Mike Schulz
P2803.6.1 Requirements for discharge pipe.The discharge piping serving a pressure-relief valve, temperature relief valve or combination valve shall:

- - 1. Not be directly connected to the drainage system. (Jerry's note: Means that "it may" be connected to the drainage system, just "not directly connected to" the drainage system, it needs an air gap.)

- - 2. Discharge through an air gap located in the same room as the water heater. (Jerry's note: The discharge pipe discharge through the air gap, and ends there at the air gap, after the air gap is an indirect waste receptor, which has a drain line which, if using an air gap, then drains to the outdoors.)
- - 3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap. (Jerry's note: Obvious what that say, do not reduce the valve outlet down to a smaller size.)
- - 4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment. (Jerry's note: Shall serve only that one relief valve.)
- - 5. Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor through an air gap located in a conditioned area. (Jerry's note: The discharge pipe may discharge to the floor, to an indirect waster receptor - 2. above -, or to the outdoors - if the water heater is installed outdoors.)
- - 6. Discharge in a manner that does not cause personal injury or structural damage. (Jerry's note: Regardless where it discharges to, it is not allowed to cause personal injury.)
- - 7. Discharge to a termination point that is readily observable by the building occupants. (Jerry's note: Means you are not allowed to hide it, which brings up the question: are water heaters now allowed in closets where the discharge is not readily observable by the occupants?)
- - 8. Not be trapped. (Jerry's note: That one is obvious.)
- - 9. Be installed to flow by gravity. (Jerry's note: If it is not trapped, then it must drain by gravity, which means slope downhill.)
- - 10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor. (Jerry's note: The termination must be within 6" of the floor or water receptor to control the discharge and help prevent it from injuring the occupants.)
- - 11. Not have a threaded connection at the end of the piping. (Jerry's note: So no valve, cap or other device can easily be attached.)
- - 12. Not have valves or tee fittings. (Jerry's note: Nothing to restrict or impede the flow.)
- - 13. Be constructed of those materials listed in Section P2904.5 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.