What is the maximum water temperature that categorizes a water heater as a pressure vessel?

A water heater is categorized as a pressure vessel based on certain characteristics, particularly its operating conditions including temperature and pressure. The temperature threshold that generally defines the classification of a water heater as a pressure vessel is established to ensure safety and compliance with industry standards.

In this context, the correct choice is 210 degrees Fahrenheit. When a water heater reaches this temperature, it begins to reflect conditions where the potential for increased pressure exists due to the expansion of heated water. At temperatures above this threshold, water can reach dangerous pressures that necessitate specific engineering standards and safety measures. This classification is vital for ensuring that the water heater is designed and built to withstand such conditions, minimizing the risks of failures that could lead to leaks or explosions.

Understanding this classification is crucial for plumbing professionals to ensure they adhere to regulations when installing, maintaining, or replacing water heaters, as well as ensuring that proper safety measures are implemented to protect users and property.