MEASURING, CUTTING, AND JOINING PIPES

Measuring, Cutting, and

Joining Pipes

Cast Iron Pipe

• it is used for all types of plumbing installation.

• was proven good and durable material for house sewer, house drain, soil, waste and vent pipe on various types of building.

• was limited by the Code to less than 25-storey high building where constant vibration is present.

• vibrations loosen the lead calk joint between the pipes causing unwanted sag and water leak.

• affected to some extent by corrosion due to chemical action in the system that is impossible to control.

Plumbing Design and Estimate• Cost - associated with the kind of pipe to

be used.• thus, it is important to know the specific

uses of each type.Recommended Uses1. Standard Pipe - used for a well-fitted hub

and spigot connections.

2. Single Hub - recommended when the length of a pipe needed is more than 150 cm long wherein cutting is not necessary.

3. Double Hub - preffered when a piece of pipe needed is shorter than 150 cm long. When the pipe is cut, both ends has hub to serve as joint connector.

4. Hubless Pipe - used in lieu of the single hub to do away with caulking of joints. it is cheaper and easily connected using a neoprene rubber sleeves.

Cutting and Connecting Pipes

The Procedures in cutting cast iron pipes are the follows:

1. A chalk mark is drawn around the pipe.2. The pipe is laid on sand.3. With the use of hammer and cold chisel,

the scored line around the pipe struck gently at first around, then continue striking harder and herder all around, until the pipe is cut or part off.

Calking Joints

• Calking joints of cast iron pipe is done through the followng steps:

1. Make sure that the pipes to be joined are perfectly aligned with spigot centered inside the bell.

2. Wrap the oakom around the spigot neck filling the space around the inner hub. With the use of a yarning iron, drive the oakom into the bottom of the hub, then, compress firmly to make a solid bed providing 20 to 25 mn clearance from the top of the bell.

3. After packing, the joint is sealed with lead monolithically poured around the inner hub at about 3 mm above the bell. Then packed against the hub by the calking iron tamping it firmly to make a water tight seal.

Galvanized Steel Pipe

• is somewhat difficult because of its regidity and the threading processes involved, plus the joining operations.

• face to face method is applied conveniently in measuring the length for a connection.

• however, allowance for the thread that will enter into the fitting should be provided.

involve the ff. consideration:

1.Direct connection2.Measuring and cutting3.Threading operations

Direct Connection

• the manner of planning the layout and re-routing of the pipes to reach the point of service.

• all pipelines should be installed as short and direct as possible.

• number of fitting and pipe cutting plus the threading work - be reduced to the minimum required if the plumbing layout was planned carefully.

Measuring and Cutting

• errors are committed in the measuring and cutting of pipes

• may mean additional pipes and fittings, cost of labor, and the risk of water leakage.

• face to face methods of measuring and cutting of pipe connection is considered the most reliable.

Cutting and Threading Operations

• on cutting and threading operations, steel pipe should be held rigidly with proper holding tools.

• cutting is done by using 14-teeth per inch hacksaw blade applying forward strokes at the rate of about one stroke per second.

remember: fast cutting will overheat and break the blade.

Basic rules governing the threading operation:

1. Never hold threaded parts with a wrench. it will surely damage the thread.

2. Put two nuts on them, lock tightly, and continue the threading operation.

3. During the process of threading, apply motor oil regularly to protect both the threader and the thread of the pipe.

4. To ensure tight and rigid connection, the threads should be slightly tapered so that the turning of the fitting will be harder the depper you screwed.

5. Provide the threaded portion of the pipe with a teflon tape in a clockwise direction before turning the fitting joint to obtain a water-sealed connection.

Determining the G.I Pipe Diameter

• The size of galvanized iron pipe is the diameter of its hole not the outside diameter.

• In the absence of a measuring caliper, the inside diameter of a pipe can be known by measuring the outside circumference of the pipe with a string.

Copper Pipe

Classified into two types:

1.Rigid type2.Flexible type

Copper Pipe Working Procedures

1.In measuring length of a rigid or flexible copper pipe, the face to face method is also applied.

2.Cutting of copper pipes with a suitable rotary tube cutter will give the best and satisfying result. In the absence of a rotary tube cutter, the hacksaw blade with 24 teeth per inch is used on heavy pipes and the 32 teeth per inch for the thinner one.

3. Cutting is done through a gentle light forward stroke. after cutting, the burrs are removed inside the pipe with a file or reamer.

4. Copper pipes are bent slowly an a wide radius to avoid kinking. bending a pipe is easily done with pipe bending machine to produce a very satisfactory result.

Soldering Copper Pipe Joints

1. Clean thoroughly both ends of the pipe to a bright finish including the inside of the fittings with emery clothe or fine sand paper.

2. Apply a tin coat of non-corrosive flux or soldering paste to all cleaned surface of the pipe and fittings.

3. Place the fitting up to the hub and rotate for several times until the flux is evenly spread.

4. Wipe the excess flux around the fitting and solder in one operation only. With a propane torch, heat the fitting uniformly around the pipe.

5. Never allow the fluxed joint to stand for more than 3 hours before soldering.

6. During the process of cooling, avoid disturbing the pipe or the fitting for it might weaken or break the seal.

7. Avoid soldering the pipe that contains water. Wrap other connections with wet rags in the same fitting before soldering to avoid melting of the finished points.

3-6 Plastic Pipes

Plastic pipe is a new concept in plumbing for all types of building. Plastic pipe has been accepted worldwide after it has in many ways proven itself to be superior as sewer and cold water pipe line material.

The simplest way of joining plastic pipe is by sementing called Solvent Welding. Solvent Welding takes only about 1/4 the time it takes to assemble bell and spigot joints.

Working With Plstic Pipes

1. Measure the face to face distance of the fittings to be connected. Add the engagement lenght before cutting the pipe.

2. Some plastic pipes can be cut with a sharp knife, but all can be cut with hacksaw or handsaw. A rotary pipe cutter should not in any manner be used in cutting plastic pipes.

3. Be sure to cut pipe ends square or at right angle with the axis of th pipe. Work on the joint at a time.

4. After cutting, remove the burrs inside the pipe, ream and clean the end portion of the pipe until smooth to allow full contact with the fitting shoulder.

5. Apply solvent cement liberally using non-synthetic brush to the shoulder fitting and butt end of the pipe.

6. Insert the pipe into the fitting and give it a quarter turn or 1/4 turn. the span of time from the cement application to the quarter turning should not be more than 30 seconds.

7. Do not disturb the pipe for several minutes after the quarter turn, wait for about 2 hours before testing the line under pressure. Drying of the cement must be far enough advance from 15 to 20 hours to permit use of the line.

8. In the process of bending, plastic pipe is packed with sand then heated using a flame torch or hot water. Apply pressure gently and gradually when the pipe is soft and ready for bending.

9. Correction or repair of lines may be done by cutting the pipe at a reasonable distance away from the side of the fitting then connect with coupling or socket.

table 3-1 weight of soil pipe 150 cm. long

Size mm

In.

Single Hubkg.

Double Hubkg.

50 2 75 3 100 4 125 5 150 6

12.5021.6029.5038.5045.50

13.022.030.039.046.0

table 3-2 effective lenght of cast iron pipe

Pipe Size Laying lenght in centemeter

mm In. Pipe with Hub Hubless Pipe

5075

100125150

23456

143143142142142

150150150150150

table 3-3 additional lenght in cutting cast iron pipe

Pipe Diameter Engagement Lenght

mm In mm cm

5075

100125150

23456

6268757575

6.26.87.57.57.5

table 3-4 quantity of oakum pipe joints

Pipe Diameter cm. In.

Weight of Oakum per point in Kilogram

50 2 75 3 100 4 125 5 150 6

.05

.08

.15

.23

.35

table 3-5 quantity of lead per pipe joint

Pipe Diametermm

Weight of Lead per joint in kilograms

5075

100125150

.50

.801.001.502.00