Which test determines the integrity of an enclosure according to NFPA 2001?

• A. Door Fan Test
• B. Visual inspection
• C. Smoke pencil test
• D. Thermal imaging

Answer: (A)

Enclosure integrity is about how well a space can retain the clean agent for the required duration. NFPA 2001 specifies a quantitative method to verify this by performing a door fan test. A calibrated fan is installed in a doorway to create a controlled pressure difference between the inside and outside. The system maintains that pressure (typically around 50 pascals), and the airflow needed to keep it steady is measured. From that flow, you determine the leakage rate (or equivalent leakage area) to see if the enclosure meets the design containment requirements. This provides objective, repeatable data on how leaky the space is, which is exactly what NFPA 2001 requires for enclosure integrity.

Visual inspection and smoke pencil tests are mainly qualitative and don’t provide the quantified containment performance NFPA 2001 needs. Thermal imaging can show temperature leaks but does not assess the enclosure’s ability to retain the agent over time.