Trap seal primers are primarily designed to supply water to floor drain traps that have infrequent use and in which water evaporation would allow sewer gas to enter the premises. The trap seal primers covered by this standard are designed to supply water to a drain trap to provide and maintain its water seal by using a supply from a fixture drainline, ballcock, flushometer valve tailpiece or an electric trap seal primer. The rate of water flow to the trap shall be permitted to be fixed or adjustable. The trap seal primers are of four (4) types: 1) Those that are installed on waste line tail pieces from fixtures, such as lavatories, sinks and similar fixtures where grease is not normally generated; 2) Those that are used in conjunction with ballcock assemblies; 3) Those that receive flow from flushometer valves; and 4) Those electric trap seal primers that discharge water automatically and are upstream of the air gap or vacuum breaker.