3.16 When the construction phase of a project commences, the procurer's design requirements, any existing service proposals, and the supporting contract provisions should have been clearly agreed in a totally unambiguous way so as to protect detailed design requirements.
A contractual obligation to follow the procurer's requirements set out in the specification (ie overall standards and choice of materials), and to give full effect to any of the service provider's proposals which have been agreed, will ensure that there is no drift in the type of materials used, or the size, location etc of key design features.
3.17 Obtaining the exact design quality standards indicated in the bid may be difficult if there is insufficient precision in the description of the design proposals submitted, as the contractor may then meet the output specification by using cheaper materials, or by working to a more convenient solution in the construction phase. The contract should prioritise the various design specifications and set out a detailed procedure to allow the procurer to assess any proposed changes that might compromise the agreed design.