Drainage pipes start from the first manhole or inspection chamber to the septic tank or sewer system. After laying the pipes, before use the drains should be tested. Each section in between the manholes should be tested. Its appropriate that this is done at least twelve hours after jointing the last pipe. There are various methods of checking the system. This ensures that the system is air tight to avoid foul smells and leakages along the lines.
The testing of drainage pipes after laying commences with the following method. First the lower end of the pipe and all junctions are securely stopped. The whole length is then filled with water. After filling with water, a stopper is inserted at the top leaving a pipe attached with drain plug. This pipe is bent at ninety degrees and terminated at an elevated tank. The vertical distance of elevation should be at least one meter. This will give gravity flow.
In testing the drainage pipes, water is poured into the header tank. This is kept full for at least three hours. It allows absorption to take place. After this time, the tank is topped up and testing commences. After a period of thirty minutes have elapsed check the water level in the tank. The water level in the header tank should not have fallen. If has dropped by there millimeters then the test is satisfactory. Give one hour and check the levels.
After testing the drain pipes and they fail the test, check the point of leakage. Its important to note that tests are run on pipes laid in trenches but are not covered. The point of leakage is then noted and fixed. This is done using a strong concrete surround with fine aggregates. A minimum cover of one hundred and fifty millimeters is done. Tests are then done again and confirmed. After passing the test, back filling is then done for the trenches.