Understanding forms of specification

The Oxford English Dictionary defines a specification as “A detailed description of the construction, workmanship, materials, etc., of work done or to be done, prepared by an architect, engineer, etc.” However in practice it is much more complicated than this.

Think of your specification as a composition, the information to be presented to the contractor can be likened to film-making. Film-making is a form of visual art, with images, but there is also the script. Roll out the red carpet and premier your movie without the sound and your audience may get some understanding of events, or vice versa by simply listening to the sound track, but to fully understand the story the pictures and words need to come together seamlessly, to create an epic that will scoop an Oscar!

For a construction project the drawings and the specifications come together in a similar manner to fully inform the contractor of what is required. Okay maybe it’s less dramatic than the latest Spielberg production, but it is important to consider each element and how it fits into the whole.

In this Blog we take a look at the various forms of specification, with a critique of the advantages and disadvantages of each and how best to support the Specifier in producing the ultimate blockbuster!

What must the specification deliver:

First of all let’s look at the ‘must haves’. Think of your film trailer and how this represents what the film is about, what rating the critics have given it, what certificate the film has and which leading actors are appearing in it. Equally the specification must reflect and support the design intent, clearly defining scope and quality with performance benchmarks. It must include national and regulatory standards, reflecting the form of contract and procurement method; confirming procedures and responsibilities.

Results or Method Based Forms of Specification

In broad terms there are either ‘Results’ or ‘Method’ based specifications. But these two broad concepts then have a number of permutations. For example open, closed, restricted, exclusive and negative.

With this form of specification the exact properties of materials, and methods of installation, are described in detail without using proprietary names. It is the responsibility of the contractor to then follow these instructions and to select a material or system complying with the performance criteria.


It indicates exactly what the design is to achieve, with a clear indication of the intended results without restricting the contractor to specific manufacturers.

It allows for the specifying of a complete system, giving the contractor flexibility in developing a solution and encouraging new technologies and innovation. It can shorten the specification and encourages competition. It also means that design responsibility is transferred to the contractor.

Often, both Descriptive and Performance specifications will include standards to which products or designs must comply or conform. By doing this there is a clear understanding and recognition by client, Specifier and Contractor of what is required without the need to write long clauses.


Great care is required in describing the design intent to provide a complete and understandable specification. Otherwise it can be ambiguous and open to misinterpretation. This tends to be both wordy and time consuming. Bids are harder to evaluate, more quality control and supervision is necessary during construction and the requirement is harder to enforce. All of this may be too elaborate for small projects.

Finally, the contractor is responsible for how the performance is achieved and can generally be expected to work to a minimum acceptable standard. Specifications can just comprise reference standards, but this may lead to specifying to the lowest common denominator.

Nominated Forms of Specification

The final specification option is to name a product or brand with a product reference. This could be ‘Closed’ naming just one brand or ‘Open’ where 2 or more brands are named or the terms ‘Or Equal’ or ‘Or Equivalent’ are used.


This approach has a number of benefits for the Specifier. It permits very precise control of product selection, especially when only one brand is named. It is quick as it is only necessary to write a short description but at the same time imply a precise specification based on manufacturer information. It indicates exactly what the Specifier requires, probably based on past experience and simplifies the bidding process as the contractor knows precisely what is intended.


The principal disadvantage is that it reduces competition. It is for this reason that it is not permitted to name brands when writing specifications for government projects.

So that contractors can retain an element of competition the Specifier will often add the clause ‘Equal Or Approved’ or ‘Or Equivalent’. While in common conversation these would be considered to have the same meaning, they have very different implications in a specification clause.

Equal Or Approved means that the product used must be the same as that nominated, and the Specifier must approve the choice. Keeping the final decision concerning product selection with the specifier.

Or Equivalent leaves the decision to the Contractor as well as the liability should the wrong choice be made.

In both cases it is becoming increasingly difficult to determine what makes two products the same. Taking an extreme example, sustainability requirements measure the embodied carbon of a product. Consequently an identical manufacturer’s product produced in two different European factories would not be the same because of the different amounts of carbon required to deliver it to site.

Conclusion – How to help the Specifier deliver their blockbuster

A great film is enhanced by having a great cast. So why not help the Specifier by providing standard descriptive and performance specification clauses for products? This way they are poised to select an all-star cast.

Epic blockbusters deliver entertainment that wins over the audience. With specification selling do not overtly promote your product, instead provide good reason for proposing an approach, this way you will position yourself as a trusted advisor with the Specifier.

Equally consider providing a service to review specifications, identifying anomalies or brands that are no longer available and giving advice on the best form of specification for a particular project. In effect become part of the production team, one of the unsung heroes that work behind the scenes: a researcher, a runner, a gaffer! This way you can support the team in delivering a five-star specification, one equal to an Oscar winning epic. And most important, improve the chance of your product being used on the project.

Specification Sales Training

WEBINAR: Specification Sales Explained
26 February 2013 at 12.30 – 13.30
Cost: £45.00
This webinar aims to give an introduction to specification selling, covering what it is and why you should be doing it.

  • Gain an overview of the specification selling process
  • Be aware of the dynamics of the decision making unit
  • Be aware of the influences on specification
  • Know of the different sales tools available

Effective Specification Selling
14 March – one day course in London
Cost: £247.00 + VAT

  • Understand the impact of market influences
  • Recognise the different contracts used and their impact on decision making
  • Appreciate how the residential sector is evolving and its future industry wide impact
  • Know different decision makers and how they influence specification
  • Effectively use the different sales tools available
  • Develop personal strategies to manage the process

In-house training
The specification sales team is an expensive resource, but used effectively it can create demand, reduce the importance of price and transfer influence away from the supply chain to the manufacturer. Chris Ashworth of Competitive Advantage Consultancy is one of the industry’s leading authorities on specification selling and can provide training for your team enabling them to operate effectively; understanding the pressures and influences, using these and a range of sales tools to build relationships and close a sale.

Further Reading

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