TCFP Plans Examiner Practice Test

Which step follows opening the main drain during a main drain test?

1. Close main drain

2. Observe and record pressure drop

3. Record pressure on system side

4. Observe and record final static pressure

The correct answer is: Observe and record pressure drop

Following the step of opening the main drain during a main drain test, the next appropriate action is to observe and record the pressure drop. This step is crucial because it helps assess the system's operational status and the integrity of its components. When the main drain is opened, water is allowed to flow out of the system, which will likely cause a change in pressure within the pipelines and the pressure gauge. By observing and recording this pressure drop, you can effectively evaluate whether the system is functioning correctly, which can indicate if there are any leaks or blockages that need to be addressed. This data is essential for ensuring that the fire protection system operates adequately in emergencies. The other options, while relevant to the overall process, do not follow directly after the opening of the main drain. Closing the main drain is a subsequent action that would occur after the test is complete. Recording pressure on the system side and observing final static pressure are also necessary steps but are typically conducted after the pressure drop has been observed and documented. Thus, the correct sequence following the opening of the main drain is to first observe and record the pressure drop.