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Cold Water Supply in BuildingWater Distribution in BuildingPlanning the water distribution in buildings for a satisfactory chemical and bacteriological quality includes:1. The system must provide adequate pressure up to extremities of the system.2. The safety and quality of the water should not be impaired by defects in the system. It should be provided with sufficient valves and blow offs, to allow repair work without undue interruption of the system.3. There should be no unprotected open reservoir, or cross connections with inferior water system to enter the distribution system.4. The water system should be tight against leakage. The main and branches connection should not be submerged in surface water, or subjected to any source of contamination.5. The water system design, shall afford effective circulation of water with minimum number of dead end mains.6. The system shall be guarded against contamination in any parts of it resulting from repair works, replacement of extension of the mains.7. When new mains are installed, or old mains repaired, they should be filled with strong chlorine solution of 40 to 60 mg. per liter for at least 24 hours, and then flushed with water supplied normally from the main.8. As much as possible, water main should be laid above the elevation of concrete sanitary sewers, or crossover points, and at least 3 maters horizontally from such sanitary sewer when they are parallel. Should this be impossible for some reasons, the sewer main must be encased in concrete.Public Water Distribution is Classified into:Direct Pressure Distribution- obtain its supply of water through a large intake pipe, installed in the lake basin extended down the water.Indirect Pressure Distribution- when the water drawn from a drilled distribution is done by indirect pressure.Household Water SupplyHouse Service the pipe connection from the public water main or any source of water supply to the building servedRiser - the vertical-supply pipe which extend upward from one floor to the nextBranches horizontal pipes that serve the faucets or fixturesWater Main

- The public water connection which are laid underground along the streets where the house service is connected.Types of Cold Water DistributionBy normal water pressure from the public main.By overhead feed system.By air pressure distribution systemThe Overhead Feed SystemSupplies water to the plumbing fixtures by means of gravity.

ADVANTAGES:Because of the water stored inside the tank, water supply distribution is not affected by the peak load hour even if the pressure at the water main becomes considerably low.Power interruptions will not in any manner affects the water supply inside the building.In case the pumping unit breaks down, the time required to replace parts will not affect the regular supply of water.

DISADVANTAGES:The water inside the tank is exposed to the natural elements of weather, subject to contamination.The water distribution unit has many working parts that require higher maintenance cost.The pumping unit and the entire installation throughout the building occupies valuable spaces.It requires stronger foundation and other structure to sustain the heavy load of the tank and its water content.Air Pressured Water DistributionIs a new concept in water distribution where compressed air is used as the delivery agent.

ADVANTAGES:It has a compact pumping unit that requires a limited space.The water chamber being air-tight makes the system a sanitary one.The oxygen in the compressed air passing through the water line, serves as purifying agent, making the water more palatable.It offers economic advantages by installing a smaller pipe diameter.It has few working parts and therefore, less initial construction and maintenance cost.Air pressurized water distribution system is well accepted for small, medium and large buildings.Air pressured water distribution system serves zones of about 10 storeys or floor intervals in buildings of extreme height.

DISADVANTAGEThe only disadvantage of the air pressurized water distribution system is the interruption of water supply.

There are four mechanical devices used in air pressurized water supply system:A large Storage Tank, with all tapping requiredA single or duplex centrifugal pumpAn air compressorAn automatic pressure control switchDirect Up-feed Pumping SystemUsed on tall building that could not be served adequately by the street main.This sophisticated process could deliver water at varying rates needed from two, three or several faucets up to the full demand of the entire building fixtures

ADVANTAGES:Eliminate the construction of large house water tank.Avoid cost of heavy structures to carry the house tank.Eliminate periodic cost.Friction in Water Supply and Distribution SystemFriction when alluded to in the plumbing system refers to the resistance produced by the flowing water with the fittings and interior surface of the pipe.

Friction in water supply and distribution system can be minimized under the following conditions:All water pipes should be installed straight and direct as [possible.The use of turns, offsets, and traps, should be minimized if cannot be avoided.Pipes with plain and smooth surface should be used.The use of fittings, stops, and other devices connected to the distribution lines, should be minimized.All fittings and joints must be connected properly.PressureIs the force required to move the water inside the pipe.

Static Pressure - the pressure exerted by the water at rest. Normal Pressure the pressure range measured over a period of 24 hours.*Pressure reducing valve installing this can minimize the excessive water pressure Critical Pressure the maximum and minimum pressure at which proper function of the water supply system can be maintained Friction Head Loss the loss in rate of flow, due to friction between the water and the walls of the pipe Pressure Lose The variations in pressure between the water main and the outlet end of the water service.Other Causes of Pressure LossSimultaneous draw or use of waterHeight or distance to which the watermust flowFluctuation of water pressure in the water mainMineral elements in water that adhere to the interior of the pipe reducing the diameter.In adequate size of the pipe

Water supply coming from the public water main is also affected by water pressure fluctuations caused by:Peak loadEmergency drawBreakdown of lines or pumping unitInsufficient water level at the water system reservoirMaximum and Probable DemandMaximum Demand the maximum water discharges of fixtures in terms of fixture units.

The maximum demand of water is equal to the Total Fixture Units in the plumbing system, where one unit is valued at 8 gallons of water discharged per minute interval.

Example:

One water closet I valued at 6 fixture units. Therefore, 6x8= 48 gallonsProbable Demand or Peak Load

the fewer the number of fixtures installed, the higher the percentage of probability of their simultaneous use, and the greater the number of fixtures installed, the lower the percentage of probable simultaneous use.

if a fixture can discharge, only a given quantity of water, wherein the water supply may not be overtaxed above this amount of water without causing overflow of the fixtures being used, the, the maximum demand of water is the total sum of its fixture units wherein each fixture unit represents 8 gallons of water.Water Service Pipes for large buildings, The National Plumbing Code provides that:

the minimum size of the water service pipes from the curb to the building shall be 38mm (1 ) diameter for the following fixturesSill Cock5. LavatoriesHot water boiler6. BathtubLaundry tray7. Water closetSink

Water Pumps and LiftsTypes of Pump:Piston Pumps is used on small water distribution system for elevating water in wells or other sources.a. The Single action pumpb. Double action pumpc. Duplex or Twin Piston pump2. Centrifugal Pump associated with tall building water distribution systemWater Service Fittings and DevicesThe different types of valves used in water supply system are:The Gate Valve used to completely close, or completely open the line but not necessarily to control the flow of water.

a. The Wedged Shape or Tapered Disc- used where the stem must be installed pointing downward

b. The Double Disc Valve- closes in the same manner as the wedged type, except that its parallel faces drop in a vertical position, and are forced apart by the disc spreader.

2. Globe Valve is actuated by a stem screw, and hand wheel, suited on installation that calls for throttling.

a. Plug Type Disc Valve- has a wide bearing surface producing good resistance to the cutting effects of scale, dirt and other kind of foreign matter found inside the pipe.

b. Conventional Disc Valve- has a pressure tight bearing between the disc and the seat recommended for cold water and any temperature service.

c. Composition Disc Valve- used for various types of services on oil, gasoline, steam, and hot or cold water.

3. Angle Valve operates in the same manner as the globe valve but is used in making 90 degree turn in a line to reduce the number of joints.

4. Foot Valve (Retention Valve) located at the lower end of the pump used to prevent loss of priming the pump.

5. Check Valve main function is to prevent the reversal flow of gas or liquid in the line. It is principally used in industrial piping connections for gas, water, steam, air and other vapor services.

6. Safety Valve used on cold water systems, heating systems, compressed air lines, and other pipelines with excessive pressure.

a. Corporation Stop inserted into the water main and serves as a control of the water service.

b. Curb Stop installed between the curb and the sidewalk line accessible to cast iron stop box equipped with removable cover.c. Meter Stop controlling stop of the entire water supply in buildingd. Water Meter a device used to measure the amount of water that passes through the water service.