How to Conduct a Main Drain Test for Your Fire Protection System
Posted on: 20 January 2020
The purpose of the main drain test is to evaluate the status of the water supply on your fire protection system. It reveals if there is any deterioration to the system's water supply and makes a comparison with previous test results. Water supply degradation can be due to a possible obstruction in the system's waterways, fully or partially closed control valve or the check valve's clapper stuck on the seat. Continue reading to understand how to conduct the initial drain test.
It's crucial to understand that this test doesn't evaluate water supply for your systems hydraulic determination purposes. You can only conduct a main drain test after commissioning the fire protection system and when you need to achieve the baseline of system values. The initial test is usually referred to as acceptance testing. During this test, more focus is given to static pressure (when water is not flowing) and residual pressure (while water is flowing).
After accomplishing the acceptance testing the main drain, testing is required either annually or when the water supply control valve is off. This test is vital to ensure that your fire protection system's water supply valve is completely open. Water sprinklers work quite well, but when they experience a breakdown, the leading cause of the failure may be because of a closed water valve. Therefore, you can't overemphasise the importance of an open water supply valve.
Criteria for Conducting the Main Drain Test
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Record the static water pressure found on the supply gauge (A).
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Open the main drain valve (B) slowly and carefully to a maximum open position. Then, allow the water to flow through until it's clear and stabilised.
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Note down the residual pressure that you see on the supply gauge after which you should close the main drain valve.
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Record the total time used for the main water supply pressure to stabilise to its original static pressure state.
After completing the process, compare the results of your previous tests alongside the acceptance tests. This way, you'll be able to pinpoint any problems and deterioration in your water supply system. If you find that there is a 10% reduction in full pressure flow against the earlier tests you conducted, you can identify and fix the leading cause of the decline.
In conclusion, this is how you conduct a main drain test for your sprinkler or fire protection system. It helps you identify and fix any current problems and keep your system working correctly. For more information, speak with a fire testing professional.
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