In the event of temporary (24 hours or less) absence of the Chief of the Fire Department, the duties of the Chief shall fall upon the subordinate officers, according to their rank, as established by the rules and regulations of the Fire Department. In the event the absence will be for a period of greater than 24 hours, the Chief Engineer shall designate a subordinate officer as the acting Chief Engineer, who shall assume the duties of the Chief Engineer. (Amended 1997, No. M-17 (Adj. Sess.), § 10.)