The specification for workmanship and materials

Part 2 of the specification will cover workmanship and materials, and will often be lengthy, perhaps comprising a volume on its own for a complex project.
It is usual to specify a material and its associated workmanship together in the same section. If workmanship is described separately from materials there is a risk that some workmanship requirement may be overlooked by tenderers.
The specification is normally divided into classes of work or trade. One method is to take trades in the order they are listed in the ICE standard method of billing quantities (CESMM). But CESMM lists miscellaneous metalwork (Class N), and softwood components (Class O), before piling, tunnelling and engineering brickwork (Classes P, T and U respectively) which is not the order in which construction normally proceeds. An alternative is to list trades, both in the specification and bill of quantities, in the order in which they will be used. This is more logical, helps drafting and makes sure matters are not missed.

In drawing up the specification it is advisable to plan out beforehand subjects
to be dealt with. An order such as the following might be adopted.
1. demolition, site clearance;
2. excavation;
3. piling;
4. concrete;
(a) in situ;
(b) reinforcement;
(c) formwork;
(d) pre-cast;
(e) pre-stressed;
5. pipe-laying (might be put later);
6. steelwork (structural);
7. brickwork/blockwork/masonry;
8. roofing;
9. cladding (if special);
10. carpentry;
11. finishing trades (as necessary);
12. roads, site restoration, fencing.
It is not advisable to use three or more levels of decimal numbering of sections, such as 2.1.1, 2.1.2, etc. Only the section headings under each class of work need be numbered; sub-sections can be un-numbered and identified by a left hand heading, and paragraphs are not numbered. This permits insertion of late additions without disturbing any numbering.
When drafting the specification, care should be taken to ensure coverage of all types of work that appear on the drawings. In civil engineering contracts the specification sets out all quality requirements so these must be complete. The items in the bill of quantities only need sufficient description for the item to be identified for the purposes of payment. If an item in a bill of quantities appears with extra description which is not in the specification, a contractor might argue that the item with the added description requires additional payment.
(See Section 4.4 where it is noted that under JCT conditions for building work the contrary practice applies.)
There have been differences of opinion among engineers as to the merits of method as against performance types of specification. Amethod specification for concrete quotes not only the materials and quantities of them to be used to make various grades of concrete but also the strengths and other physical characteristics to be achieved together with requirements for handling and placing.
A performance specification would stipulate only the strength and other physical characteristics to be achieved. This, it is said, leaves the contractor greater freedom to decide how he will achieve the performance criteria. However, opponents of performance specification point out that control by testing is only possible (in the case of concrete) 28 days after placing, and such tests may not provide sufficient proof that the structure will perform satisfactorily in the long term.
If defects appear later, how is the contractor to be held responsible? Traditional  method specification is therefore the usual practice adopted, based on longstanding practices that have proved satisfactory over many years of experience.

The specification ought to be relevant to the work required. To include provisions that are irrelevant shows signs of a careless approach. When complex matters have to be specified it is best to avoid long and complicated sentences;
short sentences are better. Occasional lists of requirements can aid clarity. The specification is a reference book which should be easy to consult. Inevitably large parts of it will cover such obvious requirements that they will not be read for example, All formwork must be true to line and level. Any unusual or special requirement should therefore not be tacked onto such standard material, or it will get missed. It should be put as a separate paragraph, even if it comprises only a couple of lines, so that it stands alone.
When writing specifications much use is made of past experience. Many engineers and consultancy firms will have model clauses available for specifying materials in common use. Both short version and comprehensive model specification clauses may need to be drawn up for a given material, so that the appropriate model clause can be used, according to the amount and importance of that material in a job. Considerable use will be made of national  standards, standard sizes or qualities of manufactured goods. But it should be noted that, although British or other national standards are often quoted, this may not be sufficient definition because many such standards cover various grades and qualities, and precise references may be needed. Permitted alternative national standards may need to be quoted also.
Use can be made of a trade-named product to specify a material required but, wherever possible, it is better to avoid restricting the contractor to just one product by adding after the named product the words or similar approved. The problems caused by nominating one supplier are dealt with in Sections 14.2 and 15.8, and it must be borne in mind that the practice could be contrary to EU competition rules.
Many sections of the civil engineering industry have their own approved technical specifications which are meant to act as standards for their particular type of work. The UK Department of Transport (Highways Agency) has published extensive clauses covering all manner of roadwork in their Highways Specification. The water companies in the UK have published a Civil Engineering Specification for the Water Industry. These documents can give an important lead to the specifier, but should not be slavishly copied, but checked, amended and extended so as to relate concisely to the needs of each particular job.
It is wise to enquire of the employer whether he wishes any particular specifications or standard requirements to be adopted. This is important when work is undertaken for governments or public utilities overseas. They often have their own printed specification, departures from which may not be permissible since they might not be noticed or understood by local tenderers. The sanction of the employer might be needed before any addition or amendment is made to such traditional specifications and, if allowed, may need to be put in a special section and carefully worded in simple English.

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