The importance of installing the correct temperature and pressure relief valve on a water heater or hot-water storage tank cannot be overemphasized. This applies to new vessels as well as relief valve replacements. The importance of installing a valve with the correct pressure rating is common knowledge to many, but it also is crucial to install a valve with the appropriate relieving capacity rating. Many times the capacity factor is overlooked.
The code of construction of the vessel itself can play a key role in choosing the correct valve capacity. Unfortunately, the code of construction criteria is unknown to many and overlooked by others.