The key precautions which can be taken to minimize claims and disputes are:
(a) adequate site investigations;
(b) checking that the works designed satisfy the employer’s needs and make reasonable provision for his possible future requirements;
(c) completing all design drawings, specifications, and arrangements for incorporation of equipment purchased separately, before tenders for construction are sought.
Under (b) the aim is to minimize changes during construction. Some may be unavoidable if the employer needs alterations due to some new regulation applying, or if his needs change due to something outside his control. But often his possible (but uncertain) changes of need can be catered for cheaply by incorporating a degree of flexibility in the design by providing extra space for additional equipment or runs of services.
Under (c) the construction contractor will see he has been given full details of what is required at the outset, reducing the likelihood of having to face additions and alterations during construction. This can encourage him to expect fast construction, which reducing his costs, enables him to submit his lowest price.
Thus any extra time needed to ensure drawings and specifications are complete can be well spent.
To ensure designs are complete, the designers will need to ascertain the requirements of all specialist suppliers and contractors involved, such as the suppliers of mechanical and electrical plant, cladding, windows, cranes, lifts, heating and ventilating equipment. For major mechanical and electrical plant it is best for the employer to let separate contracts for their supply and erection, so they come under direct control of the designer as described in Sections 2.4(d) and 5.6.