Main Drain Testing

A main drain test serves as a tool in evaluating the condition of the water supply to a fire sprinkler system. It is intended to reveal any deterioration of the water supply by comparing the test results to previous results. Deterioration of the water supply can be caused by a major obstruction in the waterway or a malfunctioning control or check valve.

It is important to keep in mind that a main drain test is not intended to evaluate a water supply for hydraulic calculation purposes. The main drain test is done when the system is commissioned in order to establish the baseline of values. This initial test is commonly known as the acceptance test. The points of evaluation are the static pressure (no water flowing), and the residual pressure (with water flowing).

After the acceptance test, a main drain test is required:

  • Annually
  • Any time the water supply control valve is closed
  • Any time a fire sprinkler system undergoes maintenance or repair

Main drain testing is essential to ensure that the water supply valve is fully open. Sprinkler systems usually perform exceptionally well. When they do fail, the most common cause of failure is that the water supply valve was closed, thus the importance of verifying the position of the water supply valve cannot be overemphasized.
Macomb Mechanical Fire Protection has a team that has been performing main drain testing for decades.

We are available 24 hours a day to provide main drain testing of your fire suppression systems. Contact us today to ensure that your suppression system if functioning properly.