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CHAPTER 5: SEWAGE TREATMENT PLANT

To protect water resources and the greater environment, all waste from buildingsand industrial processes must be treated to meet certain standards of quality. Domesticsewage from dwellings and DWV systems in buildings are permitted to be dischargedinto the public sewers system, which provides the necessary treatment prior to titsdischarge into nature.

Water Treatment and Disposal

Basic Purposes of sewage treatment

1. To destroy pathogenic micro organisms. Pathogens are disease-causingbacteria.

2. To remove most suspended and dissolved biodegradable organic materials.

Raw or untreated sewage is mostly pure water since it comprises about 99.9% waterand only about 0.1% impurities. However, sewage contains biodegradable organicmaterial, which is very likely to contain pathogenic micro organisms.

The amount of pathogens in the waste water is expected to be proportional to theconcentration of fecal coliform bacterium cal E. coli (Escherichia coli). The E. coliconcentration in raw sanitary sewage is about 1 billion/ liter, but it is not a pathogen. Infact, our bowels will not function properly without it, but as an indicator organism, thepresence of E. coli indicates that water is contaminated with fecal wastes andpathogens maybe present. DENR standard is 10,000 MPN/ 100ml.

For water to be safe for drinking the E. coli count shall not be more than 1 E. coliper 100ml (about 0.4 cup) of water.

For water to be considered safe for swimming the E. coli shall be more than 200E. coli per 100ml of water.

Biological Oxygen Demand (BOD). The measure of the strength of the sewage inrelation to the total amount of organic material it contains. Untreated domestic sanitarysewage has an average BOD of about 200mg/ liter. DENR standard is 50 mg/ liter.

Total Suspended Solids (TSS). The measure of the strength of the sewage in relation

to the total amount of suspended solids. Untreated domestic sanitary sewage has anaverage TSS of 240 mg/ liter.

Another group of impurities that is of major significance in waste water is thecompounds of nitrogen (N)and phosphorous (P)from plant nutrients. Raw sanitarysewage contains an average of 35mg/ liter of nitrogen and 10 mg/liter of phosphorous.

THE SEWAGE TREATMENT PROCESS

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The sewage treatment process may be divided into four major steps:

1. Preliminary treatment. 35% of BOD and 60% of TSS are removed.2. Primary Treatment, which is subdivided into:

Sedimentation and retention: raw sewage is retained for the preliminary

separation of indigestible solids and the start of aerobic action. Aeration: introduction of air through natural convection or mechanical

blowers to accelerate the decomposition of organic matters.

Skimming: Removal of scum that floats on top of the partially treatedsewage.

Sludge Removal: disposal of heavy sludge at the bottom of treatedsewage.

In the primary treatment, 85% of BOD and 85% TSS are removed.3. Secondary Treatment, namely, the removal of colloidal and dissolved organic

material.4. Tertiary Treatment, that is, the removal of dissolved nitrogen and phosphorous

and disinfection of effluent by the addition of chemicals, such as chlorine (10mg/liter).

Sewage Treatment PlantsThe design of sewage treatment plants for large buildings, building complexes andmunicipalities follows precisely the same processes described above. However, moderntreatment plants do require considerable mechanized equipment and controls in orderto be efficient and reliable. Sanitary Engineers or Plumbing Engineers who specializedin the subject do the design of these treatment plants.

Following are the definitions of some commonly used terms related to the subject ofsewage treatment methods and disposal processes:

1. Digestion- That portion of the sewage treatment process in which biochemicaldecomposition of organic matter takes place, resulting in the formation of simpleorganic and mineral substances. Also known as aerobic (bacterial) digestion.

2. Influent-Untreated sewage flowing into a treatment system.3. Effluent-Treated or partially treated sewage flowing out of a treatment system.4. Sedimentation- Formation of layers of heavy particles in the influent5. Aerobic (bacterial) digestion-Digestion of the waste through the natural bacteria

digestive action in a tank or chamber.6. Active Sludge-The sewage sediment, rich in destructive bacteria, which can beused to break down fresh sewage more quickly.

7. Filtration-a means of filtering out any solid matter from the effluent.8. Disinfection-A process to disinfect the effluent with chemicals.9. Percolation-the flow or trickling of a liquid downward through a filtering medium.

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A summary of waste water treatment.

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CHAPTER 6: PLUMBING MATERIALS DRAINAGE PIPES ANDFITTINGS

Drainage pipe. This is the pipe that conveys waste from the building to an approvedpoint of disposal.

Drainage Fittings. This are pipe accessories in the drainage system such as acoupling, bend, wye, etc; used to join two or more pipes together or to change theirdirections.

TYPES OF DRAINAGE PIPES

1. Waste pipe2. Soil pipe3. Storm pipe4. Vent pipe

1. Waste pipe. The pipe which carries only liquid waste, free of human excrementor fecal matter.

2. Soil pipe- the pipe which carries the waste from water closets, urinals or fixturesof similar function to the building drain. This contains human excrements.

3. Storm pipe-the pipe which convey rainwater from the roof gutter and downspout to the building storm drain.

4. Vent pipe-the pipe connected to the drainage system that conveys air to andfrom the system and keep the water from being siphoned from the trap.

Branch-is the drainage pipe that runs horizontally.

Stack- is the vertical drainage pipe.

The selection of piping materials for the drainage system depends on the following:

1. Pressure 5. Initial cost2. Velocity 6. Installation cost3. Temperature 7. Operating problem4. Corrosiveness of the medium conveyed within

Common drainage pipes and fittings materials used

a. Asbestos Cement Pipe (ACP)b. Cast Iron Soil Pipe (CISP)c. Concrete piped. Vitrified Clay Pipee. Plastic Pipe

i. Polyethylene (PE)ii. Polyvinyl Chloride (PVC)

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iii. Acrylonitrile- Butadiene- Styrene (ABS)f. Iron Pipe Size (IPS)- Iron, Steel, Brassg. Lead

i. Safe spans is 10.56 kg/m2and 1.6mm thickii. For flushing or vent terminals- 14.63 kg/ m

2and 1.2 mm thick

iii. Lead bends and lead trap shall not be less than 3.2mm in wall thickness.

ASBESTOS CEMENT PIPE

This type of pipe is made of asbestos fibers combined under pressure with Portlandcement and silica to form a dense and homogeneous material. It is dense cured forstrength.

TYPES OF ASBESTOS CEMENT PIPE

1. Pressure A.C. Pipe- is used for sewer mains, industrial effluent and process

piping, working pressure ranges at 100, 150, and 200 psi.2. Non-pressure A.C. Pipe- is used for sewer casings for electric cables and asstorm drains.

Properties:Diameter: 75mm (3) to 900 mm (13)Length: 3.00m (10) or 4.00m (13)

For 75, 100, 150mm.4.00m (13) for 200mm. (80Through 900 mm. (36)

Grades: 1500, 2400, 3000, 4000 and 5000

Lbs/ft.Joints: rubber gasket joint and cement joint

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Note:Asbestos cement pipe (ACP) is remarkably suited for embedment in concrete

structure since both materials have the same properties.

COMMON TYPES OF PIPE FITTINGS

1. Bends (elbows)- are used to complete change of direction in soil, waste anddrain lines in horizontal, vertical and diagonal directions.

2. Y (wye) branches- are used for change of direction (diagonal) and branch

connections of soil, waste and drain pipes.3. T (tee) branches- are used to join 3 or 4 pipes at perpendicular directions.

CAST IRON SOIL PIPE

Cast iron soil pipe (CISP) is made from an alloy of iron, carbon and silicon, with thecontrolled amounts of manganese, sulfur and phosphorous. This is primarily used forsanitary drain, waste and storm systems.

CLASSIFICATIONS OF CAST IRON SOIL PIPE

1. Class A- extra heavy (xh)- is often used for underground applications.2. Class B- Service weight (SV)- is used for general building installations.

TYPES OF CAST IRON SOIL PIPE

1. Single hub- is equipped with one hub and one spigot end and used in theinstallation of plumbing in its full length.

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2. Double hub- is constructed with a hub on each end so it may be cut into twopieces when a short piece of pipe is needed.

3. Hubless (no hub)- there is no hub on either ends of the pipe, it is used in lieu ofthe single hub calking of the pipe is difficult.

PROPERTIES

Available diameter (Nom. I.D.)2, 3 , 4, 5, 6, 8, 10, 12, 15

Hydrostatic Test:50 psi for service weight100 psi for extra heavy

Length: 5 and 10

TYPES OF JOINTS FOR CAST IRON SOIL PIPE

1. Lead and Oakum (calk joint)2. Neoprene Compression gasket3. Stainless Steel Couplings (for Hubless pipe)

*Oakum- a hemp treated with pitch to make it moisture proof and resistant to theelements contained in the waste.

*Calking- plugging an opening with oakum and lead that are pounded into place.

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*HUB- that portion of the pipe which, for a short distance, is sufficiently enlarged toreceive the end of another pipe of the same diameter for the purpose of making a joint.It is also known as Bell.

*SPIGOT- the end of the pipe that fits into a bell or spigot.

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FITTINGS FOR CAST IRON SOIL PIPE

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CONCRETE PIPE

Concrete pipe is cast in metal molds and compacted by tamping or spinning the molds(centrifugal casting).

TYPES OF CONCRETE PIPE

1. Non-reinforced concrete pipe- is used for drainage, sewer lines and for gravity-flow water supply lines if the joints are carefully made. Diameters available rangefrom 100mm. (4) to 900mm (36).

2. Reinforced concrete pipe (RCP)- is made by the addition of steel wire or steelbars and is primarily used for sewage and storm drainage. Diameters availablerange from 300mm (12) to 3600mm (144)

VITRIFIED CLAY PIPE

Vitrified clay pipe is extruded from a suitable grade of shale or clay and fired in kilnsproducing an extremely hard and dense corrosion resistant material. It is generally usedfor underground public sewers, house sewers, drainage (sanitary and storm) systemsand for industrial wastes such as acids.

Vitrified clay pipe is suitable for most gravity-flow systems and is not intended forpressure service. It is brittle and cracks when laid on unstable ground or base.

PROPERTIES*Diameter- 100mm (4) to 1050 mm (42)*Grades- standard

- extra strength- perforated

*Joints - cement joint- pre-fabricated compression seals

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VITRIFIED CLAY PIPE FITTINGS

PLASTIC PIPES

Plastic pipe is available in compositions designed for various applications includingdrain, waste and vent. (DWV)

BASIC TYPES OF PLASTIC PIPE

1. Thermosel Plastic- has the property of being permanently rigid. Epoxy and fiberglass are example of this.

2. Thermo Plastic- is a material having the property of softening when heated andhardening when cooled.

TYPES OF PLASTIC PIPES FOR DRAINAGE SYSTEM

1. Polyethylene (PE)- the high density P.E. spiral pipe (HDPE) is used as drainageand sewer pipe for housing complex, playground, golf course, industrial farm andstock farm.

It is sufficiently flexible to follow ground contours of snakearound obstacles.

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HIDE PIPE FITTINGS

2. Polyvinyl Chloride (PVC)- is a thermoplastic type which is composed ofmolecules of polymers. Each molecule is a long chain made of carbon, hydrogenand other atoms which are melted down and molded.

HDPE SPIRAL PIPE

Properties*Diameter- 100mm (4) to 900mm (36)*Color- black*Joint- Screw-type couplings*Brand- Atlanta

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TYPES OF PVC PIPES USED FOR DRAINAGE

1. uPVC Sanitary pipes (unplasticized)- (DWV) is designed for above andunderground sanitary piping system. It is ideal for drain, waste and ventinstallation.

2. uPVC Sewer Pipe- can be used for main sewer system and other undergroundwaste piping system which requires big diameter pipes.

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CHAPTER 8: WATER SUPPLY SOURCES

Providing water in buildings is one of the most critical utility requirements. A building

without water supply is unfit for human habitation.

Generally speaking, potable water is supplied from a local utility through a public watersystem.

For buildings without public water system, an alternative source of water must beconsidered, such as springs, wells and rain water.

Plunger. This is used to clear thetrap at floor drains, or minorobstructions through a pumpingaction. This is also known asPlumbers friend or Plumbershelper.

Calking Iron-this is used for

caulking oakum and lead forbed and spigot joints.

Tin snip. This is used for

cutting G.I. sheets for straps tanchor pipes.

Soldering Copper. This isused for soldering lead onflashing of vent pipes on G.I.Roofing.

Plumb Level. This is used to

establish and guide grades onhorizontal drain pipe runs.

File. This is used to removethe burrs of cut pipes.

Plumb Bob.This is used forestablishing vertical runs forpipes.

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SPRING WATER SOURCE

In most conditions, springs are shallow wells with water supply just a few meters fromthe ground surface. If this is the source of domestic water supply, careful attention mustbe given to yield and purify. The flow may stop during dry season or surface water may

get contaminated.

Spring water can be developed so as to secure maximum protection from contaminationby excavating sufficiently to locate the true spring openings and to insure a securefoundation for the encasing structure. This structure is known as a spring box whichserves as a collector for spring water. Water collected from the spring box flows to alarger storage tank and then to the distribution pipes.

The determination of the yield of the spring water source employs a very simpleprocedure. They are as follows:

1. Channel the flow of the spring into a collection basin. Make sure that the basincollects all available flow.2. Place an overflow pipe through the dam so that the collected water flows freely

through the pipe. There should be no leakage around the pipe.3. Put a bucket of known volume (for example, a 10-liter bucket) under the overflow

pipe to catch the flow.4. With a watch, measure the amount of time it takes to fill the bucket. At this

instance, the rate of flow can be determined.5. Check the rate of flow per day if it is sufficient to supply the daily water demand

of the occupants.

SAMPLE PROBLEMS (DETERMINATION OF SPRING YIELD)

It takes a spring 60 seconds to fill a 10-liter bucket. Determine if its daily yield issufficient to the water demand of the community of 200 people. The average daily waterconsumption per person is 60 liters.

Solution:

Determine the rate of flow ( in liters/ second)

Rate of Flow= 10 liters = 0.16 liters/ second60 seconds

Determine the daily yield ( liters/day)

Daily yield= 0.16 liter x 60 seconds x 60 minutes x 24 hoursSecond 1 minute 1 hour 1 day

= 13, 824 liters per day

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Determine total daily water demand

Total demand= 200 persons x 60 liters/ person / day

= 12,000 liters per day

Therefore, the spring with the daily flow of 13,824 liters can sufficiently meet thedemand of the community of 200 people.

WELLS

Wells are holes or shafts sunk into the earth to obtain water from an aquifer. An aquiferis a water-bearing formation of gravel, permeable rock or sand that is capable ofproviding water, in usable quantities, to springs or wells.

The design and proper construction of a well require scientific knowledge of

hydrogeology, common sense and practical experience.

The types of wells generally refer to the method of its construction, which are:

1. Dub2. Bored3. Driven4. Drilled

a. Percussion or standardb. Rotaryc. Reverse-circulation rotaryd. Jetting

1. Dug wells- These are wells 60 centimeters or more in diameter dug throughthe soft upper soil. The sides may be of masonry or concrete to prevent from caving-in.It is necessary that the well should be impervious to a depth of at least 3 meters.

2. Bored wells these are constructed using either hand or power driven earthauger. A well casing is lowered to the bottom of the hole. After the boring is complete,cement grout is poured to fill the gap between the bored hole and the well casing. Thisis to prevent contamination.

3. Driven wells- a driven well is done by forcing into the earth a 60 to 90centimeter long piece of perforated steel tube attached to a pointed screen called adrive point. This type of well varies from 32 mm diameter at a depth of 3 to 12 meters.

4. Drilled Wells- A drilling rig is used to drill the well hole and then a casing ortubular pipe is forced down the hole to prevent it from caving-in. when a water-bearingstratum of sufficient capacity is found, a well screen is set in place to permit the water toflow into the casing and to hold back the fine material. The depth of this well is limited

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only by the distance one must dig to obtain an adequate supply of fresh water, evendown to 450 meters.

RAIN WATER SOURCE

In terms of resource conservation, rainwater is an attractive alternative. Rain water issoft and is near to the purest state in the hydrological cycle. However, air pollutioncauses rainwater to be acidic which corrode non-ferrous pipes and cause rusting andclogging of steel pipes.

In spite of these conditions, rainwater collection system remains a viable water sourcealternative. This system typically employ a cistern or covered reservoir tanks to storewater collected from roofs or other relatively clean, impervious surfaces. The collectedrain can be used for flushing water closets and urinals, as well as for landscapepurposes wherein potable water is not necessary.

The city council of Cebu promulgated City Ordinance No. 1711 otherwise known as thewater conservation and Flood Prevention ordinance. This ordinance requires allprojects to provide a permanent rainwater tank or container proportionate to the roofarea. These are stated as follows:

A. For commercial, Industrial and Institutional buildings

One cubic meter of tank/ container for every fifteen (15) square meters of roofarea and deck, up to a maximum of seven (7) cubic meters.

B. For Residential Buildings (Php 500,000.00 and above project cost)

One cubic meter of tank/ container for every fifteen (15) square meters of roofarea and deck, up to a maximum of three (3) cubic meters.

SIZING OF RAIN WATER CISTERN

There are two methods that can be used in determining the size of the storage tank forrain water:

1. The use of Cebu city Ordinance 1711 which states that for every fifteen (15)square meter of roof area, one (1) cubic meter of rain water can be collected.This is the short method of sizing the cistern.

2. The use of the rain fall data of the locality. This is the long method of determiningthe size of the cistern.

SAMPLE PROBLEM1: SIZING OF RAINWATER CISTERN BY LOCAL RAINFALLDATA

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3. Solving for the amount of available rain water per month:

Available rain water = monthly rain fall x roof area x 80%

Therefore:

Average Monthly supply: 1,302, 960 / 12 = 108,580 liters

4. Add the available rain water cumulatively

January 87,200 liters July 630,320

February 144,080 August 752,480

March 187,760 September 901,840

April 234,640 October 1,062,960

May 331,360 November 1,192,800

June 472,960 December 1,302,960

January 109.00 x 1000 x 0.80 87, 200 liters

February 71.10 x 1000 x 0.80 56, 880

March 54.60 x 800 43,680

April 58.60 x800 46,880

May 120.90 x 800 96,720

June 177.00 x 800 141,600

July 197.70 x 800 157,360

August 152.70 x 800 122,160

September 186.70 x 800 149,360

October 201.40 x 800 161,120

November 162.30 x 800 129,840

December 137.70 x 800 110,160

TOTAL 1,302,960 liters

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CHAPTER 9: DOMESTIC COLD WATER SUPPLY

Definition

The domestic cold water supply of the plumbing system consists of the piping and

fittings which supply cold water from the building water supply to the fixtures, such aslavatories, bath, tubs, water closets and kitchen sinks. This is also known as waterdistribution system.

Elements of water Distribution system

1. Water service or house service2. Water meter3. Horizontal supply main or distribution main4. Riser5. Fixture branches

6. Valves and control7. Storage tanks

General types of water distribution system

1. Upfeed Distribution systema. Directb. Pneumatic air-pressure system

2. Down feed distribution system

Materials for Mains, Risers and Branches

1. Galvanized Iron (G.I.) Pipes and fittings, schedule 40- is moderately corrosionresistant and suitable for mildly acid water. It is connected to its fitting withthreaded connections. It is available in diameters form 12 mm (1/2) to 300 mm(12) at a length of 6 meters (20 feet).

2. Polyvinyl chloride (PVC) Pipes and fittings, schedule 40- is economy and ease ofinstruction make it popular, especially on low budget projects.

3. Polybutilyne (PB) pipe4. Polyethylene (PE) pipe5. Copper Pipes and Tubing

a. Type K- used primarily for underground water service. It is color-coded ingreen.

b. Type L- is most popular for use in water supply system. It is color-coded inblue.

c. Type M- it has the thinnest wall and is used where water pressure is nottoo great. It is color-coded in red.

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Fittings

A variety of fittings must be used to install the piping in the project. Fittings areaccessories usually standardized, used for joining two or more pipes together.

Fittings include:1. Nipple- a short of piece of pipe, threaded on the outside (male threads) at bothends, used to join couplings or other fittingsa. Short nipple- below 75mm in length. Also known as shoulder nipple.b. Long nipple- over 75mm in length.c. Close nipple- where threading meet.

2. Couple- a short internally threaded (female thread) at both ends and used toconnect two pipes in straight line.

3. Elbow- a pipe fitting having a bend and makes an angle (90oor 45

o) between

adjacent pipes for a change in direction. It is also known as ell or straight elbow.a. Reducing elbow- Joins two pipes of different diameters at right angle of each

other. When specifying reducer fittings, the bigger diameter is stated first,(followed by the smaller diameter. (example: reducing elbow, 25mm x 20mm)b. Street elbow- an elbow fitting having a 45oor 90obend with an inside thread

on one end and outside thread on the other. It is also known as service ell orstreet ell.

4. Tee- a T-shaped pipe fitting that joins 3 or 4 pipes at perpendicular directions.a. Straight tee c. reducing teeb. Straight cross tee d. reducing cross tee

THE WATER DISTRIBUTION SYSTEM

ELEMENTS OF WATER DISTRIBUTION SYSTEM

1. WATER SERVICE OR HOUSE SERVICE

2. WATER METER

3. HORIZONTAL SUPPLY MAIN OR DISTRIBUTION MAIN

4. RISERS

5. FIXTURES BRANCHES

6. VALVES AND CONTROLS

7. STORAGE TANKS

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SERVICE TAP CONNECTION DETAIL

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CORPORATION COCK- a valve screwed into the street water main to supply the houseservice connection.GOOSE NECK- the part of a pipe curve like the neck of a goose, usually flexible.CURB STOP- A control valve for the water supply of a building, usually placed in case ofemergency or should the water supply of the building be discontinued.

WATER CONNECTION DETAIL

WATER METER- a mechanical device used to measure the volume of water passingthrough a pipe.METER STOP- A valve placed at the street side of the water meter and serves as acontrolling device for the building installation.

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GENERAL TYPES OF WATER DISTRIBUTION SYSTEM

1. UPFEED DISTRIBUTION SYSTEMa. Direct systemb. Pneumatic air-pressure system

2. DOWNFEED DISTRIBUTION SYSTEM

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5. Reducer- a pipe coupling with inside threads, having one end with a smallerdiameter than the other and used for connecting pipes of different size. Bothopenings have the same center line.

6. Bushing- a pipe fitting which is threaded on both the inside and the outside andused to reduce the size of the pipe opening to receive a pipe or fitting of adifferent size.

7.Plug- is used to close an opening in a fitting.

8. Cap- is used to close the end of a pipe.

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9. Union- a three piece pipe fitting used to connect the ends of two pipes, neither ofwhich can be turned. It is also used on pipes that are to be taken downoccasionally. Its parts are:

a. Thread pieceb. Center piece

c. Shoulder piece

10.Flange- a ring shaped plate screwed on the end of a pipe and provided withholes for bolts, to allow joining the pipe to a similarly equipped adjoining pipe.The resulting joint is a flanged joint.

11.Extension Piece-

VALVES

Valves are used to control the flow of water throughout the supply system. The proper

location of valves simplifies repairs to the system, fixtures, or equipment being served.There are usually valves at:a. Risersb. Branchesc. And pipes to individual fixture or equipment

Types of valves1. Gate valve2. Globe valve3. Check Valve4. Angle valve

5. Ball valve/ stop cock6. Faucet/ Bibb

TYPES OF PIPE JOINTS

1. Threaded joints- used in Galvanized Iron (G.I.) pipes and fittings. The threadextensions of the G.I. pipe are as follows:

PIPE SIZE THREAD EXTENSION NO. OF THREAD PER25MM (1)

6mm (1/4) 9mm (3/8) 18

9mm (3/8) 9mm (3/8) 1812mm (1/2) 12mm (1/2) 14

19mm (3/4) 14mm (9/16) 14

25mm (1) 17mm (11/16) 11

32 mm (1 ) 17mm (11/16) 11

37mm (1 ) 17mm (11/16) 11

50mm (2) 19mm (3/4) 11

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2. Solder joints- for rigid and flexible copper tubing.3. Flared joints- for flexible copper tubing.4. Solvent weld or cement joint for plastic pipe.

NIPPLE- a short piece of pipe, threaded on the outside (malethreads) at both ends, used to join couplings or other fittings.

COUPLING- a short internallythreaded (female thread) atboth ends and used to connecttwo pipes in a straight line.

TEE- a t-shaped pipe fitting that joins 3 or 4 pipes at perpendiculardirections.

REDUCER- a pipe coupling, witinside threads, having one endwith smaller diameter than theother and used for connectingpipes of different size.

Both openings have the samecenter line.

ELBOW- a pipe fitting having abend and makes an anglebetween adjacent pipes for achange in direction.

Also know as ELL

REDUCING ELBOW- joins twopipes of different diameters atright angle of each other.When specifying reducer fittingsthe bigger is stated first,

followed by the smallerdiameter.(example: reducing elbow 25mmx 20 mm)

STREET ELBOW- a pipe fittinghaving 45

oand 90

obend with a

inside thread on one end and aoutside thread on the other.

It is also known as SERVICEELL or STREET ELL

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BUSHING- a pipefitting which isthreaded on both theinside and the outsideand used to reducethe size of the pipeopening to receive apipe or fitting of adifferent size

PLUG- is used to closean opening in a fitting.

CAP- is used to closethe end of a pipe

EXTENSION PIECE

UNION- a three piece pipe fitting used to connect the ends oftwo pipes, neither of which can be turned.It is also used on pipes that are to be taken down

Occasionally.

FLANGE- a ring sharped plate screweon the end of a pipe and provided withholes for bolts; to allow joining the pipeto a similarly equipped adjoining pipe.

The resulting joint is a flanged joint.

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WATER SUPPLY STORAGE TANKS

In the interest of economy and speed in delivery, it is recommended thatstandard sizes of water supply tanks be used wherever possible.

Types of Water supply storage tanks1. Pressure tanks- used for hydro pneumatic water supply systems. These

are most advantageous used where the peak water demand rate isrelatively low, such as in small buildings.

2. Gravity tanks- are elevated tanks recommended for large buildings andhigh peak water demand rates.

Requirements for Water Supply Tank Design and Construction1. Tanks should be designed and constructed so as to be:

a. Water tightb. Vermin-proofc. Corrosion resistant

d. Capable of withstanding the pressure under which they are to beoperated

e. Provided with safe and easy means of access for inspection2. The capacity of any single tank in or on a building shall not exceed

113,000 liters (30,000 gallons) or 113 cubic meters.3. Tanks shall not be located over openings in floor and roof construction.

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4. Potable water supply tanks for domestic supply and for standpipe orautomatic sprinkler systems shall be designed and installed to furnishwater in sufficient quantity and pressure for such systems.

5. The gravity tanks shall be provided with the following pipes:a. Intel Pipe- located not less than 100mm (4) above the top of the

overflow pipe.b. Overflow Pipe- shall be at least one pipe size larger than the inlet pipeand not less than the sizes given in Table 1. Overflow pipe shalldischarge above and within 150mm (6) of a roof or catch basin.

c. Emptying Pipe- shall be located and arranged so as to preventdamage from water discharged. Sizes shall be in accordance to thesizes given in Table 2.

d. Outlet Pipe- connected to the down feed pipe and sized according tothe water demand.

e. Air vent pipe- shall be provided with durable screens of not less than100 mesh.

Table 1. Sizes of Overflow Pipes

TANK CAPACITY SIZE OF OVERFLOW PIPE

Liters Gallons mm inches

0 - 2,842 0 - 750 25 1

2,843 5,684 751 1,500 37 1

5,685 11,369 1,501 3,000 50 2

11,370 18,948 3,001 5000 62 2

18,949 28,421 5,001 7,500 75 3

Over 28,421 More than 7,500 100 4

TANK CAPACITY SIZE OF EMPTYING PIPE

Liters Gallons mm Inches

0 18,948 0 5,000 62 2 1/2

18,949 36,895 5,000 10,000 72 3

Over 36,896 More than 10,000 100 4

SIZING OF GRAVITY TANKS

Tanks storage capacity required for domestic water supply should be based upon the

peak demand load on the water supply system and should be adequate to satisfy thatdemand for at least 30 minutes.

METHOD 1.Using Load Values (WSFUs) Assigned to Fixtures

The water supply fixture unit (WSFU) is a factor so chosen that the loadproducing effects of different kinds of fixtures and their conditions of service can be

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expressed as multiples of that factor. As an aid in this regard, tabulated values to givenloads in water supply fixture units are shown in Tables 3 and 4.

Table 3. Demand Load of Fixtures in Water Supply Fixture Units

FIXTURE TYPE WSFUPrivate Public

Bathtub 2 4

Bidet 2 4

Drinking Fountain 1 2

Kitchen Sink 2 4

Lavatory 1 2

Laundry Tray 2 4

Shower (Each head) 2 4

Service sink 2 4

Urinal - 5

Water Closet (Flush Tank) 3 5Water Closet (Flush valve) 6 10

Note: In estimating demand for water closet, use the value for flush value type.

Table 4. Estimating Demand

SUPPLY SYSTEMS PREDOMINANTLYFOR FLUSH TANKS

SUPPLY SYSTEMS PREDOMINANTLYFOR FLUSH VALVES

Loads, WSFU Demand, GPM Load, WSFU Demand, GPM

6 5

8 6.5

10 8 10 27

12 9.2 12 28.6

14 10.4 14 30.2

16 11.6 16 31.8

18 12.8 18 33.4

20 14 20 35

25 17 25 38

30 20 30 41

35 22.5 35 43.8

40 24.8 40 46.5

45 27 45 49

50 29 50 51.5

60 32 60 55

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70 35 70 58.8

80 38 80 62

90 41 90 64.8

100 43.5 100 67.5

120 48 120 72.5

140 52.5 140 77.5

160 57 160 52.8

180 61 180 87

200 65 200 91.5

225 70 225 97

250 75 250 101

275 80 275 105.5

300 85 300 110

400 105 400 126500 125 500 142

750 170 750 178

1000 208 1000 208

1250 240 1250 240

1500 267 1500 267

1750 294 1750 294

2000 321 2000 321

2250 348 2250 348

2500 375 2500 375

2750 402 2750 402

3000 432 3000 432

4000 525 4000 525

5000 593 5000 593

6000 643 6000 643

7000 685 7000 685

8000 718 8000 715

9000 745 9000 74510000 769 10000 769

SAMPLE PROBLEM:Determine Capacity of Tank by WSFU Values

Determine the capacity of the storage tank of a school building with the followingfixtures:

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45 water closets 4 showers40 lavatories 18 slop sinks14 urinals 16 drinking fountains9 kitchen sinks

Solution

1. Determine the demand load (refer to Table 3)

Water closet 43 x 10 430 WSFU

Lavatory 40 x 2 80

Urinal 14 x 5 70

Kitchen sink 9 x 4 36

Shower 4 x 4 16

Slop sink 16 x 5 80Drinking Fountain 6 x 2 12

Demand Load 728 WSFU

2. Estimate the demand in gallons per minute (refer to Table 4) from Table 4. Theestimated demand for 724 WSFU is 175 GPM.

3. Estimate capacity of the storage tank.Assume 1 hour as the duration that will adequately satisfy demand.

Capacity = 175 gallons x 1 hour (60 mins)

Mins

= 10,500 gallons

4. Determine the volume of tank*Use 1 cubic meter= 264 gallons

V= 10,500 G264

V= 39.77 cubic meter

Say: 40 cubic meter

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MODELCWT

VOL.M3

DIMENSIONm/m

PIPE CONNECTION(A)

WGT.KGS

D H f S O d RP F1 F2 F3 F4 N

500 0.5 992 1265 20 20 20 20 - - 652 864 19 8 40

1000 1.0 1322 1695 25 25 25 25 185 - 652 864 19 8 36

1500 1.5 1597 2145 40 40 40 40 185 - 917 1126 19 8 91

2000 2.0 1641 2060 40 40 40 40 210 - 955 1245 25 8 137

3000 3.0 1877 2170 40 40 40 40 225 - 1043 1345 25 8 164

5000 5.0 2180 2660 50 50 50 50 310 1102 1303 1595 25 16 2276000 6.0 2300 2780 50 50 50 50 310 1102 1303 1595 25 16 235

10000 10.0 2800 3150 65 65 65 65 325 1510 1715 2010 38 16 420

20000 20.0 3300 3770 65 65 65 65 325 1877 2077 2415 44 16 750

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METHOD 2. Using occupant load of the building.

This method provides for the design population with the assigned average daily

water consumption for various buildings and other facilities.

Table 5. Estimated Water Supply Demands

OCCUPANCY AVERAGE DEMAND(GPD per occupant)

PEAK DEMAND (GPMper occupant)

Assembly, Theaters ,Lecture Halls 5 seats + employees 0.17

Churches, Mosques, Synagogues 5 0.12

Factories: No Showers 15 0.12

Factories: with showers 25 0.50

Hospitals 15 0.50

Hotels, Motels 75 0.43Offices, Stores, Airports, Bus

Terminals10 (add 5 for food

service)0.09

Residences, Homes, Apartments 100 0.33

Restaurants: Dinner only 2 0.15

Restaurants: 2 meals/ day 35 0.13

Restaurants: 3 meals/ day 50 0.13

Schools: with food service 25 0.12

Schools: with gym and showers 30 0.40

Formula: Solving for estimated average water demand in a building

BAWD = N x OAWD [1 + 0.00077 (Td-65)] + S

Where

BAWD = Average water demand of building in gallons/dayN = Number of occupants in buildingOAWD = average water demand per occupant in gallons/dayTd = summer design temperature in

oF (use the value= 89.6

oF)

S = Average or peak demand of any special loads

Formula: Solving for Peak water demand in a building

BPWD = N x OPWD [1 + 0.00115 (Td-65)] + S

Where

BPWD = Peak water demand of building in gallons/ minute

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OPWD = Peak water demand per occupant in gallons/ minute

SAMPLE PROBLEM:Determining Capacity of Tank by Occupant Load

Determine the capacity of the storage tank of a school building with an estimatedstudent population of 1,500 people. Assume 25% of the population as daily users of thebuilding.

Solution

1. Solve for estimated average water demand in the school

BAWD = N x OAWD [1 + 0.00077 (Td-65)] + S= 1500 (0.25) x 25 [1 + 0.00077 (89.6 65)] + 0= 375 x 25.47

BAWD = 9,551.25 gallons per day(Use this value for the tank capacity)

2. Solve for the peak water demand in the school

BPWD = N x OPWD [1 + 0.00115 (Td-65)] + S= 1,500 (0.25) x 0.12 [1 + 0.00115 (89.6 65)]= 375 x 0.12

BPWD = 45 gallons per minute

3. Solve for Volume of Tank.*1 cu. Meter= 264 gallons

V= 9,551.25264

V= 36.18 cu.m.

Say: 37 cu.m.

TOOLS FOR SUPPLY PIPING WORKS

1. Pipe vise 8. Strap wrench2. Pipe cutter 9. Pipe tong/ chain wrench3. Pipe reamer 10. Basin wrench4. Pipe stock and die 11. Open end wrench5. Pipe tap 12. Adjustable wrench6. Pipe wrench 13. Flaring tool7. Monkey wrench

WATER SUPPLY PIPE TESTS

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PIPE CUTTER- this is used

for cutting G.I. or Coppertubing.

PIPE TAP- This is used for

making internal threads inG.I. Pipes.

PIPE WRENCH-this is used to

screw pipes into or out of theirfittings.

PIPE REAMER- This is usedto remove the burrs form theinside of the pipe or toenlarge an opening.

Burr- a rough or sharp edgeleft on metal by a cutting tool,also known ar burl.

STRAP WRENCH- This isused when working with brassor plated pipes and fittingssince it does not damage the

surfaced being tightened. It isalso used in places too small toadmit a pipe wrench.

MONKEY WRENCH- thisuse to tighten or loosenfittings with parallel sides

hexagonal ends such as nvalves and unions.

BASIN WRENCH-

CHAIN WRENCH- This is usfor turning pipes usually with150mm diameter or larger.

FLARING TOOL- This is used towiden the end of a soft metaltubing usually copper, to make amechanical seal.

PIPE STOCK AND DIES- Thisis used to make externalthreads on G.I. Pipes.

DJUSTABLE WRENCH- thisused the same as that of aonkey wrench.

OPEN-END WRENCH- This isused to pull up flange bolts andnuts.

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CHAPTER 10: PUMPS FOR WATER SUPPLY

Classification of Pumps

1. Reciprocating Pumpsa. Lift pumpsb. Piston or plunger pumpsc. Deep-well piston pumps

2. Centrifugal Pumps

a. Submersible pump3. Deep-weel jet pumps4. Hydraulic Rams5. Hydropneumatic pressure system

1. RECIPROCATING PUMP- a pump which operates with a to- and fro motion.

a. Lift Pump- the simplest of the reciprocating pumps and consists of a pistonmoving up and down in a cylinder or barrel. A lift pump cannot be used toraise water above 7.50 to 8.50 meter at a normal atmospheric pressure

(101 kPa) due to:- Loss of efficiency in the pump- Friction in the intake pipe- Impossible to obtain a perfect vacuum

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b. Piston or Plunger Pump- is a positive displacement reciprocating pump in

which a plunger is driven backwards and forwards, or up and down by amechanical working head.

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ILLUSTRATION

c. Deep-well piston pump-when water is more than 7.5m below the ground,it is visually necessary to place the pump in or near the water in the welland pump from there. Water is forced up th drop pipe and out into the

delivery pipe.

ILLUSTRATION

CHART 1. FAULT FINDING: Reciprocating Pump

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Fault Cause Remedy or action

No discharge Not printedExcessive suction lift

Air leaks

Vapour lock

Blockage

Deterioration

Prime.Reduce static lift,eliminate or reduce friction

on suction side with largerpipes.Check and eliminate airleaks by sealing. Checkgland.Suction lift excessive forfluid temperature.Check for blockage insuction pipe, foot valve orstrainer. Check suctionvalves.

Check cylinder liner forwear, bucket leathers andvalves

Low discharge, lowpressure, single-acting

Faulty valvesCylinder linerBucket leathers

Air leaksExcessive back pressure

Check valves.Check liner.Check leathers. Checkand rectify.Check that totaldischarge head is notexcessive.

Excessive noise No oil or contamination

Worn bearings, pinion,main gear, gear, shafteccentric or strapExcessive speed

Excessive suction lift

Entrained gas or airWorn valves or faulty valveoperation;

Drain and refill

Check for worn parts.

Reduce to maximumspecified level.Reduce suction lift and/orincrease pipe size toreduce friction head.Modify suction pipepositionCheck valves and springs.

Excessive vibration Undersize piping

Cavitation

Deterioration

Counter balancing

Fit large pipes to reduceflow velocity.Check against causes ofcavitation. Increase netpositive suction head.Check for and replaceworn parts.Fit extension beams and

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Fault Cause Remedy of Action

No Discharge Lack of prime

Excessive suction lift

Excessive Discharge head

Speed too low

Pump cloggedWrong direction of rotation

Air leaks

Vapour lock

Prime pump and suction line,allowing trapped air to escapethrough bleed vent.Check suction head. Reduce liftand/or increase pipe size to negatefriction head. Check foot valve and

suction pipe for obstruction.Cheack total head. Ensure allvalves open. Check piping forblockages. Ensure non-return valvesare installed correct way round.Check that pump revolutions areconsistent with recommendations.Check that impeller is not clogged.Check pump is rotating in rightdirection.Check suction pipe and connection

for leaks. Check seal or gland.Check fluid temperature to ensurethat fluid in the suction line is notflashing to vapour when the pressureis reduced.

Low delivery Air leaks/ vapour locksWorn or clogged impellerIncorrect pipe size

Check and rectify.Replace and correct.Check recommendation.

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Blockage or constrictionPoor suctionWrong pumpHigh fluid viscosity

Increase size reduce friction head.Check total head etc.Ask for recommendation.Check recommendations.

Low Pressure Worn impellerWrong rotationFlow velocityUnbalanced impeller

Faulty bearings/ bent shaftMisalignmentBadly installed

Check and replace.Check and correct.Check recommendation.Increase size to reduce frictionhead.Check total head etc.Ask for recommendationCheck recommendation

Vibration andnoise

Cavitation

Incorrect rotation

Flow velocityUnbalanced impellerFaulty bearings/ bent shaftMisalignmentBadly installed

Check operation conditions, fluidtemperature and NPSH.Check and rectify.

Increase pipe size. Reduce flow.Check for wear or cloggingReplace if necessary.Check alignment with prime-mover.Check mounting for rigidity.

Excessive wear Corrosion

CavitationAbrassive fluid

Check that pump material and fluidare compatible.Check operating conditions.Ask for recommendations.

Heating bearing Running too fastBelts too tight

MisalignmentLack of lubricantDistortion

Check maximum operating speed.Slacken tension.

Check alignmentRepack with grease or replace.Bearings too tight.

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DEEP WELL JET PUMP.A pump consisting of a revolving impeller in the pumphousing which forces water down a pressure line to an ejector assembly below waterlevel.

ILLUSTRATION

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HYDRAULIC RAM OR RAM PUMP.A pump in which the power generated from flowingin an enclosed pipe is used to raise part of the water to a height above that from whichthe flow began.

ILLUSTRATION: A typical hydraulic ram pump

ILLUSTRATION: A typical Hydraulic Ram Installation

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Definite Conditions Required for Hydraulic Ram to work Effectively

1. The fall (h) must be more than 0.66m, but should not exceed 6m.2. The drive pipe should be straight and laid to an even grade, and its length should

be 6 to 8 times the available fall. The drive pipe must be long enough to ensurethat when the recoil of water takes place more resistance is offeered by temoving water in the drive pipe than by the delivery valve and the waterimmediately above it.

3. The amount of water available should be at least 10 times the required supplyand there must be a get away for the waste water.

4. The height (H) to which the water is to be delivered should not, in general, bemore than 6 to 8 times the available fall.

5. As a rule, the diameter of the drive pipe should be at least twice the diameter ofthe delivery pipe.

CalculationIn calculating for the quantity of water delivered by a hydraulic ram, use theformula:

q= Q x h x eH

Where:

q= Quantity (in liters) delivered from the ram in a given timeQ= Quantity (in liters) flowing to the ram in the same time

h= Head (in meters) of water on inlet side of ramH= Height (in meters) to which water is raisede= Effeciency of ram

SAMPLE PROBLEM

To supply a ram, 200 liters of water per hour are available. The head of the ram is1.00m and the height to which is raised is 5.00mm if the ram is assumed to have anefficiency of 60%, what quantity of water will be delivered per hour?

SOLUTION:

q= Q x h x eH

= 200 x 1 x 0.65

q= 24 liters per hour

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HYDROPNEUMATIC PRESSURE SYSTEM. A pumping system that provide water,within pre-set flow and pressure ratings, automically on demand.

Three basic Elements of the Pressure System1. A pump (of any type or manufacturer)

2. A pressure sensing electric switch- opens and closes the electricalcontacts causing the pump to stop and start.3. Pressure vessel which contains an elastic medium, usually air.

ILLUSTRATION

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WELL PUMP SELECTION

PUMP

CAPACITY

DEPTH OF WELL

0 to 8.00m 8.00 to 18.00m 18.00 to27.00m

27.00 to46.00m

46.00 and over

1,136 to2,271 LPH(300-600GPH)

SubmersiblepumpJet pumpPistonPump

SubmersiblepumpJet pumpDeep wellReciprocatingPump




2,271 to4,542 LPH(600-1200

GPH)

SubmersiblePumpJet Pump

PlungerPump

SubmersiblepumpJet pump



Submersiblepump

Over 4,542LPH (1200GPH)

SubmersiblePumpJet PumpPlungerPump



Submersiblepump

Submersiblepump

THE PUMPING OF WATER

In the pumping of water, the following are to be considered:

1. Mass of water to be lifted2. The height through which it must be lifted or forced.3. The distance it must travel in moving from one place to another.4. The ways in which in water may be affected by friction.

Pressure-is defined as force per unit area, the area being measured at right angles todirecton of the force. The unit of pressure N/m2is called Pascal (Pa). Kilo Pascal (kPa)and Mega Pascal (MPa) are commonly used.

Head- is the height or vertical distance from the point of measurement to the free levelof water in the system.

a. Positive Head- occurs when the free water level is higher than the point ofmeasurement.

b. Negative Head- occurs where the free water level is lower than the pointof measurement. It is also known as suction, partial vacuum or negativepressure.

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*Water with head of 1.00m and a base of 1m2will exert a pressure of 9810 N/m2, or9810 Pa, that is 9.81 kPa.

Classification of HeadsThere are different kinds of head according to their effect on pumping operations.

1. Static Discharge Head or Gravity Head-results from the vertical height of acolumn of water. It is the weight of water exerted as a result of the force ofgravity. In pumping operatons, it is the vertical distance (in meters) from thecenter line of the pump to the point of free discharge.

2. Pressure head- the vertical height to to which a given pressure will force water toa certain level

3. Suction Lift- the term used when the source of supply is below the center line ofthe pump.

4. Static Suction Lift- the vertical distance (in meters) from the liquid level to thecenter line of the pump.

5. Total Suction Lift- the static suction lift plus friction head in the entire suction pipeand fittings.6. Suction head- the term used when the source of supply is above the center lne of

the pump. Also known as flooded suction.7. Static Suction Head- the vertical distance (in meters) from the center line of the

pump to the level of the liquid being pumped.8. Total Suction Head- the static suction head minus the friction head in the entire

suction pipe and fittings.9. Total discharge Head-the static delivery head plus the friction head plus the

friction head in all of the delivery pipe and fittings.10.Velocity Head- the head required to accelerate the water in the delivery pipe. It

should be included in the total pump head but it so nominal that it is usuallyignored.11.Total Pump Head- the total suction lift plus the total delivery plus the velocity

head.

CHAPTER 11: DOMESTIC HOT WATER SUPPLY SYSTEM

DOMESTIC HOT WATER SUPPLYThe supply of hot water of domestic use is based on the need for personal hygiene andwashing in order to remain healthy and safe.

1. Personal hygiene-through science, people became aware that dirt harborsdisease, to keep away from this condition people attend to constantly maintaintheir bodies clean. To achieve this, a regular supply of hot water is required tobreak down and dissolve oil and dirt. Soap lathers much better in hot water thancold. Hot water is friendlier to our skin temperature since we are warm blooded

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animals. Hot water also helps to open skin pores, letting the soap get down intothe tissue to lift out the oil and dirt.

2. Washing- certain substances, such as fatty foods on a plate, require atemperature of 60 degrees centigrade to lift them.

There are several methods of heating water , but the availability of fuel and the costinvolved in operating and maintaining the system are main concerns in choosing thesuitable type. The types of fuel currently available are:

1. Electricity 5. steam2. Solid fuel- coal 6. Oil3. Gas 7. Heat pumps4. Solar

HEAT-UP TIMEIn order to achieve the greatest convenience and the best running cost, knowledge ofthe heat-up time for water heaters is important. Capacities of water heaters varyaccording to requirements, storage size and heat input. This is the reason why most

heaters have to be turned- on before use as they need time to heat up. To be able tocalculate the heat- up time we need to understand a few facts about heating water.

1. Specific heat- is the specific amount of heat for a specific temperature rise. Ittakes 4.187 kJ (kilo Joules) of energy to raise 1 kilogram of water through 1degree centigrade.

2. For the purpose of calculations, 1 liter of water has a mass of 1 kilogram.3. Temperature Rise (TR)- is the difference between the cold water temperature

and the final required temperature. This is expressed in the formula: TR= (t2-t1)4. Often the water heater is electrical equipment that is related in kilowatts (kW), it

is necessary to convert kJ to kW. The conversion is kW= 3600 kJ.

Knowing the quantity of water to be heated, the temperature rise and the specific heatof water, we can calculate the amount of heat required, and because electricalappliances have the input based on an hourly rate, these figures can be reversed to findthe time it would take to heat up.SAMPLE PROBLEMCalculate the amount of electrical energy and the time required to heat 13 liters of waterfrom 10oC to 60oC at 100% efficiency.Solution

1. Solving for Temperature Rise: TR=60oC - 10

oC= 50

oC

2. Solving for Energy RequiredEnergy Required = liters x temperature x specific heat

= 13 liters x 50

o

C x 4.187 kJ/ liter

o

C= 13 liters x 50oC x 4.187 kJLiter degree centigrade

= 2,721.55 kJ3. Convert kJ to kW

kW= 2721.55 kJ3600 kJ/ kW

4. Solving for Time Required

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T= 2721.55 kJ3600 kJ/ kWh x 0.76 kW

Convert hours to minutes: T= 0.99 hours x 60 minutes / hour = 59.4 minutesThe above time of 59.4 minutes is quite impractical for a waiting time before hot water isavailable. To shorten the waiting time, the input should be increased.

ADDENDUM OF SAMPLE PROBLEM*If we double the input from 0.76 kW to 1.52kW, calculate the time it will take to reachthe required temperature.Solution. Use the same figures but this time double the input.

T= 13 liters x 50oC x 4.187 k3600kJ/ kWh x 1.52kW

= 2721.55 kJ = 0.497 hours5472 kJ/ h

Convert hours to minutes

T= 0.497h x 60 min/ hTime= 29.82 minutes

TYPES OF HOT WATER SYSTEM AVAILABLE

The above stated types of fuel can be used to heat the water in the following systems:1. Localized water heating (single appliances)

a. High Pressureb. Low Pressure

2. Centralized hot water systema. High Pressureb. Low Pressure

3. Storage water heatersa. High Pressureb. Low Pressure

4. Instantaneous water heatersa. High Pressureb. Low Pressure

STORAGE WATER HEATER- OPEN OUTLET SINGLE POINT, ABOVE SINKAll heaters of this type are designed to serve one fixture at a time. Although, it ispossible to install the heater between two adjacent fixtures so the swivel spout can beturned to supply both. They are available from 7 to 34 liters storage and normally have a2000 watt element fitted. This means that there is heat-up time of 12 minutes to 1 hour.

STORAGE WATER HEATER- OPEN OULET SINGLE POINT, UNDER SINKThe under sink water heater works on the principle of displacement, hot water onlyflowing when cold water enters the cylinder and pushes the hot out. To prevent unduepressure from the cold water inlet, a restrictor is fitted to the inlet connection. Provisionmust be made for expansion and this is done by leaving the hot water outlet open and

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discharging it over the sink. The cold water faucet controls the flow of hot water and thehot outlet pipe allows for expansion. Under sink water heaters are not suitable for usewith dish washers, unless installed as low-pressure water heaters.

INSTANTANEOUS HEATERSInstantaneous heaters instantly heat cold water as it passes through the heater. Theseheaters are compact since storage is not required. They are popularly used at showersand lavatories and due to this condition; there is a shower model and lavatory model.

1. Shower model- has rated power consumption of 6000 watts (6kW)

- provides a continuous supply of hot water at a maximum rate of 3liters per minute at a showering temperature of 40 degreescentigrade.

2. Lavatory model- has a rated power consumption of 3000 watts (3kW)-provides a continuous supply of warm water for hand washing at

the rate of approximately 1.4 liters per minute.3. Multi-point model- serves several fixtures such as a range of lavatories, sink or

. shower.

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OPERATION OF INSTANTANEOUS HEATER

1. When the cold water control valve is turned on, water flows and exerts pressureon a pressure switch which in turn completes the electrical circuit so that theelement can now heat the water as it passes through. The pressure switch is thesafeguard that the heating element is only on when water is flowing.

2. A preset thermal cut-out switch is also incorporated as a safety measure againstoverheating the water.

3. The heating element is thermostatically controlled using a rod thermostat or invarsteel which expands very little. This is fixed inside a tube of brass which expands

very little. This is fixed inside a tube of brass which expands approximately 18times as much as the invar steel. When the brass tube, which is in contact withthe water, expands, it draws out the invar rod with it and breaks the electricalcontact.

4. A magnet ensures a clean snap action, as the magnet will hold the control switchuntil the last minute, so preventing excessive arcing and rapid deterioration of thecontact points.

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CENTRALIZED HOT WATER SUPPLY

In centralized systems, water is heated and stored centrally and distributed to thehot water faucets via the hot water piping. In the average home, an electricheating element is directly immersed into the water to be heated. But, forcommercial and larger projects an independent boiler or furnace is used to heatthe water remotely. The hot water is stored in a range boiler or storage tank thatis located as near the boiler as possible to keep heat losses at a minimum.

To provide an adequate supply of hot water for the average family, a 180 liter

storage cylinder is recommended and is designed to provide the central bulk ofthe hot water requirements. The aforementioned value should be increased ifthere is an abnormally high usage of hot water or be supplemented withsecondary forms of heating water.

1. The hot water storage vessel holds sufficient water to meet a large draw-off atpeak times.

2. It may be possible to use cheaper, lower grade fuel oil, coal, natural gas or othersolid fuel.

3. The boiler can be housed in its own room, keeping noise and dust out of themain building.

4. One boiler plant reduces maintenance.

PARTS OF CENTRALIZED HOT WATER SUPPLY1. Heating element/ boiler 3. Range boiler/ hot water storage tank2. Thermostat 4. Hot water pipes

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Heating element-the size of the heating element has a direct bearing on theheating up time, which is also related to the size of the storage cylinder. Ageneral guide for adequate supply is: 135 liters 1500 watts

180 liters2000 watts

Both the 180 liter with a 2000 watt element and the 135 liter with a 1500 wattelement will reach a temperature of 60 degrees centigrade in 5 hours and 15 minutes,based on cold water entering the cylinder at 10 degrees centigrade.

Caution: It is not uncommon for higher wattage elements to be installed, up to3000 watts in a 135 liter cylinder, but when this is done in an old installation, the wiringshould be checked to avoid electrical overloading that may result to fire.

Thermostat- is the key to a satisfactory and economical water heater,automatically switching off the power when the preset temperature is reachedand switching on again when hot water is drawn off, or the temperature drops

through heat loss. Recommended thermostat settings for average familyrequirement are 65 to 0 degrees centigrade. Where there are smaller demands,60 degrees centigrade is more economical temperature. Some savings can bemade by lowering the temperature setting during summer.

Range boiler/ hot water storage tank- the hot water tank serves the domestichot water system in a storage capacity. There are two types of tanks used for thestorage of hot water:

1. Range boiler- the small cylindrical hot water tank that varies in size from300 mm to 600 mm in diameter and is not more than 1800 mm long. The

range boiler is made of galvanized steel sheet of standard and extraheavy gauge. It can be used in either horizontal or vertical position.

2. Storage tank- the large cylindrical hot water tank with a range of diameterat 600mm to 1350 mm and not more than 4500 mm long.

The proper size of the hot water storage tank depends on the following:1. The design of the building2. The number of occupants and3. The heating capacity of the supply device

Hot water pipes- should be as short as possible in order to avoid the use ofdead legs. A dead leg is a long pipe run whereby it takes a long time to pushout the cold water for the sake of a small amount of hot water. The smallest sizeof piping that will provide a satisfactory flow should be used. Short, small sizedpipes are less expensive and they waste less heat and less water.

HOT WATER DISTRIBUTION SYSTEM

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The storage tank and heating device of a hot water distribution system are soassembled as to create a circulation of water within them. The movement of the water isthe result of molecular activity. The application of heat to a body of water caused it toexpand and become less dense, which give it a natural tendency to rise. The inequalityof weights between the hot and the cold water contained in the tank results a circulation

of the liquid. The operation and efficiency of the hot water distribution system isdependent upon the following:

1. Type of heating system useda. Direct systemb. Indirect system

2. Type of tank connection used

a. Vertical positionb. Horizontal position

c. Pipes, valves and fittings

3. Types of installation used

a. Upfeed and Gravity returnb. Overhead feed and gravity returnc. Pump circuit system

DIRECT HEATING SYSTEM

In this system the water that is being heated by the boiler is actually used out of the hotwater faucets.

Direct water heaters are classified into four categories:1. Range boilers

a. Range boiler and furnace coilb. Range boiler and heater

2. Gas water heatersa. Side-arm gas heaterb. Gas water heater

3. Oil-Fired water heater4. Electric water heater

Each type should have a temperature and pressure relief valve and sediment drain atthe lowest part of the tank. Relief valves are set to allow water to blow into a drain linewhen the temperature exceeds 100 degrees centigrade or when the pressure exceeds860 kPa.

Range Boiler and furnace coil- the range boiler is usually mounted upright on astand. A drain is placed at the bottom to remove sediment; a temperature and

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pressure relief valve is placed at the top for safety. The furnace coil is located inthe furnace box.

Range boiler and Heater- the range boiler is usually installed horizontally on astand. The heater maybe fired by coal, gas or oil.

Side-Arm Gas Heater- is used mostly during summer months in temperatecountries to support furnace oil heaters.

Gas water heater- a galvanized iron, copper, or porcelain- lined steel tankenclosed in an insulating jacket. A gas (LPG) burner provides the heat. Thethermostat controls the temperature of the water in the insulated tank. Itsoperation is automatic and will keep water at any temperature from 45 to 75degree centigrade, according to the setting of the thermostat. Gas water heaters

provide an efficient and inexpensive way to supply hot water at all times.

Oil-Fired water heaters- are similar to the gas water heater, except that avaporizing or pressure oil burner supplies the heat.

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Electric Water Heater-normally has two immersion type heating elements. Theupper heater usually has higher wattage than the lower. Thermostats controlthese elements to ensure that the operation is automatic. The heater does notneed a flue or smoke stack since there are no burning products. The electricwater heater may be located in a closet.

INDIRECT HEATING SYSTEMIn this system the water that is heated by the boiler is never used out of the hot waterfaucets, but circulates through a heat exchanger. This takes the form of a coil pipewithin the hot water storage tank. The heated water circulates through the system and

in turn heats the water held within the storage tank, then results to the boiler to bereheated. The advantages of this system are:

1. Since the water in the boiler does not mix with the water in the storage tank, therisk of rusty water being drawn off through the faucets is eliminated.

2. It keeps the carbonate deposits to a minimum level because once the temporaryhardness of the water has been released it will not recur as the same water isreheated over and over again.

3. It can use steam as the heating medium instead of water.

There are 3 types of indirect heating system currently used in buildings, these are:1. Primatic Cylinder

2. Calorifiers3. Annular Cylinder

1. Primatic cylinder- is a single feed cylinder with a patented internal heatexchanger. It is designed with two air locks, which prevent the mixing of theheated water with the useable water.

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2. Calorifiers- is a continuous coil of pipe within a vertical cylinder. In hospitals andfactories where steam is already being generated for other uses, it can be usedto heat the water by the indirect method through the calorifier. The steam entersthe coil through the top connection. The strainer removes any solid mattersuspended in the controlled. The thermostat prevents overheating or boiling ofthe stored water. A steam trap, fitted near the outlet of the coil, prevents thesteam from leaving the coil until it condenses.

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It is advisable to seat the tank in a vertical position on small installations and in ahorizontal position on the larger installations. In both the vertical and horizontal position,the tank must be set above the heater to allow the heated water to rise and permit amore rapid circulation.

Other necessary connections to the tank are:

a. Cold water supply- delivered into the tank via a boiler tube that extends towithin 150mm of the tank bottom. The purpose for this is to avoid the possibilityof cooling the hot water which accumulates at the top of the tank. This cold waterline must have a small hole within 150mm from the top of the tank. This holeserves as a vacuum breaker and prevents siphonage. The supply line into thetank must be equipped with a control valve located as close to the hot water tankas possible.

b. Flow connection- is connected to an opening on the tank somewhere above itscenter point. This line is called the flow connectionbecause the heated water

flows from the heater in the tank.c. Return connection- is connected to a tapping on the bottom of the tank. Thisline is called the return connectionbecause it returns the colder water from thebottom of the tank of the heater.

d. Drain valve- is located at the lowest point of the storage tank.e. Hot water distribution pipe- is connected to a tapping on the top of the tank at

the point near the flow inlet.f. Blow-off valve- is installed to the storage tank to control the temperature and

pressure and to prevent serious difficulties should the tank become overheated.

HOT WATER DISTRIBUTION: Types of installationsThe installation for hot water distribution consists of the piping work that conveys theheated water from the storage tank to the plumbing fixtures.

Upfeed and Gravity Return system- Commonly used in residential installations- The purpose of this system is to permit circulation of hot water within the

piping arrangement- The circulating return is economical since it eliminates water waste.- The principle on which this system functions is provided in the unequal

weights of 2 columns of heated water of uniform height. The inequality ofweight is the result of a variation in temperature in the 2 columns.

FEATURES OF THE UPFEED AND GRAVITY RETURN SYSTEM:a. The distribution main is connected to a tapping on the top of the storage tank

close to the flow from the heater.This pipe is usually suspended from the basement ceiling.

b. Hot water rises are generally connected to the distribution main by means of 45degree connection.

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However, this practice may vary according to the length of the risers, in order toavoid one riser circulating faster and more thoroughly than the others. Forexample, should an installation consists of 3 risers of varying heights, the longestcan be connected to the main horizontally; the shorter riser by a verticalconnection; and the third riser maybe connected with a 45 degree fitting.

c. The flow riser is passed as near the fixtures as possible. Swing joints areprovided in the supports of risers to allow for expansion and prevent breakage ofthe pipes. The flow riser is equipped with a control valve and a drip at its base.

d. The circulating return is connected to a tee that is installed in the riser below thehighest fixture to overcome air lock. The return is usually one size smaller thatthe flow riser. It is connected to a return main often suspended from thebasement ceiling. The return riser is also equipped with a drip and a control valveat its base.

e. The circulating main is usually suspended from the basement ceiling andinstalled with a slope to a Y fitting installed in the return connection between thestorage tank and the heating unit. A valve must be placed at this connection.

f. All valves used in the system should be of the gate valve type in order to beassured of a full way water flow and to overcome trapped water lines- a faultwhich occurs in the use of disc or globe valves.

g. The largest diameter of the pipe is at the bottom of the riser, the size diminishingas it passes through the upper floor s of the building.

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OVERHEAD FEED AND GRAVITY RETURN SYSTEM- The most efficient method of delivering hot water to fixtures.- It is generally used in multi-storey buildings.- It is dependent on the natural laws governing expansion and gravity- Its advantage is that it allows continuous circulation even if there is a

mechanical defect in the system.- The operating principle of the overhead system is based on the fact that in aclosed system of piping, water rises when heated. After it has reached thehigh point of the system, natural forces of gravity return it to the storage unit.

FEATURES OF THE OVERHEAD FEED AND GRAVITY RETURN SYSTEMa. The storage tank should be located at the lowest point of the distribution piping.b. Overhead feed riser is connected to a tapping at the top of the storage tank close

to the flow connection of the heater. This riser must be extended as direct andfree from offsets as possible to the work space or the ceiling above the top floorof the building. This riser must not have connections from fixtures.

c. Distribution main is connected to the top of the riser, and is suspended from theceiling or the building framework by means of metal hangers. The main must bepitched away from the riser so that the water will flow to the last drop. The mainshoulder be located so as to make the horizontal runs of the riser as short ans asequal in length as possible.

d. The horizontal riser branch is connected into the main by means of inverted 45degree fitting and is pitched to the drop or vertical riser proper. The horizontalriser branch must be equipped with a valve installed as close as may bepractical.

e. The largest pipe diameter is at the top of the riser, the size diminishing as itpasses through the lower floors.

f. The circulating return main is a line suspended from the basement or lowestfloor. It is pitched and connected to a Y located at the return piping between theheater and the storage tank.

g. The return risers are connected to the circulating return main.h. The system is equipped with a relief ventthat eliminates the accumulation of air

(air bound) at the top most point of the distributing piping. Air bound is a conditionin the pipe works that retards or prevents the circulation of hot water. There aretwo methods to provide a relief vent in the system; 1 connects an uncirculatedriser to the highest point of the overhead distribution main. It is possible to relievethe air lock from time to time by opening the fixture/ faucet that the riser serves.2, by installing an air relief valve, which opens when the air accumulates andautomatically closes when the air is released. The relief valve is equipped with adrain pipe that allows water to drip to an open fixture.

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PUMP CIRCUIT SYSTEM-The circulation of hot water to the plumbing fixture by means of mechanical

device, usually a centrifugal pump. The rotary motion of the impeller of the centrifugalpump creates an even movement of hot water flow in the pipes which makes this pumppractical to use.

- this is used in buildings where it is impossible to produce a circulation of hotwater.

FEATURES OF THE PUMP CIRCUIT SYTEMa. The pump is installed on the circulating return main as close to the heater as

possible.b. The circulating return is connected to the inlet side of the pump and the outlet

side of the pump is connected into the return of the heater.c. It is advisable to equip the pump with a by-pass, which is done by inserting tees

of the same diameter as the circulating return ahead of the valves. The tees areconnected and the line is equipped with a gate valve. Should the pump get out oforder, the control valves may be closed and the hot water will circulate aroundthe pump into the return pipe of the heater. This practice serves as a temporarymeans of water circulation. When the by-pass is not in use, the valve with whichit is equipped must be closed. The valves on either side of the pump must beopen at all times when the pump is in operation.

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plumbing notes 2

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