers to an arbitrary view from informationavailable relating to potential for prevention or reduction in probability by the nameddesigner.

10 Designer could probably have prevented8 Designer could have done a lot more to prevent6 Designer could have reduced likelihood significantly4 Designer had opportunities to reduce likelihood or prevent2 Designer may have been able to reduce likelihood

0 Designer could not have done anything

Extent of failure to prevent incident.This refers to an arbitrary view of the lost opportunityby the designer. Notes on dutyto have intervened are in the main text.

J Complete failure to prevent or reduce probabilityG Failure to make additional efforts using specialist supportE Failure to research issues and apply themC General lack of design contribution/communication opportunityA No designer failings


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Design effort refers to an estimate of the additional effort and consequently resource likelyfor designer to include a suggested feature.

H A lot of effortM Some effortL Very little effort

Degree of specialist knowledge refers to an estimate of whether a designer could be expectedto know or to have found out from standard sources, where:

0 Should know at basic designer level1 Generally expected to know to fulfil defined designer role2 Should easily be able to find out3 Would need some research to discover this or higher than general

competence4 Would need specialist expert help

Cost implications refers to an estimate of increased cost to the project

R Reduction in costL Little additional costE Some additional costS Significant additional cost

Interventions

Two additional boxes are included for interest. These relate to external interventions fromindividuals outside the direct line of design or construction. They are the Planning Supervisor(or equivalent such as Client Advisor) and the Site Safety Advisor/Supervisor. Would such

interventions have prevented the incident or potential incident?

0 No difference1 Unlikely2 Possibly3 Probably4 Yes


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APPENDIX 2ACCIDENT ANALYSIS SHEETS

The following 73 sheets each summarise an incident that was investigated by the Health andSafety Executive (HSE) Construction Specialist Group and assign it categories as listed in

Appendix 1.

In most cases the HSE reports were made following an incident but in some cases they wereas a result of requests for advice or followed on from the serving of notices. All categorieswere included because it was felt that where HSE had been involved at specialist level therewas an implied potential for an incident. Whether the potential was realised or not and theextent of that realisation is captured in the summary sheets but was not transferred to the finalanalysis.

It is certain that industry will be able to argue about the detail of the findings relating to eachincident reported in summary but the author is confident that the results are fair because of the

very close agreement between the original assessor and the reviewer. Only in a very smallnumber of cases was there a need for final arbitration and significant adjustment.

In many cases additional information would have assisted the analysis process considerablyand assumptions had to be made.


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Quick Ref 8FDesigner Contractor

HSE Peer review: Ref 4467/R33.115Case worksheet HAB 01H

30

Description of incident

An agricultural steel portal framed building collapsed during erection. The columns were not secured tothe ground, there was no bracing in the walls and the temporary bracing was of dynamic fibre ropes

mainly in the across the bay direction. The structure was intended to be stabilised when complete by

having the columns cast into concrete perimeter bund or walls.

Keywords from list Collapse/partial collapse; Erecting structures;Steel/rc frame

Job nature type of activity F

Incident rating potential 8

Incident rating actual 0

Reference category Architect Engineer TW Designer Other

(Specify)

Designers involved N/A N/A N/A Contractor

Could the designer have done

more?

8

Did the designer miss the

opportunity to do more?

G

Design effort L

Designer specialist knowledge 0

Cost implications L

Could external intervention at

design stage (PS) have made a

difference?

4

Could site supervision at

construction/ site detail have

made a difference?

3

Remarks

No consideration appears to have been given to temporary instability problems during construction thatcould have been within the design remit.The report notes that the structure was to be built similarly to a previous one and that consequently

there were no separate drawings or calculations in this case. However there is no information in the

report concerning the provisions against collapse in the design for the original structure.

The design effort is unlikely to have been any greater than the loss of time experienced on site due tothat effort not being made.


40/113

Quick Ref 4J/4GDesigners Consultant

Manufact.

HSE Peer review: Ref 4467/R33.115Case worksheet HAB02H

31


A U-shaped [in plan] runway beam was being installed as a new steel framed building was being

constructed. This runway beam was in two halves joined at the centre of the U, i.e. each half was J-

shaped in plan and was spanning 2 bays of the steel frame. The runway beam halves had approx. 1.5m

pedestals bolted to their top flange which were to be the means the beam was to be secured to the

rafters. When one half was being lifted a temporary clamp providing a lifting anchorage for the slingsapparently slipped and possibly dislodged a steel erector who was about to secure it. The erector was

wearing a safety harness but it was not secured.

Keywords from list Fall from height; Erecting structures;

Steel/rc frame

Job nature type of activity F



Reference category Architect Consulting

Engineer

TW Designer Other

(Specify)

Designers involved N/A N/A Manufacture


more?

4 4



J G

Design effort L L

Designer specialist knowledge 2 1

Cost implications L L



difference?

3 3



made a difference?

1 0

RemarksWhile the general lack of enforcement of securing the safety harnesses by the contractor was an

important contributing factor. Better design consideration for the need to provide secure lifting

positions and means of anchorage for the safety harnesses was also a factor. There could have been a

problem with the stability of such an unsymmetrical shape while lifting, although the report notes that

when lifted later it hung perfectly. The report does question the suggested slipping of the temporary

anchorage point although the beam was possibly basically unstable because of the two pedestals and its

plan shape.


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Quick Ref N/ADesigners N/A


32


This is the same incident as HAB 03H but includes the further research into manufacturers

capability to intervene. This aspect is incorporated in HAB 02H.

This report looks at the clamps used to provide lifting points for the roof trusses. The manufacturers of

these would have only been happy with them being used where there was no lateral force beingimposed. In this case they should have been used with a lifting beam.

Keywords from list

Job nature type of activity

Incident rating potential

Incident rating actual


(Specify)Designers involved


more?



Design effort

Designer specialist knowledge

Cost implications



difference?



made a difference?

RemarksThere appears to have been a lack of communication between the manufacturer and the user of these

clamps.

The users appear to have been unaware of the limitations on the use of the clamps which could have

been easily dealt with by the use of spreader/lifting beams. This could have been dealt with by

attaching a warning to the clamps.

While the clamps must have been capable of taking some lateral load the manufacturers did not appear

to want to take any responsibility for such use.


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Quick Ref 6GDesigners Manufact


33


A temporary roof edge barrier blew off the edge of a single storey bridge link between two otherbuildings. No one was injured.

The barrier should have had uprights at no more than 2m centres held down by 30kg sandbag ballast.

The uprights had been placed at 4.3m centres and no ballast had been used.

However the report comments on the likely possibility that the bridge was in an exposed position and

subject to funnelling effects so that ballast weighing 50kg would have been required to give a suitableFOS in this case.

Keywords from list Falls from height off edge; Struck by falling object; Roof work;

Job nature type of activity O




(Specify)

Designers involved possibly possibly possibly Manufact


more?

6



G

Design effort M


Cost implications L



difference?

3



made a difference?

4

RemarksThe designers of the temporary barriers had failed to deal with the possibility that they could have beenused in more severe situations than that envisaged. They also failed to appreciate that where a

contractor was expected to obtain other equipment (i.e. sandbag ballast) then there was a real

possibility that these would be omitted.

Part of the answer to the design faults would have been to have provided better advice on the spacing

of the uprights and their ballast weights, ideally permanently attached to the equipment. The failurecould also possibly have been avoided by having designated ballast weights as part of the kit.

Information is only given in the report about system edge protection. It may have been possible for

other design professionals to have intervened to the extent that such system protection was not needed.

This cannot be presumed, however, so is not included in statistics.


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Quick Ref 6JDesigners Manufact


34


A prefabricated building was being dismantled and moved to another location. The building wasconstructed from a series of 2.74m pre-clad portal frames spanning 12m and consisting of two portal

frames, which would be bolted to adjacent sections to form the full length of the building. Each section

was handled by being slung from two lifting points on the roof requiring the slinger(s) to walk on the

roof to attach the lifting slings.

Each side of the roof portal had a plastic roof-light that occupied a significant percentage of the totalroof area.

Keywords from list Falls from height; Lifting Machinery; Roof work





(Specify)

Designers involved Manufacturer


more?

6



J

Design effort L


Cost implications L



difference?

3



made a difference?

1

RemarksWhile it is possible that the lifting points were at the edge of each section this would still mean thatsomeone would have to go on the roof to remove the slings or reattach them on relocation along at least

one edge. In addition someone would have to work along the ridge to install or remove the flashings at

this point.

Therefore, as it appears, the building was intended to be easily relocated, it would have been reasonable

to ensure the whole roof was non-fragile and perhaps even build in facilities for edge protection.The report does not state the nature of the lifting points but it has been assumed that there were 2 on

each edge of the sections.

The building appears to be one that had been designed to facilitate easy relocation. Therefore, the

incidence of someone working over the roof could have been something that frequently occurred. If it

was intended to be readily reassembled then ensuring that this could be simply and safely achieved

should have been part of the designers brief.


44/113

Quick Ref 6GDesigners Consultant


35


A fairly standard sandwich skin roof was being installed that had roof-lights in it. The inner skin wasbeing installed ahead of the outer skin and a roofer fell through an unsecured section of the inner skin

roof-light.

Keywords from list Falls from height through; Roof work; Commercial building





(Specify)

Designers involved N/A N/A N/A


more?

6



G

Design effort L


Cost implications L



difference?

3



made a difference?

4

RemarksThe designer could have avoided the separate installation of inner and outer roof skins. In addition The

designer could have ensured (at a cost) that each skin was none fragile and that there was provision at

the eaves for the installation of edge protection.

Finally the designer could have included in the specification for the works a provision for suitable edge

protection.While the contractor can provide means to install these types of roof the reliability of any such

protective systems would be improved where the designers had planned for safe access or facilitated its

provision.


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Quick Ref 2EDesigners Consultant


36


A roofer fell through an inner lining sheet. This had only been secured by one fixing at its top edgeinstead of the recommended 3 because a curved ridge/crown sheet was still to be installed requiring the

removal of the single fixing.

The roofer had walked over the inner liner as an easy way to get to an electrical junction box.

Keywords from list Falls from height through; Roof work; Commercial building





(Specify)



more?

2



E

Design effort L


Cost implications L



difference?

2



made a difference?

2

RemarksThe sequence of fixing the roof sheets appears to have made some contribution to the accident althoughthe greater part was due to poor site management and a mistake on the part of the roofer.

A small contribution to this accident also came from the design. If this had allowed different types of

sheets to be fixed independently of others then the accident could have been avoided.

Clearer details or sufficient details from the designer could have helped prevent this accident.

Properly fixed the inner skin of the roof construction was non-fragile. However, the safety of thoseinstalling the roof depended on them keeping off the liner sheets until they were fixed; the planning of

the work should have ensured this.


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Quick Ref 6JDesigners Consultant/

Architect


38


A bricklayer fell through a 1.2m square PVC domed roof-light.

Keywords from list Falls from height through; Refurbishment; Commercial





(Specify)

Designers involved Possibly inoriginal only

Possibly insite

investigation

N/A N/A


more?

10 6



J J

Design effort L L


Cost implications L L



difference?

3 3



made a difference?

3 3

RemarksThe designer contributed to this accident by specifying the use of a fragile roofing element.

The contractor should have been aware of this and could have taken various types of precautions. In

addition it is possible that the bricklayer was particularly careless or deliberately stood on the roof-

light.

Habilis assessment assumes this is refurbishment so not due to architect or engineer as originaldesigner. (Assume err in favour of designer). As a result only engineer as refurbishment designer taken

to summary at top of page. Note that this could have been an architect rather than an engineer.


48/113

Quick Ref 6JDesigners Architect

HSE Peer review: Ref 4467/R33.115Case worksheet HA 10H

39


A new church was under construction having steeply pitched roofs to a maximum height of 13m. Noprovision had been made to safeguard those working on the roof and a PN was issued.

Keywords from list Falls from height off edge; Erecting structure; Access





(Specify)

Designers involved Possibly N/A N/A


more?

6



J

Design effort M


Cost implications E



difference?

3



made a difference?

3

RemarksThe designer could have included features in his design to support a working platform and/or to

provide anchorages for safety lines.

The provision of anchors to support a safety line or similar facility could have been done by the

designer working alone. However the installation of means to support working platforms would have to

be done in consultation with the contractor.


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40


A roofer helping to build a new cattle shed adjacent to an older, and 1m lower, cattle shed. The olderbuilding was clad with single skin corrugated asbestos sheets while similar new sheets were being

installed on the new shed.

The roofer stepped down from the higher new roof and fell through the older sheets. The report is not

clear whether there was a temporary barrier at the point where the roofer fell.

Keywords from list Falls from height through; Roof work





(Specify)

Designers involved Possibly Possibly N/A N/A


more?

6



J

Design effort L


Cost implications L



difference?

2



made a difference?

2

RemarksWhile control of this risk lay chiefly with the contractor, the designer should have flagged up the realrisks of someone stepping or falling down onto the old roof. This could have encouraged the

construction of effective protective measures.

Control of this risk lay chiefly with the contractor. However, designing a building adjoining to a lower

one should have flagged up the risks of someone stepping or falling down onto the old roof. It is

possible that increased production resulting from a proper edge protection system could have beengreater than the original design effort.

This was a cattle shed either an architect or an engineer could have been retained. Architect assumed

here after discussion. Initial site inspection would have indicated access difficulties that required

additional attachments or similar to be included.


50/113

Quick Ref 8EDesigners Architect


41


An old warehouse was being converted into flats. The roof was completely stripped leaving the oldroof trusses. These were of a substantial construction, spanning 13m, standing 5.5m high and weighing

an estimated 1.3 tonnes. Some longitudinal 100mm x 50mm timbers had been nailed between the

trusses at approx.1/3their height using 2 100mm nails at each truss.

The masonry against the ends of the trusses was being removed to allow checks to be made on the

condition of the timber at the time when a moderate to fresh gale was blowing and 8 trusses fell over.

Keywords from list Partial collapse; Refurbishment

Job nature type of activity O/R




(Specify)



more?

8



E

Design effort L

Designer specialist knowledge O

Cost implications L



difference?

3



made a difference?

1

RemarksThe designer would know that the roof was to be stripped and that effective temporary bracing would

be required. Therefore, he should have anticipated that the method of stripping the roof would have

left, at some stage, the old trusses standing without covering and perhaps the bracing. He should have

provided details of how the trusses should have been stabilised, including the strength of the fixings.

Even if the collapse had been avoided, it is probable that the increase in production would have paid for

the slightly additional design effort.


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42


A cradle runway was installed on the roof of a hospital for the use of window cleaners. The roofhowever had only a very low parapet that would not give any protection to anyone using or maintaining

the cradles.

In addition the cradles were intended to be worked by one man but could only be accessed by this

person from the roof. This meant that this person would have to step over the parapet down into the

cradle.There was a risk that someone could fall off the roof.

Keywords from list Falls from height off edge; Maintenance; Cradles





(Specify)

Designers involved


more?

10



J

Design effort M


Cost implications E



difference?

3



made a difference?

1

RemarksThe cradles could have been designed so that they could be landed on the roof of the hospital to allow

the window cleaner to gain access and then be driven from inside the cradle over the parapet.

A suitable system of protecting persons working on or around the cradle tracks would need to be

provided.

This is a case where inadequate design resulted not only in a risk of serious falling accidents but alsoresulted in increased operational costs.


52/113

Quick Ref 8E/4EDesigners TW/A


43


A proprietary scaffold had been erected completely around the site of a new building, which was to bebuilt from prefabricated timber sections lifted over the scaffold into position, followed by a

considerable amount of work for follow-up trades to complete the faade.

There were problems with the scaffolding concerning: flexing under load, decking members springing

free, unauthorised removal of members and difficulties in maintaining a safe gap between the inner

edge of the scaffold and the new building.

Keywords from list Scaffold; Access

Job nature type of activity G




(Specify)

Designers involved N/A N/A


more?

4 8



E E

Design effort M M


Cost implications L E



difference?

2 0



made a difference?

2 3

RemarksWith a building design such as this there is an even closer relationship between the building panels andthe faade access system if a safe, efficient and effective construction method is to be devised.

It was therefore important for the panel design to be linked to the design of the access system being

fully integrated by the designer.

It is possible that this type of scaffold was not intended for moderate or heavy duties and therefore it

had been a poor choice. However the manufacturers/suppliers claims for this equipment would tend tosuggest that it could give an economic performance in such applications. Therefore some investigation

and consideration would be needed to ensure the job operated properly.

Had this been done then the economic benefit would have almost certainly exceeded the additional

design effort.


53/113

Quick Ref 8J(A)

10E(C)

10J(M)Designers Various


44


Two 30m long, 44 tonne Y7 bridge beams overturned shortly after being placed.

Their lifting arrangement, accepted by the manufacturer, was via end diaphragm holes, which were

approx. 200mm lower than the beam centre of gravity. This and the lack of adjustment in the liftingarrangements probably resulted in the beam being set unevenly on its bearings.

The temporary propping of the beams was ad-hoc and inadequate and could not stop the beams rolling

over.

Keywords from list Erection of structures; Temporary Works; Material handling

Job nature type of activity G




(Specify)

Designers involved N/A Manufacturer

(Consulted)


more?

8 10 10



J E J

Design effort L M L

Designer specialist knowledge 1 1 1

Cost implications L L L



difference?

3 1 N/A



made a difference?

1 1 N/A

Remarks

The satisfactory, and safe, handling of such large and ungainly units, particularly when set on sliding

bearings, depends very much on the on the proper design followed by proper preparation & planning,

on site, of all associated temporary works.

There was no reason why the beams could not have been designed with proper lifting hooks so that the

centre of gravity was below the lifting sling making the handling of the beams easier and reducing the

risk of rotation. In addition, the temporary propping arrangement was inadequate and should have been

properly designed.

The losses in this case for not doing this almost certainly far outweighed the effort of carrying such aproper design. Even if the beams had not failed the time lost in trying to position the beams and trying

to sort out some form of temporary stabilisation would possibly still have been greater than the timerequired to prepare a proper design.


54/113

Quick Ref 6J(C)

8J(M)Designers C & M


45


A workman was levering a pre-cast floor slab into position while standing on the top flange of a steel

suppor

review of cause of construction accidents - hse rr218.pdf

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