In writing specifications care must be exercised to ensure consistency of requirements throughout and conformity with what is written in other documents.
This consistency can be promoted if one person drafts all the documents or, if parts are written by others, one person carefully reads through the whole finished set of documents. An inconsistency in the documents can give rise to a major dispute under the contract, having a serious effect on its financial outcome.
Some guiding principles are as follows.
• The layout and grouping of subjects should be logical. These need planning out beforehand.
• Requirements for each subject should be stated clearly, in logical order,
and checked to see all aspects are covered.
• Language and punctuation should be checked to see they cannot give rise to ambiguity.
• Legal terms and phrases should not be used.
• To define obligations the words ‘shall’ or ‘must’ (not ‘should’ or ‘is to’, etc.) should be used.
• Quality must be precisely defined, not described as ‘best’, etc.
• Brevity should be sought by keeping to essential matters.
It is not easy to achieve an error-free specification. It is of considerable assistance to copy model clauses that, by use and modification over many previous contracts, have proved satisfactory in their wording. Such model clauses can be held on computer files so they are easy to reproduce and modify to make relevant to the particular project in hand. Copying whole texts from a previous specification which can result in contradictory requirements should not be adopted. Entirely new material is quite difficult to write and will almost certainly require more than one attempt to get it satisfactory.
The specification has to tell the contractor precisely:
• the extent of the work to be carried out;
• the quality and type of materials and workmanship required;
• where necessary, the methods he is required to use, or may not use, to construct the works.
Under the first an informative description is given of what the contractor is to provide and all special factors, limitations, etc. applied. Under the second the detailed requirements are set out. The extent of detail adopted should relate to the quantity and importance of any particular type of work in relation to the works required. Thus the specification for concrete quality may be very extensive where much structural concrete is to be placed; but it may be quite short if concrete is only required as bedding or thrust blocks to a pipeline. A ‘tailormade’
specification appropriate to the nature of the work in the contract should be the aim.
Repetition of requirements should be avoided. If requirements appear in two places, ambiguity or conflict can be caused by differences of wording.
Also there is a danger that a late alteration alters one statement but fails to alter its repetition elsewhere.
The third of the items noted above needs careful consideration, as there may be dangers and liabilities involved in telling the contractor how to go about his work. Some methods may need to be specified, such as the requirements concerning the handling and placing of concrete, but these and similar matters should be specified under workmanship and materials clauses. Other directions on method should be given only if essential for the design. For instance, if it is necessary to under-pin or shore up an existing structure, the exact method used should not be specified for, if the contractor follows the method and damage ensues, the liability for damage may lie on the designer. Usually there is no need to specify a particular method, but there may be a need to rule out certain methods; for example, that the contractor is not to use explosives.
It is important to avoid vague phraseology such as requiring the contractor to provide ‘matters, things and requisites of any kind’, or ‘materials of any sort or description’, etc. Clause 8 of the ICE conditions is sufficient to put on the contractor the obligation to do everything necessary to complete the works – ‘so far as the necessity for providing the same is specified or reasonably to be inferred from the contract.’ Similarly the phrase ‘excavation in all materials’ is ineffectual. The drafter might think it covers any rock encountered but it does not if the geological data supplied with the contract or reasonably available to the contractor provides no evidence of the existence of rock. Definitions such as those used in the Civil Engineering Standard Method of Measurement (see Section 15.3) should be followed. If there is evidence that rock might be encountered, a definition of it is required as discussed in Section 15.7.