All openings must be closed with threaded plugs or caps. Split pipe or broken fittings must not be repaired with cement or lead or any other similar product but shall be replaced with sound pipe and fittings. Bushings shall not be used in any case and instead nipples and reducing couplings shall be used.
No connections except connection for stoves shall hereafter be made with a union.
(`85 Code, § 20-75)