15. Where an application is made to a building control authority for a fire safety certificate, the authority, in considering such application, shall—

(a) be restricted to considering only the extent to which the design of the building or works complies with the requirements of Part B of the Second Schedule to the Building Regulations, and

(b) have due regard to any dispensation or relaxation in respect of, or which is relevant to, the works or building to which the application relates.