Room Integrity Testing (Door Fan Test) Service

What This Service Covers

Room integrity testing, commonly known as the door fan test, is one of the most critical verification steps for a gas fire suppression system. This test determines — measurably and repeatably, without an actual gas discharge — whether the protected space can hold the suppression agent at sufficient concentration for the required time. It works by using a calibrated fan temporarily mounted in the doorway to apply controlled pressure differentials across the space.

This method is preferred precisely because an actual gas discharge is both costly and a one-time, irreversible event; the door fan test relies on the same physical principles to calculate the result mathematically instead.

How the Process Works

The test begins with a calibrated fan unit temporarily fitted into the doorway of the protected space using an airtight frame. The fan is run to create staged pressure differentials between the inside and outside of the room, and the airflow entering or leaving the space is recorded at each pressure step. This pressure-versus-flow data is used to calculate the room’s total equivalent leakage area.

The calculated leakage area, together with the room’s geometry and the properties of the chosen suppression agent, is fed into software to calculate how long the design concentration will be held — the hold time. The result is compared against the minimum hold time required by the applicable suppression standard (such as NFPA 2001 or ISO 14520), and the test is documented with a pass/fail result and a detailed report.

Why It Matters

This test is the only objective way to confirm whether the sealing work carried out during room integrity construction is actually sufficient — a visual inspection or an “it looks fine” judgment gives no reliable indication of a space’s real leakage performance. If the result falls short of the standard, additional sealing work is carried out and the test is repeated.

How the measurement works, and how a pressure relief vent is planned for the discharge pressure, is explained in our room integrity and door fan testing guide.

For this reason, room integrity testing should be treated as a mandatory verification step the system must pass before commissioning — not an optional extra, but an integral part of the project.

Which Systems Is It For?

Room integrity testing applies to all gas suppression systems that work on the total flooding principle: FM-200, FK-5-1-12 (Novec 1230), IG-541, IG-55 and other inert gases, and CO2. In-panel systems are designed for the cabinet volume and are outside the scope of this test.

Which Standard Is It Done To?

The test follows the enclosure integrity procedure in NFPA 2001 Annex C or the door fan method in the annex of ISO 14520-1. Two results are calculated from the measured leakage area: how long the agent will be held at design concentration, and the peak pressure in the room on discharge. A common acceptance criterion in the industry is a hold time of at least 10 minutes; the standard used on the project and the authority’s requirement govern.

How the Test Day Runs

1. Preparation check: Doors, dampers and ventilation are checked against the preparation list below.
2. System made safe: Automatic discharge is temporarily disabled for the test, in coordination with the facility manager.
3. Measurement: The door fan is fitted in the doorway; the room is pressurized and depressurized and pressure-flow readings are taken.
4. Leak finding: If the result falls short, leak points are found with smoke and recorded.
5. Back to normal: The system is re-armed, and doors and dampers are returned to their normal position.
6. Reporting: The result is reported with the calculated hold time, the peak pressure assessment and the leak points.

Preparing for the Test

For the test to give a sound result on the first visit, the room has to be in the state it would be in during a real discharge. Before the test day we plan the following together:

• Access to the protected room and adjacent voids (suspended ceiling, raised floor), and controlled use of the doors during the test
• The ability to close the dampers and ventilation connections that must close on discharge
• The ability to stop air conditioning and ventilation as in the discharge scenario
• Known openings (cable/pipe penetrations, door undercuts) sealed before the test
• The system design, if available: protected volume, agent, design concentration and height of the protected equipment

You can download this list as a printable PDF.

What the Test Report Contains

• The total equivalent leakage area measured and the measurement data used
• The predicted hold time calculated to the applicable standard, compared with the required minimum
• A pass/fail result
• Leak locations found and, where needed, recommended remedial work
• An assessment of whether pressure relief is needed for the discharge pressure

This service is one step in the life cycle of a gas fire suppression system project, from survey to maintenance; every step and agent option is on our home page.