Operational bills

Operational bills are a tendering document for estimating costs prepared by architects that describes a construction project in terms of the operations (which include labour and plant) needed to build it. This form of document contrasts with that of bills of quantities in which such tendering and estimation is limited to the materials in the completed work. Operational bills have the advantages of enhancing communication between design and production, enabling realistic tender pricing, and making the preparation of critical-path analysis easy for the contractor.

Operational bills were proposed and developed by Edward Skoyles at Building Research Establishment in the 1960s. Priced-activity schedules of the NEC Engineering and Construction Contract are a modern related form, prepared by the contractor.

An operation is defined as a piece of construction work which can be carried out by a gang of operatives without interruption from another gang. A procedure diagram is provided that shows the relationship of operations to each other and so which are done in sequence and which are done in parallel. This allows a critical-path analysis to be quickly created by the contractor. There are two sections: the first deals with site operations in terms of schedules of materials, labour and plant requirements, and the second, any work prefabricated adjacent or off site. At the end of the bill, management and plant resources are given so they are included.

After operational bills were proposed, a second half-way house version with bills of quantities was suggested initially called “activity bills”, but then as “Bills of quantities (operations)”. In this, the operations are described in terms of the rules of the standard method of measurement rather than labour and materials. A further development was the use of the principles of operational bills in the priced-activity schedules of the NEC Engineering and Construction Contract.

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