When water mains are installed, they must be connected to the cities water distributing system. However, there are several procedures that must be carried out before it can be accepted. Read on as we discuss the in's and outs of this entire process.
As we've previously mentioned, the installed water main must be connected to the distributing system. And it must be commissioned as well as properly disinfected before it can be accepted. Typically, this particular project must consist of a consulting engineer and a contractor who installs the pipe. Both of them are initially responsible for making sure that the water mains are disinfected as well as pressure tested. However, as long as a pipe is greater than that of 75mm, it must be subjected to disinfection as well as pressure testing.
Additionally, a bacteriological sample session must be conducted by either a representative from the City or the consulting engineer from companies such as bluelinetesting.ie. As such, samples must then be submitted to the relevant health authorities for further analysis. And, a testing plan of the water mains must be submitted for approval at least five days before the test can actually be scheduled. However, the plan must include the initial plan of the water main as well as flushing locations, test ports, profile drawings, chlorine injection points, pressure testing sections, sampling points, de-chlorination and disposal points.
Before the disinfecting process could be carried out, the water mains must be flushed first. However, they must be flushed with that of a 0.8 m/s minimum flow in order to ensure that any or for that matter all foreign materials and contaminants are removed from within the system. A representative from the City or the consulting engineer must be there to actually witness and sign off on the flushing process. After this has been done, a pressure test must be carried out.
Both leakage and pressure testing must be carried out in order to test the integrity of the system. This is done to ensure that the system is capable of handling various operating pressures as well as to determine if there are any leaks at the connections or joints. After the service connections are installed, the contractors working on the project can perform an unofficial pressure testing after the installation and before the connections are done in order to determine if there are leaks anywhere in the system.
The pressure pump must also be able to live up to the required test pressure. And it must also be able to include two pressure gauges, a backflow preventer and even a pressure relief valve with an upper limit of 1400 KPa. When the test is being carried out, the pipe is pressurized and water is added into the pipe where it is allowed to flow until it reaches deformation. This deformation level is usually attained after roughly 4 or even 3 hours.
During this period, the actual water test begins. The test is typically carried out during a period of 2 hours. And at the end the measured makeup water is added to the return in order to test the pressure.