No fire shall be started or maintained and no burning shall be done at any time in any building or structure in the city, except in an approved type stove or furnace, approved by a fire underwriters organization having national or state recognition, or by the chief of the fire department, hereinafter referred to as the fire chief. In absence of the fire chief, his duties and functions under this chapter shall be performed by the first assistant fire chief; and in absence of the latter, by the second assistant fire chief.