Water Distribution System Design  

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07/02/2023
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A water distribution system design is a blueprint for building and operating a water distribution system that provides drinkable water to a community. The arrangement of pipes, pumps, and other infrastructure required to carry water from a source, such as a treatment plant, to end customers is included in the design.

The design includes key factors such as estimating the water demand, selecting proper pipe sizes and materials, and constructing pump and storage systems. The design also contains provisions for future system expansion and enhancements.

Furthermore, water is used in most daily activities, such as washing, cooking, drinking, gardening, bathing, and other commercial operations. Pipes and other water delivery components are hidden beneath streets. The pipe pattern is comparable to the road layout of the distribution system, which helps cover most of the region.

This post will cover the essential features of water distribution system design, such as system types, techniques, equipment used, and design concerns. This article will also examine the regulatory procedures and approvals that must be obtained before a system can be built.

We can better appreciate the effort and knowledge required to supply clean, safe water to communities if we understand the numerous components and factors involved in water distribution system design.

Types of Water Distribution Systems

The following are the four main types of water distribution systems:

Dead End System

The name “dead-end system” refers to the fact that it is made up of dead ends in the pipe system. As a result, water does not flow continuously through the closed system. The entire pipe network is divided into multiple subnetworks in this approach. 

The main line, secondary lines, branch lines, and service connections are examples of these. First, a significant line is built through the city or region’s heart. 

Sub mains are created on both sides of the main line and then divided into branch lines from which service connections are made. A shutdown valve is installed at the beginning of each sub-main line to regulate the flow for maintenance, etc. 

This network diagram will resemble a tree in general; hence it is also known as a tree system. This type of system is commonly used in historic cities that were built without good planning. This system is currently unsatisfactory.

Advantages 

  • This system is cost-effective.
  • Laying pipe does not necessitate the use of expert labor.
  • Because there are fewer valves, determining the amount of discharge and pressure is simple.

Disadvantages

  • In rural places, the pressure is erratic and severely low.
  • Dead ends cause water stagnation, which leads to silt accumulation. More scour valves at dead ends must be placed to remove these sediments, enhancing efficiency.
  • If any damage occurs on the branch line, the entire section must be halted so that it can be repaired so that other users on that sub-main line are not inconvenienced.
  • In this arrangement, a limited discharge is available for firefighting.

Radial System

The land is divided into zones by a radial method. The primary water supply pipeline connects to the distribution reservoir or storage tank, which is centrally positioned. Then, from the distribution reservoir to the houses, supply pipes are laid radially. 

Advantages

  • This water distribution technology is ideal for high-rise projects.
  • Water supply outages are uncommon during maintenance or repair operations.
  • The radial system delivers water at a high flow rate with less head loss.
  • This system delivers quick service.

Disadvantages

  • The project is more expensive due to the increasing number of individual distribution reservoirs.

Ring Distribution System

The entire system in this water distribution system is enclosed by a radial or rectangular main pipeline. as illustrated in the figure above. The sub-main pipeline covers the smaller portions. In the event of a system failure, only a small area will be affected.

Water can be delivered to the region in front of the damaged area from other system points. A more significant number of valves are required for the ring distribution system. Water may be accessed from two directions in this configuration.

Advantages

  • In comparison to other distribution systems, the discharge rate is considerable.
  • It can do maintenance and repairs without interfering with water flow.
  • The head loss is modest because there are fewer links.
  • Water stagnation is little or nonexistent because there are no ends.

Disadvantages

  • Pipes of greater length and diameter are required. More shutdown valves are necessary. Skilled laborers are essential when laying pipelines.

Grid Iron System

The main pipeline, the submarine pipeline, and the branch pipelines are interconnected in a grid pattern in a grid-iron system. Interlaced and reticulation systems are other names for grid-iron water delivery systems.

To maintain uniform water pressure, the overall length of the pipeline must be expanded due to the increased number of connections.

A Grid-iron water distribution system is ideal for modern, well-planned municipalities since the main pipeline and branches are rectangular.

Advantages

  • Water flows continuously through pipelines due to the lack of dead ends.
  • It can do maintenance and repairs without interfering with water flow.
  • This water distribution system complies with fire suppression discharge regulations.
  • The connection of pipes reduces head loss to a bare minimum.

Disadvantages

  • Because of the flow recirculation from all directions, the pipes used in this system must have large diameters and longer lengths.
  • We cannot determine the pipe’s discharge, velocity, or pressure. As a result, the design could be simpler.
  • Professional laborers will do pipe laying, which will be more expensive.
  • More needed shutdown valves should be installed in this system.

Methods of Water Distribution System

Blue industrial handwheels of valve
Source: iStock

For a functional distribution system, various locations must have adequate water pressure. Water is pumped into the distribution system in the following ways, depending on the elevation of the source, the topography, and other local factors:

Gravity Supply

Gravity transports water from its source to its distribution area in this water distribution method. The water source, such as a reservoir or lake, must be higher in elevation than the distribution zone for this technique to be effective. 

Because no pumps are required, this method is both energy-efficient and low-maintenance. Furthermore, the system has no rapid pressure fluctuations, making it a constant water delivery method.

Pumped Supply

Pumps pump water into the system when the water source is at a lower elevation than the distribution zone. This approach is required when the source cannot maintain the minimum pressure for the distribution system to function correctly. This method can be more expensive because pumps consume electricity and require periodic maintenance.

Combined Supply

This method combines gravity and pump power. It uses a combination of pumps and storage reservoirs to distribute water to the distribution region. 

This method can be employed when two water sources provide water, when an elevated storage tank is coupled to the system, or when the source is lower than the consumer area. This method provides a more consistent and reliable water supply but is more expensive and requires more maintenance.

Equipment Used in Water Distribution System

Infrastructure

Pipes, pumps, meters, storage tanks, valves, reservoirs, couplings, and other hydraulic components that connect treatment facilities or well supplies to consumers’ faucets are examples of distribution system infrastructure. 

The characteristics, usual maintenance requirements, and desirable qualities of the fundamental infrastructural components of a drinking water distribution system are briefly discussed here.

Industrial Valves

industrial valves used in Water Distribution System
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The two types of valves commonly used in a water distribution system are isolation valves (also known as stop or shutdown valves) and control valves. Isolation valves (typically gate valves or butterfly valves) are used to isolate sections for maintenance and repair. They are positioned to cause as little disruption to adjacent service areas as feasible.

One of the most crucial responsibilities undertaken by a utility is valve maintenance. Many utilities have a regular valve-turning program in which a portion of the valves are opened and closed regularly.

Each system valve should be turned at least once a year. Implementing such a program ensures that water may be switched off or diverted as necessary, particularly in an emergency, and that valves are not accidentally turned off.

Control valves are used to adjust flow and pressure in a distribution system. They are typically sized according to the planned maximum and minimum flow rates, upstream and downstream pressure differentials, and flow velocities.

Control valves include pressure-reducing, pressure-sustaining, and pressure-relief valves, flow-control valves, throttling valves, float valves, and check valves. Most industrial valves are made of steel or cast iron, except those found in premise plumbing to allow for quick shut-off in the event of repairs, which are often made of brass.

In contrast to the smaller-diameter pipes, the transmission mains are spaced more apart throughout the distribution system. Blow-off and air-release/vacuum valves for flushing water mains and releasing entrained air are also components of a water system.

Pipes

The networks of pipes used to transport water from the source (such as a treatment facility) to the customer are commonly classified as transmission or trunk mains, distribution mains, service lines, and premise plumbing. Transmission or trunk mains generally convey large amounts of water across long distances, from a water treatment facility to a distribution system storage tank.

Transmission mains are often more significant in diameter than distribution mains, which generally follow city streets. Service lines transport water from the distribution main to the supplied building or property.

Service lines are sized to maintain the utility’s design pressure at the customer’s property for the planned flows. They can be any size, depending on how much water is required to service a given customer. Premise plumbing refers to the plumbing within a facility or house that distributes water to the point of use. Premise plumbing pipe sizes are typically reasonably small, resulting in a larger surface-to-volume ratio than conventional distribution system pipes.

The three requirements for a pipe are the ability to deliver the proper amount of water, resistance to all external and internal forces acting on it, and durability and longevity. Steel, ductile iron, pre-stressed concrete, polyvinyl chloride (PVC), and reinforced plastic are today’s most often used materials to fulfill these goals.

Notably, this study includes service lines and premise plumbing as part of the distribution system and investigates the effects of service lines and premise plumbing on drinking water quality. When premise plumbing is factored in, the overall length of the distribution system climbs from around one million miles to more than six million miles.

The residence plumbing and service lines have longer residence times, lower flow conditions, more stagnation, and higher temperatures than the main distribution system. Because of their fluctuating ownership, which ultimately determines who is liable for their upkeep, it is uncommon to include premise plumbing and service lines in a public water supply distribution system.

Most drinking water utilities and regulatory bodies are exclusively responsible for water delivered to the curb stop, which is often only a portion of the service line. The building owner is entirely liable for the part of the service line not under the utility’s control and the whole plumbing system on the site.

Pipe-Network Configurations

Most water distribution systems are divided into branches and grids/loops. A branched system is similar to a tree branch in that it consists of tiny pipes that branch off of larger pipes over the service area, allowing water to take only one route from the source to the consumer. This type of technology is mainly used in rural areas.

The most frequent configuration in large municipal regions is a looped/grid system, it consists of connected pipe loops throughout the area to be supplied. Water can follow a variety of pathways to reach the consumer in this type of system.

In the case of a line failure, looped systems provide a high level of reliability since the breakdown can be isolated and have no impact on users beyond the surrounding area. Looping also reduces some of the problems associated with water stagnation, such as unwanted reactions with pipe walls, and increases firefighting capabilities.

On the other hand, loops can be dead ends, especially in suburban areas such as cul-de-sacs, and can cause water quality issues. The vast majority of systems have both looped and branched portions.

Pumps

Pumps provide energy to water to enhance its altitude or pressure. Pumps are often made of steel or cast iron. Most pumps used in distribution systems are centrifugal, meaning water enters the pump through an intake pipe and is expelled outward between vanes and output pipes. One of the most expensive running expenses for a water supply is the cost of electricity for pumping.

What Are the Water Supply Distribution Pipes Designed For

Blue faucet to control sewerage system in ground
Source: iStock

Village

Water supply pipes and water distribution systems are designed for a village project and are essential for providing a settlement with clean and safe drinking water. The location, population size, accessible water supplies, and potential health issues must all be considered while designing water supply pipes. This article will describe how village water supply distribution pipes are designed.

First, the pipe design must consider the village’s population and expected demand. Water distribution pipes should be large enough to meet the predicted flow rate without being excessively massive or expensive. An industrial valve supplier can assist in the selection of the appropriate valves to regulate the flow of water through the pipes. 

Calculations must be performed to calculate the size of pipes required, considering anticipated seasonal variations in water usage and other factors that may influence total water demand.

Second, pipe materials that can survive various climatic conditions while also being corrosion-resistant must be picked. Copper, steel, ductile iron, cast iron, polyethylene, and PVC are common materials used in water delivery pipe designs. All of these materials are adaptable to diverse locales with varying environmental conditions.

Lastly, different types of fittings that are used to connect pipes and regulate the flow of water through them must be considered. Pipe connectors come in various styles intended to suit multiple requirements regarding pressure rating, durability, and cost-effectiveness.

City

City water supply distribution pipes deliver clean, safe drinking water to residential and commercial sectors. In cities, a variety of water delivery systems are used, including:

Water is transported from a central source to a series of branches with no outlets in a system with dead-end branches. This strategy is typically used in areas with a low population density. The gridiron system is similar to the dead-end system, except that the branches are organized in a grid. This approach is used in densely populated areas.

In a radial system, water is transported from a central source to a network of radially oriented branches. This method is commonly used in highly populated areas and is well-known for its efficiency and durability.

The ring system is a cross between the radial and gridiron systems. Water is delivered from a central source to several branches structured in a ring, with a grid pattern within the ring. This method is used in areas with a high population density and provides a more consistent and reliable water supply throughout the distribution region.

Design a Water Distribution System

Open or close valve of cooling tower butterfly valve beside of cooling Tower
Source: iStock

Water distribution systems are among the most important types of infrastructure. The Water distribution design‘s principal role is to provide water to all consumers. 

A sufficient amount of water must be supplied at an adequate pressure. Additional considerations for water delivery systems’ design, construction, and maintenance include environmental preservation, natural resource conservation, and system cost-effectiveness.

Water Distribution Systems Based on Gravity and Pressure

Water distribution systems are classified into two types based on how they work: gravity and pressure systems.

If geography allows, water is distributed from a reservoir at a sufficient height to the distribution region in a gravity system.

Pumps that generate appropriate water pressure aid in water distribution layout. A water system often comprises both gravity and pressure components. Gravity systems are more cost-effective in terms of maintenance.

Water Distribution Network Topology

We distinguish between branching and annular networks in the structure of the water delivery system. The branch network distributes water via one or more distribution lines that terminate at specific locations.

An annular network allows water to be delivered from several routes to a single place. Water supply networks sometimes have both annular and branching components. The branched network’s problem is the tiny flow of water at the branches’ extremities (with a lowered flow rate).

Design Objective

Water distribution systems must meet fire prevention regulations in addition to routine water usage for industry and families. These constraints can significantly increase the cost of building and maintaining water distribution networks.

Water delivery system design follows the same principles and project categories as other constructions. A conceptual solution, conceptual design, main project, or implementation project may be the subject of the project documentation. The concept, substance, and specifics for each project type are given.

What Variables Influence Water Supply System Design?

Spatial variables substantially influence the design of water distribution systems. This covers the effect of geography on pressure distribution in the pipe network.

Land usage and ownership influence construction costs, but soil spatial features influence excavation costs. Construction may cause issues with existing communal infrastructures because the bulk of water supply lines is installed on existing or proposed highways.

What Need to be Consider When Design Water Distribution System

Pressure gauge on condenser water pump
Source: iStock

Several significant criteria must be considered while constructing a water distribution system to guarantee that the system is efficient, reliable, and safe. These are some examples:

The Force of Water

Adequate water pressure is required for the distribution system to work correctly. The system must be built to deliver sufficient water pressure in all locations, including high-rise structures and remote areas.

The Flow Rate of Water

The system must be constructed to produce a sufficient flow rate to suit the population’s needs. This includes considering population density, building and company kinds, and future growth possibilities.

Flow Rate and Pipe Diameter

The flow rate and pipe size must be selected to ensure that the system can provide water at the needed pressure and flow rate. This includes choosing the appropriate size pipes and valves, such as an industrial butterfly valve, to reduce pressure loss and maintain a steady flow rate throughout the system.

Acceptable Alternatives

The system must adhere to all applicable legislation, standards, and guidelines. This involves verifying that the system complies with the local water authority’s and other appropriate regulatory bodies’ requirements.

System design

The system plan must be developed to reduce the danger of contamination while ensuring that the water supply is accessible to all users. This includes considering the position of the water source, the area’s geography, and the location of houses and other structures.

Connection to the Power Grid

The system must be linked to the main water supply to ensure a continuous and reliable supply. This includes where the main supply is located, the size and capacity of the pipes, and the type of valves and fittings utilized.

Backflow

Backflow, or the flow of water in the reverse direction of its intended flow, must be avoided by designing the system. This is necessary to avoid contaminating the drinking water supply.

Connection to the Power Grid

The system must be linked to the main water supply to ensure a continuous and reliable supply. This includes where the main supply is located, the size and capacity of the pipes, and the type of valves and fittings utilized.

Materials and Standards for Pipes

The system must be constructed of appropriate materials and meet the required norms and regulations. Considerations include the type of water delivered, the estimated flow rate, and the expected longevity of the pipes.

These aspects must be considered while constructing a water distribution system to ensure efficiency, dependability, and safety.

Conclusion

A water distribution system is a complex process that necessitates the consideration of numerous elements, ranging from water pressure and flow rate to system structure and regulatory compliance. Engineers can ensure that a water distribution system is efficient, reliable, and safe by knowing the fundamental elements involved in its design.

Industrial valves are one of the most critical parts of a water distribution system. They are essential in regulating water flow and maintaining adequate water pressure. To guarantee that the valves used in the water distribution system are of the highest quality and fulfill all applicable standards and requirements. It is critical to select a reputable and dependable valve manufacturer, such as Dombor.

Dombor is a leading industrial ball valve manufacturer with a large selection of valves for water distribution systems. They offer the knowledge, technical expertise, and a large selection of valves, making them an excellent part of the water distribution system.

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