Calculating pipeline diameters for water supply systems


The purpose of design calculations

Determine the pipeline diameters of a water supply system, which will ensure that all consumers have a design water flow rate with a required pressure head.

These calculations are used when:

  • designing water supply systems
  • econstructing water supply systems

Calculation features

  • Design calculations are performed for a design operating mode of a water supply system.

  • It is possible to perform calculations for dead-end and circular water supply systems operating on one or several sources.

  • Any system element can serve as a source, for example, a spring, water well, or trunk main.

  • Users can indicate water or any other service fluid, such as oil, as a working fluid.

  • When reconstructing a water supply system or planning a prospective development, you can lock the diameters of the existing pipelines; in this case, diameters will be calculated selectively.

  • In order to improve the reliability of a water supply system, calculations can be performed according to the disconnection of sections in loops. The program allows users to disconnect all or select sections. When performing calculations that factor in the disconnection of sections, the system sequentially completes several hydraulic calculations. The first calculation is always carried out without taking into account the disconnections; it records the initial diameters. The calculated diameters are subsequently adjusted in accordance with disconnected sections; when performing subsequent calculations, consumers can be assigned a flow rate reduction factor determined by the consumer category

Calculation criteria for pipelines

Calculated diameters must ensure that design flow rates reach every consumer.

  • Optimum velocity in a network section.
  • Maximum specific line loss in a network section.
  • Minimum required pressure head at points of delivery.
  • It is possible to test for disconnected sections in loops (all or those indicated by the user)
  • Users can set pressure at the connection point.
  • The module complies with the principle of telescoping.

Input data for calculations

The main input data is a diagram of a water supply system created in the ZuluGIS graphics editor. Users subsequently enter a list of input data required for hydraulic calculations for all objects of a water supply system.
  • A model of a water supply system comprises a connection point – it can be any water well, water supply source, or multiple sources. Calculations can be performed based on a known pressure head; if the pressure head is not specified, it will be determined as a result of the calculations.
  • All objects of a water supply system, such as water wells, shut-off or regulating equipment, are encoded in nodal points. Nodes are defined by survey benchmarks.
  • Users can indicate a water supply system of consumer connections or a broader load for the entire block as consumers. Consumers are characterized by design flow rate and minimum required pressure head.
  • Sections of a water supply system are the main calculation units. In order to determine a pipeline diameter, it is necessary to specify its hydraulic properties, such as length, roughness, local resistance and schedule with a list of diameters.

The results of design calculations

  • Pipeline diameters
  • Head required at the connection point
  • Flow rate, head loss and water velocity in sections of the network
  • Pressure in each node
Calculated results are recorded in databases by objects and can be displayed on a map, used to create thematic maps, pressure drop graphs, or put together in a report as specifications for diameters, construction stages, etc.

More about design calculations