In this article, John Gelder explores substitution, the use of 'or equal' and its ilk, and 'deemed-to-comply' specifications, and makes a few suggestions.

Brand substitution

Contracts usually do not permit substitution by the contractor without approval from the contract administrator (e.g. JCT Management Works Contract 2008 clause 2.4.1). NBS Preliminaries provide the mechanism by which approval is to be applied for (see clause A31/200 Substitution of products). This mechanism makes no mention of the substituted product or system having to be equal or equivalent. It merely requires the submission of enough information for an informed decision to be made one way or the other.

Accordingly, if one is specifying by brand, one only needs to name the manufacturer and product reference (and maybe some option selections), full stop. There is no need for any further qualifying text such as 'or approved alternative' – most contracts already allow approved alternatives, as noted above.

Actually, if a brand is specified and the specifier has done his or her homework properly, there should be no acceptable alternatives, in which case suggesting that alternatives might exist only serves to send the contractor on a wild goose chase. A brand should of course only be specified outright if that brand, and no other, will meet the project requirements. Interestingly, because specifiers routinely consider a very wide range of parameters in product selection, it is often the case that only one or two brands will do the job. It may even turn out to be the case that no brands comply, in which case the project must resort to custom-made products, or the specifier must change the values or reduce the number of parameters! When project participants consider a small number of parameters, e.g. contractors proposing a substitution and focusing on expedience, then more complying products are likely to appear to exist.

Brand specification represents the end of a chain of decisions which begins with a definition of the project requirements for the product. At this time it will be recognized that the requirements are unusual and may only be satisfied by a few brands, possibly only one. Accordingly, a careful trawl through products available in the market place will be carried out. This will be iterative, as characteristics not previously considered come to light in the product literature, and are added to the constraints. As the constraints increase, so the number of available complying products diminishes until only one is left. This is the brand that is specified, at least in theory.

The reality is that brands are specified for all sorts of reasons, not all of them good. Habit is one such reason – we have always specified this brand of hand basin and we are not going to revisit the decision we made on this 10 years ago. Another is that the market leading brand is specified as it is the first one that came into our heads, it must be good, and this decision will save us a great deal of research. This is of course why manufacturers go to so much trouble to be the first brand that comes into your head. They know that this is how brand selection works. This is one route to becoming the market leading brand, and has nothing to do with the merits of the product.

Other substitutions

Though the issue is usually raised in respect of brands, anything can be substituted. For example, the specification might refer to BS 1234, but the successful subcontractor is German and is used to working to (and may be licensed to work to) DIN 5678. The substitution of the BS by the DIN might be proposed. See clause A31/240 Substitution of standards, in the NBS Preliminaries.

The specification might refer to a post and rail fence system, but the contractor might consider that a panelled fence system would be more appropriate. This substitution can be proposed.

The drawings might show a 900 mm wide door in one position and the contractor may suggest a 950 mm door of the same type, but in another position, and with a different sign to that scheduled. This substitution (of position, size and sign) can of course be proposed, too. And so on. The rules for managing substitution need to be broad enough to accommodate the whole gamut of possibilities.

'Or equal'

Sometimes the only reason a particular brand is identified is to indicate the type of product that is acceptable. In these cases specifiers add 'or equal', 'or equivalent' and the like, to suggest that other similar products are acceptable. 'Or equivalent' can also be added for legislative reasons externallink, in public sector procurement. This does not actually indicate that (a) an equivalent exists, or (b) that the specifier is happy for another product to be used. The term is merely being used to comply with European pro-competition legislation.

Use of these terms in the specification means that the contractor can use another brand that it considers equal or equivalent, without having to notify the contract administrator or seek approval. However, it is difficult for a contractor to judge equality or equivalence based on the specification of a brand. The branded product will have all sorts of properties, some of which are critical to the project, some of which are desirable, and some of which are of no consequence. There is no way that the contractor can judge with certainty which is which – the reasoning behind the selection of the brand is not given (just as the project documents do not include reasons for the location of the door here, or the selection of that colour, etc). However, the contractor is constrained by legislative provisions requiring products to be of satisfactory quality, fit for purpose where that purpose is known, and so forth (e.g. Supply of Goods and Services Act 1982 externallink, Sale and Supply of Goods Act 1994 externallink, Building Regulations 2010 externallink – see also clause A33/110 Incomplete documentation, in the NBS Preliminaries). Adding these requirements to 'or equal' should give some further clues.

Because many specifiers are not comfortable with the idea that the contractor can use another product without notification or approval, they often add 'approved' to the phrase, e.g. 'or equal approved'. This doesn't actually solve the problem. Instead, it makes it worse, as there will often be disagreement about equality or equivalence, and agreement is required. The contractor will have one view (perhaps coloured by a desire to make a little more profit, or to catch up with the programme), and the specifier another (perhaps coloured by a desire to ensure a stylish hand basin, even though it is technically equivalent to the very un-stylish one proposed by the contractor – not a point of view a judge is likely to have much sympathy with – being 'reasonable' is the usual legal requirement). Jobs have ground to a halt over arguments about equality.

Compounding all this of course is the reality that the approved product (if any) probably won't be equal or equivalent in every respect. It probably doesn't need to be. The terms themselves are inherently meaningless, and even misleading. They are perhaps best viewed as a starting point for negotiation!

The whole problem is solved if one simply names the brand, full stop.


If the only reason a particular brand is identified is that it indicates the type of product that is acceptable, then there are better ways of conveying this information. One is to name several complying brands (typically three), allowing the contractor to choose. Another suggestion is to use a deemed-to-comply form of specification. This would work in a similar fashion to the Building Regulations 2010 and the Approved Documents (ADs) that serve them. The specification gives a mandatory generic description of the system or product (akin to the Building Regulations 2010, Schedule 1). It then supplements this with a deemed-to-comply brand specification (akin to the ADs). This ensures that the generic description has priority over the brand description, avoiding any confusion on this point:

350 Widgets

  • Standard: To BS 1234
  • Tensile strength (minimum): 50 N/mm²
  • Colour: Pink
  • Deemed to comply: Acme Widgets Ltd, Model W45, Rose.

If the contractor uses this brand, then this has been predetermined by the specifier to meet the generic requirements, and no extra evidence is needed. If the contractor does not use the deemed-to-comply brand, then sufficient information must be submitted to demonstrate that the proposed product or system meets the generic description (see clause A33/140 Compliance, in the NBS Preliminaries). This description should make it clear just what attributes are critical, and what the pass/fail points are for each one. Aesthetic matters can be covered by a requirement (specified on a product by product basis) to submit samples along with the other evidence needed to demonstrate compliance.

In conclusion, substitution rules should be respected, where only one brand will do then it should be specified outright, 'or equal' and its ilk should be avoided (except where required under legislation), and 'deemed-to-comply' specifications should be considered where more than one brand may be suitable.