The National Building Specification, and now known as the NBS, is a British based system of construction specification used by architects and other building professionals to describe the materials, standards and workmanship of a construction project. It was launched in 1973 and is now used by over 5000 offices.

A specification often forms part of the tender documentation along with architectural drawings for a contractor to price and then forms part of the contract documentation for the builder to construct the building from.

The NBS is owned by the Royal Institute of British Architects

Royal Institute of British Architects

The Royal Institute of British Architects is a professional body for architects primarily in the United Kingdom, but also internationally.-History:...

 (RIBA) via the RIBA Enterprises subsidiary. Since 1988 the Specification is structured on the Common Arrangement of Work Sections

Common Arrangement of Work Sections

Common Arrangement of Work Sections, first published in 1987, is a working convention designed to promote standardisation of, and detailed coordination between, bills of quantities and specifications...

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