There are several of types of specifications that are commonly used. The following are some of the most common forms:
- Functional Specifications: These are specifications that define the function, duty or role of the goods or services. It nominates what the goods or services are broadly required to do. Functional specifications define the task or desired result by focusing on what is to be achieved rather than how it is to be done. They do not describe the method of achieving the intended result. This enables suppliers to provide solutions to defined problems.
A functional specification is a clear indication of the purpose, function, application and performance expected of the supplied material or service, whereby the supplier is allowed or encouraged to provide an appropriate product. These specifications describe the capabilities that the article where applicable, performance specifications are to be selected as they allow wider competition and enable suppliers to suggest new or improved ways of meeting the requirement. Tests or criteria are developed to measure a product’s ability to perform and to last, as required.
- Performance Specification–These are specifications that define the purpose of the goods or services in terms of how effectively it will perform, that is, in capability or performance terms. Performance is a logical extension of function. Performance specifications define the task or desired result by focusing on what is to be achieved. They do not describe the method of achieving the desired result. This enables suppliers to provide solutions to defined problems.
A type of specification in which the goods and/or services are described in terms of required performance. They may include such details as required power, strength of material, test methods, and standards of acceptability and recommended practices.
Performance specifications define the task or desired result by focusing on what is to be achieved (e.g., truck or airplane).
- Design or technical Specification- These are detailed descriptions of a good or service, including such things as details of construction or production, dimensions, chemical composition, physical properties, materials, ingredients and other details needed for the provider to produce an item of minimum acceptability. Design specifications are usually required for construction projects and custom produced items and for many services. Architects and engineers typically prepare design specifications for construction and manufactured products (e.g., buildings, highways, or other public works projects).
- Combination Specification -This type of specification includes elements of both design and performance specifications.
- Brand Name or Equal – This type of specification is used to describe a commodity of a fairly common nature. It states a detailed description and a manufacturer and catalog or model number which meets the description and has been determined to be acceptable. Competition among brands is usually attained by specifying ―brand A or equal‖ in the specification.
- Industry Standard – In this type of specification, all goods made to an industry standard are identical, regardless of manufacturer, and will result in acquisition of goods of uniform quality. An example is the UIL standard for electrical products.
Why are functional and performance specifications preferred to technical specifications?
- Suppliers can offer alternative and innovative ideas and solutions.
- Offerors can focus on providing the best solution.
- The focus on outcomes should result in better value for money.
Principles of specification writing
1. If something is not specified, it is unlikely to be provided.
2. The specification is equally binding on both the supplier and the vendor
3. Every requirement increases the price – all specifications should therefore subjected to rigorous value analysis
4. The shorter the specifications as possible be presented in performance terms.
5. Specification should whenever possible be ‗open‘ not closed ‗closed‘ specification
6. Specification must not conflict with national or international standards or safety or environmental laws and regulations. National and international specifications should be incorporated into individual specifications.
