The pressurization factor is expressed as a percentage of which airflow?

The pressurization factor is expressed as a percentage of which airflow?

• A. Supply airflow
• B. Return airflow
• C. Outdoor airflow
• D. Ventilation airflow

Answer: (A)

Pressurization in a space is set by the balance between air entering and leaving the space. To keep a room positively pressurized, the amount of air being supplied must be high enough relative to what is exhausted or returned. The pressurization factor is expressed as a percentage of the supply airflow because it reflects how large the share of the total airflow is coming from the supply side. In practical terms, you take the supply airflow and compare it to the total airflow moving through the space (supply plus return/exhaust). This ratio, shown as a percent, tells you how dominated the space is by incoming air, which is what creates positive pressure. For example, if supply is 600 cfm and return is 400 cfm, the pressurization factor is 600 divided by (600 + 400), or 60%. Outdoor (ventilation) airflow and the amount of air drawn from the space for exhausting or returning to the system influence overall ventilation and pressure dynamics, but the pressurization factor itself is specifically the share of total airflow that is supply.

Pressurization in a space is set by the balance between air entering and leaving the space. To keep a room positively pressurized, the amount of air being supplied must be high enough relative to what is exhausted or returned.

The pressurization factor is expressed as a percentage of the supply airflow because it reflects how large the share of the total airflow is coming from the supply side. In practical terms, you take the supply airflow and compare it to the total airflow moving through the space (supply plus return/exhaust). This ratio, shown as a percent, tells you how dominated the space is by incoming air, which is what creates positive pressure. For example, if supply is 600 cfm and return is 400 cfm, the pressurization factor is 600 divided by (600 + 400), or 60%.

Outdoor (ventilation) airflow and the amount of air drawn from the space for exhausting or returning to the system influence overall ventilation and pressure dynamics, but the pressurization factor itself is specifically the share of total airflow that is supply.