It shall be unlawful for any person, directly or through an agent, to sell, offer for sale, distribute or lease in the county any make, type or model of fire extinguisher, either new or used, unless such make, type or model of extinguisher has first been tested and is approved or labeled by the Factory Mutual Laboratories, Underwriters’ Laboratories, Inc., or other testing laboratory approved by the Director as providing adequate and reliable tests and examination. The provisions of this section shall not apply to the sale or trade of fire extinguishers to any person or firm engaged in the business of selling or handling such equipment for junk. (1975 L.M.C., ch. 23, § 1.)