Before starting an installation, a gas installer shall have in his possession an up to date valid gas fitter's license issued by the city indicating said gas installer has successfully passed a gas fitter's examination; provided, however, that the owner of any single-family dwelling occupied by him shall not be required to have a gas fitter's license or procure the bond and insurance hereinafter provided for to do gas fitting work on said premises if said work is to be done by the owner or a member of his immediate family, in which case such owner shall obtain the necessary permit, perform the works and tests in accordance with other provisions of this chapter, subject to the approval of the designated enforcement officer except, however, that an owner not be permitted to do gas fitting work in any building which is used as a place of business, apartment house, rental unit or a house to be offered for sale. (Ord. 200, 1969)