Last edited 31 Jul 2019

Common Arrangement of Work Sections

The Common Arrangement of Work Sections (CAWS) was developed by the Construction Project Information Committee (CPIC), a pan-industry organisation with representatives from key industry institutes.

It was developed as a result of research demonstrating that the quality of construction information was a very significant determinant of the quality of construction. It was recognised that standardisation of the way production information was created and classified could help improve quality, and that the commonly used CISfb classification was not sufficiently comprehensive to achieve this.

CAWS established a consistent arrangement for specifications and bills of quantities. It was first published in 1987 and was updated by CPIC in 1998 to align it with the Unified Classification for the Construction Industry (Uniclass). In 2005 nbs submitted to CPIC, modifications to the services sections of CAWS for consideration and following 5 years of consultation these changes were accepted.

CAWS is the categorisation of work that is used for the National Building Specification (NBS – which before 1987 followed the CISfB structure), National Engineering Specification (NES), the Standard Method of Measurement, currently in its 7th Edition (SMM7) and a number of industry pricing books such as Spons, Laxtons and Wessex.

CAWS has since been incorporated into Table J of Uniclass, which was also developed by CPIC. Uniclass is a classification system for organising library materials, product literature and project information.

In 2011, the CPIC used the nbs proposals for re-classification of the work sections in CAWS and Uniclass Table J as the basis of a consultation process for revising Uniclass. This development of Uniclass as a whole is considered to better accommodate civil engineering and process engineering alongside architecture and landscape, it also better enables the description of systems in performance terms, and is more suited to accommodating facilities management.

The main categories are:

A - Preliminaries
B - Complete buildings / structures / units
C - Demolition / Alteration /Renovation
D - Groundwork
E - In situ concrete / Large precast concrete
F - Masonry
G - Structural / Carcassing metal / timber
H - Cladding / Covering
J - Waterproofing
K - Linings / Sheathing / Dry partitioning
L - Windows / Doors / Stairs
M - Surface finishes
N - Furniture / Equipment
P - Building fabric sundries
Q - Paving / Planting / Fencing / Site furniture
R - Disposal Systems
S - Piped supply systems
T - Mechanical heating / Cooling / Refrigeration systems
U - Ventilation / Air conditioning systems
V - Electrical supply / power / lighting systems
W - Communications / Security / Control systems
X - Transport systems
Z - Building fabric reference specification

Each section includes further sub-classification and offers detailed information and supplementary rules. For more information see: Common arrangement of work sections classification.

NB: SMM7 has been replaced by the New Rules of Measurement (NRM) which has moved away from CAWS, to adopt its own system of indexing. See New Rules of Measurement for more information.