A SUMMER TRAINING REPORT ON “RESIDENTIAL BUILDING CONSTRUCTION” TAKEN AT
“G.S. CONSTRUCTION” Submitted in Partial Fulfillment for the Award Of BACHELOR OF TECHNOLOGY In Civil Engineering
2015-2016 Submitted by:
AZAM KHAN Roll No.-
1000111048 Civil Engineering 4th Year
DEPARTMENT OF CIVIL ENGINEERING
INTEGRAL UNIVERSITY Lucknow
ACKNOWLEGEMENT It is a great pleasure for me to prevent this training report .I would be an undoing my job if don’t thank to everyone who helped me starting this report. First and foremost I would like to thank Mr. Faizan Ilahi, CONSTRUCTION MANAGER and special thanks to Mr. Zaid, SITE INCHARGE who support me through inspiring towards this report. He had provided me a nice industrial experience. Secondly, I am no less grateful to the other employees and members of the department for their kind co-operation and spontaneous response. Last but not the least; I would like to thank my seniors who extend their advices and suggestions which helped me a lot in compiling my seminar report.
INTRODUCTION
1.1ABOUT THE PROJECT 1.
NAME OF PROJECT
MULTISTOREY
RESIDENTIAL
2.
AREA
BUILDING (G+4) 4500 Sq.fit
3.
PROJECT MANAGER
MR. FAIZAN ILAHI
4. 5. 6.
COMPANY G.S. Constructions LOCATION OF SITE SIR SYED NAGAR, ALIGARH DATE OF STARTING 01-06-2015
7.
TRAINING DATE OF
8.
TRAINING DURATION OF PROJECT
1 YEAR AND 7 MONTH
9.
DURATION OF TRAINING
30 DAY’S
COMPLETING 30-06-2015
1.2ABOUT THE BUILDING It project is a multi-storey residential building. This building is constructing for middle class people. company has divided the residential buildings in different group as mentioned below-
HIG (HIGH INCOME GROUP) : This group includes the flats of cost is more than 15 lac. MIG (MIDDLE INCOME GROUP) : This group includes the flats of cost varies between 5 to 15 lac. LIG (LOW INCOME GROUP) : This group includes the flats of cost is less than 5 lac. This building insists In MIG (Middle Income Group).It is a four storey building (G+3).Entire building is constructed in two combined apartments. The number of flats in each floor is four in each apartment. Each flat consists two bed room, a living room and a kitchen (2 BHK) with separate bathroom and toilet. The height of each floor is 3 meter. The dimensions of all flats were same. Dimensional detail of a flat: Living Room
:
(3.18*4.00) meter
Bed Room (1)
:
(3.00*3.30) meter
Bed Room (2)
:
(2.70*3.30) meter
Kitchen
:
(1.80*2.50) meter
Toilet
:
(2.1*1.20) meter
Bath Room
:
(1.20*1.20) meter
Water Closet
:
(0.90*1.20) meter
Single window has provided in living room, bed rooms and kitchen .Each flat consists a balcony in front and rear sides of apartments.
1.3TYPES OF BUILDING: Buildig are classified on the basis of character of occupancy and type of use as – Residential Building Educational Building Institutional Building Industrial Building RESIDENTIAL BUILDING: In such building sleeping accommodation is provided. IT includes the living room, bed room, kitchen, hall, toilet and bath room. It may be a single storey building or apartments. EDUCATIONAL BUILDING: These includes any building using for school, college, assembly for instruction, education or recreation.
MATERIALS FOR CONSTRUCTION 2.1CEMENT The function of cement is to combine with water and to form cement paste. This paste first sets i.e. it becomes firms and then hardens due to chemical reaction, called hydration, between the cement and water. On setting & hardening, the cement binds the aggregate together into a stone like hard mass & thus provides strength, durability & water-tighten to the concrete. Quality of cement is based on grade of cement. The grades of cement are as33 Grades 43 Grades 53 Grades At the site Portland cement of 53 grades (JK SUPER CEMENT) is used. The cost per beg = 275 rupees The initial setting time of cement = 30 minutes (1/2 hr) The final setting time of cement = 10 hrs.
2.2AGGREGATE: Aggregates are small pieces of broken stones in irregular size and shapes. Neat cement is very rarely used in construction works since it is liable to shrink too much and become cracks on setting. More over, it will be costly to use neat cement in construction work. Therefore cement is mixed with some inert strong & durable hard materials. They also reduce the cost of concrete because they are comparative much cheaper as cement. TYPES OF AGGREGATES: .Fine Aggregate .Coarse Aggregate FINE AGGREGATE (SAND): The aggregate, which pass through 4.75 mm, I.S. sieve and entirely retain on 75 micron (.075mm) I.S. sieve is known as fine aggregate.
FUNCTION OF FINE AGGREGATE: The function of using fine aggregate in a concrete mix is to fill up the voids existing in the coarse aggregate and to obtain a dense and strong concrete with less quantity of cement and increase the workability of the concrete mix. COARSE AGGREGATE: The aggregate, which pass through 75 mm I.S. sieve and entirely retain on 4.75 I.S. sieve is known as coarse aggregates. At the site the coarse aggregate was 10mm & 20mm (graded).
FUNCTION OF COARSE AGGREGATE: The coarse aggregates are used in mixing of concrete. It is mixed cement, sand with water. These aggregates increase the strength of bonding in aggregates. Coarse aggregates are used in construction of plan cement concrete(PCC), foundation, beams and columns etc. GRADING OF CONCRETE: The art of doing gradation of an aggregate as determined by sieve analysis is known as grading of aggregate. The grade of concrete is depends on size of aggregates. The principle of grading is that the smaller particles will fill up the voids between large particles. This results in the most economical use of cement paste for filling the voids & binding together the aggregate in the preparation of concrete. Thus proper grading of fine & coarse aggregate in concrete mix produces a dense concrete with less quantity of cement.
REINFORCEMENT: The material that develops a good bond with concrete in order to increase its strength is called reinforcement. Steel bars are highly strong in tension, shear, bending moment, torsion and compression. FUNCTION OF REINFORCEMENT: Reinforcement working as a tension member because concrete is strong in compression and week in tension so reinforcement resists the tensile stresses in the concrete members. At the site contractor using the high strength steel bars and T.M.T. (Thermo Mechanically Treated) bars of diameter 8 mm, 10 mm, 16 mm, & 32 mm as per requirement of design.
2.3WATER: It is an important ingredient of concrete because it combines with cement and forms a binding paste. The paste thus formed fills up the voids of the sand and coarse aggregate bringing them into close adhesion. In this project source of water is a tube well which is closely spaced to the building. The quality of water is good and can be used for drinking purpose aiso.
2.4R.C.C.: Though plain cement concrete has high compressive strength and its tensile strength is relatively low. Normally, the tensile strength of a concrete is about 10% to 15% of its compressive strength. Hence if a beam is made up of plain cement concrete, it has a very low load carrying capacity since its low tensile strength limits its overall strength. It is, there reinforced by placing steel bars in the tensile zone of the concrete beam so that the compressive bending stress is carried by concrete and tensile bending stress is carried by steel reinforcing bars. Generally in simply supported and Cantilever beams the tension zone occurs at bottom and top of beam respectively.
EQUIPMENTS AND MACHINES 3.1 BATCHING MACHINE: The measurement of materials for making concrete is known as batching. The machines which used for batching is known as batching machine.
3.2 GRINDING MACHINE: This is a power mechanically operated machine which is used to mix the concrete. It consists a hollow cylindrical part with inner side wings. In which cement, sand, aggregates and water is mix properly.
3.3 TRANSPORTATION: The process of carrying the concrete mix from the place of it’s mixing to final position of deposition is termed as transportation of concrete. There are many methods of transportation as mentioned belowTransport of concrete by pans Transport of concrete by wheel barrows
Transport of concrete by tipping lorries Transport of concrete by pumps Transport of concrete by belt conveyors At this site belt conveyors were used.
3.4 COMPACTORS: When the concrete has been placed, it shows a very loose structure. Hence, it must be compacted to remove the air bubbles and voids so as to make it dense and solid concrete to obtain a high strength. There are two method- of compaction. Manual compaction Mechanical compaction Generally in large projects mechanical compactors are used . There are various mechanical compactors which uses according to requirement as needle and screed vibrators needed to compact the column and floor respectively. FOOTING: It is part of structural transfer the load of superstructure through columns to soil strata. Combined Footing
Isolated Footing Raft Footing In this project RAFT footing is provided. STAIRS: Stairs are defined as the access to reach one floor to another floor. Stairs are designed so as it gives maximum comfort and safety.
There are several types of stairs .
Straight flight stairs Half turn stairs Circular stairs Spiral stairs
In this project DOGG _ LEGGED STAIRS (Half Turn Stairs) are provided.
BRICK MASONARY The bricks are obtained by moulding clay in rectangular block of uniform size and then drying and burning these blocks. Brick masonry easy to constrct compare stone masonry. It is less time consuming and there is no need of skilled labour to construct it. The bricks do not require dressing and the arty of laying bricks is so simple.
7.1 CLASS OF BRICK: On the basis of quality and performance of brick is classified in three partsCLASS A CLASS B CLASS C At this site A class brick is used.
7.2 SIZE AND WEIGHT OF BRICKS The bricks are prepared in various sizes. On the basis of size , BIS bricks are categories in two partsMODULAR BRICKS: BIS recommends a standard size of brick which is 190mm*90mm*90mm. With mortar thickness, size of such a brick become 200mm*100mm*100mm. TRADITIONAL BRICKS: The brick of which size varies and not standardized known as traditional brick. WEIGHT OF BRICK: It is found that the weight of 1 cubic meter brick earth is about 1800 kg. Hence the average weight of a brick will be about 3 to 3.5 kg.
7.3 STRUCTURE OF BRICK STRETCHER: If brick laid along its length then front view of brick is known as stretcher. HEADER: If brick laid along it’s width , then front view of brick is known as header. FROG: It is top of brick. It provides strong bonding between two courses of masonry by filling the mortar. It also consists the name of company. QUEEN CLOSER: This is obtained by cutting the bricks longitudinally in two equal parts. BAT: This is piece of brick , considered in relation to the length of brick as half bat, three quarter bat, etc.
7.4 TYPES OF BRICK MASONARY: Brick work is classified according to quality of mortar, quality of brick and thickness of joints. They types of brick work as followsBRICK WORK IN MUD MORTAR: IN this type of brick work mud is used to fill up the joints. Mud is mixer of sand and clay. The thickness of mortar joint is 12mm. BRICK WORK IN LIME MORTAR:
In this type of brick work, lime mortar is used to fill up the joints. Lime mortar is mixer of lime and sand the thickness of joints does not exceeds 10mm. BRICK WORK IN CEMENT MORTAR: In this type of brick work ,cement mortar is used to fill up the joints. Cement mortar is mixer of cement and sand in ceftain ratio. The ratio Of cement and sand varies according to construction as in brick masonary it generally kept 1:6.The thickness of joint does not exceeds 10mm. The brick work with cement mortar provide high adopted in building construction. At this site cement mortar is used in brick work. The ratio of Cement to sand is 1:6.
7.5 TOOLS USED IN BRICK MASONRY: The tools used in brick masonry are trowel, spirit level, plumb bob, square, hammer, straight edge. BONDS IN BRICK WORK: There various bonds which provided in brick work to increase the stability of walls. Various types of bonds are as followsStretcher Bond Header Bond English Bond Flemish Bond STRETCHER BOND : The bricks are laid along its length in all courses. A half and three quarter bat is used in alternative courses to break the verticality of joints.
HEADER BOND: The bricks are laid along its width in all courses. A half and three quarter bat is also used in alternative courses to break the verticality of joints. ENGLISH BOND: This bond is widely used in practice. It is consider the strongest bond. Alternate courses consist of stretcher and header. A queen closer is put next to quoin header to break the verticality of joints. Generally such types of bond is provided in walls width is 9 inches. At this site ENGLISH BOND is prefer in main wall and STRETCHER BOND in partition walls.
FLEMISH BOND: This is also widely used because it gives better appearance to English bond. It also provides good strength. Stretcher and header is provided in each course alternatively. A queen closer is put next to quoin header in each alternate course to break the verticality of joints. THICKNESS OF WALLS: Thickness of wall depend on load, strength of material ,length of wallet. In this project the thickness of main wall is 9 inches and partition wall is 4.5 inches.
7.6 PROCEDURE OF BRICK MASONRY: In frame structure brick work starts after construction of foundation, column, beam, and slabs. Following procedure is adopt to construct the brick masonry1. 2. 3. 4. 5. 6.
Initially clean and wet the surface on which brick wall is be constructed. Set a straight alignment by using threads in both side of a wall . Prepare the cement mortar. At this site cement sand ratio is 1:6 for all walls. Mortar is laid on surface base and then bricks are laid over it . Prepare a course and then again laid the mortar on existing course and provides bricks
in such a way that the vertical joint should not stand in a line. 7. To break the verticality of joints generally English or Flemish bond is adopted. 8. Use the plumb bob to check the verticality at regular interval. 9. Also use square to check the wall is constructing straight or not. 10. After each 1meter height of wall provide a layer of reinforced cement concrete of 1.5 to 2 inches. 11. It will increase the strength of structure.
PLASTER
The term plastering is used to describe thin cover that is applied on the surface of walls. It removes unevenness of surface of walls. Sometimes it is use for decorative purpose also.
8.1MORTARFOR PLASTERING: Selection of type of mortar depends on various factors such as suitability of building material, atmospheric conditions, durability etc. there are mainly three type of mortar which can be used for the purpose of mortar Lime mortar Cement mortar Water proof mortar LIME MORTAR: The main content of lime mortar is lime that is mixed with correct proportion of sand. Generally fat lime is recommended for plaster work because the fat lime contains 75% of Cao and it combines with CO2 of atmosphere and gives CaCO3 quickly. Thus, the lime sets quickly, but it imparts low strength. So it can be use only for plaster work. The sand to be used for preparing lime mortar for plastering work should be clean, coarse and free from any organic impurities. CEMENT MORTAR: The cement mortar consists of one part of cement to four part of clean and coarse sand by volume. The materials are thoroughly mix in dry condition before water is added to them. The mixing of material is done on a watertight platform. It is better than lime mortar. It is widely used in construction work.
WATER PROOF MORTAR: Water proof mortar is prepared by mixing one part of cement, two part of sand and pulverized alum at the rate of 120Nperm3 of sand. In the water to be used, 0.75 of soft soap is dissolve per one liter of water and this soap water is added to the dry mix.
8.2 TOOLS FOR PLASTERING: Gauging Trowel
Metal Float
Plumb Bob
Sprit Level
Floating Rule Brushes
8.3 METHOD OF PLASTERING: According to the thickness of wall there are three method of plastering. One coat method Two coat method Three coat method ONE COAT METHOD: It is in the cheapest form of construction that plaster is applied in one coat. This method is quitely used in rural areas for the construction of low category and cheap house. TWO COAT METHOD: Following procedure is carried out for two coating plaster work Clean the surface and keep it well watered on which plaster wor to be done. If it is found that the surface to be plastered is very rough and uneven,a preliminary coat is applied to fill up the hollows before the first coat of plaster is put up on the surface. Now the first coat is applied on the surface.The usual thickness of first coat for brick masonry is 9mm to10mm. Second coat of plaster is applied after about 6 hours and the thickness of second caot is usually about 2mm to 3mm.It is finished as per requirement.
THREE COAT METHOD: The procedure for plaster in three coats is the same as above except that the num of coats of plaster is three. Table: First coat Second coat Third coat
Name of coat Rendering coat Floating coat Finishing coat
Thicknessa 9 to 10 mm 6 to 9 mm 3 mm
Evaluating Municipal Water Distribution Systems
9.1Primary Considerations This topic has two primary objectives: The first is to understand the evaluation of an installed municipal water supply delivery system by identifying all the physical components of any specific water distribution system. The same basic concepts and principles apply to small community water systems and large city water systems. For a basic understanding of these concepts, two illustrations are provided that include a relatively small water distribution system and a medium size water distribution system. These concepts will cover 92 percent of all the water supply systems in the United States. While there are similarities to all water systems, it should be recognized that the likelihood of two water systems being exactly alike in physical features is remote because the raw water sources in relation to the water delivery demands can hardly be the same. The second objective is to provide recognized practices for conducting water supply tests at prescribed intervals to measure the water system delivery capability and ensure that the system is meeting the water supply demand. An important part of this second objective is to use the results of water supply tests to monitor the performance of the water delivery system in relation to the existing water supply and the constant changes in demand on the water system. The following material will illustrate the broad features of water supply systems in order to understand how this can be accomplished. Chapter 2 presents a basic understanding of hydraulic fundamentals needed to accomplish water supply testing and evaluation accurately, and Chapter 3 presents water supply system evaluation methods for determining existing water supplies for consumer consumption and especially for fire protection
9.2Functional Components of a Water Utility System A water utility system can be relatively simple for a community of 3,000 to 5,000. At this level of population, communities often are served by wells. The well water is treated typically by chlorination and then either pumped directly into water distribution mains to supply customers or pumped into ground-level or elevated storage tanks where the water flows by gravity on demand to each customer on the water system. Some fire hydrants may be located on the distribution system to provide a minimum fire flow capability in the range of 250
gallons per minute (gpm) to 500 gpm. Figure 1-1 illustrates an actual example of a community that has these characteristics.
As the population served in the illustration of a small community increases, so does the complexity of the water delivery system. Figure 1-2 depicts the functional components expected to be in place in communities with populations ranging from 25,000 to 50,000. This is fairly typical of what one needs to understand in evaluating water supply systems to assure that rates of water can be delivered through the distribution system to simultaneously meet consumer consumption demands and meet Needed Fire Flow (NFF) criteria for structural fire
suppression. Therefore, before specifically examining and tracing the water system component diagramed in Figure 1-2, it is essential that each component be evaluated in relationship to the capability of the water delivery system, plus the function of selected components of the water system to meet the needed domestic and fire protection demands on the system. This needs to be assessed for each and every water system as a function of rates of water usage. Three historical or predicted water demand rates are involved in the discussion of consumer demand and fire protection: Average daily demand–the average of the total amount of water used each day during a 1year (designed) period. Maximum daily demand–the maximum total amount of water used during any 24-hour period. The Insurance Services Office. Inc. (ISO) bases this calculation on the highest demand during the previous 3 years from the years of an ISO Grading Schedule evaluation. Note: This number should consider and exclude any unusual and excessive uses of water that would affect the calculation i.e., a broken water main. Maximum hourly demand–the maximum amount of water used in any single hour of any day in a 3-year period. It normally is expressed in gallons per day by multiplying the actual peak hour by 24.
When specific data on past consumption levels are not available, a good rule of thumb is that maximum daily demand may vary from 1.5 to 3.0 times the average daily demand, while the peak hourly rate may vary from 2 to 8 times the average daily rate. In small water systems, peaking factors may vary significantly higher. Design flow and analysis should be based on the maximum hourly demand or the maximum daily demand plus the fire flow requirement, whichever is greater. This distribution system should be designed to maintain a minimum pressure of 20 pounds per square inch (psi) at all water taps including fire hydrant locations under all conditions of design flow. [This is a recommended practice of the American Water Works Association (AWWA) Manual of Water Supplies Practices–M-31 and M-17 along with criteria published by the ISO in accordance with Grading Schedule evaluations.] In order to account for system demands, chart recorders should be in place at every separate location where purified water enters the distribution system, including finished water holding basins, direct pumping facilities, finished water standpipe tanks, and finished water gravity tanks. This is the only reasonably accurate way to monitor water system demand on
an hourly, or less frequent, time period, 24 hours a day, 365 days a year. This is a key consideration in matching water system demand to water system availability.
9.3Tracing the Components of an Urban Water Distribution System The following information is presented in the context of Figure 1-2. 1. Raw water source shown in the upper left of the drawing marked #1. The water source may be a lake, a river, a reservoir, a well field, or, more recently, salt water sources which can be purified through new techniques in water filtration and reverse osmosis. The Tampa, Florida, municipal water system now has the capability of producing 60 percent of the city’s water demand using salt water. The AWWA recommended guideline on raw water capability is that the supply source(s) have a sufficient capacity at all time to meet maximum daily demand for a continuous period of 5 days. (Reference #1, pg. 12) This is demonstrated on the drawing by a raw water storage pond marked #2. Water Department action needed: A depth gauge is needed on each raw water source. A hydrologist or geologist needs to asses the gallons of water in storage at gauge level. There typically is not an equal drop or increase as water is drawn off or is supplemented by rain and runoff, due to the slope of the container sides and the slope of the bottom of the holding basin. This monitoring needs to be done daily if a diminishing supply is observed, to predict long-term supply conditions. 2. Typical raw water pumping facility marked #3. In the case of the illustrated water system, the pumping facility has a dual purpose. First it can pump the raw water, which is filtered by trash racks (coarse screws) and other finer screening, if necessary, to the treatment facility where the water is processed to meet Environment Protection Agency (EPA) criteria and even more rigid requirements for water treatment in several States through State health departments. Second, there needs to be the capability to transfer water to and from the raw water storage facility. This builds reliability into the water system. Constant-recording flow meters are needed on each of the pumps in this facility to assess how and when water is being transported through facility and the rate of water in gpm. Water Department action needed: The secondary raw water storage facility is important for retaining a reserve supply of water in case of a major pipe failure on the distribution piping,
or if the main source of water become depleted due to drought conditions or contamination of the primary supply. 3. The treatment facility marked #4. Chapter 6 covers the basic of water supply treatment and the sampling of water required to meet EPA criteria. There is a need to know the maximum water processing rate and the length of time that water can be processed at this rate, because this could limit water delivery to the distribution piping system. Process flow rates need to be monitored on a continuous timeline, which also will account for the downtime in the treatment plant to flush and clean equipment. Note in the illustration that a finished water facility is provided on the delivery side of the treatment plant; this is commonly called a clear well. In gravity feed systems, water flows from the clear well(s) into the distribution piping, or it is pumped where the land surface is relatively level. Water levels in the clear well(s) needed to be monitored closely on a daily basis with data recorded hour. 4. A high service pumping station marked #5. Note that this pumping station is located on the water distribution delivery side of the water treatment plant. High-level service pumps may be needed to: a. Pump water up to service areas that have higher elevations than other areas of a community. b. Fill gravity tanks that float on the water supply distribution system. c. When service pumping stations are used to distribute water, and no water storage is provided, the pumps force water directly into the water mains. From a water system evaluation perspective, there is no outlet for the water except as it furnishes consumer consumption for actual fire flows. Variable speed pumps or multiple pumps may be required to provide adequate water delivery service because of fluctuating demands. The efficiency and expense of this pumping equipment needs to be considered carefully. For example, it is a disadvantage that the peak power demand of the water plant is likely to occur during periods of high electrical consumption, and thus increase power costs. Furthermore, systems with little or no storage should be provided with standby electrical generating capability or pumps driven directly by internal combustion engines. These standby generators and engines needs to be tested routinely (e.g., several hours per week). 5. A gravity storage facility marked #6. An extremely important element in a water distribution system is water storage. (Reference #3, pg. 12) System storage facilities have a far-reaching effect on a system’s ability to provide adequate consumer consumption during periods of high demand while meeting fire protection
requirements. The two common storage methods are ground-level storage and elevated storage. The finished water storage at number 4 on Figure 1-2 is an example of ground-level storage; this type of storage also may be contained in covered tanks. Emphasis is put on elevated storage as a stand-alone in Chapter 7 of this Manual. 6. Water entering the distribution system marked #7. There are two basic types of pipe layout for delivering water to consumer taps and to supply water to individual fire hydrants. The preferred method is to loop the entire service area with a primary feeder main; the size is determined by hydraulic analysis. Interior to the ring main are cross-connected secondary feeders provided along the major streets in the community. Interior water mains that essentially provide water to residential areas are cross-connected to the secondary feeders. The advantages of this type of pipe system layout are two fold: 1) the water to every service location or demand point is supplied from two directions, which is considered to be the most efficient hydraulic design to minimize pipe sizes; and 2) in the event that a pipe section is out of service for cleaning, breakage from an accident, tapping for service extension, or whatever reason, water can be supplied to any demand point from a different travel path. In older community water systems a single primary feeder supplies secondary feeders and distributor pipes along block fronts in a branched layout configuration where at any demand point water is supplied from one direction only. This arrangement decreases the reliability of a water system significantly and has a tendency to decrease fire flow capability for larger scale fires. The capability of water main systems for meeting fire flow criteria can be determined only by semiannual fire flow tests as presented below.
9.4Evaluating Distribution System Appurtenances 1. Piping and valve arrangement. A piping system serving the consumers in a small community is illustrated in Figure 1-3. The primary feeders, sometimes called arterial mains, form the skeleton of the distribution system. They are located so that large quantities of water can be carried from the pumping plant to and from the storage tanks and the distribution system. (Reference #7, pg. 12) Primary feeders should be arranged in several interlocking loops, with the mains not more than 3,000 feet apart. Looping allows continuous service as previously identified through the rest of the primary mains, even when one portion is shut down temporarily for repairs. Under normal conditions, looping also allows supply from two directions for large fire flows. Large
feeders and long feeders should be equipped with blow-off valves at low points and air relief valves at high points. Valves should be placed so that a pipe break will affect water service only in the immediat area of the break. The secondary feeders carry large quantities of water from the primary feeders to points in the system in order to provide for normal domestic consumption supply and fire suppression. They form smaller loops within the loops of the primary mains by running from one primary feeder to another. Secondary feeders should be spaced only about three blocks apart, or a maximum of 1,500 feet. This spacing allows concentration of large amounts of water for firefighting without excessive head loss and resulting low pressure. Small distribution mains (i.e., distributors) are to form a grid over the area to be served. They supply water to residential taps and fire hydrants along residential block fronts throughout areas with this occupancy classification. In no case should the pipe size be less than 6 inches in diameter. Larger size pipes may be needed in residential areas for multiple occupancy buildings. In this case, pipe sizing is based on the sum of the peak day water use plus fireflow requirements. Where there are multiple-occupancy buildings of more than one floor, required pipe sizing is almost always controlled by the fire-flow requirement. Water distribution piping should be sized and spaced to meet design flow. The minimum size water main for providing fire protection and serving fire hydrants is 6 inches in diameter. Typical values for distribution system piping are summarized in Table 1-2. (Reference #8, pg. 12) Appurtenance Minimum Standard Lines Smallest pipes in network 6 inch Smallest branching pipes (dead ends) 8 inch Largest spacing of 6” grid (8” pipe used beyond this value) 600 ft. Smallest pipes in high-value district 8 inch Smallest pipes on principal streets in central district 12 inch Largest spacing of supply mains or feeders 3,000 ft. Valves Spacing in single and dual main systems: Largest spacing on long branches 800 ft. Largest spacing in high-value district 500 ft.
All areas served by a water distribution system should have fire hydrants installed in locations and with spacing for fire department use. The following method of locating fire hydrants should be observed in the United States. This method is outlined in Section 614 of the the ISO Fire Suppression Rating Schedule–2003 edition. (Reference #9, pg. 12) [Sidebar: Canada uses an area method.] Briefly summarized, the procedure examines a representative fire-risk location and a computed NFF at that location. The first determination is that a recognized fire hydrant be within 1,000 feet of the fire risk, as fire hose is laid from the fire hydrant to the fire risk. A recognized fire hydrant on a municipal water system must flow a minimum of 250 gpm at 20 psi residual pressure for 2 hours. The actual flow capability from each fire hydrant in the vicinity of the fire risk is limited by the distance to the fire risk as follows: (Reference #9, pg. 12) Credit is awarded up to 1,000 gpm from each hydrant within 300 feet of the fire-risk building; 670 gpm from hydrants within 301 to 600 feet of the fire-risk building; and 250 gpm from hydrants within 601 to 1,000 feet of the fire-risk building. Furthermore, the water utility should review hydrant spacing or representative fire risks in the community with the responsible first-due fire company because the supply hose capacity on fire apparatus may limit the credit assigned by ISO to this item in the Fire Suppression Rating Schedule. The pipe connecting the fire hydrant to the water main is call the hydrant branch or lateral. Every lateral needs to have an installed valve to enable the water utility to isolate the fire hydrant for repair or general maintenance. In addition, fire department use typically requires a maximum lineal distance between fire hydrants along street fronts in commercial and congested built-up areas of 300 feet, and 600 feet for light single-family residential areas. Good practice calls for fire hydrants at intersections, in the middle of a block where the NFF equals or exceeds 1,200 gpm, and at the end of dead-end streets.
9.5Summary Statement on Water Supply Distribution Water supply distribution systems are rather straightforward to evaluate in small communities with a population range up 5,000. The proper evaluation of water supplies and distribution for larger communities, up to cities over 100,000 population, is no simple thing. Water system
maps that are kept current and electronic graph records for all of the water supply that enters the distribution system are essential to establish an understanding of actual supply versus consumption on an hourly basis, daily basis, monthly basis, and yearly basis. If this information is not in place, the first step to the evaluation of a water system is to put in place a records management system, and then to pay close attention to this system. The water utility has the responsibility to keep public officials, especially fire officials, apprised of the current conditions of the water system. This topic paints the big picture for developing and maintaining a comprehensive evaluation of a water system.
RAIN WATER HARVESTING SYSTEM 10.1 INTRODUCTION What is rainwater harvesting? Rainwater harvesting is a technology used to collect, convey and store rain for later use from relatively clean surfaces such as a roof, land surface or rock catchment. The water is generally stored in a rainwater tank or directed to recharge groundwater. Rainwater infiltration is another aspect of rainwater harvesting playing an important role in stormwater management and in the replenishment of the groundwater levels. Rainwater harvesting has been pr acticed for over 4,000 years throughout the world, acticed for over 4,000 years throughout the world, traditionally in arid and semi-arid areas, and has provided drinking water, domestic water and water for livestock and small irrigation. Today, rainwater harvesting has gained much on significance as a modern, water-saving and simple technology. The practice of collecting rainwater from rainfall events can be classified into two broad categories: land-based and roof-based. Land-based rainwater harvesting occurs when runoff from land surfaces is collected in furrow dikes, ponds, tanks and reservoirs. Roof-based rainwater harvesting refers to collecting rainwater runoff from roof surfaces which usually provides a much cleaner source of water that can be also used for drinking. Gould and Nissen-Petersen (1999) categorised rainwater harvesting according to the type of catchment surface used and the scale of activity (Figure 1).
Fig. 1. Small-scale rainwater harvesting systems and uses (adapted from Gould and Nissen-Petersen, 1999). 1
Rooftop rainwater harvesting at the household level is most commonly used for domestic purposes. It is popular as a household option as the water source is close to people and thus requires a minimum of energy to collect it. An added advantage is that users own, maintain and control their system without the need to rely on other community members.
Why rainwater harvesting? In many regions of the world, clean drinking water is not always available and this is only possible with tremendous investment costs and expenditure. Rainwater is a free source and relatively clean and with proper treatment it can be even used as a potable water source. Rainwater harvesting saves high-quality drinking water sources and relieves the pressure on sewers and the environment by mitigating floods, soil erosions and replenishing groundwater levels. In addition, rainwater harvesting reduces the potable water consumption and consequently, the volume of generated wastewater. Application areas Rainwater harvesting systems can be installed in both new and existing buildings and harvested rainwater used for different applications that do not require drinking water quality such as toilet flushing, garden watering, irrigation, cleaning and laundry washing. Harvested rainwater is also used in many parts of the world as a drinking water source. As rainwater is very soft there is also less consumption of washing and cleaning powder. With rainwater harvesting, the savings in potable water could amount up to 50% of the total household consumption.
10.2Criteria for selection of rainwater harvesting technologies Several factors should be considered when selecting rainwater harvesting systems for domestic use: • type and size of catchment area • local rainfall data and weather patterns • family size • length of the drought period
• alternative water sources • cost of the rainwater harvesting system. When rainwater harvesting is mainly considered for irrigation, several factors should be taken into consideration. These include: • rainfall amounts, intensities, and evapo-transpiration rates • soil infiltration rate, water holding capacity, fertility and depth of soil • crop characteristics such as water requirement and length of growing period • hydrogeology of the site • socio-economic factors such as population density, labour, costs of materials and regulations governing water resources use. Fig.
Fig. 2: A schematic diagram of a rooftop rainwater harvesting system.
(1) A collection or catchment system is generally a simple structure such as roofs and/or gutters that direct rainwater into the storage facility. Roofs are ideal as catchment areas as they easily collect large volumes of rainwater. The amount and quality of rainwater collected from a catchment area depends upon the rain intensity, roof surface area, type of roofing material and the surrounding environment. Roofs should be constructed of chemically inert materials such as wood, plastic, aluminium, or fibreglass. Roofing materials that are well suited include slates, clay tiles and concrete tiles. Galvanised corrugated iron and thatched roofs made from palm leaves are also suitable. Generally, unpainted and uncoated surface areas are most suitable. If paint is used, it should be non-toxic (no lead-based paints). (2) A conveyance system is required to transfer the rainwater from the roof catchment area to the storage system by connecting roof drains (drain pipes) and piping from the roof top to one or more downspouts that transport the rainwater through a filter system to the storage tanks. Materials suitable for the pipework include polyethylene (PE), polypropylene (PP) or stainless steel. Before water is stored in a storage tank or cistern, and prior to use, it should be filtered to remove particles and debris. The choice of the filtering system depends on the construction conditions. Low-maintenance filters with a good filter output and high water flow should be preferred. “First flush” systems which filter out the first rain and diverts it away from the storage tank should be also installed. This will remove the contaminants in rainwater which are highest in the first rain shower. (3) Storage tank or cistern to store harvested rainwater for use when needed. Depending on the space available these tanks can be constructed above grade, partly underground, or below grade. They may be constructed as part of the building, or may be built as a separate unit located some distance away from the building. The storage tank should be also constructed of an inert material such as reinforced concrete, ferrocement (reinforced steel and concrete), fibreglass, polyethylene, or stainless steel, or they could be made of wood, metal, or earth. The choice of material depends on local availability and affordability. Various types can be used including cylindrical ferrocement tanks, mortar jars (large jar shaped vessels constructed from wire reinforced mortar) and single and battery (interconnected) tanks. Polyethylene tanks are the most common and easiest to clean and connect to the piping system. Storage tanks must be opaque to inhibit
algal growth and should be located near to the supply and demand points to reduce the distance water is conveyed. Water flow into the storage tank or cistern is also decisive for the quality of the cistern water. Calm rainwater inlet will prevent the stirring up of the sediment. Upon leaving the cistern, the stored water is extracted from the cleanest part of the tank, just below the surface of the water, using a floating extraction filter. A sloping overflow trap is necessary to drain away any floating matter and to protect from sewer gases. Storage tanks should be also kept closed to prevent the entry of insects and other animals.
(4) Delivery system which delivers rainwater and it usually includes a small pump, a pressure tank and a tap, if delivery by means of simple gravity on site is not feasible. Disinfection of the harvested rainwater, which includes filtration and/or ozone or UV disinfection, is necessary if rainwater is to be used as a potable water source.
10.4Designing a rainwater harvesting system For the design of a rainwater harvesting system, rainfall data is required preferably for a period of at least 10 years. The more reliable and specific the data is for the location, the better the design will be. Data for a given area can be obtained at the meteorological departments, agricultural and hydrological research centres and airports. One simple method of determining the required storage volume, and consequently the size of the storage tank, is shown below: With an estimated water consumption of 20 l/c*d, which is the commonly accepted minimum, the water demand will be = 20 x n x 365 l/year, where n=number of people in the household. If there are five people in the household then the annual water demand is 36,500 litres or about 3,000 l/month. For a dry period of four months, the required minimum storage capacity would be about 12,000 litres. As rainwater supply depends on the annual rainfall, roof surface and the runoff coefficient, the amount of rainwater that can be collected = rainfall (mm/year) x area (m2) x runoff coefficient. As an example: a metal sheet roof of 80 m2 with 800 mm rainfall/year will yield = 80 x 800 x 0.8 = 51,200 l/year.
Figure 3 demonstrates the cumulative roof runoff (m3) over a one-year period and the cumulative water demand (m3). The greatest distance between these two lines gives the required storage volume (m3) to minimise the loss of rainwater.
Fig. 3: Graphical method to determine the required storage volume for a rainwater cistern (adapted from Gould and Nissen-Petersen, 1999).
10.5Types of rainwater use Rainwater systems can be classified according to their reliability, yielding four types of user regimes: • Occasional - water is stored for only a few days in a small container. This is suitable when there is a uniform rainfall pattern with very few days without rain and when a reliable alternative water source is available. • Intermittent - in situations with one long rainy season when all water demands are met by rainwater. During the dry season, water is collected from other sources. • Partial - rainwater is used throughout the year but the 'harvest' is not sufficient for all domestic demands. For example, rainwater is used for drinking and cooking, while for other domestic uses (e.g. bathing and laundry) water from other sources is used. • Full - for the whole year, all water for all domestic purposes comes from rainwater. In such cases, there is usually no alternative water source other than rainwater, and the available water should be well managed, with enough storage to bridge the dry period. Which of the user regimes to be followed depends on many variables including rainfall quantity and pattern, available surface area and storage capacity, daily consumption rate, number of users, cost and affordability, and the presence of alternative water sources.
10.6Benefits of rainwater harvesting Rainwater harvesting in urban and rural areas offers several benefits including provision of supplemental water, increasing soil moisture levels for urban greenery, increasing the groundwater table via artificial recharge, mitigating urban flooding and improving the quality of groundwater. In homes and buildings, collected rainwater can be used for irrigation, toilet flushing and laundry. With proper filtration and treatment, harvested rainwater can also be used for showering, bathing, or drinking. The major benefits of rainwater harvesting are summarised below: • rainwater is a relatively clean and free source of water • rainwater harvesting provides a source of water at the point where it is needed • it is owner-operated and managed • it is socially acceptable and environmentally responsible • it promotes self-sufficiency and conserves water resources • rainwater is friendly to landscape plants and gardens • it reduces stormwater runoff and non-point source pollution • it uses simple, flexible technologies that are easy to maintain • offers potential cost savings especially with rising water costs • provides safe water for human consumption after proper treatment • low running costs • construction, operation and maintenance are not labour-intensive. Disadvantages The main disadvantages of rainwater harvesting technologies are the limited supply and uncertainty of rainfall. Rainwater is not a reliable water source in times of dry periods or prolonged drought. Other disadvantages include: • low storage capacity which will limit rainwater harvesting, whereas, increasing the storage capacity will add to the construction and operating costs making the technology less economically feasible • possible contamination of the rainwater with animal wastes and organic matter which may result in health risks if rainwater is not treated prior to consumption as a drinking water source • leakage from cisterns can cause the deterioration of load-bearing slopes
• cisterns and storage tanks can be unsafe for small children if proper access protection is not provided. Maintenance Maintenance is generally limited to the annual cleaning of the tank and regular inspection and cleaning of gutters and down-pipes. Maintenance typically consists of the removal of dirt, leaves and other accumulated material. Cleaning should take place annually before the start of the major rainfall season. Filters in the inlet should be inspected every about three months. Cracks in storage tanks can create major problems and should be repaired immediately. Costs The associated costs of a rainwater harvesting system are for installation, operation and maintenance. Of the costs for installation, the storage tank represents the largest investment which can vary between 30 and 45% of the total cost of the system dependent on system size. A pump, a pressure controller and fittings in addition to plumber’s labour represent other major costs of the investment. In general, a rainwater harvesting system designed as an integrated element of a new construction project is more cost-effective than retrofitting a system. This can be explained by the fact that many of the shared costs (such as for roofs and gutters) can be designed to optimise system performance and the investment can be spread over time.
10.7Rainwater quality standards The quality of rainwater used for domestic supply is of vital importance because, in most cases, it is used for drinking. Rainwater does not always meet drinking water standards especially with respect to bacteriological water quality. However, just because water quality does not meet some arbitrary national or international standards, it does not automatically mean that the water is harmful to drink. Compared with most unprotected traditional water resources, drinking rainwater from wellmaintained roof catchments is usually safe, even if it is untreated. The official policy of the Australian Government towards the question “Is rainwater safe to drink?” is as follows: “Providing the rainwater is clear, has little taste or smell and is from a well-maintained system, it is probably safe and unlikely to cause any illness for most users”. For immuno-
compromised persons, however, it is recommended that rainwater is disinfected through boiling prior to consumption. Drinking water from rainwater In many countries of the world where water resources are not available at a sufficient quality fit for human consumption, rainwater acts as a substitute for drinking water and other domestic uses. In some remote islands around the globe, rainwater may even act as the major potable water source for their population. The most important issue in collecting rainwater is keeping it free of dirt such as leaves, bird droppings and dead animals, and avoiding contamination with pollutants like heavy metals and dust. Rainwater can be also treated for use as a potable water source. The use of slow sand filtration has proved to be a simple and effective treatment technology for the elimination of most of the organic and inorganic pollutants that may be present in rainwater, as well as producing a virtually pathogen-free water for drinking.
CONCLUSION As per my training report I have conclude that , during last 30 days I am familiar with the construction of brick masonry & plastering and study of water distribution & rain water harvesting system under a Rajasthan Housing Board project. Brick masonry is provided to transfer the load of structure to foundation. All though maximum load of building comes on columns and beams. Plaster is necessary to cover and protect the masonry from weathering factor. It is a layer of cement mortar of thickness is 1 to 1.5 inches. The basic knowledge of rainwater harvesting system also important for future water saving planning. I am very thankful to all those people who help me to get knowledge of brick masonry and plastering & RWHS.
