PLUMBING 51 Chapter - 4 PLUMBING 4.1 INTRODUCTION Plumbing deals with the laying ofpipe lines. Pipeline provides the means of transporting the fluid. Itis obvious that laying-out the pipe line, requires a number of joints to be made and anumber of valves incorporated, while connecting different lengths of pipes. Plumbing work does not require many tools except pipe wrenches, hacksaw, pipe cutter, threading equipment and a pipe vice. 4.2 PLUMBING TOOLS 4.2.1 Pipe Wrench Pipe wrench is the most important tool used for holding and turning the pipes, rods and machine parts. Wrenches of size 300 mm and 450 mm are more useful. The adjustable wrench shown in Fig 4.1. consists ofa fixed jaw and a movable jaw. The movable jaw facilitates the adjustment of the opening between the jaws. The jaws are serrated inside, to enable a firm grip over the pipes. Pipe Wrench Fig 4.1 Adjustable Pipe Wrench 4.2.2 Pipe Vice ‘The use ofa regular pipe vice is advisable, though ordinary bench vice can serve the Purpose in most of the occasions. The pipe vice is fitted on the work bench. Itholds the Pipes in position during cutting, threading and fitting of bends, couplings, etc. Fig 4.2 shows a pipe vice. It consists of two jaws for holding the work, which are serrated to ensure firm grip.§2. CENTRAL WORKSHOP - ENGINEERING PRACTICE LAB MANUay Fig4.2 Pipe vice 4.2.3 Pipe Cutter For an occasional pipe work, a hacksaw is quite satisfactory. Pipe cutters are also ‘used where considerable amount of pipe work is involved. The pipe cutter mainly consists ofthree wheels, which are hardened and with sharp cutting edges along their periphery ‘Of these three wheels one can be adjusted to any desired distance from the other two fixed wheels, to accommodate different sizes of pipes. After adjusting the cutter ona pipe, itis turned around the pipe so that the cutter wheels cut the pipe along a circle. Fig 4.3 shows apipe cutter. Fig 4.3 Pipe Cutter 4.2.4 Pipe Bending Machine Se While laying the pipeline, sometimes a part of a pipe may have to be bent to the required curvature, For this, a pipe bending machine is used. Itis mounted ona tripod stand and can swivel about a vertical axis to any desired angle, to cover the required range forthe operation, The unit consists ofa number of bending blocks to obtain any desired curvature at the bend. aPLUMBING 53 4.2.5 Dies Apipe die is used for cutting external threads on Pipes is shown in Fig 4.4. One or two piece dies are used in. the diestock, Itisahand operated tool, which may be considered asahardened steel nut, having flutes cut along its inside surface, Fig 4.4 Pipe Die ‘These flutes serve the same purpose as in a twist drill, In case of two piece die, the two pieces are set at a desired distance and secured in position by means of. set screw. 4.3 PIPES AND PIPE FITTINGS Pipesare used for carrying fluids such as water, steam, gas, oil, etc., from one place toanother. As pipes are made to standard lengths, the desired length of pipe may be obiained by joining them, The type of joint used depends upon the material of the pipe and the purpose for which it is used. Generally, pipes are made of cast iron, wrought iron, steel, brass or copper. The material selection is based on the nature of the fluid to be conveyed, viz., pressure, temperature, chemical properties, etc. Now-a-days, PVC pipes are extensively used with ease for various applications. ‘The standard codes of practice followed for specification of pipes in British system only. However, the sizes may be converted into metric units by taking 1 inch=25.4mm.as amultiplying factor. There does not exist a separate metric system of specification. The size of a metallic pipe is designated by its inside diameter. The size of a pipe fitting is designated by the size of the pipe on which tits. There are different types of pipe fittings available in the market, These should be selected, keeping in mind the desired pipe layout,ee 54 CENTRAL WORKSHOP - ENGINEERING PRACTICE LAB MANY A 4.4 PIPE FITTINGS Cast iron (C.}): Pipe fittings Cast iron pipe fittings such as couplings. bends, el, tees, crosses, etc,, are used with wrought iron and steel pipes of relatively smaller sine that they are either connected or branched-offat required angles. se GL pipe fittings: Wrought iron is coated with zine by a process knownas galvanizin, make galvanized iron (Gi) pipe fittings, which do notrustreadily like C.Lfittings, Sonic the commonly used Gil pipe fittings are shown in Fig4.5. 7 Coupling: Itisa short cylindrical sleeve with internal threads throughout. Itisused, joining two pipes ina straight line and where at least one: pipe can be tured. Union: Itis used for joining two pipes, where neither can be tumed. It consists of thre. parts; two parts will be screwed on to the two pipe endsand the third one, which isanyy | draws the pipes together tightly. Nipple: It isa short piece of pipe (less than 300 mm in length) with external threads at both the ends. Nipples are available in standard short lengths. Itis used to make-up the | Tequired length of the pipe line. Elbow: It is used to make an angle between adjacent pipes. ‘The angle is always 900, unless another angleis stated. Tee: It isa fitting thathas one side outlet at right angle to the run. Itis used for a single outlet branch pipe. Plug: It is used to screw onto a: threaded opening, for closing it temporarily. Globevalve: This controls the fluid flow ina pipe line; however, the passage of flowis restricted. Check valve: It is used to prevent reverse flow inapipe line. The swing type valveis ()@eraQ Fig4.5 Pipe FittingsBN 58 a La ween ‘Tap Globe Valve Ss Elbow Cross i [Ss] Reducer Coupling Dummy Union Fig4.6 Pipe Fittings Reducer coupling: It is used to connect two different sized pipes. Bushs Itis a short sleeve-like piece, used to reduce the size ofa threaded opening. It is a fully on the inside and square end on the other, to receive the spanner for operation. ‘apmay be used for closing external threaded openings temporarily.ot 56 CENTRAL WORKSHOP - ENGINEERING PRACTICE LAB MANUay Flange: Flanges are available either in oval or in circular shapes. These contain in : threads in the hub and holes in the body to receive bolts. Two pipes may be Joiney together in line, using flanges and bolts, Gatealve: Pipe valves are ited inthe pipe lin fo contol the fluid low through it, Gay Valve offers lessresistance tothe lowof waterthrovghit Itisused whereitisimp otto obsiuctthe low andl where the valveis closed only rarely. In this valve, the flowy, reduced by lowering the wedge shaped gate towards its seat, Common tap: This is used for tapping the fluid flow at required points in the pipe line PYC Pipes and fittings: Plastic pipes and pipe fittings made of Poly Vinyl Chloride (PVC) areextensively used foragricultural, industrial and domestic applications, Pye pipes exhibitthe following salient features: - Smoother bore in comparison to CLL, GI; thereby better flow characteristic Seamless, strong.and resilient. Lightweight offering total economy in handling, transportation and installation Resistance to chemical, electrolytic and galvanic corrosion Hygienic for transporting potable water, as they do not subject to contamination, Maintenance free. Long-lasting PVCisftee from weakening, caused by scale formation, rusting, weathering and chemical action and hence more durable for rated working conditions, 2, a 4. 5: 6. a NOTE: The PVC pipe size indicates the outside diameter ofthe pipe. Threaded PVC pipe fittings should not be over-tightened, as the threads may get damaged. Threads should not be cut on PVC Pipes. They should only be formed during manufacturing, PVC pipes, are joined by solyent cement or ‘by suitable threaded fitting. Thesteps tobe followed while joining the PVC pipes are: 1, Cutthe pipes as ‘Square as possible. The dry, Clean the surface with emery paper 2. Apply thick coat of solvent a P itcement on the outer surface of the pipe and also on | the innersutface of the socket, : 3, nsert the pipe into the socket and tum throu 4, Hold the joint fimly, pipe and socket should be clean and beforejoining. igh 90? for even distribution of cement ‘without slipping for2 minutes and allowitto dry. Pe57 «so fittings are available in varioussizes from. 20 to 160mm. The dimensions oinmotl pipe fittingsare shown inFig4.6. Itmay be noted that the fitting sizes weet inside diameter ote opening, inc js RELAYOUE gorbeter pipe works itis advisable to sketch first, the pipe layout is shown in red? showing | dimensions and types of fittings to be used. Careful planning makes it pssbleto complete the work with fewer joints and fittings. Gjobe ave a Stopcock, pee tock nwt | Fig 4.7 Pipe Layout fap Incuttng pipe to Length, the portion ofthe pipe what will be screw tings, must also be taken into account. ed or inserted into58 CENTRAL WORKSHOP - ENGINEERING PRACTICE LAB MANUa, 4.6 PIPE THREADING Afterpipes are cut to lengths, to suit the layout, they must be threaded before assembly. The following are the steps involved while threading a pipe bymeans of apip, die: 1. Clamp the pipe securely in a pipe vice. 2. Select proper size of the die and insert into the stock. 3. Place the die on the end of the pipe and apply pressure, while the die is slowly tumed. 4. Once the threading is started, apply cutting oil and continue to turn the die into the pipe, till one thread projects through the die. NOTE: 1. Pipe die produces tapered threads. The tapered pipe threads tighten securely into the pipe fittings. 2. While threading, turn the die stock handle back and forth frequently, to loosen the chips. 4.7 ASSEMBLY Pipe layout should be made so as to avoid strains and bending at the joints. To ensure tight joints in pipe work, the threads are ‘applied with some kind of thread compound, before screwing them together, While ‘screwing the pipe in its fitting, itis advised to use two pipe wrenches, making one to fit the pipe and the other to fitthe pipe fitting. To avoid damaging a valve or a tap with wrench marks, it is advised to use amonkey wrench with smooth jaws. Some fittings like unions and flanges Tequire gaskets to make tight joints. When fitting are dissembled, gaskets are usually damaged and must be replaced. Gaskets are made from materials such as rubber or leather.et 59 wane Ss spire MATER i A ‘Advantages Disadvantages Primary Use Coated? waters xcllent Ino longer manufactured; |large, old systems _ |yes cater | chinability, Lower|deteriorates in some soils density and higher thermal conductivity than steels | fatrong ductile |deteriorates in some soils {large systems yes De repensive jwall thickness mustbe [raw water mains _|yes el lcarefully considered Trace [Cost Savings, Expensive, weaker material|raw water mains and no Durability, when handling tension _| industrial systems |competitiveness and Aesthetics, reseilinexpensive More expensive in lraw. water mains and {no i materials, fabrication, industrial systems delivery its |Durability , brittle; no longer lreplaced cast iron; in [no it inexpensive and Fire |manufactured old systems Proofing, lnc inexpensive gasoline from soil can pass |<10 inch pipes Ino into pipe powsigid Jexceptional corrosion | requires special heat fusion |service lines in water |no jit esac good joining toolsinorganfe systems and main Jpressure-bearing, ~~ |chemicals in soil weaken _ lines in gas systems capability; and ease | pa lofhandling and _|PIP© installation Pr Good Conductor, [Expensive lservice lines Ino [Malleable and Ductile ized JResistance to lcorrodes; produces Rust resistance is |no corrosion, discolored water;hasa _|needed Affordability and __|short life; deteriorates in Durability lsome soilsAMM: 3 A qooutthe threads at the end of given pipe, as shown in fig by tiscg «pipe die 0035 REQUIRED: pipe with stock and cutting oil. Pipe vices .gQuence oF OPERATION: 1, Thegiven pipe is securely clamped in the pipe vice. 9, propersize of the die is selected and inserted into the stock. 3 ‘The die is positioned at the end of the pipe and pressure i i . . isslowly tumed. ane ne die 4, Once the threading is started, the cutting oil is applied and conti dieinto the pipe, till one thread projects through the die, Sate Notes while threading, the die stock is turned back and forth frequently, to loosen the hips. RESULT: ‘Threads are cut at the end of the given pipe.