Conveyance System: Regulation and compliance
Before a water supply system is constructed or modified, the designer and contractor need to consult the local plumbing code and obtain a building permits prior to construction. Even replacing an existing water heater may require a permit and inspection of the work. NSF 61 is the U.S. national standard for potable water piping guidelines. National and local fire codes should be integrated in the design phase of the water system too to prevent "failure comply with regulations" notices. Some areas of the United States require on-site water reserves of potable and fire water by law.
• Closed - rectangular or Circular or horse shoe section built of masonry or R.C.C.
• They are generally designed as ½ or 3/4th full.
• When designed as grade aqueducts, should not made to run full under pressure.
• Because of tension developed - open out joints of masonry work endangering structural stability - causing serious leakage.
• Closed conduits - no air can enter into it.
• Water flows under pressure above the atmospheric pressure.
• Pressure pipes follow the natural available ground surface.
• Moves freely up and down hills or can dip beneath valleys or mountains.
• Pressure aqueducts / Pressure tunnels - closed pipes
or closed aqueducts and tunnels.
• Circular in shape always - Hydraulic and structural reason.
• Due to Circular shape - pressure conduits are termed as Pressure pipe.
• Pressure pipe - drops beneath a valley, stream or some other depression - So called Sag / Depressed pipe / Inverted siphon.
Significance of Pressure Conduits
• Economical than canal or flumes
• Follow short routes
• Moving water - not exposed anywhere - no chances of getting polluted
• Invariably and universally used for water supplies
- Gravity conduits - used for carrying sewage and drainage
• No percolation and evaporation takes place as in canals
• Preferably used when water is scarce
Hydraulics of Flow in Pipes
There are many basic principles that must be considered when preparing the hydraulic profile through the plant.
1.The hydraulic profiles are prepared at peak and average design flows and at minimum initial flow.
2.The hydraulic profile is generally prepared for all main paths of flow through the plant.
3.The head loss through the treatment plant is the sum of head losses in the treatment units and the connecting piping and appurtenances.
The head losses through the treatment unit include the following:
• Head losses at the influent structure.
• Head losses at the effluent structure.
• Head losses through the unit.
The total loss through the connecting piping's, channels and appurtenances is the sum of following:
• Head loss due to entrance.
• Head loss due to exit.
• Head loss due to contraction and enlargement.
• Head loss due to friction.
• Head loss due to bends, fittings, gates, valves, and meters.
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