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HSE Health & Safety

Executive

Peer review of analysis of specialist group reports on causes of construction accidents

Prepared by Habilis Ltd for the Health and Safety Executive 2004

RESEARCH REPORT 218

HSE Health & Safety

Executive

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

Liz Bennett BSc PGCE CEng MICE MIOSH FRSA Habilis Ltd

3 Market Place Shipston 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). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

HSE BOOKS

© 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 1BQ or by e-mail to [email protected]

ii

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.

iii

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 Executive……………………………2

1.5 Industry Wide Initiatives……………………………………………………………3

2 PROJECT OBJECTIVES AND WORK PHASES…………….5 2.1 Project Objectives

2.2 Work Phases

3 SOURCE DOCUMENTS………………………………………..73.1 Accident Reports…………………………………………………………………… 7

3.2 Original Research Reports………………………………………………………….7

4 AUTHOR’S REMARKS………………………………………...94.1 Author Entry View…………………………………………………………………..9

4.2 Impact Of Fatal Accident Reports………………………………………………….9

5 ASSUMPTIONS AND PROCESSES………………………….11 5.1 Processes and Iterations……………………………………………………………11

5.2 Agreed Assumptions………………………………………………………………..11

6 FINDINGS………………………………………………………13

7 COMMENTARY……………………………………………….21

8 RECOMMENDATIONS……………………………………….25

APPENDIX 1 – CATEGORIES………………………………………27

APPENDIX 2- ACCIDENT ANALYSIS SHEETS………………….29

v

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 by

some of the industry and underpinned by Regulations that designers could make a significant

difference. The key changes required are for designers to design structures that are safer and

healthier to build, maintain and demolish. Clearly operational issues must be considered as

well since they have a major effect on maintenance capability.

There are many in the industry, and in particular in the design community, who remain

unconvinced by the arguments that designers can and should make a difference to the way

they 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 additional

requirements for information collection were identified. This research must therefore be seen

as part of an unfolding investigation into the best way to identify some of the key change

points for the industry.

The author has chosen to track personal views of the research for the reader as this was

judged helpful. In particular a certain amount of cynicism towards the arguments for real

intervention 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 for

radical 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 the

collection 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 the

development of the methodology for the study and also summarised and analysed the

incidents in the first instance. The peer review that is the subject of this report acknowledges

the importance of Malcolm’s work but takes complete responsibility for statements within the

report.

The Report concludes that almost half of all accidents in construction could have been

prevented by designer intervention and that at least 1 in 6 of all incidents are at least partially

the 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.

vii

1 BACKGROUND

1.1 ACCIDENT RATES

The United Kingdom construction industry has one of the lowest accident rates in the world

following generally declining rates over recent decades. Latterly, however, a levelling off has

been observed and there remain various categories of seemingly intractable accidents. In 2002

there where 80 fatal accidents in construction, which is nearly seven each month. The cost of

these deaths to the families and friends of those killed is incalculable. The cost to the industry

and 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 and

building processes from both clients and designers could make a radical improvement to the

construction processes during the whole life of a structure. Anecdotal evidence from industry

showed that the construction and building industry is capable of delivering safe construction

but that it regularly fails to do so. Changing the emphasis of responsibility towards those who

commission, scope and design works so that the end result is seen as a team approach to life

long safety and health management was expected to deliver benefits.

The Temporary and mobile construction sites Directive 89/391/EEC was introduced across

the European Economic Community to change the way construction health and safety is

managed. 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 of

Planning Supervisor. The concept behind CDM was one of teams of competent appointees

providing appropriate information throughout the life of the project for use by those who had

the capacity to influence health and safety for good or ill. There was also a requirement to

allow 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 other

relevant regulations, without which their application becomes meaningless.

Further, the Regulations were not so ordered as to make duty holders’ duties easily apparent

to the vast numbers of those who were obliged to wrestle with legal terminology for the first

time.

Designers’ duties are generally encapsulated in Regulation 13, which is often considered as

stand 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

1

ensure that clients are aware of their duties, allowing the non-expert client to be kept

informed 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 of

industry. Various reasons for this may exist.

· The wording of the regulation is insufficiently precise to set standards in relation to

legal duties.

· There has been an assumption that CDM could stand alone without an understanding

of building, construction and maintenance processes, including demolition, and of

other requirements such as operational constraints. These other factors are often

overlooked to the detriment of decision making.

· Many designers are either unaware of, or not up to date in, modern construction and

building processes. For them to make any real contribution to safety and health they

clearly 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 as DRA or Design Risk Assessment. Generally the teaching of

CDM to the industry has been conducted by health and safety professionals with

experience in contractor risk assessments. They have tended to translate this across to

the 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 contractor

risk 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 early

intervention difficult from a commercial perspective.

· Civil law is at odds with CDM in that case law exists that states that responsibility for

safety 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 only

present as a challenge to this where there is, for whatever reason, enforcer

intervention.

· The fear of criminal action has resulted in production of excessive paperwork as an

attempt to manage liability. In fact such paper trails are generally of poor quality and

do 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 the

smaller projects, frequently under resourced in terms of competent advice, continue to

be 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 and

experience. For inspectors to challenge decisions taken by designers or to ask why

alternatives have not been considered is not possible except for those inspectors with

a specialist background in the appropriate discipline. Even within the industry there is

a considerable range of specialist disciplines at work and the provision of competent

inspectors 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.

2

1.5 INDUSTRY WIDE INITIATIVES

The Deputy Prime Minister, John Prescott, held a construction health and safety summit

where he challenged industry to make commitment to improvement. Several strategic

initiatives were launched to bring the construction industry together and improve performance

across all aspects of the construction process.

Rethinking Construction and its daughter report, Rethinking Health and Safety in

Construction were produced.

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

construction.

3

2 PROJECT OBJECTIVES AND WORK PHASES

2.1 PROJECT OBJECTIVES

The objectives of the whole project were to examine a randomly selected sample of specialist

inspector reports to establish:

· Whether the case for CDM can be supported

· Whether designers are really missing opportunities to contribute to health and safety

in 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 final

numerical computations. The categories selected for this analysis were in the first instance

iteratively developed by Malcolm James, who also assigned scores to most categories. These

categories are listed in Appendix 1.

Each report was summarised, assessed according to categories and notes made in relation to

such 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 an

incident. 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 second

assessment reconsidered the data and original assessor’s remarks to gain clearer

understanding of the reasons for disparity.

Outstanding differences were discussed at a meeting between the two reviewers. One of the

difficulties 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 the

same designer the opportunity assessment could easily differ.

Keywords were a further area of difficulty since these depended on a range of variables. Their

use 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 as

important for future analysis of findings in relation to particular work activities or common

failings as it will facilitate a general search enquiry.

5

Almost all the reports predate CDM and focus largely on construction processes. This means

that 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 of

each designer should also be made so that temporary works may be selected out to consider

other 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 for

the original works. From time to time where the original design had been a clear contributing

factor, 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 stakeholder

competence ie the competence of the designer in specialist design areas. This would allow

clearer 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 economic

benefits accrue to the project. These benefits are generally delivered to the contractor and/or

the 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 the

existing sections and providing opportunity to assess separately the different designers

contributing to a project. It was anticipated that this would be particularly useful for future

analysis.

It was recognised that what the designer should have done encompasses moral, professional,

economic and statutory obligations. It was agreed that the review should concentrate on what

the 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 courts

to decide.

It was agreed that while a ten point separation was useful during the analysis phase this

should be grouped for the final table into five double sections. The final table is thus

presented as 5x5 rather than 10x10

It was agreed that the scales should be more closely prescribed in the introduction to reduce

the variation amongst assessors. This is to echo the level of detail given in the accident

severity 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 value

but assumptions need to be clearly identified.

Some of the reports assessed advisory visits. It was agreed that where there was a report there

was a potential for harm and inclusion of such reports was thus valid as they described

opportunities 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, Malcolm

James, with occasional additional remarks by Liz Bennett of Habilis, where it was felt that

these added greater clarity or useful comment.

6

3 SOURCE DOCUMENTS

3.1 ACCIDENT REPORTS

When an accident occurs it is usually the local HSE Enforcement Officer who attends in the

first instance. If it is likely that specialist construction expertise is required the case or

elements of the case may be passed to the construction specialist for additional input to the

enquiry. Where the report relates to request for specialist advice, this is referred to an

inspector with the necessary competence.

All construction specialist reports are stored together, being sorted by type of activity and

date. Thus roof work incidents are kept in sequential order. Ground works are similarly

sorted.

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 making

a random selection of bundles of reports.

At first review those reports that clearly did not have anything to do with design were sifted

out 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 real

happenings affecting the lives of many people. Because the documents must remain

confidential 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 be

able 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 this

additional 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 in

that industry is clear and his comments and notes form a critical part of the completed

document. His development of some ways to assess incidents in a structured manner is very

helpful to both industry and enforcer alike as it provides a framework and breakdown of the

critical 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 main

source document sets is available for public scrutiny.

7

4 AUTHOR’S REMARKS

4.1 AUTHOR ENTRY VIEW

The following remarks are provided to give the reader an indication of the mindset of the

reviewer and author of this report throughout the process. They are personal commentary and

provided to give background information to those who may wish to accept or refute the

findings.

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 of

sectors 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 industry

activity can fit all work.

The author is passionate about reducing harm to at risk groups of people and while convinced

that designers can make a contribution to the process of safe and healthy construction was less

persuaded that this change was worth seeking given the costs to individuals, industry and

society at large. Further, industry wide problems with CDM compliance already experienced

seemed to indicate that the chance of delivering significant added value change to the culture

of a diverse industry was small.

The author was and is also concerned that health and safety professionals still hold the main

power base in terms of delivering advice, training and proposing solutions. While their

contribution 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 can

make.

Standards of training and competence for designers have not been established across industry

by those experts in design who could be demonstrating best practice and the added value of

this additional effort. Steps are being taken through the Construction Industry Council and its

member 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 arguments

relating to this problem and in any case change is also afoot here. It is clear, however, that

undergraduate 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 but

arguably only able to deliver skewed results, set out as a politically correct sop to the

requirements 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

9

required highly competent designers to provide creative solutions or the spending of

considerable time and therefore cost to deliver solutions.

Some of the accidents were simply avoidable. Some of these were fatal or resulted in serious

injury. Reading of incidents that have destroyed lives and had a knock on effect to many

others 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 Temporary

Works 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. The

clear message should be one of warning and challenge for the whole design community.

10

5 ASSUMPTIONS AND PROCESSES

5.1 PROCESSES AND ITERATIONS

The process for the research was driven by Malcolm James’ original work, which was slightly

modified in the third iteration.

Each incident was sanitised as a summary description from the report. Various measures were

given quantitative values from what it is agreed must be inadequate information in many

instances. These assessments were validated, however, by peer review and comparison and

the 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, level

of specialist knowledge required etc which enrich the central debate. There is also an

assessment made of whether a Planning Supervisor appointment could have made a

difference 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 coordination

role 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 made

reference to construction products and processes with little reference within those reports to

design and planning aspects of construction. Certain assumptions were made for the purposes

of 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 original

design of the structure. Where poor design had led to difficulties with maintenance

this was pointed out in the notes but not given any value in the overall quantitative

assessment.

· Where assumptions about designer competence were critical to the assessment these

are stated.

· Designer effort is judged to be roughly equivalent to designer costs. It should be

recognised that no indication of the procurement route or contract arrangements is

given in the reports and this can have a significant effect on the ability of designers to

contribute effectively.

· It is here assumed that the designer is appointed prior to any design. In some

instances some designers are required to make speculative outline design as part of

the tender process. No allowance is made for such factors.

· No assumptions are made about designer culpability in law, which assessment must

be a matter for the courts.

· Apportionment of responsibility to architects or consulting engineers is in most cases

arbitrary since most reports are silent on the nature of the design professionals

involved. For the final commentary these two groups have been assessed together as

principal designers.

11

6 FINDINGS

6.1 Prior to CDM data collection by HSE specialist inspectors concentrated on the facts

at 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 considered

part 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 must

be remembered that the assumption was that any doubts should be resolved in the

designers’ favour. In other words, the results are indicative of the level of potential

change 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 to

effect improvements.

13

Table 1 Summary 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 8E

15. 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. 4E

27. 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. 4C

52. 2C

14

53.

54. 4C M

55. 10G

56.

57.

58. 4E

59. 4E

60.

61. 10J

62. 8J M

63. 6C M

64. 8G

65. 8G

66. 8G

67. 6E 10J

68. -

69. 2A

70. -

71. 8G

72. 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 with

responsibility for design issues.

2. The summary diagram takes several views of the data. It considers the reports and is the source for the

following 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; and

Table 6 – Supplier/Manufacturer only.

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

engineer.

15

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

Wh

at

desi

gn

er

did

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

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 the

designer has failed to take enough action when such action could have made a major contribution to

accident 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 to

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

16


All design: All contributions to each incident



contribution


significant

0-2 4 6 8 10

Wh

at

desi

gn

er

did

What was

necessary

A 1 0 0 0 0



Not nearly

enough

G 0 2 4 7 2


Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of one or more designers because

the 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 almost

half of all cases reported.



17


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



contribution


significant

0-2 4 6 8 10

Wh

at

desi

gn

er

did

What was

necessary

A 0 0 0 0 0



Not nearly

enough

G 0 0 2 4 1

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 that

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 1 in 6 cases.



18


Temporary works design



contribution


significant

0-2 4 6 8 10

Wh

at

desi

gn

er

did

What was

necessary

A 1 0 0 0 0



Not nearly

enough

G 0 0 0 0 1


Summary by category






Notes:




4 Percentage of incidents likely to be the subject of further investigation of a temporary works designer

because 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.



19


Supplier or manufacturer



contribution


significant

0-2 4 6 8 10

Wh

at

desi

gn

er

did

What was

necessary

A 0 0 0 0 0



Not nearly

enough

G 0 2 2 1 0

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 designer

because 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 to

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

20

7 COMMENTARY

7.1 It must be remembered that the figures relate not to all projects but only to those that

were 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 6

of those investigated showed this lack.

7.2 Case law exists that states that consultant engineers and architects should have no

involvement in the construction processes even when the methods chosen by the

constructor threaten safety. There will need to be greater clarity in relation to

legislative changes before designers would be advised to be prescriptive in any great

manner. This attitude of separation of responsibilities clearly pervaded the industry

throughout the period during which the reported incidents took place.

7.3 There were some key themes to the incidents themselves. In particular poor

communication 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 would

have 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 with

the 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 the

Temporary Works designer or manufacturer have been separated out and dealt with

as a different industry issue.

7.7 Table 2 shows that in almost half of reported cases a designer could have taken steps

to prevent realisation of an accident but failed to take such steps. There is a clear

message here for all of those involved in design, specification and communication of

critical information.

7.8 Table 3 shows much the same as Table 2. It includes multiple responsibility for

incident 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 of

main designers who could have, but failed to, intervene to prevent accident

realisation. In approximately 1 in 6 cases the original designer could have done

something to prevent an accident happening but failed to take that opportunity. If this

figure is translated across to the annual accident statistics this means that 1/6x80 = 13

deaths a year could be prevented by designer action. Proportionate savings in injury

and ill health could presumably be made. This clearly is a significant difference by

any measure and well worth setting out a change agenda to achieve. It is particularly

telling when it is remembered that this peer review chose to err in favour of the

designer in the event of doubt and also the fact that the reports did not generally

comment on the original designer activity. Further, maintenance accidents included

did not blame the original designer because it was decided to consider only the

current project. There are, however, several incidents where the original design made

21

maintenance activities difficult and unsafe. It is the view of the author that, because

of 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 failed

to take the opportunities presented to intervene effectively to prevent accidents. It is

judged likely that this statistic is more accurate since at the time of the reports

temporary works design involvement was more often considered by the investigating

inspector than principal design. In any case there clearly need to be improvements

made by the temporary works community. Common mistakes here included incorrect

assumptions, poor communication and not involving expert designers at the

appropriate time, even when they were available.

7.11 Table 6 shows that a significant number of incidents could have been prevented, but

were not, by better intervention from the construction products design community. In

particular systems scaffolding incorrectly used, systems building units poorly handled

or inadequately seated and access systems with inferior failure modes or emergency

controls were found to be root causes. Generally the product design community did

not give adequate information about the suitability or otherwise of their products for

particular situations.

7.12 Information collection by the Health and Safety Executive (HSE) inspectors rarely

enquired about designer involvement in buildability. This was appropriate to the

prevailing culture and to the civil law of the time. For the effective delivery of closer

understanding of the potential for designer contribution to accident prevention it will

be necessary for this strategy to change and for enquiry methodologies to incorporate

investigation of complex design processes and decision making. It is likely that this

will need a considerable amount of additional research to be carried out as many front

line HSE inspectors do not have the technical competence in design to make

appropriate 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 where

a contractor takes on a contract to construct a particular design he is making a

statement about his capability to do so. An integral part of this capability is his

competence and presumably his competence to manage the risks to the safety and

health of his workforce. Designers need clearer advice about the relationship between

competence of contractors and their own increased liability if they instruct

contractors, or may be seen so to do, in methods of building. Clearer information is

needed too about the kind of information that would be of use to a contractor. The

industry has evolved a methodology for this process usually called design risk assessment. In fact designers usually retrofit poor quality contractor risk assessments

to their final design. Many do engage in design decisions that take account of

buildability and maintainability but do not recognise these for what they are, which is

a correct response to statutory duty.

7.14 Designers often did not obtain adequate information about existing site conditions or

the fabric and condition of existing structures. Their duty to obtain clearer

information 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 such

matters where information is available is a failure to provide proper design services

even without consideration of the safety aspects of those who will be affected. In

particular access to lighting, services and minor fixtures and fittings continues to

22

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

requirements.

7.16 The Planning Supervisor potential contribution to accident prevention was also

considered. In every case where the Planning Supervisor could have intervened for

good it would only have been possible if that Planning Supervisor was highly

competent in both design and construction processes and also had the character,

authority and opportunity to intervene at the correct time in the project delivery. No

general electronic or paper based system frequently used by Planning Supervisors

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

adequately.

7.17 The Site Safety Supervisor could in some instances have intervened, for example

when system scaffold or building units were not being safely used or installed. In

many cases, however, technical knowledge beyond that of the general site safety

supervisor was needed to make adequate intervention.

7.18 Procurement routes and the costs to the design community are seen as a real barrier to

effective delivery of change. Where health and safety is an early contract requirement

designers and constructors alike can deliver high standards. Where designers would

need to spend considerable sums of unrecoverable money to deliver change it is no

surprise that they fail to take that opportunity. This must be a matter for regulators

and government.

7.19 In many instances contractor design incompetence was a major contributor to an

accident. No designer had been involved at all. It may be necessary to put a

requirement on certain types of project for such specialist intervention in some

manner.

7.20 It is the Author’s very strong conclusion that the case for CDM is made by this

analysis 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 is

the 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 through

intervention in the design phase of projects. Methodologies for enforcement

intervention need to be developed.

23

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 penalty

through enforcement action. To achieve the latter the revised Regulations or

Approved Code of Practice will need to emphasis the requirements on designers in

this respect and the HSE will need to develop enquiry methodologies that probe the

design process.

8.2 The manner in which designers can intervene effectively needs to be more clearly

expressed in industry standard documentation and training. The culture of acceptance

of poor quality design needs to change.

8.3 It could be extremely helpful to refine this research methodology in the light of new

understanding about barriers to change and opportunities for improvement. The best

means of making proper enquiry of designers by enforcers without the appropriate

depth of technical skills needs to be developed. Engagement with IT data

management 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 and

the impact on the data management capabilities need further development. Significant

information could be delivered to the industry, including HSE, through a closer

understanding of what initiating factors tend to cause later incidents. For instance

procurement 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 demand

high qualities of health and safety then procure competent and well resourced

suppliers 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 a

certain manner needs to be further explored. In particular the tension between the

civil 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. The

information so gathered can serve several purposes. It can encourage and require

improvement from the design community; it can provide a better source of data for

future incident review such as this; it can provide better data for appropriate

enforcement action.

25

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.

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

F Steelwork and steel frame erection

O Roofing

G General construction including scaffolding

R Refurbishment

A Falsework, formwork etc

E Excavations and foundations etc

C Cleaning and maintenance

W Window cleaning

D Demolition

Incident rating refers in sequential rows to potential for incident then for actual harm done,

where:

10 Most severe. Major disaster with members of the public affected as well.

8 Multiple fatalities to workers on site

6 Single fatality to worker

4 Serious injury to worker

2 Minor injury

0 Non injury report or event

Note that property damage almost always has potential to cause harm to people, so will be

picked up in the first listing of incident rating.

Could the designer have done more? This refers to an arbitrary view from information

available relating to potential for prevention or reduction in probability by the named

designer.

10 Designer could probably have prevented 8 Designer could have done a lot more to prevent 6 Designer could have reduced likelihood significantly4 Designer had opportunities to reduce likelihood or prevent 2 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 opportunity

by the designer. Notes on duty to have intervened are in the main text.

J Complete failure to prevent or reduce probability

G Failure to make additional efforts using specialist support

E Failure to research issues and apply them

C General lack of design contribution/communication opportunity

A No designer failings

27

Design effort refers to an estimate of the additional effort and consequently resource likely

for designer to include a suggested feature.

H A lot of effort

M Some effort

L Very little effort

Degree of specialist knowledge refers to an estimate of whether a designer could be expected

to know or to have found out from standard sources, where:

0 Should know at basic designer level

1 Generally expected to know to fulfil defined designer role

2 Should easily be able to find out

3 Would need some research to discover this or higher than general

competence 4 Would need specialist expert help

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

R Reduction in cost L Little additional cost E Some additional cost S Significant additional cost

Interventions

Two additional boxes are included for interest. These relate to external interventions from

individuals 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 difference 1 Unlikely2 Possibly3 Probably 4 Yes

28

APPENDIX 2 ACCIDENT ANALYSIS SHEETS

The following 73 sheets each summarise an incident that was investigated by the Health and

Safety 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 were

as a result of requests for advice or followed on from the serving of notices. All categories

were included because it was felt that where HSE had been involved at specialist level there

was an implied potential for an incident. Whether the potential was realised or not and the

extent of that realisation is captured in the summary sheets but was not transferred to the final

analysis.

It is certain that industry will be able to argue about the detail of the findings relating to each

incident 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 small

number of cases was there a need for final arbitration and significant adjustment.

In many cases additional information would have assisted the analysis process considerably

and assumptions had to be made.

29

Quick Ref 8F Designer Contractor

Description of incident

An agricultural steel portal framed building collapsed during erection. The columns were not secured to

the 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 that

could 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 to

that effort not being made.

HSE Peer review: Ref 4467/R33.115 30 Case worksheet HAB 01H

Quick Ref 4J/4G Designers Consultant

Manufact.


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 slings

apparently 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 ü 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

Remarks

While 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.

HSE Peer review: Ref 4467/R33.115 31 Case worksheet HAB02H

Quick Ref N/A Designers N/A


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 being

imposed. 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?

Remarks

There 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.


Quick Ref 6G Designers Manufact


A temporary roof edge barrier blew off the edge of a single storey ‘bridge’ link between two other

buildings. 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 suitable

FOS 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 ü possibly ü possibly ü possibly ü Manufact


more?

6



G

Design effort M


Cost implications L



difference?

3



made a difference?

4

Remarks

The designers of the temporary barriers had failed to deal with the possibility that they could have been

used 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 failure

could 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.


Quick Ref 6J Designers Manufact


A prefabricated building was being dismantled and moved to another location. The building was

constructed 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 total

roof 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

Remarks

While it is possible that the lifting points were at the edge of each section this would still mean that

someone 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.


Quick Ref 6G Designers Consultant


A fairly standard sandwich skin roof was being installed that had roof-lights in it. The inner skin was

being 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 ü N/A N/A


more?

6



G

Design effort L


Cost implications L



difference?

3



made a difference?

4

Remarks

The 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.


Quick Ref 2E Designers Consultant


A roofer fell through an inner lining sheet. This had only been secured by one fixing at its top edge

instead 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)

Designers involved N/A ü N/A N/A


more?

2



E

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

The sequence of fixing the roof sheets appears to have made some contribution to the accident although

the 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 those

installing the roof depended on them keeping off the liner sheets until they were fixed; the planning of

the work should have ensured this.


Quick Ref 4J Designers Consultant


An accident occurred when two men fell from a steel roof frame while they were unslinging a pack of

roof sheets with no means of protection.

Keywords from list Falls from height off edge; Structural erection; Steel frame





(Specify)

Designers involved Unlikely ü N/A N/A


more?

4



J

Design effort L


Cost implications L



difference?

3



made a difference?

3

Remarks

While the major contributory factor to this accident was a failure of site management and unreasonable

behaviour by the roofers involved, it could have been possible for the designer of the building to have

provided some form of anchorage for those carrying out this necessary and foreseeable operation.

The designer could have encouraged the use of safety lines or nets in designing suitable anchorages for

this type of equipment.


Quick Ref 6J Designers Consultant/

Architect


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

Keywords from list Falls from height through; Refurbishment; Commercial





(Specify)

Designers involved ü Possibly in ü Possibly in N/A N/A

original only site

investigation

Could the designer have done 10 6

more?



J J

Design effort L L



Could external intervention at 3 3


difference?

Could site supervision at 3 3


made a difference?

Remarks

The 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 original

designer. (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.


Quick Ref 6J Designers Architect


A new church was under construction having steeply pitched roofs to a maximum height of 13m. No

provision 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 ü Possibly N/A N/A


more?

6



J

Design effort M


Cost implications E



difference?

3



made a difference?

3

Remarks

The 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.

HSE Peer review: Ref 4467/R33.115 39 Case worksheet HA 10H



A roofer helping to build a new cattle shed adjacent to an older, and 1m lower, cattle shed. The older

building 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 ü Possibly ü Possibly N/A N/A


more?

6



J

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

While control of this risk lay chiefly with the contractor, the designer should have flagged up the real

risks 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 been

greater 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.


Quick Ref 8E Designers Architect


An old warehouse was being converted into flats. The roof was completely stripped leaving the old

roof 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. 1/3 their 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)

Designers involved ü N/A N/A N/A


more?

8



E

Design effort L

Designer specialist knowledge O

Cost implications L



difference?

3



made a difference?

1

Remarks

The 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.




A cradle runway was installed on the roof of a hospital for the use of window cleaners. The roof

however 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 ü


more?

10



J

Design effort M


Cost implications E



difference?

3



made a difference?

1

Remarks

The 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 also

resulted in increased operational costs.


Quick Ref 8E/4E Designers TW/A


A proprietary scaffold had been erected completely around the site of a new building, which was to be

built from prefabricated timber sections lifted over the scaffold into position, followed by a

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

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 ü N/A ü N/A


more?

4 8



E E

Design effort M M


Cost implications L E



difference?

2 0



made a difference?

2 3

Remarks

With a building design such as this there is an even closer relationship between the building panels and

the façade 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 to

suggest 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.


Quick Ref 8J(A)

10E(C)

10J(M) Designers Various


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 lifting

arrangements 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





(Specify)

Designers involved N/A ü ü 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 a

proper 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 time

required to prepare a proper design.


Quick Ref 6J(C)

8J(M) Designers C & M


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

support beam. The bar he was using slipped and he fell from the exposed edge suffering injuries.

Keywords from list Fall from height from; Erection of structures; Pre-cast units





(Specify)

Designers involved N/A ü N/A Manufacturer


more?

6 8



J J

Design effort L L





difference?

2 2



made a difference?

3 3

Remarks

Designers who specify pc units should be aware that they often require levering into position on site.

Therefore, they should specify for the manufacturer to design in anchorage points for lanyards.

The same applies to the manufacturer. If this was a standard design issue, it would be done as a matter

of course.

The additional handling described is a feature of the product and failure to build in suitable facilities to

support this could be argued that the manufacturer’s products are not fully complete. It is unlikely that

such additions to the slabs would be very expensive and given the large number of units manufactured

even small production gains made during erection could make these cost effective.


Quick Ref 4E(A/C)

4G(M) Designers Various


A worker stepped or fell off a perimeter scaffold onto a pre-cast beam and block floor and either fell

through a hole in the floor or his impact broke out the in-fill blocks so forming a hole through which he

fell.

The in-fill blocks had poor/minimal seatings in some cases due to slight displacement of the beams and

those that fell had virtually no seating at all. In addition the blocks had not been grouted in and were

incapable of carrying much load.

Keywords from list Fall from height through;

Job nature – type of activity R




(Specify)

Designers involved ü or C ü or A Manufacturer


more?

4 4 4



E E G

Design effort L L M


Cost implications L L L



difference?

2 2 N/A



made a difference?

1 1 N/A

Remarks

The main responsibility for this accident lies with the contractor: he failed to ensure that the pre-cast

beams were accurately positioned and that the floors were grouted immediately they were laid.

However, as the creator of the hazard, the designer should have informed the Contractor about the

residual hazard. Not doing this represented a design failure.

The manufacturer has designed a system with an obvious safety deficiency: the risk highlighted by this

accident would also exist for the person grouting up.

It might have been possible to incorporate or provide a gauge to ensure that the pre-cast beams were

correctly placed.

It is possible that the provision of a suitable gauge would be cost effective as it could provide a limited

production benefit.


Quick Ref 6E(C)

10J(T) Designers Various


A sloping rc floor was being cast on profiled metal deck sheeting laid to varying slopes. One area of

decking failed and a worker fell through the hole.

The framework supporting the decking was at varying slopes therefore, the decking could not always

sit properly on its support. In addition, while the concrete being placed did, in some cases,

significantly overload the decking.

A consulting engineer had had involvement on the site but does not appear to have had complete

control over the works. A sub-contractor who may not have understood the structural significance of

the decking’s limitations carried out the actual choice and installation of the decking in this area.

Keywords from list Falls from height through; Pre-cast units

Job nature – type of activity A




(Specify)

Designers involved N/A ü ü ü See note


more?

6 10



E J

Design effort L M


Cost implications E E



difference?

2 3



made a difference?

1 1

Remarks

The limitations in the decking could have been dealt with in a variety of ways either by themselves or

in combinations. These include using stronger decking, using appropriate wedges to give adequate

seating, using temporary supports to back prop the floor until the in-situ concrete had gained sufficient

strength, placing additional reinforcement in the thick in-situ concrete.

The selection of the most appropriate system should have been done by a suitably competent designer

In this case the designer was the sub-contractor who was not competent to appreciate the structural

significance of what he was doing.

The cost of the failure was clearly far greater than the cost of a competent person carrying out the

necessary calculations.


Quick Ref 10J(A)

10J(Con)

Designers Various


A person was injured when a section of pc flooring together with supporting lintel and block work

collapsed.

The flooring was being installed and was not grouted in. It was resting at one end on a steel lintel

spanning onto the block work reveals at the side of a window opening. The floor was heavily loaded

with blocks in the area of the failure.

The lintel was grossly under-designed and possibly could not have supported its service load. The

block work reveal was also severely overloaded. No calculations had been prepared for this work.

Keywords from list Collapse of structure; Pre-cast flooring





(Specify)

Designers involved ü N/A N/A ü Contractor

modification


more?

10 10



J J

Design effort M M


Cost implications R R



difference?

2 2



made a difference?

1 1

Remarks

Appropriate calculations by a competent person should have easily prevented this incident.

While the pre-cast floor used was a substitute for in-situ concrete on permanent shuttering, this would

not have solved the overloading problem although could have resulted in a greater distribution of the

loads.

The accident could have been avoided by normal (pre CDM) procedures a safety appraisal should have

indicated that suitable calculations had not been carried out.




A design change required a section of a suspended concrete floor to be omitted. The method of work

for the installation of ceiling ducts to the upper floor required the use of a mobile access tower and the

gap in the floor prevented this tower from being moved along the line of the ducts.

Spandecks were laid across the void and a tower was placed on these. Possibly due to either a worker

climbing down the outside of the tower or because the tower was being pushed along the Spandeck and

perhaps pushed this off its seating, the tower and one Spandeck fell into the void.

Keywords from list Falls from height through; Pre-cast flooring; Access





(Specify)

Designers involved C


more?

4



E

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

The designer had only a small part in this accident but the incident does illustrate the possible

consequences of design changes, especially structural ones.

When the change was made the designer should have checked, through the planning supervisor, its

impact on the method statements for the work surrounding the new hole and ensured these were revised

as necessary.

The consequences, both from an accident prevention and a financial point of view, of not following

through on the consequences of design changes can be very significant and far outweigh the minimal

effort usually required to check these out.




A putlog scaffold was being used to build a cavity wall dividing two roof spaces. The scaffold was up

to two lifts high and supported only on one skin of block work. The other skin was to be built

separately. Possible wind loading caused the block wall and scaffold to collapse.

Keywords from list Collapse of structure; Scaffold





(Specify)



more?

6



E

Design effort L


Cost implications L



difference?

1



made a difference?

2

Remarks

Knowledge of the vulnerability of thin block walls to a variety of loads is known equally by contractors

and designers. However as the designer created the hazard: lightweight walls, it should have been his

responsibility to emphasise the restrictions on progressing one leaf ahead of the other. Was the wall

checked for wind loads?

Following the same argument by expressly giving such instructions would be a normal means of

ensuring the quality and therefore minimising the cost of the project.


Quick Ref 8J Designers Manuf.


A roller shutter door previously fitted into a building collapsed killing a person. It was found that the

door had been secured by Rawlbolts of the correct size and number. However these had been placed

into oversize holes, some into mortar joints only and others penetrating into the voids caused by laying

bricks with frogs upside down.

Keywords from list Collapse onto; Building products;

Job nature – type of activity C




(Specify)



more?

8



J

Design effort L


Cost implications L



difference?

0



made a difference?

0

Remarks

The construction products were too heavy for the fixing available with no means of external inspection.While the supplier of the doors had specified suitable bolts no details appear to have been provided ontheir installation. Had this been done then possibly the accident would not have occurred. While the size of the bolts is important this cannot be separated from a clear specification of the natureof the anchorage holes and materials. Without the two sets of information a reliable fixing cannot beassured. This means that such a failure could have both economic and safety consequences.




A 3-storey building was being rendered off an external scaffold erected all around the building. There

were no ties between the scaffold and the building because of the need to give clear areas for the

rendering to proceed. Therefore, the scaffold was generally stabilised by the end returns. The scaffold

on one elevation was removed and a section along the return wall where a gin wheel was being used,

collapsed.

Keywords from list Scaffold collapse





(Specify)



more?

6



J

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

The designer specified the render and it should have been clear that the scaffold could not be tied to the

building or that ties would have to be moved and not replaced. Therefore, the designer should have

provided suitable anchorage points in the façade.

While it would not be normal for the designer to get involved with scaffold design and use, in this case

the scaffold could have seriously affected work that had been specified. It was therefore in the client’s

interest for the scaffold to be designed and arranged so as not to impair the harling work.


Quick Ref 8G Designers Manuf.


Three men were preparing to install ducting working from suspended ceiling panels. The panels failed;

2 men fell 5.9m. The ceiling sat in 33x33x1.8 aluminium angles. In some cases only two 3mm rivets

secured this angle to the wall section. It was found that some of the rivets had been badly placed, were

subject to both bending and shear and had in fact sheared or were missing. The rivets connecting the

suspended panels to the angles had failed in tension pulling out of the panel. The suspended panels

were supported by an inverted top hat section hung by M12 threaded bars from the concrete roof

structure.

No signs had been posted about the safe working conditions for the panels and the panel manufacturer

supplied no fixing instructions on the basis that this was something the installer should deal with.

Keywords from list Collapse of access platform;





(Specify)



more?

8



G

Design effort L


Cost implications R



difference?

2



made a difference?

0

Remarks

There were three major failings: (1) The manufacturers had not calculated the sorts of loads that could

be imposed on the fixings that could be used to support their product; (2) They had not provided clear

information to the installers or the owners/users of the product on the design and load limitations

relevant to it; and (3) They failed to provide typical installation details. As a consequence no one, the

manufacturers, installers or owners/users of the product, was aware of how safe the product was when

used for access purposes.

From the report it appears that their was a variety of fixing arrangements, some quite nominal, which is

hardly surprising given the lack of consideration given by the manufacturer.


Quick Ref 4E Designers TW


A temporary platform that had been slung under a motorway bridge was being lowered when it broke

in two and a scaffolder who was on it fell. The platform was found to have been overloaded with

access boards and tubes, was being carried at its extreme ends instead of 2m in as required by the

design, and had been manufactured from some materials that were defective. The decision to move the

suspension points out was taken by a site foreman, without consulting the designer. Investigations

showed that the platform was failed for three reasons: (a) it was overloaded, (b) it was slung

incorrectly, which exacerbated (a), and (c) there was a defective [weak] component in the failed joints.

Keywords from list Access; Cradle collapse





(Specify)

Designers involved N/A N/A ü But not

involved


more?

4



E

Design effort L


Cost implications L



difference?

0



made a difference?

2

Remarks

The temporary platform would possibly not have failed if any of the three weaknesses had not been

present i.e. if it had been properly slung, not been overloaded and not had defective materials in its

manufacture. However the possibilities of both overloading and slinging at excessive spans are typical

forms of misuse for this type of equipment therefore requiring increased factors of safety.

Perhaps the designer could have anticipated misuses (a) and (b).

There is a need to ensure that all components in a modular temporary access system are manufactured

to a high standard as there can be no guarantee that weak items won’t be used in highly stressed

positions.




A temporary work platform had been created by placing 3 floor boards across the stub ends of timber

joists which had been left in place after the joists themselves had been removed. Although the stub

ends of the joists were built into the wall this was only one brick wide and there was no brickwork

above the joist ends, which could have held them down. Three men stood on this platform to move a

staging towards a mobile access platform and the stub ends of the joists broke free.

Keywords from list Access collapse





(Specify)



more?

4



E

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

In refurbishment work unexpected situations occur. While it is largely up to the site staff to deal with

these, designers can assist by encouraging the contractor to adopt a safe methodical approach to the

work.

However it appears that there was a major site supervision failing through first allowing the stub ends

of the joists to remain in place once the rest of the joists had been removed and secondly in not

preventing the workers using such a hazardous form of access.


Quick Ref 10J Designers TW


Work in converting an old chapel built within a row of terraced houses required that the cellar floor

should be lowered. This was being done without the use of any shoring and a party wall collapsed.

Keywords from list Collapse of structure; Shoring





(Specify)

Designers involved N/A ü ü N/A


more?

TW aspects of

design are key

10



J

Design effort M


Cost implications L



difference?

3



made a difference?

3

Remarks

Underpinning work and excavation work adjacent to walls should be carried out to a suitable design

that will ensure that the structure will always remain stable. Such a design should have been provided

in this case.

Underpinning and similar work is a highly skilled job and requires that those involved in it, particularly

those managing and supervising it, are experienced, competent and reliable.


Quick Ref 10J(T)

1C(A) Designers


While a roll of lead was being hauled to a roof by means of a gin wheel attached to a 9m high scaffold,

the scaffold partly overturned. The scaffold was tied to the building partly by rakers and partly by

reveal ties. However the number and quality of both these types of support was less than that required

by the code of practice. In addition the joints in the scaffold tubes were not staggered making the

scaffold less able to resist rotating.

Keywords from list Scaffold collapse; Material handling





(Specify)

Designers involved ü ü


more?

2 10



C J

Design effort L L





difference?

0 2



made a difference?

2 2

Remarks

The designer could have detailed secure positions to provide tie anchorage points, especially as the

design required to installation of new building materials which would have to be hoisted to the roof of

the building. Alternatively other means could have been specified for lifting materials etc.

The lifting of new materials to roof level etc, was part of the design which required that effective lateral

supports would be required if the access scaffold was to be used to mount lifting equipment.


Quick Ref 10J Designers Scaffolder


The taller of two adjacent adjoining buildings needed its exposed gable re-pointing. A narrow access

scaffold was erected on the pavement as the local authority would not allow further obstruction. In

addition, the owners refused to allow the scaffold to be tied to the building. When ordinary ladder was

supported on the working platform on the scaffold and laid up the lower roof i.e. it was not hooked

over the ridge the reaction from the ladder pushed the scaffold over.

Keywords from list Access constraints; Scaffold collapse





(Specify)

Designers involved Scaffolder


more?

10



J

Design effort L


Cost implications L



difference?

0



made a difference?

2

Remarks

Scaffold design has not generally been considered to be part of Reg 13 except where it is temporary

works or very substantial but it is a serious matter in most cases.

Both the local authority and the owners had taken some responsibility for the design of the scaffold by

imposing conditions on its layout.



TW


A flat roofed section of corridor was being altered. This required the roof to be lifted higher and the

sidewalls, originally of timber framed glass panels, to be replaced by block-work. The original

sidewalls had been fixed to the ground cill and “portalised” with the roof joists, to resist rotational

forces. There was nothing in the new design to provide lateral restraint. In addition, the flat roof itself

was being used as a working platform. The structure collapsed as the second sidewall was being

replaced.

Keywords from list Structural collapse





(Specify)



more?

10 10



J J

Design effort L L





difference?

2 2



made a difference?

2 2

Remarks

The new design did not make any allowances for lateral restraint either during the construction phase

or after completion.

While the method of construction made no provision for supporting any lateral forces, which would be

created when working on top of the roof, this only compounded a principle design failure. Therefore

even if the builders had used bracing during the refurbishment, the building could still remain unstable

to some degree after completion.


Quick Ref 10J Designers Contractor


A prefabricated temporary roof was being used which had plastic sheets fixed to aluminium trusses

supported at each end by a scaffold. This system would be unlikely to fail under wind loading as the

plastic panels would rip open before the loads became so high. However while the suppliers of the

equipment recommend that each installation is designed, this was not the case with this structure.

Keywords from list Temporary structure; Collapse





(Specify)

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

scaffold

design


more?

10



J

Design effort M


Cost implications L



difference?

0



made a difference?

1

Remarks

A full design of each installation is recommended by the manufacturer/supplier and while the structure

has a tendency to fail to safety, not carrying out a design check could open the way for problems to

occur.

Although not mentioned in the report the design of the temporary roof requires the erectors to climb

along the roof trusses fixing the plastic sheets. This in itself is a design weakness.

Contractor should have designed protective scaffold.




A wide, up to 2m, scaffold was erected around a church tower for maintenance and refurbishment. The

scaffold was about 24m high and erected around each of the four 12m wide faces of the tower. The

scaffold probably had some original faults that were not particularly serious but had then been altered

by the contractors carrying out the work as well as increasing the loading on the scaffold. The scaffold

was not tied at any point to the tower.

Keywords from list Scaffold; Alterations; Refurbishment





(Specify)



more?

10



J

Design effort M


Cost implications E



difference?

3



made a difference?

2

Remarks

Scaffolds of this size and configuration, particularly because of being unusually wide and not being

tied back to the tower, need to be designed and carefully detailed. Such a design should carefully

consider both the self-weight of the scaffold and the maximum imposed loads to ensure that the

buckling strength was adequate.

The unusual width of the scaffold was something that could have reduced the mutual support provided

by each of the standards, increasing their slenderness ratio. The scaffold design therefore needed to be

checked by an experienced scaffold designer. This is something that the client or architect should have

realised.


Quick Ref 10J(A/C) Designers Consultant


Steel beams 305mm deep, to support to roof trusses, were positioned on the top of slender brick

columns [215x185] approx. 2.17m high, but were not fixed in place. There were gaps of varying depths

between the top of the steel beams and the underside of the trusses. The design intention was for the

beams to be trapped under the roof trusses by their increased deflection from the increased deadweight

of the roof as it was completed. In one position the beam had apparently been dislodged and fallen onto

a person.

Keywords from list Collapse of structure; Erection; Steelwork; Material handling





(Specify)

Designers involved ü If used

rather than

Engineer

ü


more?

10



J

Design effort L


Cost implications L



difference?

3



made a difference?

2

Remarks

The seating of the beams was inadequate, because the design intention ignored the reality of the

construction process. Consequently, the beams were vulnerable to movement in a variety of scenarios.

Had the beams been designed so that they were securely held in place in their temporary condition then

the accident would not have occurred. This could have been achieved by either bolting them onto the

brick columns or by using a temporary fixing to the trusses, which would still allow them to deflect.

The space between the beam and the truss varied to an extent that it is possible that some of the trusses

may not have fully settled onto the beam.


Quick Ref 6E Designers TW


A slung scaffold was to be hung over a parapet of a tall office building, surrounded by public rights of

way. The scaffold was to be used to remove defective tiles at the top of the building and had 3 working

platforms. While the design of the scaffold was acceptable, measures to protect the public below were

required.

Keywords from list Falls of objects from height; Scaffolding





(Specify)



more?

6



E

Design effort L


Cost implications L



difference?

3



made a difference?

3

Remarks

The design for the work should have included all its aspects including full details for protecting the

public.

While to measures for protecting the public may have been picked up by the contractor when the work

commenced not including them in the design could have resulted in omissions or unsatisfactory ad hoc

solutions being used


Quick Ref 8G Designers Contractor


A Victorian house was being refurbished. Concerns were raised about some temporary & some

permanent structural provisions being made in the course of these works. These arrangements appear to

have been organised without any comprehensive design work being carried out.

Keywords from list Temporary Works; Structural collapse





(Specify)

Designers involved Contractor No

formal design


more?

8



G

Design effort L


Cost implications L



difference?

4



made a difference?

3

Remarks

The report indicates that the works had not been designed properly. Proper detailing of all permanent

structural features should be carried out. Suitable planning of temporary structural requirements should

be undertaken relative to the complexity and significance of the loads to be supported.

The description of the conditions found strongly suggests that things were getting out of hand and there

was little or no effective management/supervision.

These problems should have been obvious to the designer of the project on site visits prompting

remedial works or a change of contractor.




A badly laminated and friable rock face was being stabilised by casting up to 2m thick concrete against

it. The formwork being used was held in place by rock anchors drilled into the friable rock at 0.7m

centres. While casting the concrete the pressures created by vibrating and placing it caused the anchors

to fail pushing over the formwork and adjoining access scaffolding.

No attempt seems to have been made to assess the pull-out strengths of the anchors.

Keywords from list Rock face; Formwork;





(Specify)



more?

10



J

Design effort M


Cost implications L



difference?

2



made a difference?

1

Remarks

Designers are aware that concrete needs to be retained until it has hardened. Tests should have been

carried out to check whether the pull-out strengths on the anchors was adequate. Calculations should

have been made by a competent person to assess the pressures that could be exerted by the concrete

and controls put in place to ensure that such pressures did not become excessive.

In this situation the concrete pressure could be affected by the moisture content, the rate of pouring, the

amount of vibration used and any surcharges from men or materials. All these are features that could

have required control in the design.

The nature of the rock surfaces suggests that frequent testing of the rock anchors would be required as

the pull-out strengths could be significantly affected depending on the strata the anchors were being

drilled into. Again this is a feature that the design should have dealt with.


Quick Ref 4J Designers Subcontr


Following a commercial dispute a sub-contractor started to remove the shoring to a building’s façade.

This could have become unstable if much of the support offered by the shoring had not been available.

Keywords from list Structural instability; Temporary Works





(Specify)

Designers involved Sub contractor


more?

4



J

Design effort L


Cost implications L



difference?

0



made a difference?

0

Remarks

No temporary supporting structures should be interfered with while the structures they are supporting

have not been strengthened in other ways without careful assessment of the likely consequences of

such an action.




During its 14th

pour the roof section of a reinforced concrete box culvert collapsed. The work was

under the direction of a city council acting on behalf of a water authority. The formwork sub-contractor

had employed consulting engineers to design the falsework and formwork. The roof slab was 550mm

thick x 6m wide. An inspection of similar adjoining falsework revealed a series of inadequacies

including no bracing, eccentrically loaded props and missing base plates.

The design had been carried out in accordance with the code for the structural use of timber and not

that for falsework. The design did not include any horizontal loading usually assumed from placing the

concrete.

Keywords from list Falsework; Temporary works





(Specify)



more?

4 10



C J

Design effort L M





difference?

3 3



made a difference?

1 1

Remarks

There was a serious failure by both the design engineer for the temporary works and the supervising

engineer. The temporary works design was not to the appropriate code and suggests the engineer was

not experienced in this type of work. The supervising engineer should have been aware of the gross

shortcomings in the design and construction of the temporary works.

The works probably suffered through the length of the chain of authority both for the client and for

work on site. This could have resulted in each level of the construction hierarchy paying little attention

to how the others carried out their work.

In particular there appears to be a lack of competence as far as the design and construction of the

temporary works is concerned. For instance the 3 tiers of support to the formwork seem unnecessary

and should have prompted questions by the supervising staff.




A 225 thick rc floor slab collapsed as it was being poured. The slab spanned 5.7m between steel beams.

The formwork was plywood sheets on telescopic centres, which were carried on the beam shutters and

a central 150x75 timber bearer layed on its side, which was carried by telescopic props at 0.75 – 1.20m

centres. The props were not laced or braced and, in some cases, were up to 125 out of plumb. In

addition, there were instances of poor foundations to the props.

Checks revealed that in places the centre supporting timber and the props were up to 4 times

overloaded sufficient to explain the flexural failure of this timber and the buckling of some props.

The work had been carried out by a formwork sub-contractor without any design being undertaken.

Keywords from list Collapse; Formwork





(Specify)



more?

10



J

Design effort M


Cost implications L



difference?

3



made a difference?

1

Remarks

The failure could have been prevented if a proper design had been undertaken and a suitably competent

person had supervised the works.

The failings were quite basic and should have raised questions by anyone having a reasonable

knowledge of these types of temporary works.

Telescopic props are made with a large reserve of strength and the fact that some buckled indicates a

serious degree of overloading. However, this large reserve of strength does tend to encourage abuse by

incompetent persons as does therefore require proper control.


Quick Ref 6E Designers


A proprietary falsework system was being dismantled. The materials used to build the non-standard

falsework and access ways around the system, were scaffold materials and plywood. This resulted in

tripping hazards which compounded the absence of guard rails in some instances.

There was a potential for persons to fall over 5m due to the ad hoc nature of the temporary works

which had not been dealt with in the design.

Keywords from list Falsework; Access





(Specify)



more?

6



E

Design effort L


Cost implications L



difference?

3



made a difference?

1

Remarks

Temporary works should be designed so that they are safe to erect, use and then dismantle. The design

of this falsework system did not consider the needs for access during each of these stages. This should

have been dealt with when arranging the layout of the proprietary equipment and associated make-up

areas and formalised in the method statement.

The use of proprietary equipment, which incorporates ‘typical’ solutions for access etc., can lead to a

false sense of security. This is because the difficulties that can arise when dealing with the non-

standard areas around the proprietary system can be forgotten, meaning that the contractor must do the

best he can.

The quality and suitability of the resulting in-fill will then depend on the experience and reliability of

those doing the work and on the materials or equipment that is at hand.


Quick Ref 4C Designers T/W


A large steel reinforcement cage, approx. 4.25m highx4.1m long backed by a 2.1m wide and 1.6m deep

chamber area, was being prefabricated prior to being lifted into an existing sewage tank but collapsed

before the work had been completed. No additional bracing or strengthening had been incorporated

within the cage either to support it while being prefabricated or when being lifted into position. No

access had been provided for the steel fixers who therefore climbed the steel bars and rigged some

100mm wide timbers to stand on.

The work was being done by a specialist steelwork and formwork sub-contractor for the main civil

engineering sub-contractor who was working for the main contractor.

Keywords from list Reinforcement cage; Bracing; Temporary works





(Specify)



more?

4



C

Design effort L


Cost implications L



difference?

1



made a difference?

1

Remarks

The re-ordering of the construction sequence by the sub-contractor was a sensible decision but did

involve structural issues.

The decision to prefabricate the reinforcement was taken by the re-Ø sub-contractor but should have

involved a full design review. Additional materials were required over the minimum necessary for the

original design which envisaged the reinforcement being erected in place against the formwork wall

shutter.


Quick Ref 4F Designers Contractor


Steel re-Ø was being placed for a 45m long x 7.3m high x 0.6m thick wall. The work was nearing

completion except for the upper 3.3m section at the end 9m of wall. The reinforcement partly collapsed

when an access ladder, fixed to it for use by the steel fixers, was removed. A full collapse was probably

averted because of the stiffening effect of the starter bars from the concrete kicker and because at one

end of the wall the reinforcement returned onto a section of wall that had already been cast. As a result

the heavier reinforcement at the lower section of the outside face of the wall remained in place. The

reason for such a large length of wall was being worked on was because delivery of water bars had

prevented the casting of a shorter length of wall.

Keywords from list Reinforcement; Temporary works





(Specify)

Designers involved Contractor


more?

4



F

Design effort M


Cost implications L



difference?

1



made a difference?

0

Remarks

The reinforcement cage was a substantial structure in itself and contained over 22 tonnes of steel. The

erection of such structures requires proper consideration, particularly when unusual circumstances

come into play, and this should have flagged up the need for effective lateral supports.

Apparently the reinforcement cage appeared to be quite stable before the collapse and both faces of the

cage were well tied together. The collapse was attributed to the removal of a ladder from the

uncompleted end which may have pulled on the reinforcement initiating the collapse.

There was also a failing on the part of the site supervision that they failed to react and question the

stability of such a large structure.


Quick Ref 8E(C)

8J(T) Designers Consultant

TW


A 12m long x 330mm wide block wall was being used as an external shutter for a 4.7m high mass

concrete filling, to be done in 3 lifts. During the pouring of the upper lift the block wall failed and the

wet concrete cascaded down onto a railway line below, forcing its temporary closure.

The concrete density had been increased without reference to the designer and was also very fluid.

However the design had not made proper allowance for the fluidity of the original concrete mix and

had not required any temporary supports to the block wall.

Keywords from list Falsework; Concrete;





(Specify)



more?

8 8



E J

Design effort M M





difference?

3 3



made a difference?

1 1

Remarks

The design seems to have been carried out by someone who was not sufficiently experienced to

temporary works design and who mistakenly assumed that the loads, pressures and situations can be

narrowly predicted. Errors or omissions in the original design meant that there was insufficient

allowance for the possibility of site variations in concrete pressure, from changes in the density and

fluidity of the concrete, instigated on site. However, these changes alone should not have led to failure

if the original design had been sound.

The consequences of a shutter failure on this site could have been extremely serious. Therefore, the

design of the shutter should have been extremely detailed and adhered to.


Quick Ref 10G Designers TW


The reinforcement for large 12 – 15m high walls was being fixed in a 97mx47m building that also had

a central spine wall. While some walls in this building had been concreted, most consisted only of the

reinforcement cage. The walls were 1.6m wide with 3 layers of vertical re-Ø EF & 3 layers of

horizontal re- Ø EF: mostly 32mm diam. bars at 174mm c/c, with frequent laps, which meant that high

wind pressures could develop. Generally, the two opposite faces of the cage were tied together, but at

one length only the reinforcement to the internal face had been erected.

Strong winds blew this reinforcement over which dragged adjoining large areas of the fully erected

cage and large sections of access scaffolding.

Keywords from list Wind loading; Reinforcement; Stability





(Specify)



more?

10



G

Design effort H


Cost implications S



difference?

0



made a difference?

0

Remarks

Even after the event the specialist researchers could not agree the cause of the failure. With such huge

areas of free-standing re- Ø it is reasonable to expect design checks to be made on the stability of such

structures. This is especially true where only one face of the reinforcement was being erected. It

appears that the approach adopted on site was little different from when erecting reinforcement against

wall shutters for relatively short lengths, medium height walls and not realising that they had moved

into a very different league. There are a variety of provisions that could have been made to reduce the

risk of collapse. These include welding the faces of the cages together so ensuring that they acted

together, using the access scaffold to prop the reinforcement effectively significantly increasing the

overall width of this temporary structure, or by limiting the area of reinforcement that would be

exposed to wind loading. This latter provision would include making use of the corners as a strong

point, casting these first to provide rigid anchors to hold the adjoining rebar cages.


Quick Ref 6E Designers Manuf


A proprietary formwork system consisted of waffle moulds resting on a framework of beams and in-

filler beams. These were supported by a system of props, lacing tubes and braces.

One of the beams had not been correctly fitted into position, possibly because one end had been

damaged, and in the same area the bracing to the prop heads had been omitted. This possibly allowed

the prop heads to move slightly and allowed the beam to fall.

Keywords from list System formwork; Structural erection





(Specify)

Designers involved Manuf


more?

6



E

Design effort H

Designer specialist knowledge H

Cost implications E



difference?

1



made a difference?

2

Remarks

The design of proprietary systems should take account of the possibility of erector error and limited

component damage. The end fixing for the beams should be designed so that they are either correctly

located or cannot be fitted at all. Being able to use a damaged/incorrectly fitted item is a recipe for

disaster. Any damage that could be significant but would not be easily recognised presents a serious

hazard. Items should be so designed that any defects that could be a problem are easily recognised.


Quick Ref 2C Designers Consultant


A proprietary falsework system was being used to support plywood formwork. Areas between the

proprietary system were being individually supported on props.

The falsework was being stripped without ensuring that the plywood formwork was also removed. In

one area a hole for a duct had been formed in the slab although the plywood formwork continuously

covered the area. This area of plywood also remained in place after the supporting falsework and props

had been removed.

A person stood on the plywood that then collapsed.

Keywords from list System falsework





(Specify)



more?

2



C

Design effort L


Cost implications L



difference?

2



made a difference?

3

Remarks

The main circumstances that contributed to this incident were due to failures by the site management.

However had a detailed design procedure been provided it is possible that some of these circumstances

would not have occurred.


Quick Ref 10J(T)

4E(A) Designers TW/Arch


An existing 3-storey building was being completely stripped for conversion into offices. This work also

included excavating in the basement area requiring temporary propping to the ground. The fabrication,

standard of construction and design of these earth retaining structures was very suspect, as was the

means of access into the ground works and a PN was issued.

Keywords from list Refurbishment; Temporary stability; Ground stability





(Specify)



more?

4 10



E J

Design effort M M





difference?

4 4



made a difference?

3 3

Remarks

The arrangements required to support ground which is in the vicinity of load bearing walls needs

careful assessment and the temporary works necessary to support the ground needs to be designed by

an experienced engineer having the relevant competencies in this type of work.

No mention is made of the need to fully investigate the loads on the walls being left in place and

particularly the depth of their footings in relation to the depth of the excavation.


Quick Ref 8G Designers Consultant


A brick wall surrounding a site collapsed after some excavations had taken place close to it. The site

area was 2-3m below the adjoining street level and the wall foundation extended another metre below

the general site level. An earth embankment formed on its side facing the site supported the wall. This

embankment was being modified to form an access way to road level by cutting part of it away and

depositing the removed material lower down the ramp.

While the wall itself was reasonably sound it had been underpinned at some time with 2-3m concrete.

This was in a poor condition with its vertical and horizontal casting joints in a very poor condition. The

exposed face of the concrete had been rendered partially hiding the condition of the concrete.

Keywords from list Excavations; Structural stability; Adjacent structures

Job nature – type of activity E




(Specify)



more?

8



G

Design effort M


Cost implications E



difference?

4



made a difference?

3

Remarks

When retaining old structures, facades, etc, designers should ensure that their true conditions are

known. In this case, the condition of the of the wall should have been checked and measures designed

in or information provided, to ensure that it remained stable.

Any situation where major forces could occur and especially where some interference will be made to

materials that support buildings, roads, railways or major services, should be thoroughly examined

before starting work.


Quick Ref 10J(T)

6G(A) Designers TW/Arch


An excavation was being carried out beside an existing retaining wall into a sandy soil. The wall was

570mm thick, some 1.2 – 1.5m above the lower ground level with the u/side of its foundations 1.2 -

1.5m below lower ground surface. The trench had been excavated to a depth of 0.65 – 1.2m below the

wall’s foundations. Approx. 7.4m length of wall collapsed into the trench.

Keywords from list Excavation; Collapse of structure





(Specify)



more?

6 10



G J

Design effort M M





difference?

3 3



made a difference?

1 1

Remarks

The design required the excavation adjacent to the wall therefore, the effects of this process on the

stability of the wall should have been investigated. Effective temporary ground support should have

been installed against the wall before excavation started, driven to such a depth so as to prevent the

wall collapsing. To be able to do this effectively proper ground investigations should have been carried

out.

While there was a design failing in not providing information on the nature and depth of the wall those

carrying out the excavation work should have realised there could be a potential problem when they

first exposed the bottom of the retaining wall.


Quick Ref 2C(A)

8E(C)

6C(M) Designers A/C/M


Excavations were being carried out in clay soil, the upper 1.2m generally being disturbed material:

generally, the exc’s were 1.2m deep but at one location 2.7m. The sides of the trenches were being

lined with polystyrene sheets to protect the new structure from clay heave. A person went into the

deepest part of the trench to secure these sheets when one side of the excavation partly collapsed.

Keywords from list Excavations; Trench work





(Specify)

Designers involved ü ü Manufacturer


more?

2 8 6



C E C

Design effort L L L


Cost implications R R R



difference?

2 2 2



made a difference?

3 3 3

Remarks

The principal error was by the contractor and the individual.




A worker was setting up a laser target in a trench approx. 3.1m below ground level [Approx. 1.1m of

made up ground overlying a sandy clay] when he was struck by falling earth. The trench had near

vertical sides 1.75m high and then battered back at less than 450. A trench box was on site but had not

been installed at the time of the accident. Trial pits had been dug in the vicinity of the works that

clearly revealed the nature of the ground. The excavation had been opened at least the day before the

accident.

Keywords from list Excavation; Trench collapse





(Specify)



more?

4



C

Design effort L


Cost implications L



difference?

2



made a difference?

3

Remarks

The designer should have highlighted the risk of falling debris in the DRA.This type of ground is well known to be very suspect, particularly as the trench was quite deep. Thisinformation was available to the ‘designer’ even if he did not commission it.




A labourer was working in a 1.5m trench with near vertical sides. No support was provided to the

trench and while the labourer was crouched over his work earth material fell on him causing serious

injuries. The ground was formed from a top 600mm layer of made ground overlaying coarse sand and

gravel.

Keywords from list Excavation; Trench collapse





(Specify)



more?

2



C

Design effort L


Cost implications L



difference?

1



made a difference?

3

Remarks

The designer should have highlighted the risk of falling debris in the DRA.Although the ground was not particularly deep its nature made it particularly susceptible to falls.However as the ground was covered by fill material it required trial pits to be dug to investigate thegrounds true character.


Quick Ref N/A Designers


A light fitting, one of around 200 was being changed in a college dining room with a 6.15m high

ceiling. A ladder was being used for access resting on a smooth marble floor area and resting against

the side of a polished concrete drop beam.

The ladder slipped. After the accident a small portable hydraulic vertical lift access platform was used.

Keywords from list Ladder work;





(Specify)

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


more?



Design effort


Cost implications



difference?



made a difference?

Remarks

Where there are items that could need maintenance at frequent intervals more permanent access

provision should be made than for items that are unlikely to need much or any maintenance. Any

systems provided should be appropriate to the likely skills of those who would use them.


Quick Ref 4C Designers Manuf


A suspended access platform was being used for repairs on a block of flats when the power supply

failed causing the automatic locking system to activate and trap the persons using the equipment on the

platform.

No means had been provided for the workers to signal for help and they were not aware of how to

release the locking mechanism.

Keywords from list Access; Fail safe





(Specify)



more?

4



C

Design effort L


Cost implications L



difference?

0



made a difference?

2

Remarks

It is important that the design of the system, especially the systems of control, is very obvious to the

persons who are likely to use those systems. It is common for persons with little or no experience or

knowledge of the mechanics of powered suspended access platforms to be expected to use them. The

means of using this type of equipment should therefore be very obvious. A large part of this problem

was that the occurrence was rare and the workers on the platform had either forgotten or not been told

how to deal with it. In addition the initiation of the failure through a damp and loose electrical

connector suggests that the maintenance of the access platform was suspect.


Quick Ref 10G Designers Architect


A cleaner climbed into a spirally wound overhead ducting to clean it out. A 3m approx. length, which

was supported directly at only one end collapsed at a point where an inspection hatch had been

installed. The structural supports to the ducting were noted as being completely inadequate.

Keywords from list Cleaning



Incident rating – actual ?


(Specify)



more?

10



G

Design effort L


Cost implications E



difference?

3



made a difference?

2

Remarks

The designer should have been aware that the ducting would need cleaning from time to time, most

likely by someone working inside it The supports to the ducting, and possibly the ducting, were not

strong enough to support the weight of the cleaner. This should have been obvious to anyone concerned

with the design.

Although it is probable that the ducting was designed and installed by someone who would have little

appreciation of the cleaning needs of the site, this should have been obvious to the architect.




A 100-year old 33m high building was being repainted. The working platforms for the painters were on

a light duty scaffold secured to the building with ring ties. The scaffold had been built in sections and

was moved progressively around the building as the work proceeded, with the section of the scaffold

being dismantled carried around and stored on an adjoining section prior to rebuilding it. The weight of

the stored scaffold materials overloaded the scaffold and it collapsed. Some of the ring ties failed in

shear and others pulled out og the building’s façade.

Keywords from list Access; Scaffolding





(Specify)



more?



Design effort


Cost implications



difference?



made a difference?

Remarks

Facilitating routine maintenance by some form of permanent feature(s) will vary in practicality

according to both the frequency of the maintenance and the cost effectiveness in supplying the feature.

For instance if this is complex and expensive to install then it could be cost effective to make it

permanent even if the maintenance frequency was low. On the other hand even a simple, low cost

feature required for very regular work could be permanently installed so as to be cost effective. All

such measures are likely to be more reliable than temporary ones.




A maintenance worker was looking for the source of a water leak by standing on/crossing over a

suspended ceiling. This was only designed for very light use such as carrying insulation material, and it

failed. The area above the ceiling contained ducting and air conditioning equipment and there was

evidence that occasional access took place over the suspended ceiling.

Keywords from list Access; Maintenance





(Specify)



more?



Design effort


Cost implications



difference?



made a difference?

Remarks

Any ceiling or platform that has any sort of plant/equipment above it and is relatively easily accessed

can be almost guaranteed to be used as an access or working place. Consequently the only practical

solutions of ensuring persons cannot fall through them is to either make them strong enough or make

access impossible.




Scaffold walkways were being installed over the fragile ceiling to a swimming pool. One length of tube

fell through the ceiling and hit a swimmer below. The area above the ceiling was a plant room for the

pool. The ceiling itself had quite a complex shape which would be a major discouragement for persons

to stand directly on it.

Keywords from list Access; Fragile ceiling



Incident rating – actual 4(public)


(Specify)



more?

4



E

Design effort L


Cost implications L



difference?

3



made a difference?

3

Remarks




A building was being refurbished and in the course of this staircase balustrade and handrails had been

removed and plastic warning tape placed around the stair well. Upholsters were working on the upper

floor in the neighbourhood of the stairs and one fell down the stair. well.

Keywords from list Access; Unprotected edge





(Specify)



more?

6



E

Design effort L


Cost implications L



difference?

3



made a difference?

4

Remarks

The sequence of installing new balustrading after the removal of the old should have been strictly

controlled and suitable temporary barriers should have been installed in the meantime.

The more complex the maintenance or refurbishment works the greater the need to plan and design it to

minimise errors. This planning and design would clearly require contributions from all those involved.




An electrician was installing cabling on a 5m high cable tray, which rested on a small beam. The floor

below was mostly filled by plant and the electrician was using a portable ladder to gain access to the

cable tray. There were faults with the ladder feet and the floor was of a sealed concrete making the

coefficient between ladder and floor quite low. The ladder apparently slipped while the electrician was

on it and he fell.

Keywords from list Ladder access; Original design





(Specify)



more?



Design effort


Cost implications



difference?



made a difference?

Remarks

The problem here was congestion in the area under the cable-tray. Perhaps it could have been installed

in an area where access could have been more easily provided. Alternatively hooks could perhaps have

been fitted to the tray or supporting beam to allow a ladder to be engaged on them for added security.

Using a ladder at this height and in a poor condition would be a gamble which would be made worse

by only having the small depth of the supporting beam to rest against. As ladders can only be altered in

length by approx. 220mm increments, the opportunities of arranging the ladder in the limited floor

space, at a reasonable angle and against the beam would be limited




A new building that partly extended over a motorway had arrangements for the window cleaners where

they worked off mesh walkways and were secured by a waist high safety line to which they were

attached via lanyards and harnesses. There were no guard-rails or other form of barrier. Little provision

had been made, through the use of toe-boards etc, to prevent the fall of materials to the pedestrian areas

and motorway below.

Keywords from list Edge protection; Access; Falls of materials

Job nature – type of activity W




(Specify)



more?

10



J

Design effort L


Cost implications E



difference?

3



made a difference?

0

Remarks

The designer tried to minimise the visual impact of the access and protective systems for the window

cleaners. Although it should have ensured that the window cleaners were safe and that people below

were protected from falling objects, it did not.

This is an example where a safe system of work can be provided which still does not meet the legal

requirements.


Quick Ref 8J Designers Manuf


A luffing screw on a window-cleaning cradle broke allowing the cradle jib to drop onto the roof

parapet. The screw had become stiff at a fixing position causing a rotational failure.

Keywords from list Equipment failure; Access





(Specify)



more?

8



J

Design effort M


Cost implications L



difference?

0



made a difference?

0

Remarks

No facilities were provided in the design to allow access, for routine inspections, to the area where the

failure of a safety-critical item occurred.

All surfaces of items that are subject to abrasion, loosening or corrosion should be capable of being

properly inspected, serviced and lubricated.


Quick Ref 6C Designers Manuf


The roof rig of a permanent window-cleaning cradle became dislodged off the roof runway beam. The

problem occurred where a turntable had been installed to allow the rig to be moved off the perimeter

runway beam into a parking bay. It was found that the turntable had a guard plate to prevent the rig run

off, over the turntable but this was on the wrong side. In addition the rail on the turntable was not

correctly aligned with the perimeter rail when the turntable was locked into position ready for use.

Keywords from list System access cradle





(Specify)



more?

6



C

Design effort L


Cost implications L



difference?

2



made a difference?

2

Remarks

While the main part of the fault probably lies with the construction of the rig runway, the design was

not as foolproof as such a vulnerable system should be.

The cradle rig was fairly simple to use and it is probable that the rig was used previously across the

turntable without incident through not going too far. The failure occurred when the rig travelled too far

and should have been stopped by guard plate if it had been in the right place. The incorrect alignment

of the turntable rail only compounded the problem. An effective inspection after the rig was installed

should have revealed the problem.




Advice was given on two window cleaning systems. In the first case cradles were to be slung from a

permanent beam fixed at eaves level. The fixings for this beam were to be largely hidden behind a

fascia panel making inspection difficult. Advice was given for the inspection to be at more frequent

intervals. In the second case a powered gantry was to climb a 300 glass atria roof and the cradle for the

cleaners would have to be manhandled to its different faces. It was recommended that some form of

trolley should be provided to help with this. Installing the cradle was quite complicated and required

the cleaners to be well trained.

Keywords from list Window cleaning system; System access





(Specify)



more?

8



G

Design effort M


Cost implications E



difference?

3



made a difference?

0

Remarks

The advice given dealt with necessary precautions and these should have been obvious to the designer

without requiring the HSE Inspector to intervene. In addition the atria gantry cradle should have been

designed to be more easy to use.

The decision to provide a relatively complicated mechanical system for use by window cleaners could

lead to problems and training costs. Window cleaners regularly change jobs and are often recruited

from the bottom of the employment ladder. This could mean that there would be a steady turnover of

trained cleaners requiring a continual commitment to train new staff.

All fixings for suspended or slung equipment should be readily observable so that any deterioration or

damage will be quickly seen.




Suspension wires for overhead tramway cables were to be fixed to a building that had its windows

cleaned through the use of a suspended cradle. It was found that the travel of the cradle could not easily

interfere with the suspension wires but to be sure projecting ‘stops’ were fixed to the building to

prevent the cradle moving too close to them.

Keywords from list Access equipment





(Specify)



more?

8



G

Design effort M


Cost implications E



difference?

3



made a difference?

0

Remarks

During the lifetime of most buildings, especially those in busy areas, there will be frequent and

numerous demands for alterations and changes. It is part of the designers job to facilitate such changes

as simply as possible


Quick Ref 8G Designers Manuf


A window-cleaning cradle collapsed when a stainless steel bolt failed. This had been made by welding

a head onto the shaft rather than turning it down from larger diameter bar. The manufacturers of the

bolt had not been informed of the critical nature of the bolt.

Keywords from list Acc equipment failure;





(Specify)


of cradle, not

pin


more?

8



G

Design effort L


Cost implications L



difference?

0



made a difference?

0

Remarks

It is probable that a more structurally reliable component would have been produced if the

manufacturers had been aware of its critical nature and how it was to be loaded.

The designer had two options that could have helped to avoid this incident. The first was to have

provided details on how the bolt was to be used, the second to have provided a detailed specification of

how it should be tested. By not doing either the design failed as insufficient information was provided

to allow the bolt to be properly manufactured.


Quick Ref 6E(A)

10J(T) Designers A/T


The insides of two adjoining buildings were being demolished prior to their renovation. One building

had been extensively vandalised and left open to the weather for approx. 2 years causing deterioration

to the internal timbers. As the demolition progressed one floor collapsed causing other floors below to

fail. Subsequent investigation showed that the joists were rotten and that the structural arrangement of

the floors was not as straightforward as could be assumed without detailed investigation.

The façade of the buildings was being retained to a design prepared by an engineering consultant.

Keywords from list Structural collapse; Demolition

Job nature – type of activity D




(Specify)



more?

6 10



E J

Design effort M M


Cost implications S S



difference?

4 4



made a difference?

4 4

Remarks

The state of the buildings should have been carefully surveyed prior to work starting and detailed plans

drawn up to ensure the stability of the structural components as each level was removed. Such a survey

should have investigated both the structural format of the buildings and the condition of the various

structural components.

In designing any temporary support work it would be necessary to allow for the accumulation of debris

etc. following the removed of upper levels.


Quick Ref N/A

Designers N/A


Collapse of a series of 48 roof trusses during erection. Bracing had been specified but not fixed in the

main and in any case inadequately fixed.

Keywords from list Bracing; Roof truss erection collapse





(Specify)

Designers involved N/A

Contractor

management


more?



Design effort


Cost implications



difference?

0



made a difference?

3

Remarks

While this matter was not designer related in the main it could have been that had additional

information been provide on the drawings that the sub-sub-contractor used would have been less likely

to make the omissions made. The information may have been in place and benefit is given to the

designer in this case.


Quick Ref 2A Designers TW


Special pin jointed roof truss installation in difficult site. Report based on prior test of erection method.

This summary based on future project as well.

Keywords from list Access; Roof truss erection





(Specify)



more?

2



A

Design effort L


Cost implications L



difference?

1



made a difference?

1

Remarks

This was a significant project in a public place so additional resources had been applied to manage risk.




Fall through a fragile roof. Crane driver giving advice to contractor regarding slinging of gable end

section of a building.

Keywords from list Fall from height through; Fragile roof





(Specify)


management


more?



Design effort


Cost implications



difference?



made a difference?

Remarks

The only moot point here is whether a designer should have provided information to the contractor

about the nature of the roof lights. It would however have been just as dangerous for the designer to

have established this fact unless a desk study could have provided the information. All roof lights

should be assumed to be fragile unless otherwise indicated.


Quick Ref 8G Designers Consultants


This report relates to steel work erection requiring tandem lifts due to design.

Keywords from list Structural erection; Lifting operations





(Specify)



more?

8



G

Design effort M


Cost implications L



difference?

3



made a difference?

1

Remarks

Designers could have designed in such a manner that tandem lifts were not required. Further difficult

marrying of two elements required by design introduced unnecessary hazards.


4E M

Quick Ref

Designers


Failure of pre-cast, pre-stressed floor slab under its own weight. Report states that the units may have

been damaged in transit or during erection. No information available to inform in relation to product

quality.

Keywords from list Structural failure; Pre-cast units





(Specify)


Handler


more?

4



E

Design effort M


Cost implications E



difference?

1



made a difference?

0

Remarks

Manufacturers of system building products should expect some mishandling in transit and during

fabrication. If this is critical to safety and stability of their product, specifiers and users should be

alerted to the need for caution.




Collapse of floor slabs during construction of a block of flats. The pre-cast slabs rested on lintels that

showed excessive deflection. The slabs were propped with timber which subsequently failed leading to

progressive collapse of structural elements. The lintel was a replacement element that had been selected

by an individual with no technical training together with a builder’s merchant.

Keywords from list Structural failure; Pre-cast units





(Specify)



more?



Design effort


Cost implications



difference?



made a difference?

Remarks

Such “on the hoof” solutions to problems of supply or construction are very common. Where they

succeed in solving a problem they tend to be commended. Where they do not they are roundly

criticised. Clearly design input was needed and was not used.


Printed and published by the Health and Safety ExecutiveC30 1/98

Printed and published by the Health and Safety Executive C1.10 04/04

ISBN 0-7176-2836-1

RR 218

78071 7 628360£25.00 9

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