What are the steps for conducting a main drain test?

The correct process for conducting a main drain test involves a specific sequence to accurately assess the water flow and pressure in a fire protection system. Opening the main drain allows for the observation and measurement of the pressure drop that occurs when the system is in use.

Starting with the observation of pressure at the riser provides a baseline for understanding the system's normal operating condition. By opening the main drain, the technician allows water to flow out, which typically results in a measurable reduction in pressure within the system. This pressure drop is crucial data that reflects the system's ability to deliver water during an emergency situation, which informs the effectiveness of the fire protection system.

Finally, recording the pressure drop is essential for documentation and analysis. It helps in evaluating the system's performance and determining whether any maintenance or repairs are needed. This approach ensures a comprehensive understanding of the system’s operational status.

Other sequences listed do not follow the logical flow necessary for a successful evaluation of the fire protection system, either by not obtaining relevant baseline information or by inverting essential steps that could lead to inaccurate readings.