Expansion in long chilled water piping is primarily used to accommodate what?

• A. Increase flow velocity
• B. Accommodate thermal expansion of water over temperature changes
• C. Reduce noise
• D. Improve filtration

Answer: (B)

The main idea here is that long piping must be able to absorb the change in fluid volume as water temperature changes. Water expands when it warms, and in a long chilled-water loop that expansion adds up to a noticeable increase in volume. If the system were rigid, this extra volume would push pressure up and put stress on pipes and joints. Expansion devices or air chambers give that extra space so the system pressure stays within design limits. This is why expansion in long chilled water piping is about accommodating thermal expansion of the water as temperatures change. It isn’t primarily about increasing flow velocity, reducing noise, or improving filtration.