TPR Valve Drainage
What is a TPR Valve?
The Temperature Pressure Relief Valve (TPR Valve) is a crucial safety valve on your hot water system responsible for ensuring your hot water tank stays within its designed pressure and temperature limits. The valve is located on the top or side of your water heater with a lever for manual operation and connected to a discharge pipe for drainage.
Your Venatic report will not comment on the operation of the TPR valve itself however you may find comments relating to the appropriate drainage of the valve to avoid damage to the home.
TPR Valve Drainage
A Venatic inspection will inspect all aspects of external drainage around the home including the TPR Valve for the potential impact the drainage may have on the long-term health of the home or impact the safety of the home.
It is recommended that the TPR valve is connected to the homes drainage system wherever possible or practical. If this is not possible or practical, it is crucial to ensure the TPR valve is discharged to an area that introduces no risk of harm to the home or any person operating the valve. An example of this is discharging to a gravel pit >100mm in diameter within a paved area.
AS/NZS 3500.4 does not specify a termination distance but introduces a performance measure to eliminate risk of injury to the operator during activation of the TPR valve.
The TPR valve must-
- Not damage buildings
- Be directed away from building footings
- Not pose a risk of injury to persons
- A gravel pit may only be used subject to the above and must be a minimum 100mm diameter in a paved surface.
- The TPR drain must discharge 75mm minimum or 300mm maximum above the gravel pit.
- Where discharge is to an overflow gully (ORG) it must be 75mm minimum or 300mm maximum above the ORG and must not obstruct operation of the ORG grate.