13 PIPE FITTINGS AND VALVES OF PLASTIC OR METAL OR A COMBINATION OF BOTH * FOR USE IN FIRE PROTECTION SERVICES * -NAMELY, ELBOWS, T'S, CROSSES, LATERALS, COUPLINGS, REDUCERS, RETURN BENDS, CAPS, NUTS, FLANGES, BUSHINGS, PLUGS, INCREASERS, TRAPS, BENDS, CONNECTORS, SLEEVES, UNIONS, CLAMPS, NIPPLES, PLATES, PIPE HANGERS, PIPE AND BEAM CLAMPS, BRACKETS AND SUPPORTS, CONCRETE INSERTS, SPRING HANGERS AND CONSTANT SUPPORT SPRING HANGERS, DIAPHRAGM VALVES, GLOBE AND ANGLE VALVES AND CHECK VALVES; AND FOR AUTOMATIC FIRE PROTECTION APPARATUS COMPOSED WHOLLY OR IN PART OF METAL-NAMELY, AUTOMATIC SPRINKLER SYSTEMS AND PARTS AND ACCESSORIES THEREOF, FIRE DEPARTMENT CONNECTIONS, INDICATOR POSTS, DRY-VALVE ACCELERATORS, WATER MOTOR GONGS AND GONG HOODS, FUSIBLE LINKS, AND AUTOMATIC SPRINKLERS