456. Dual function of architect or engineer.

The architect or engineer may often act in two capacities in respect of the same matter. For example, he may first be acting as the agent of the building owner, and in that capacity have to decide whether work or materials are acceptable to his client, the employer, and then as certifier have to decide whether the work or materials do or do not comply with the contractual standards, whether payment should be made, or the value of the relevant work or materials, and when acting in this capacity he must act fairly and impartially between the parties