2.1 Demanddesign Water Supply System



Which may affect the operation of the water supply system, or which may affect the quality of the supply. 1.1.8 Sources of water supply - Describe the proposed source or sources of water supply to be developed, the reasons for their selection, and information as follows: a. Surface water sources. Hydrological data, stream flow and weather. Online Design of Water Supply Systems - Online design tool for a water supply system; PE Water Supply Pipes - Properties - Nominal pipe size, outside diameter, wall thickness, weight and working pressure; Plumbing Codes - Plumbing or sanitation codes are a set of rules and regulations imposed by cities, counties or states.

Calculating expected demand of water supply in service lines

The total theoretical demand for a water supply system can easily be calculated by adding known maximum demand for all fixtures in the system. Due to the nature of intermittent use this will unfortunate add up to unrealistic demands for the main supply service lines. A realistic demand for a supply system will always be far less than the total theoretical demand.

Expected demand in a water supply system can be estimated as

qet = qnl + 0.015 ( Σqn - qnl ) + 0.17 ( Σqn - qnl )1/2 (1)

where

qet = expected total water flow (l/s)

Supply

qnl = demand of largest consumer (l/s)

Σqn = total theoretical water flow - all fixtures summarized (l/s)

Note that minimum expected total water flow can never be less than the demand from the largest fixture. This equation is valid for ordinary systems with consumption patterns like

  • homes
  • offices
  • nursing homes
  • etc.

Be aware when using the equation for systems serving large groups of people where the use is intermittent, like in

  • hotels
  • hospitals
  • schools
  • theaters
  • wardrobes in factories
  • etc

For these kind of applications, like a wardrobe, it is likely that all showers are used at the same time. Using the formula blindly would result in insufficient supply lines.

Example - Main Water Supply to a Nursing Home

If the theoretical demand from all fixtures in a nursing home adds up to 50 l/s and the larges fixture requires 0.4 l/s, the expected water supply demand can be estimated like

qet = (0.4 l/s) + 0.015 ((50 l/s) - (0.4 l/s)) + 0.17 ((50 l/s) - (0.4 l/s))1/2

= 2.3 (l/s)

Total Theoretical Water Flow and Expected Flow

Expected demand for a supply system at different total theoretical demand can based on the formula above be expressed as

2.1 Demanddesign Water Supply System

Total Theoretical Demand Summarized
(liter/s)
Expected Demand
(liter/s)
0.20.2
0.80.4
1.60.5
4.00.6
8.00.85
151.1
201.5
301.8
402.1
652.8
702.9
1003.7

The maximum fixture load is 0.2 liter/s.

Related Topics

  • Water Systems - Hot and cold water service systems - design properties, capacities, sizing and more

Related Documents

  • Cross-Contamination Control - It is fundamental to keep the potable water in the water supply systems uncontaminated
  • Domestic Hot Water Service Systems - Design Procedure - Design procedure for domestic hot water service systems
  • Fixture Units - WSFU vs GPM and Liters/sec - Converting WSFU - Water Supply Fixture Units - to GPM
  • Fixture Water Requirements - Water outlets demand
  • Online Design of Water Supply Systems - Online design tool for a water supply system
  • PE Water Supply Pipes - Properties - Nominal pipe size, outside diameter, wall thickness, weight and working pressure
  • Sizing Water Supply Lines - Sizing water supply service and distribution lines based on Water Supply Fixture Units (WSFU)
  • Water - Human Activity and Consumption - Activity and average water consumption
  • Water Distribution Pipes - Materials used in water distribution pipes
  • Water Service Pipe Lines - Water service pipe lines extends from the potable water source to the interior of buildings
  • Water Supply - Fixture Units WSFU - WSFU is used to calculate water supply service systems
  • Water Supply Pipe Lines - Sizing - Sizing of water supply pipe lines
  • Water Supply to Public Buildings - Required water supply to public buildings

Demand Supply And Price

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