In the fan flow equation, what does the variable 'C' stand for?

In the context of the fan flow equation, the variable 'C' represents the flow coefficient. The flow coefficient is a crucial parameter as it quantifies the performance of the fan or the system in terms of the air volume it can move under a specific pressure difference. It allows for the correlation between the flow rate and the pressure differential across the fan or other airflow devices.

This coefficient is derived from empirical testing and characterizes the characteristics of a specific fan installation, taking into account factors like duct design and fan efficiency. Understanding the flow coefficient helps professionals and engineers accurately predict airflow in building airtightness assessments and allows for the effective design of ventilation systems.

The other variables mentioned, such as pressure differential, flow exponent, and air density, play important roles in the overall fan flow equation but are not represented by 'C'. They correspond to other aspects of flow dynamics and measurements but do not encapsulate the flow characteristics the way the flow coefficient does. This makes it clear that 'C' specifically refers to the flow coefficient and its role in evaluating performance in the context of whole-building airtightness testing.