Gubici vode
 Nepa�nja ?ovjeka Gre�ka institucija Stara infrastruktura Nemarnost odgovornih

 Determining the Leakage Value   Tuesday, 04 September 2012 23:00

As a part of detection and repair, leakages must be defined in the context of volume of water being wasted through them.  There are two empirical and one mathematical methods for determining the value of the defect (leakage)

### Determining the Value of the Defect by Using a Container of Known Volume and a Stopwatch

This is the simplest method for determining the value of the leakage.

The container of known volume is being filled with water during a certain period of time based on which the water flow through the leak is calculated.  If the leakage is smaller, the container is used for one minute and the figure obtained is expressed in l/min.

If the container is to be used for a shorter period of time, then the calculations are performed in accordance with the following table:

 Time in seconds 6 10 15 30 Multiply the volume of the container in liters with 10 6 4 2

Table  - Multiplication coefficient for the container of known volume for the purpose of determining the leakage value

Obtained value represents the value of the leakage expressed in l/min.

### Determining the Value of the Defect by Using a Hose and a Water Meter

This method requires certain intervention on the pipeline.  Handy tools are being made in the ViK�s workshop comprising of a saddle to which the hose and the water meter are connected.

Leakage value is simply read on the water meter.  This is the most precise way to determine the value of the leakage and it is especially convenient for ViK having frequent leakages on the same type of pipeline.

Determining the Value of the Defect by the Application of Greeley�s Formula

For this type of calculation with the application of this formula, it is required to know data on pressure in the system, as well as the cross-sectional area and the shape of the opening through which the water is leaking.  Most often, it is not possible to precisely measure the cross-section and therefore it has to be estimated.

According toGreeley, water outflow is calculated with the following formula:

Qh= 67,947 x A x P1/2

Where:

Qkv- Outflow through the opening expressed in l/min,

A � outflow opening cross-section area expressed in cm2 ,

P � Pressure in the network at outflow location expressed in bars

In the event of leakages appearing on the fittings, valve gaskets and taps, the above formula is being multiplied by the coefficient 0,8.

The following two tables show leakage values through different cross-sections depending on the pressure and values of defects through which the water is flowing drop by drop. Table - Water volume flowing from the openings / crack at different pressure values

 No. of drops per second l/min l/day m3/year 1 0,023 32,71 11,94 2 0,045 65,42 23,88 3 0,068 98,13 35,82 4 0,091 130,84 47,76 5 0,114 163,56 59,70

Table - No. of drops and leakage value ratio