TheOverThinker
Member
In our area inspectors are now tagging TPR valves that don't have a constant gravity drain slope, even in otherwise simple water heater replacements in basements. This is supported by IAMPO 608.5:
What's the safety reason behind prohibiting the line from going up and over to the outside? Under water heater pressure, it would easily blow out any standing water in a line that went up. For basement retrofits finding a way to get the TPR out can be a big constraint, leading to non-optimal water heater placement, and/or strange kludges like the Watts 210 for gas or stranger solutions for electric.
To see water heaters blowing up, see Mythbusters. They did it twice.
https://go.discovery.com/tv-shows/mythbusters/videos/exploding-water-heater
The pressure is immense.
Are there other places in the US or Internationally that allow a TPR exit pipe to be routed above the water heater, beyond Georgia?
-------
For Georgia is a spring loaded drain valve at the low point acceptable, so nobody leaves it open?
608.5 Discharge Piping. The discharge piping serving a temperature relief valve, pressure relief valve, or combination of both shall have no valves, obstructions, or means of isolation and be provided with the following:
(1) Equal to the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down.
(2) Materials shall be rated at not less than the operating temperature of the system and approved for such use or shall comply with ASME A112.4.1.
(3)Discharge pipe shall discharge independently by gravity through an air gap into the drainage system or outside of the building with the end of the pipe not exceeding 2 feet (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downwards.
(4)Discharge in such a manner that does not cause personal injury or structural damage.
(5)No part of such discharge pipe shall be trapped or subject to freezing.
(6)The terminal end of the pipe shall not be threaded.
(7)Discharge from a relief valve into a water heater pan shall be prohibited.
(1) Equal to the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down.
(2) Materials shall be rated at not less than the operating temperature of the system and approved for such use or shall comply with ASME A112.4.1.
(3)Discharge pipe shall discharge independently by gravity through an air gap into the drainage system or outside of the building with the end of the pipe not exceeding 2 feet (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downwards.
(4)Discharge in such a manner that does not cause personal injury or structural damage.
(5)No part of such discharge pipe shall be trapped or subject to freezing.
(6)The terminal end of the pipe shall not be threaded.
(7)Discharge from a relief valve into a water heater pan shall be prohibited.
What's the safety reason behind prohibiting the line from going up and over to the outside? Under water heater pressure, it would easily blow out any standing water in a line that went up. For basement retrofits finding a way to get the TPR out can be a big constraint, leading to non-optimal water heater placement, and/or strange kludges like the Watts 210 for gas or stranger solutions for electric.
To see water heaters blowing up, see Mythbusters. They did it twice.
https://go.discovery.com/tv-shows/mythbusters/videos/exploding-water-heater
The pressure is immense.
Are there other places in the US or Internationally that allow a TPR exit pipe to be routed above the water heater, beyond Georgia?
*SECTION 504
**SAFETY DEVICES
*Delete Section 504.6.1 and substitute the following:
**504.6.1 IPC Discharge.
**The relief valve shall discharge full size to a safe place of disposal such as a concrete floor, outside the building, an indirect waste receptor, or other approved location. The discharge shall terminate in a manner that does not cause injury to occupants in the immediate area or structural damage to the building. The discharge pipe shall not be trapped. When the relief valve discharge piping goes upward a thermal expansion control device shall be installed on the cold water distribution or service pipe in accordance with Section 607.3.2 (GA.
Georgia GA Standard Plumbing Code (International Plumbing Code) Amendments 2002
Amendments). Provisions shall be made at the low point to drain the trapped portion of the discharge pipe.
https://www.dca.ga.gov/sites/default/files/2005_ipcamendments.pdf
**SAFETY DEVICES
*Delete Section 504.6.1 and substitute the following:
**504.6.1 IPC Discharge.
**The relief valve shall discharge full size to a safe place of disposal such as a concrete floor, outside the building, an indirect waste receptor, or other approved location. The discharge shall terminate in a manner that does not cause injury to occupants in the immediate area or structural damage to the building. The discharge pipe shall not be trapped. When the relief valve discharge piping goes upward a thermal expansion control device shall be installed on the cold water distribution or service pipe in accordance with Section 607.3.2 (GA.
Georgia GA Standard Plumbing Code (International Plumbing Code) Amendments 2002
Amendments). Provisions shall be made at the low point to drain the trapped portion of the discharge pipe.
https://www.dca.ga.gov/sites/default/files/2005_ipcamendments.pdf
-------
For Georgia is a spring loaded drain valve at the low point acceptable, so nobody leaves it open?