Which of the following statements does NOT pertain to the fan laws?

The statement regarding static pressure in a duct increasing as velocity decreases aligns with the principles of fluid dynamics, specifically the inverse relationship described by Bernoulli's principle. In a duct system, when the velocity of the air decreases, static pressure tends to increase due to the conservation of energy within the system. Therefore, this statement is an accurate representation of fan laws and fluid dynamics, making it relevant.

In contrast, the other statements relate directly to fan performance and the operational characteristics as defined by the fan laws:

• Increased airflow reducing static pressure pertains to the balance within a system where increasing the flow rate typically results in a drop in static pressure due to the higher demand for energy to maintain flow.

• Fan speed correlating with airflow volume indicates that as you increase the speed of the fan, the air volume moved by the fan also increases, which is a foundational aspect of fan laws.

• Efficiency being affected by fan design highlights that the design of a fan severely influences how effectively it can move air, which is integral to understanding fan performance.

Given this understanding, the correct answer indicates that the statement about static pressure increasing as velocity decreases does not belong with the fan laws since it accurately describes a fundamental dynamic, while the other statements reflect specific aspects of fan performance