What is the maximum temperature a building should deliver domestic hot water at?

What is the maximum temperature a building should deliver domestic hot water at?

• A. 120 °F
• B. 140 °F
• C. 100 °F
• D. 110 °F

Answer: (A)

The key idea here is safety at the point of use. The water that residents actually experience at taps and showers should be limited to a temperature that minimizes the risk of scalding, especially for children and elderly occupants. That’s why the maximum temperature delivered to fixtures is 120 °F. In practice, a building can heat water hotter in the storage tank (often around 140 °F) to help with sanitation, but a mixing or tempering valve blends in cold water so the water that reaches the faucet does not exceed 120 °F. Water at 120 °F is hot enough for comfort and usability while significantly reducing burn risk, whereas 140 °F or higher can cause burns quickly, and 100 °F or 110 °F would be too cool for normal purposes.

The key idea here is safety at the point of use. The water that residents actually experience at taps and showers should be limited to a temperature that minimizes the risk of scalding, especially for children and elderly occupants. That’s why the maximum temperature delivered to fixtures is 120 °F. In practice, a building can heat water hotter in the storage tank (often around 140 °F) to help with sanitation, but a mixing or tempering valve blends in cold water so the water that reaches the faucet does not exceed 120 °F. Water at 120 °F is hot enough for comfort and usability while significantly reducing burn risk, whereas 140 °F or higher can cause burns quickly, and 100 °F or 110 °F would be too cool for normal purposes.