Temporary Works by definition - “those parts of the works that allow or enable construction of, protect, support or provide access to the permanent works and which might or might not remain in place at the completion of the works”.

1. Health and Safety
Health and Safety
Executive
Executive
Managing Temporary
Works
Andrea Robbins
HM Inspector of Health and Safety

2. What are temporary works?
BS 5975:2008+A1:2011 defines temporary
works as:
“those parts of the works that allow or
enable construction of, protect, support or
provide access to the permanent works
and which might or might not remain in
place at the completion of the works”

3. Temporary Works Examples -
Earthworks
• Piling Platforms, Underpinning and Cofferdams
etc.
Construction of a Piling Platform
Completed Piling Platform Underpinning

4. Temporary Works Examples
• Earthworks – (Supports) for Trenches, Excavations
Waler Frames –
For Medium Sized Trenches
Close Boarded
Trench Support
Design of trench box -
access ladder and
edge protection
Trench Boxes attached to box Hydraulic / Mechanical Struts
Strutting Frame

5. Temporary Works Examples
• Structures – Formwork & Falsework
Formwork (Shuttering) Falsework (Supports)

6. Temporary Works Examples
• Structures – Scaffold, Propping & Façade Retention
Propping
Façade Retention

7. Temporary Works Examples
• Structures – Edge Protection, Loading Bays,
Temporary Bridges, Hoarding, and Signage etc
Signage
Edge Protection
Temporary Bridges
Hoarding Signage On Scaffolds etc
Loading Bays

8. Temporary Works Examples
• Plant - Mobile Crane Outrigger Design, Hoists /
Mast Climbers, Tower Crane Bases etc.
Hoists / Mast Climbers
Tower Crane
Base
Mobile Crane Outrigger Design

9. Legal obligations – CDM Regulations
2007
• Reg 4 – competence required of all those with a role to discharge
in planning, design and execution of TW;
• Regs 5 & 6 - co-operation and co-ordination of activities, including
TW, incumbent on all involved;
• Reg 10 – client’s duty to provide pre-construction information, e.g.
ground conditions, structural drawings;
• Reg 11 – duties of designers: avoidance of foreseeable risk
arising from preparing or modifying designs;
• Reg 18 – additional duties of designers: provision of information to
assist the CDM Co-ordinator;
• Regs 13 & 22 – duties of contractors and the principal contractor:
planning, management and monitoring of construction work;

10. Legal obligations – CDM Regulations
2007
• Reg 20 – duties of CDM(Cs) – all reasonable steps to
ensure designers comply with their duties and to ensure
co-operation between designers and principal contractors
in relation to any design or design change;
• Reg 26 – safe place of work – scaffolding, flooring, stairs
etc;
• Reg 28 – stability of structures: any support or temporary
structure must be designed, installed and maintained so as
to withstand foreseeable loads;
• Reg 29 – demolition or dismantling: planning and recording
of arrangements;
• Reg 31 – excavations: planning and execution;
• Reg 32 – cofferdams and caissons: design, planning and
execution;

11. Temporary Works Procedure
• Appointment of a Temporary Works Co-ordinator (TWC)
• Completion and maintenance of a Temporary Works Register
• Preparation of design briefs for elements identified in the register
• Production of temporary works designs
• Temporary works design check
• Preparation of risk assessments/method statements
• Pre-erection inspection of the TW materials and components
• Supervision of erection of temporary works
• Check that the TW have been erected in accordance with the design
• Issue a formal “permit to load” where necessary
• Confirm that the TW have attained adequate strength to allow TW to
be dismantled
• Issue a formal “permit to dismantle” where necessary

12. Temporary Works Co-ordinator
• Formal appointment in writing
• Must be competent = experience + a formal
qualification, e.g.
[1] Degree/HND qualified as a minimum
[2] Chartered Civil/Structural Engineer
[3] Has completed formal temporary works
training

13. Temporary Works Co-ordinator
Typical duties:
• To determine the TW for a project, compile a TW register
and keep all TW records;
• To ensure the procedures for the control of TW are
implemented on site;
• To determine the type and risk class of TW on a project;
• To ensure that all TW are designed and checked
appropriately;
• To issue the permit to load and permit to dismantle; and
• To ensure that all TW activities are adequately planned
and supervised.

14. Temporary Works Supervisor
• Assists the TW Co-ordinator
• Carries out checks on the implementation
process of the TW.
• May issue the permit to load and permit to
dismantle when specifically authorised for
a defined scope and range of work.

15. CDM Co-ordinator
• Ensures co-operation between
permanent and temporary design;
• Check suitability of construction phase
plan – stability of structures – have they
been addressed;
• Advises client of the suitability of the
construction phase plan.

16. Temporary works register
Should include:
• Design brief number;
• Short description of temporary works;
• Date required for design solution;
• Risk category of temporary works;
• Designer and design checker;
• Date design complete;
• Date design checked/approved; and
• Erection complete and checked or “permit to
load” then “permit to dismantle”.

17. Risk classes of temporary works
High risk (class 1 or class A)
• Falsework and formwork over 3m high
• Hoarding and fencing over 3m high
• Façade retention schemes
• Complex designed scaffold
• Complex propping schemes – multiple props and multiple levels
• Needling of structures greater than 2 storeys high
• Working platforms for cranes and piling rigs; tower crane bases
• Ground support schemes greater than 3m deep
• Trenchless construction including headings, thrust bores, mini
tunnels
• Cofferdams
• Complex structural steelwork and pre-cast concrete erection
schemes

18. Risk classes of temporary works
Medium risk (class 2 or class B)
• Hoardings & fencing up to 3m high
• Simple designed scaffolds
• Falsework up to 3m high
• Formwork for concrete columns and walls up to 3m high
• More complex propping schemes – multiple props at single
level
• Needling of structures up to 2 storeys high
• Foundation underpinning not using piles
• Excavations up to 3m deep in good ground
• Safety net systems fixed to robust primary members
• Temporary roofs

19. Risk classes of temporary works
Low risk (class 3 or class C)
• Internal hoarding systems and temporary partitions not
subject to wind or differential air pressure or crowd loading
• Fencing and hoarding up to 1.2m high
• Standard scaffold
• Formwork less than 1.2m high
• Shallow excavations less than 1.2m deep in good ground
• Simple propping schemes – 1 or 2 props
• Small MEWPs operating on a pavement designed for
HGV’s or on internal ground bearing slabs and working
within the level of tolerances set by the manufacturer

20. Temporary works design brief
• Purpose of TW – include drawings of permanent
works and any specifications;
• Required dimensions and any known
constraints;
• Particular loads including impact loads;
• Ground conditions – i.e. soils, groundwater etc;
• Site conditions including services, adjacent
structures and access;
• Available materials and equipment; and
• Construction sequence and loading stages.

21. Categories of Design Checks
Table 1 BS5975:2008+A1:2011
Category Scope Comment Independence
of checker
Restricted to standard solutions only, This applies to the use of standard Because this is a site issue, the
0 to ensure the site conditions do not
conflict with the scope or limitations of
solutions and Not the original
design, which will require both
check may be carried out by
another member of site or design
the chosen standard solution. structural calculation and checking team.
to category 1, 2 or 3 as
appropriate.
For simple designs. These may Such designs would be The check may be carried out by
1 include: formwork: false work (where
top restraint is not assumed): needling
undertaken using simple methods
of analysis and be in accordance
another member of the design
team.
and propping to brickwork openings in with the relevant standards,
single storey construction. supplier’s technical literature or
other reference publications.
On more complex or involved designs. Category 2 checks would include The check should be carried out
2 Designs for excavations, for
foundations, for structural steelwork
designs where a considerable
degree of interpretation of loading
by an individual not involved in the
design and not consulted by the
connections, for reinforced concrete. or soils’ information is required designer.
before the design of the
foundations or excavation support
or slope
For complex or innovative designs, These designs include unusual The check should be carried out
3 which result in complex sequences of
moving and/or construction of either
designs or where significant
departures from standards, novel
by another organization.
the temporary works or permanent methods of analysis or
works. considerable exercise of
engineering judgement are
involved.

22. Temporary works design checks
• For high risk TW there must be an
independent check made on the design.
• For medium risk TW the check can be
undertaken by the same organisation as
long as there is documentary proof of the
independence of the checkers.
• For low risk TW the checks can be
undertaken by someone in the site team
or the design team.

23. Temporary works design checks
In all cases the design check should provide
an independent check on:
1) Design concept;
2) Strength and structural adequacy
(including lateral stability and overturning
etc); and
3) Compliance with the design brief.

24. Why are temporary works important?
GOOD temporary works can bring:
• Better safety;
• Enhanced efficiency, quality, productivity;
and
• More certainty on completion times and
cost.

25. What happens when TW go wrong?
Causes:
• No (or inadequate) TW procedure
• No (or inadequate) TWC appointed
• Lack of competent contractor/developer/ builder
• No (or inadequate) TW design
• Inadequate design brief or failure to carry out
proper investigation of ground conditions,
underground services or structural condition of
existing buildings
• Unauthorised changes to an approved TW
design
• Lack of competent TW designer and/or erectors

26. What happens when TW go wrong?
Causes:
• Incorrect estimation of loads to be supported
(overloading)
• Lack of adequate lateral stability: inadequate
horizontal and/or diagonal bracing to resist
lateral (wind) loads
• Inadequate foundations
• No temporary works equipment available
• Inappropriate use of TW equipment or other non
TW equipment being used for the purpose of TW
• TW poorly constructed

27. What happens when TW go wrong?
Consequences:
• Collapse or failure of the TW;
• Structural failure and/or collapse of the
permanent works;
• Uncontrolled ingress or egress of materials,
spoils or water;
• Collapse of adjacent structures;
• Risk of fatalities and injuries to workers and
members of the public;
• Delays and increased costs; and
• Financial & commercial risks to contractors, sub-
contractors, designers, suppliers & clients.

28. Basement construction, London E17

29. Basement construction, London E17

30. When it goes wrong
• Was the contractor
competent ?
• Was the initial
construction phase
plan suitable?

31. CASE STUDIES

32. AA Fanum House, Cardiff
Scaffold collapse, 13 December 2000

33. White Hart Lane, London

34. Shanghai June 2009

35. Shanghai June 2009

36. Shanghai June 2009

37. Shanghai June 2009

38. Shanghai June 2009

39. Shanghai June 2009

40. Shanghai June 2009

41. Shanghai June 2009

42. Shanghai June 2009

43. Shanghai June 2009

44. What is HSE doing?
Work Plan 2011/12 – Aims for Temporary
Works
• Promote awareness & knowledge of the importance
of managing TW effectively;
• Improve contractors’ management arrangements
for TW;
• Increase the competence of those involved in TW
management & design; and
• Reduce accidents arising from TW failures

45. What is HSE doing?
How will this be achieved?
• HSE Construction inspectors to target TW
activities during routine site inspections;
• A programme of targeted visits by HSE
Civil/Structural Engineers
• Initial engagement with principal
contractors
• May involve some “tracking back” from
site to the CDM-C and the TW designer

46. Sources of information
• HSE website - http://www.hse.gov.uk
• SIM 02/2010/04 – The Management of
Temporary Works in Construction
• BS5975:2008+A1:2011 – Code of
practice for temporary works procedures
and the permissible stress design of
falsework

47. Any questions?