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Alasdair’s Engineering Pages

The Structural Engineer, Vol. 8 No. 2, 21st January 2003

CDM and site safety - is it a fair ACOP?

Alasdair Beal

The Construction (Design and Management) Regulations first appeared in 1994. Although they have failed significantly to reduce injuries and deaths on building sites, they now form a well-established part of health and safety legislation in the UK. Since publication there have been only minor amendments to the Regulations, but on 1 February 2002 the Health & Safety Executive published a new CDM ‘Approved Code of Practice’ (ACOP) which features important changes from its predeces­sor.

The Introduction to the ACOP claims that ‘the Code has a special legal status. If you are prosecuted for breach of health and safety law, and it is proved that you did not follow the rele­vant provisions of the Code, you will need to show that you have complied with the law in some other way or a Court will find you at fault’.

The legal basis for this claim is not clear - only the provisions of the CDM Regulations themselves actually form part of the law of the land - but accord­ing to HSE inspector Barry Mullen: ‘Designers’ duties have been spelt out more stringently in the new ACOP. So whenever there is an accident we will go to the designer, and if they have not met the requirements of the ACOP they will be prosecuted’.

In this situation, engineers would do well to look rather carefully at what the ACOP says and remember that its words are not intended just as friendly advice - they have been written with the intention that they may also be used by lawyers prosecuting designers in Court. They need to be taken seri­ously. Designers should note that the new ACOP introduces recommenda­tions which, if they are taken to be legally binding, could transform construction practices, contractual rela­tionships and designers’ liabilities. There has been surprisingly little analysis of this in the technical and legal press.

Prohibited materials

The CDM Regulations ask designers to take account of health and safety issues in their designs but they do not ban the use of particular materials and construction methods. However, if the new ACOP is held to have the force of law, some of its clauses could change all this. Examples are listed below (with emphasis added).

Cl. 127: The designer should, where possible: ...

(b)design out health hazards, e.g.:

* specify less hazardous materials, e.g. solvent-free or low solvent adhesives and water-based paints;

* avoid processes that create hazardous fumes, vapours, dust, noise or vibration, including distur­bance of existing asbestos, cutting chases in brickwork and concrete, scabbling concrete, breaking down cast in situ piles to level, hand digging tunnels;

(c) design out safety hazards, e.g:

* fragile roof materials;

* materials that could create a signifi­cant fire risk during construction;

(g) design to simplify future mainte­nance and cleaning work, e.g:

* specify windows that can be cleaned from the inside.’

Remember the ACOP’s claims of ‘special legal status’ and look again at the words which start Clause 127: ‘The designer should, where possible.... If this means anything, it means that these are recommendations which must be complied with in all cases except where it is not possible to use alterna­tives. If this clause is taken to have the force of law, it would effectively make some common materials and methods of construction illegal (See Table 1).


Table 1: Material which could be banned

These are only examples and no doubt more could be identified. However they illustrate the profound effect this ACOP clause could have on manufacturers and materials suppliers. Maybe some people will agree with banning materials and items on the above list, but if this is the HSE’s intention, why does it propose to prose­cute only the designers who specify them? Why is there to be no action against the companies which manufac­ture and sell these items, or the contractors who buy and use them? Conversely, if the HSE does not intend there to be a ban on the use of these items in the construction industry, what exactly is Cl. 127 of the ACOP intended to mean?

Design and risk

Clause 113 of the new ACOP says: ‘Under CDM designers must ensure that any designs they prepare for the purposes of construction avoid risks to anybody carrying out construction or cleaning work... on or in the structure at any time...’

This is a major change from the CDM Regulations, which say:

‘Every designer shall:...

(a) ensure that any design he prepares and which he is aware will be used for the purposes of construction work includes among the design considera­tions adequate regard to the need:

(i) to avoid foreseeable risks to the health and safety of any person at work carrying out construction work or cleaning work in or on the structure at any time ...’ (emphasis added).

One does not need to be a lawyer to see that the differences between the two documents are significant: a requirement that designers should ‘include among the design considera­tions adequate regard to the need’ is changed to ‘designers must ensure and the requirement that there should be ‘adequate regard to the need to avoid foreseeable risks’ changes to a require­ment that that ‘any designs they prepare ... avoid risks’.

It is not clear at all what Courts will make of this situation: will they hold that where there is a conflict between the ACOP and the Regulations, the latter must take precedence, or will they hold that the ‘special legal status’ claimed for the ACOP allows its provi­sions to effectively supersede the Regulations?

Designers who have complete confi­dence that judges can always be relied on to stick to the letter of the law may not be unduly worried about all this. However, for those who believe (or fear) that the Courts might be tempted to entertain extending the law along the lines outlined in the ACOP, it is not so easy. They may find themselves reread­ing those words in clause 113 and wondering what they actually mean. ‘Designers must ensure’ is clear enough - what follows is clearly an absolute responsibility, with no discretion allowed. However in what follows there is a problem with the English used. It is not possible for a design to ‘avoid’ risks. A design can only ‘minimise’ or ‘identify’ risks, and it can only do this by also making the assumption that the contractor knows what he is doing and does not do anything silly. It is not clear what the authors of the ACOP intended to mean here. Also, is it sufficient for the design to ‘avoid’ some risks, or must it ‘avoid’ all risks - and does the clause mean only serious risks, or does it mean any risks, no matter how slight?

The most fundamental problem is that a building site is a dangerous place and a designer can only influence what happens on it to a limited extent. The degree of risk depends critically on the quality of the contractor’s site management and the skill of the people employed. Under ACOP Cl. 113 do designers have to create designs which ‘avoid’ risks on the assumption that the work will be carried out by competent, well-managed contractors, or have they to try to create designs which could be constructed by ‘anyone’ without risks?

Responsibility for temporary works

Under the terms of most designers’ appointments and most construction contracts, the designer is only responsi­ble for the design of permanent works. The choice of method of construction, the design of any temporary works required and the stability of the struc­ture during construction are all firmly established as the responsibility of the contractor, not the designer. This is a long-established principle, based on the fact that it is the contractor who decides how the structure will be erected and controls what happens on site during the work.

The CDM Regulations respect this division of responsibility, only requiring the designer to provide ‘adequate information’ to the contractor about any aspect of the design which might affect the health and safety of people building it (Regulation 13 (2 (b)).

Regulation 13 (3) confirms that details are required ‘of only the matters referred to therein, to the extent that it is reasonable to expect the designer to address them at the time the design is prepared, and to the extent that it is otherwise reasonably practicable to do so’.

The new ACOP respects this to some extent: Cl. 136 acknowledges that ‘Under CDM, designers are not required to ...  specify construction methods ... or exercise health and safety management function over contractors’. However some of the requirements in other clauses suggest a quite different approach:

Cl. 127: ‘The designer should, where possible:...

(f) provide lifting points and mark the weight, and centre of gravity of heavy or awkward items requiring slinging both on the drawings and on the items themselves’

Cl. 132: ‘Examples of significant hazards where designers always need to provide information include: ...

(b) temporary works, required to ensure stability during the construc­tion, alteration or demolition of the whole or any part of the structure, e.g. bracing during construction of steel or concrete framed buildings’.

Most designers of steel-framed struc­tures would regard a requirement to design lifting points and mark the centre of gravity for every heavy member they show on their drawings as an unreasonable imposition on them and in this respect ACOP Cl. 127 (f) clearly contravenes the intentions of CDM Regulation 13 (3).

It is not clear precisely what ‘information’ is supposed to be provided by the designer about temporary works in ACOP Cl. 132 (b). Depending on how this is interpreted, it could be deemed effectively to transfer responsibility for temporary works design from the contractor to the designer. Indeed the clause as written goes further than this, requiring the designer to also provide ‘information’ about the tempo­rary works required for any possible future alterations and even for the eventual demolition of the structure (presumably with alternatives provided for either its altered or unaltered states). Clearly any such moves poten­tially could involve design engineers in a large amount of additional work and impose serious additional liabilities on them.

The legal basis of this clause appears to be weak: there are no corresponding requirements in the CDM Regulations and a requirement for designers to design temporary works for possible future alterations and also demolition is clearly unreasonable and contra­venes the terms of Regulation 13 (3). It is also obviously completely impractical to expect a designer to specify the temporary works required for construc­tion when s/he has no knowledge of (or control over) the contractor’s chosen construction method.

Nonetheless this Clause must be taken seriously: as noted already, ‘special legal status’ is claimed for this ACOP and the HSE has already tried once to prosecute a designer for the collapse of a steel frame during erec­tion. On that occasion, the judge threw the case out but if provisions of the new ACOP were to be accepted as legally binding by the Courts, and they inter­preted the requirement for ‘Information’ in an onerous way, design engineers could find themselves saddled with responsibility for design­ing temporary works on all their contracts.

There are many good reasons for resisting any move in this direction. For a start, it would impose on design­ers a duty to carry out work which no one has appointed them to do - or offered to pay them for. However it is more serious than that: not only is it unreasonable for the ACOP to expect designers who have no knowledge of the contractor’s proposed construction method (or control over it) to design the temporary works for the contract, but also most design engineers are not, and do not claim to be, experts in temporary works design.

A move to make designers legally responsible for the design of temporary works on the projects they work on would require a major retraining programme for structural engineers. Standard building and professional contracts and professional indemnity insurance policies would also need to be rewritten - and it could spell the end for contractor-led ‘Design and Build’ contracts. Worst of all, if the designer was made responsible for the tempo­rary works design, but responsibility for everything else that happens on site was left with the contractor, there would inevitably be confusion over precisely who was responsible for what - and there are few things more dangerous on a building site than confusion and divided responsibilities.

If this is what ACOP Cl. 132(b) is intended to mean, then the HSE really should say so clearly, seek the necessary legal backing for the change - and start serious discussions with relevant parties in the construction industry about how it might be implemented. If this is not what ACOP Cl. 132(b) was intended to mean, could the HSE please clarify what exactly it does mean?

Setting a bad example

To assist interpretation of the CDM Regulations, the ACOP includes exam­ples of how they may be applied in practice. Unfortunately, copying some of these could lead to very unfortunate conclusions. In Example 24, a ware­house owner decided to carry building work by employing various contractors directly and appointing a project manager to coordinate and manage them. He then took on the role of Principal Contractor himself. In Example 35, a pharmaceutical company appointed itself as Principal Contractor for commissioning a new process plant.

However, according to CDM Regulation 8 (3), ‘no person shall arrange for a contractor to carry out or manage construction work unless he is reasonably satisfied that the contractor has the competence to carry out or, as the case may be, manage, that construction work’ and Regulation 6 (2) states: ‘The client shall not appoint as principal contractor any person who is not a contractor’. Both the warehouse and the pharmaceutical company appear to have contravened Regulation 6(2). Any other company which took the advice of the ACOP and followed in their footsteps could end up in serious trouble. How did these examples find their way into the ACOP as ‘illustrating good practice’?


Depending on how they are inter­preted, some clauses in the new ACOP for the CDM Regulations could have major effects on the construction indus­try and on design engineers. This follows from the way the ACOP has been drafted and the special legal status which is claimed for it.

There is no problem where it only reaffirms or clarifies the provisions of the existing CDM Regulations. However, some of the ACOP clauses introduce wording which appears to change what is said in the Regulations, and others introduce new requirements which do not appear in the Regulations at all. As the HSE has signalled its intention to use the new ACOP as the basis for prosecuting designers after site accidents, it is important that the legal status and precise meaning of some of its clauses are clarified as a matter of urgency.


1. ‘Designers face clamp down after safety blitz’, New Civil Engineer, 16 May 2002


Possible banned materials/items


Solvent-based paints

In most situations it is possible to substitute a water-based or low-solvent alternative

Standard epoxy adhesives, grouts, paints etc.

In most situations it is possible to substitute non-epoxy or low-solvent epoxy alternatives

Cutting chases in walls

It is almost always possible to place cables etc. in surface-mounted conduits instead of setting them into chases

Fibre-cement roof sheeting

It is almost always possible to subsiute alternatives such as steel profiled sheeting which are not fragile

Polystyrene and other inflammable insulation materials

It is usually possible to substitute a less inflammable or non-inflammable alternative

Standard synthetic roof sarking felts

It is always possible to substitute less inflammable alternatives (though these tend to be more expensive)

Timber-framed wall construction

When there is a fire on a building site, timber is almost always involved - but in wall construction it is almost always possible to eliminate timber and use non-combustible alternatives such as metal studwork or masonry

Fixed-pane windows, or windows that only open outwards

It is always possible to specify the alternative of an opening window which can be cleaned from the inside

Table 1: Materials which could be banned

The original copy of this paper is available from