16 Pipe Drafting - blogs · Pipe Systems Section 16.2 Creating Pipe Drawings 16 Pipe Drafting Chapter Objectives Describe various types of pipe and explain their uses. Identify pipe

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Section 16.1 Pipe Systems

Section 16.2 Creating Pipe Drawings

16 Pipe Drafting

Chapter ObjectivesDescribe various types of pipe and explain their uses.Identify pipe connec-tions and fi ttings.Explain the functions of various valves.Identify various components of a pipe drawing.Prepare basic ortho-graphic pipe drawings and isometric drawings using board drafting and CAD techniques. Prepare a 3D wireframe model of a pipe system using CAD techniques.

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Main Squeeze Starck has created an eye-catching design that is as famous for the way it looks as for how useful it is. What everyday objects can you think of that might be given an imaginative makeover?

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Go to glencoe.com for this book’s OLC to learn more about Philippe Starck.

Can a work of art have a practical, everyday use? Can a tool be a work of art? One day in 1990, the designer Philippe Starck squeezed a lemon over a plate of squid he was eating, and had an inspiration. He grabbed a nearby paper napkin and started sketch-ing. He drew what became the Juicy Salif, a citrus squeezer that has been hailed as an icon of industrial design in the twentieth century.

The original Juicy Salif was made from polished,

cast aluminum and sold by Alessi, an Italian kitchen-ware company. It is also on display in art museums; a special gold-plated version was created for its tenth anniversary and sold as art. However, the gold Juicy Salif couldn’t be used to squeeze lemons because cit-ric acid erodes and discolors gold. So, depending on which version you have, you may store it in a kitchen cabinet and use it once in a while, or display it on your mantel as a piece of sculpture.

Drafting CareerPhilippe Starck, Industrial Designer

Academic Skills and Abilities• Sketching and drawing• Visual orientation• Mold making• Metallurgy

Career PathwaysCreativity and technical knowledge are keys to suc-

cess in industrial design. An eye for color and detail, a sense of balance and proportion, and an ability to sketch and draw from your imagination are impor-tant. Therefore, developing a good portfolio contain-ing examples of your work is a key to getting into a good design program and fi nding a job in this fi eld.

549

http://www.glencoe.com

Pipe Systems16.1

Preview From ancient times, pipes have played crucial roles in moving liquid materials. Today pipes and the materials they transport vary from simple to elaborate. What types of materials do you think are carried in pipes now?

Content Vocabulary• pipe drawing• nominal diameter

• pipe fi tting• reduced fi tting

• screw fi tting• gate valve

• check valve• globe valve

Academic VocabularyLearning these words while you read this section will also help you in your other subjects and tests.• chemical • schedule

Graphic Organizer

Use a chart like the one below to organize notes about pipes, pipe fi ttings, and valves.

Go to glencoe.com for this book’s OLC for a downloadable version of this graphic organizer.

Academic Standards

Industry Standards

English Language Arts

Read texts to acquire new information (NCTE)

Mathematics

Measurement Understand measurable attributes of objects and the units, systems, and processes

of measurement (NCTM)

ADDA Section 11

Piping Drafting (ANSI Z32.2.3)

NCTE National Council of Teachers of English

NCTM National Council of Teachers of Mathematics

ADDA American Design Drafting Association

ANSI American National Standards Institute

Pipes Fittings/

ConnectionsValves

Piping Components

550 Chapter 16 Pipe Drafting


M

M

BIBB

BIBB

LEGEND

COLD WATER SUPPLY TEE (TURNED UP)

TEE (TURNED DOWN)

ELBOW (TURNED UP)

ELBOW (TURNED DOWN)

HOT WATER SUPPLY

GATE VALVE

WATER METER

PARTIAL BASEMENT PLAN

HOT AND COLD WATER PIPE DRAWING

1"2

1"2

HW

1"2 HW

1"2

1"2

HW

1"2 HW

1"2 CW

CW

1"2

3"4

3"4CW CW

CW

CW

CURB VALVE BYWATER AUTHORITYCORPORATION VALVE BYWATER AUTHORITYMAIN

Pipe ComponentsWhat kinds of components are represented in pipe system drawings?

For centuries, the only thing that moved from one point to another in pipes and pipe systems was water. The fi rst pipes were made of hollow logs fastened end-to-end with tree pitch. Now, various liquid and gaseous mate-rials such as metals, oil, oxygen, nitrogen, steam, and acids move through simple and complex pipe systems. Pipes are also used for structural purposes such as hand rails, the framework for soccer goals, and columns.

Pipe drawing is a specialized form of drafting that uses lines and symbols to describe the construction of piping systems. The plumbing diagram for a residence in Figure 16-1 shows the plumbing contractor precisely where to lay out and install the hot and cold water lines. A more complex plumb-

ing drawing might also show gas, sewage, and hot and cold water lines. On a much larger scale, pipe drawings describe the complex design of oil refi neries, chemical plants, and liquid materials processing plants.

Pipes, joints and fi ttings, and valves are the basic elements of a pipe system. Additional components, including pumps, tanks, fur-naces, and boilers, can be added to complete the fi nal integrated system.

Types of PipePipe is available in different types of mate-

rial and various sizes. The kind of pipe useddepends on the substance to be transported.

Steel and Wrought-Iron PipeSteel or wrought-iron pipes carry material

such as water, steam, oil, and gas. Sizes of stan-dard steel and wrought-iron pipe are specifi ed by the nominal diameter, which refers to the

Figure 16-1

Pipe (plumbing) drawing for a residence

Section 16.1 Pipe Systems 551

INSIDE (NOMINAL) DIAMETEROUTSIDE DIAMETER

STANDARDSCHEDULE 40

EXTRA-STRONGSCHEDULE 80

DOUBLEEXTRA-STRONGSCHEDULE 160

A B C

LEAD

OAKUM

B

A

pipe’s inside diameter (ID) (see Figure 16-2). Several wall thicknesses are available to accommodate various pressures within a pipe system. In fi ttings for pipe of different wall thicknesses, the outside diameter (OD) of each end of the fi tting remains the same. Extra metal can be added inside the pipe to increase the wall thickness. Therefore, the nominal size is simply the general size that is used to identify the pipe. For example, the inside diameter of 2″ nominal diameter pipe could vary from Ø1.687″ for double extra-strong pipe to Ø2.067″ for standard pipe.

Thicknesses are designated by schedule(see Figure 16-2). Because of the demand for greater variety of wall thicknesses in pipe, we now have 10 different wall thicknesses, or schedules. Standard pipe is generally referred to as “schedule 40 pipe,” and extra-strong pipe is referred to as “schedule 80.” Pipe over 12″ is referred to as “OD pipe.” This means that the nominal size is the outside diameter of the pipe.

The nominal size of pipe is always given in inches for both the customary inch system and the metric system. However, the actual inside diameter and the actual outside diam-eter are given in inches for customary inch drawings and in millimeters for metric draw-ings. In both the customary and metric sys-tems, a 2″ pipe fi tting, such as an elbow, has 11.5 threads per inch. This allows for a stan-dardized system worldwide. Refer to the pipe charts in Appendixes C-19 through C-23. Notice that the metric outside diameters and wall thicknesses are given there in millimeters.

Although this appears confusing, it provides effi ciency in the use of pipes and fi ttings in international pipe systems.

Defi ne What does the term nominal diameter mean?

Cast-Iron PipeCast-iron pipe, used to carry water, natural

gas, and sewage, is specifi ed using American Water Works Association (AWWA) standards. It is available in a variety of diameters and wall thicknesses. Sections of cast-iron pipe are joined using fl anged fi ttings or bell-and-spigot joints (see Figure 16-3).

Figure 16-2

Comparison of wall thicknesses of 1 __ 2 ″ nominal-size steel pipe

Figure 16-3

Cast-iron pipe joints: (A) fl anged and (B) bell and spigot


4

3 3

4CROSS

4

3 2

4CROSS

3

2 1.5

4CROSS

42

4LATERAL

32

4LATERAL

4

2

4TEE

3

2

4TEE

SCREWED (THREADED)A SOLDERED OR GLUEDB WELDEDC

Seamless Brass and Copper PipeBecause of their ability to withstand cor-

rosion, seamless brass and copper pipe have been used for plumbing in residential and commercial buildings. However, due to their much lower purchase and installation costs, plastic pipe and fi ttings are replacing these materials.

Copper TubingCopper tubing is used for plumbing and

heating. It is much more fl exible than iron pipe, and can be bent to align with fi ttings or other tubing. Compression and fl are fi ttings make copper tubing easy to use.

Plastic PipePlastic pipe is used in residential and small

commercial construction, to move water and sewage. It is not recommended where high temperatures or high pressures are likely. Steel pipe lined with various types of plastic is sometimes used for high-temperature and-pressure applications.

Pipe Fittings and Connections Parts used to join sections of pipe are

called pipe fi ttings. Fittings such as elbows and tees are used to make special connec-tions and to turn corners. Sections of pipe can be joined without fi ttings, such as by welding, or by using an adhesive or a heat-fusion process. This is known simply as a pipe connection.

Pipe fi ttings generally fall into four classes: screw, weld, glue, and fl ange. Figure 16-3 showsa fl ange fi tting and Figure 16-4 shows a screwed (threaded) fi tting, a soldered or glued fi tting, and a welded fi tting.

Pipe fi ttings are specifi ed by the nominal pipe size, the name of the fi tting, and the material. Some fi ttings, such as tees, crosses, and elbows, are used to connect pipes that are not the same size. These are called reduced fi ttings, and their nominal pipe sizes must be specifi ed. The largest opening of the through run is given fi rst, followed by the opposite end and the outlet. Figure 16-5 illustrates the order in which sizes of reduced fi ttings are designated.

Figure 16-5

Order for specifying the openings of reduced fi ttings

Figure 16-4

Common types of pipe joints

Section 16.1 Pipes, Joints, and Fittings 553

90° ELBOW

45° ELBOW 45° STREET ELBOW90° STREET ELBOW

TEE45° Y BEND

REDUCER

COUPLING CAP

CROSSA

rnold and

Brow

n

Screw FittingsScrew fi ttings, also called threaded fi ttings,

are shown in Figure 16-6. They are generally used on small pipe of Ø2.50″ or less, but they can be used on pipe as large as Ø6.00″. A paste-type joint compound or Tefl on® tape is used to lubricate the threads and to close, or seal, any irregularities in the mating threads.

The two types of pipe threads are tapered and straight. The tapered thread is the most com-mon. It has a 1:16 taper on both the internal thread in the fi tting and the external thread on the pipe. This same taper is also used on the external threads of certain fi ttings such as street elbows and service tees (see Figure 16-6).

Taper on a thread determines the distance to which the thread of the pipe enters the thread of the fi tting. It ensures a perfectly tight fi t between the two parts. Straight pipe threads are used only for very special applications. Information about these may be found in ASME ( American Society of Mechanical Engineers) standards.

Evaluate What do you know about the size of a pipe in an application that uses a screw fi tting?

Pipe ConnectionsRefer to Figure 16-7, which shows how

the threads are represented and specifi ed on a drawing. Tapered threads are designated on drawings as national pipe tapers (NPT), which means American Standard Pipe Taper Thread. Notice in Figure 16-7 that pipe threads may be

drawn with the taper shown or straight. In the thread note, NPT indicates that the thread is tapered. The ASME standard is B1.20.1. When threads are drawn in tapered form, the taper is exaggerated, and the amount of taper is esti-mated. Straight pipe threads are specifi ed on the drawings as NPS, which refers to American Standard Pipe Straight Thread. All pipe threads are assumed to be tapered unless otherwise specifi ed. Figure 16-7 includes both schematic and simplifi ed representations. Simplifi ed rep-resentation is most commonly used.

Weld ConnectionsWeld connections are used mainly on per-

manent, high-pressure, and high-temperature pipe systems. The two types of weld connec-tions used are butt and socket. See Figure 16-8for various types of fi ttings that are butt welded.

Figure 16-6

Screw-type pipe fi ttings

OR

TAPER SHOWN

TAPER SHOWN TAPER NOT SHOWN

END VIEW SECTION VIEW

END VIEW SECTION VIEW

TAPER NOT SHOWN

EXTERNAL THREAD

INTERNAL THREAD

EXTERNAL THREAD

INTERNAL THREAD

SCHEMATIC REPRESENTATION

SIMPLIFIED REPRESENTATION

TAPER EXAGGERATION

1 NPTASME 1.20.1

1 - 11.5 NPT, ASME B1.20.1

Figure 16-7

Pipe thread representation


WELD

Arn

old

and

Bro

wn

Figure 16-8

Welded pipe fi ttings

Figure 16-9

Socket-type weld connection

For help with this math activity, go to the Math Appendix at the back of this book.

Academic Standards

Mathematics

Measurement Apply appropriate techniques, tools,

and formulas to determine measurements (NCTM)

Pipe Length for BendsIt is often necessary to make large-radius bends on pipe or round tubing rather than weld square corners or use fi ttings. To do so, you may need to know how much pipe is needed to make the bend. An example of this is the design and construction of the roll cage for a race car. Follow these steps to fi nd out how much pipe is needed for the bend shown in the illustration.

90°

R12"

1. Determine the radius of the bend. In this example, the radius is 12″.

2. Determine the angle of the bend. In this example, the angle is 90°.

3. Calculate the circumference of the entire circle.

C = πDC = 3.1416 × 24″C = 75.40″

4. Calculate the percentage of the full circle used for the bend.

90º ____ 360º = 1 __ 4 = 25%

5. Multiply the percentage by the circumfer-ence to determine the length of the bend. 75.40 × 25% = 18.85″ (length of bend on centerline)

ValvesValves are used to stop, start, or regulate

the fl ow of fl uids and gases in a pipe sys-tem. A few of the more common types are described here.

Notice that they are beveled on the edges to receive the weld. Butt welds are generally used on pipe Ø2.00″ or larger. A socket weld joint (Figure 16-9) is generally used on pipe Ø2.00″ or smaller.

Section 16.1 Pipes, Joints, and Fittings 555

GATE VALVEA

CHECK VALVEB

A B

Figure 16-11

Globe valves

Figure 16-10

Gate and check valves

Gate ValvesGate valves are used to control the fl ow of

liquids (see Figure 16-10A). These valves are generally for on/off operation. The wedge, or gate, rises to allow full fl ow and falls to stop it completely. They are normally used where valve operation is infrequent.

Check ValvesCheck valves permit fl ow in one direction

only. They check, or stop, any reverse fl ow (see Figure 16-10B). These valves are controlled by the pressure and velocity of the material fl ow. They provide no external means of con-trolling fl ow pressure or velocity.

Globe ValvesGlobe valves control the fl ow of liquids

or gases. Their primary use is to closely and accurately regulate pressure and volume. The two types of globe valves in Figure 16-11 are slightly different. The one in Figure 16-11Ais used for the control of air, steam, and other compressibles where instant on/off operation is required. It is installed so that pressure is on the disk, which allows the spring to make a tight closure. The type shown in Figure 16-11B is for the control of liquids where sudden closure might be problematic or dan-gerous. The cap is fi tted with a spring-loaded piston arrangement that slows closure time.

Section 16.1 AssessmentAfter You Read

Self-Check 1. Identify each type of pipe and explain

the use of each. 2. Name the types of pipe connections

and fi ttings. 3. Describe the different uses for gate

valves, check valves, and globe valves.

Academic Integration Mathematics

4. Determine how much pipe will be needed to make a 120° bend, given that the radius of the corner is 8″.

Drafting Practice 5. Design a soccer goal to be constructed

using steel or wrought-iron pipe and steel fencing material. Obtain informa-tion on sizes and other specifi cations from your school’s soccer coach. Decide on the best method for connecting the joints of pipe. Make a complete set of orthographic and isometric drawings, including a materials list.

Go to glencoe.com for this book’s OLC for help with this drafting practice.



Go to glencoe.com for this book’s OLC for a downloadable version of this graphic organizer.

Connect You will prepare orthographic and pictorial drawings of pipe systems using board-drafting and CAD techniques and create a 3D wireframe model. What advantages do wireframes off er?

Content Vocabulary

• double-line drawing • single-line drawing

Academic VocabularyLearning these words while you read this section will also help you in your other subjects and tests.• indicate

Graphic Organizer

Use a chart like the one below to organize notes about pipe system representations.

Creating Pipe Drawings16.2

Pipe System

Representations

OrthographicPictorial

3D Wireframe

English Language Arts

Use information resources to gather information and create and communicate knowledge (NCTE)

Mathematics

Geometry Specify locations and describe spatial relationships using coordinate geometry and

other representational systems (NCTM)

ADDA Section 11

Piping Drafting (ANSI Z32.2.3)

Industry Standards

NCTE National Council of Teachers of English

NCTM National Council of Teachers of Mathematics

ADDA American Design Drafting Association

ANSI American National Standards Institute

Academic Standards

Section 16.2 Creating Pipe Drawings 557


ELBOWGLOBE VALVE

CROSS

PLUGUNION

THIN LINES FOR FITTINGS

GATE VALVE

TEE FLANGEDJOINT

CHECKVALVE

45° ELBOW

45° ELBOW

LATERALCAP

THICK LINES FORPIPE AND FLANGES

ELBOW (USED ONLY TO INDICATE DIRECTION OF PIPE)

SINGLE-LINE DRAWING

DOUBLE-LINE DRAWING

GLOBEVALVE

CROSS GATE VALVE CAP

LATERALUNIONPLUG

ELBOW

ELBOW

FLANGEDJOINT

CHECKVALVE

CONCENTRICREDUCER

CONCENTRICREDUCER

TEE

Pipe DrawingsWhy do pipe drawings not need to be as detailed as other technical drawings?

Pipe drawings show the size and location of pipes, fi ttings, valves, and other related com-ponents. A set of uniform symbols has been developed to represent individual features on a drawing.

Two types of pipe drawings are single-line and double-line drawings (see Figure 16-12). Double-line drawings are more time-con-suming and expensive to produce, so they are generally not used for production or construc-tion work. They are used for illustrations in catalogs and applications in which the visual appearance is important.

Figure 16-12

Single- and double-line pipe drawings


SIDE ELEVATION(SIDE VIEW)

72.00

TEE

ADJOINING APPARTUS (TANK)

PIPE LINE

40.00

PLAN VIEW(TOP VIEW)

VALVE

FLANGE

ELBOW

37.00

FRONT ELEVATION(FRONT VIEW)

ORTHOGRAPHICATEE

ADJOINING APPARTUS(TANK)

PIPELINE

40.00

VALVE

FLANGE

ELBOW

37.00

PICTORIALB

Single-Line DrawingsSingle-line drawings, also called sim-

plifi ed drawings, use single lines to show the arrangement of the components. The single lines represent the centerlines of the pipe. They are drawn as thick black lines with symbols for fi ttings, valves, and other com-ponents added. Symbol sizes are not critical. When pipe systems carry various liquids, such as hot and cold water, a coded line symbol is often used (see Figure 16-1).

Because single-line drawings provide excel-lent clarity, they are the method of choice throughout most of the industry.

Drawing ProjectionTwo methods of projection are used to

prepare pipe drawings: orthographic (see Figure 16-13A) and pictorial (see Figure 16-13B). Orthographic projection is most suitable for showing single pipes, either straight or bent, in one plane only. It can also

Figure 16-13

Orthographic and pictorial pipe drawings


A

NEAR PIPE

FAR PIPE

FAR PIPE

NEAR PIPE

B

PERMANENT DETACHABLE

DETACHABLE CONNECTIONSUCH AS A FLANGE

ADJOININGAPPARATUS

be used for complicated systems, even if they fall into several planes. In pipe drafting, the front, top, and side views are more commonly called front elevations, plan views, and side ele-vations, respectively.

Pictorial projection is recommended for all pipe systems in which the pipes are positioned in more than one plane. Notice how much easier it is to understand the pictorial drawing than the orthographic drawing, although both drawings represent the same pipe system.

CrossingsWhen lines representing pipes cross on a

drawing, they normally are shown without interruption (see Figure 16-14A). When it is necessary to show that one pipe must pass behind the other, the line representing the pipe farthest from the viewer is shown with a break, or interruption, where the other pipe passes in front of it (see Figure 16-14B).

Explain On a pipe drawing, how do you show that one pipe passes behind another?

ConnectionsHeavy dots on a drawing indicate per-

manent connections, by welding or another process such as gluing or soldering (see Figure 16-15). A general note or specifi ca-tion may be used to indicate the process. A single, thick line instead of a heavy dot may be used to show detachable connections ( see Figures 16-15 and 16-16). The specifi -cations, a general note, or the item list indi-cates the types of fi ttings and whether they are fl anged or threaded.

FittingsStandard fi ttings such as elbows and tees

are generally not shown on a pipe drawing. They appear, like pipe, as a continuous line. Engineers and designers are responsible for determining where and what type of fi ttings to use. The circular symbol for a tee or elbowmay be used, when necessary, to show whether the pipe is going away from or coming toward the viewer (see Figure 16-17). Elbows on iso-metric pipe drawings may be shown without the radius, using square corners. However, the change of direction that the pipe takes should be made clear if this method is used.

Figure 16-14

Methods used to show the crossing of pipes: pipe crossings shown (A) without interrupting the pipe passing behind the nearest pipe and (B) using an interrupted line to indicate the pipe farthest away

Figure 16-15

Permanent and detachable pipe connections

Figure 16-16

Detachable connection symbol used at an apparatus


PIPE COMINGTOWARD VIEWER

PIPE GOING AWAYFROM VIEWER

FRONT VIEWOF FLANGE

REAR VIEW OF FLANGE

PIPELINE WITHOUT FLANGES CONNECTED TO ENDS OF PIPEA

FLANGES CONNECTED TO ENDS OF PIPELINEB

Ø1.66 X .14

Ø2.38 X .16

WALL THICKNESSOUTSIDE DIAMETER

R2.0020°

SHOWING RADIUS OFELBOW IS OPTIONAL

LINEAR DIMENSIONS

RADII AND ANGLES OF BENDS

PIPE SIZE INDICATED ON DRAWINGS

A

B

C

A

B

C

C

B

A

Figure 16-17

Indicating pipe direction

Adjoining ApparatusIf needed, an apparatus that adjoins but

does not belong to the pipe itself, such as a tank, may be shown by an outline drawn with a thin phantom line (see Figure 16-16). For example, if a boiler is already in place and the drafter simply needs to show the pipe sys-tem connected to it, phantom lines are used to represent the boiler.

DimensioningFollow these guidelines for dimensioning

pipe drawings:

Dimensions for pipe and pipe fi ttings are always given from center to center of pipe and to the outer face of the pipe end or fl ange (see Figure 16-18A).Pipe lengths are not normally shown on the drawings but are left to the installer to determine.Pipe and fi tting sizes and general notes are placed on the drawing beside the part concerned or, where space is restricted, indicated with a leader.An item list is usually provided with the drawing.Pipes with bends are dimensioned from vertex to vertex (see Figure 16-18A).Radii and angles of bends may be dimen-sioned as shown in Figure 16-18B.

•

•

•

•

•

•

Whenever possible, the smaller of the supplementary angles should be specifi ed.The outer diameter of the pipe’s wall thickness may be specifi ed on the line representing the pipe or elsewhere (item list, general note, specifi cation, etc.). See Figure 16-18C.

Orthographic Pipe SymbolsIn orthographic projection, if fl anges are

not required on the ends of pipe, use symbols to indicate the direction of the pipe. If the pipe is coming toward the viewer, it is shown by two concentric circles, the smaller one being solid (see Figure 16-17A). If the pipe is going away from the viewer, it is shown by one circle. No extra lines are required on other views.

Flanges are represented by two concentric circles in the front view, by one circle in the rear view, and by a short stroke in the side view (see Figure 16-17B) regardless of their type or size.

Symbols representing valves are drawn with continuous thin lines. The valve spindles should be shown only if it is necessary to indi-cate their positions. It is assumed that unless otherwise specifi ed, the valve spindle should be in the position shown in Figure 16-19.

•

Figure 16-18

Dimensioning pipes


40.00

40.00

40.00

60.00

25.00

28.00

72.00

60.00

36.00

75.00

40.00

42.00

12.00

STOP VALVE

PUMP 1

PUMP 2

COUPLING

TO OILRETURN

TO OILSUPPLY

RELIEFVALVE

FLANGEDCONNECTION THREADED

CONNECTION

THIN LINES

ASSUMEDSPINDLEPOSITION

Isometric Pipe DrawingsIsometric pipe drawings are pictorial rep-

resentations of a complete pipe system. They include the pipes, fi ttings, valves, and com-ponents such as tanks or boilers. They also provide dimensions. In board drafting, ortho-graphic views are drawn before the pictorial drawing. In CAD, you only need to create the pipe system in 3D. The isometric drawing is created automatically.

See Figure 16-20 for an isometric drawing of a complete pipe system with dimensions. The procedures for creating this type of draw-ing are the same as those for producing an iso-metric drawing of any object.

Infer Why do pipe drawings normally not include pipe lengths?

Figure 16-20

Isometric pipe drawing

Figure 16-19

Valve symbols. When valve spindles are not shown, they are assumed to be in the positions indicated in this illustration


PUMP 1

PUMP 2

72.00 40.00

A

B

B37.00

A

PUMP 1

PUMP 2

PUMP 1

PUMP 2

A

B

VALVECODE

A RELIEF PUMPS 1 AND 2B STOP PUMP 2

NOTE: ALL PIPE Ø1.00,SCHEDULE 40

SERVICE

simple systems, a single view may be suf-fi cient. On more complex systems, two or more views may be required. We will use three views in this exercise.

2. Begin by laying out the centerlines of the pipe sections for the front elevation (front view) using light construction lines (see Figure 16-21).

3. Project from the front elevation to develop the layout for the plan view and right-side elevation (see Figure 16-22).

4. Add fi ttings, valves, and other necessary components. Unless they are needed for clarity, symbols for fi ttings are not shown on single-line drawings. Darken lines and add dimensions and notes as needed.

5. Add reference letters or numbers and pre-pare a materials list for all components. If the pipe is the same size and type throughout, add a general note for its specifi cation instead of adding it to the materials list. The fi nished orthographic drawing is shown in Figure 16-23.

Figure 16-21

Layout of centerlines for pipe sections of the front elevation (front view)

Figure 16-22

Layout of centerlines for all three views

Figure 16-23

The fi nished orthographic pipe drawing

Board-Drafting TechniquesWhat two types of drawings are used to represent pipe systems?

The pipe system in Figure 16-20 was drawn to scale and is completely dimen-sioned. Many pipe drawings are not made to scale or completely dimensioned. Known as schematic diagrams, they indicate only the relative positions of the various components. Details, such as lengths of pipe sections and specifi c locations of fi ttings, are left to the installer’s judgment.

Orthographic Drawing You will use the following procedure to cre-

ate a single-line orthographic pipe drawing of the pipe system shown in Figure 16-20.

1. Determine the number of views required to describe the pipe system fully. On very


Isometric Drawing We will reverse the process from the previous

section to produce an isometric pipe drawing of the same system. Refer to Figure 16-23 for basic information on the design of the system.

1. Begin by laying out the centerlines of the sections of pipe in isometric format (see Figure 16-24).

2. Add fi ttings, valves, and other neces-sary components (see Figure 16-25). Again, do not show symbols for fi ttings unless needed for clarity. Darken lines as shown.

3. Add dimensions, notes, and other symbols as necessary. The fi nished isometric should look like the one in Figure 16-23.

Recall What is another name for pipe drawings that are not made to scale or completely dimensioned?

CAD Techniques How does 3D modeling aid in the creation of CAD pipe drawings?

The CAD drafter has a choice in the method used to create simple pipe drawings.

For systems that fall within a single plane, an orthographic drawing is appropriate. If the system incorporates more than one plane, the drafter may create a 2D isometric drawing.

When pipe systems are complex, CAD operators often create 3D models. The advan-tage of 3D models is that they can be viewed from any point in space. The engineer or designer can “walk through” the system to discover potential problems before fi nalizing the design.

Orthographic CAD Drawing The procedure for creating an ortho-

graphic pipe drawing using CAD is similar to that for creating any other orthographic drawing, and it parallels the board draft-ing method. Use your CAD skills to create the three views. Use the XLINE and OFFSET commands to develop the drawings most effi ciently. Use the appropriate object snaps to ensure accuracy.

2D Isometric CAD Drawing The procedure for creating a 2D isometric

drawing of a pipe system follows the princi-ples and techniques discussed in Chapter 12. Practice the CAD techniques by following the directions for an ‶Isometric Drawing″ under ‶Board Drafting Techniques″ using CAD. Set the snap style to Isometric before you begin, and set the snap interval and grid at 5′ or 10′.

Figure 16-25

Pipes with symbols

Figure 16-24

Layout of centerlines for pipe sections in an isometric pipe drawing


75.0075.00

A B

40.0042.00

12.00

40.00

60.00

122.00

70.00

28.00

TO OIL

SUPPLY

STOPVALVE 40.00 200.00

COUPLING

36.00

60.00

75.00

40.00

TO OIL

RETURN

RELIEF

VALVE

Figure 16-26

Use the Oblique option of the DIMEDIT command to correct the angle of the aligned dimension (A) to place it on the isometric grid (B). Enter −30° when asked for the angle.

When you dimension the drawing, you will notice that many of the dimensions donot line up neatly with the isometric lines. See Figure 16-26A for an example of one of the dimensions from the pipe system as it appears when you fi rst create it. AutoCAD provides a way to rotate the extension lines into a more natural position (see Figure 16-26B). To do this, pick the Dimension Edit button on the Dimension toolbar, or enter DIMEDIT at the keyboard, and select the dimension to be changed. At the next prompt, enter O to acti-vate the Oblique option. The obliquing angle for the dimension shown here is 30. For other dimensions, you may need to enter different obliquing angles. If the angle does not appear as it should, try angles of 30, −30, 15, and −15.

3D Solid Models and WireframesAutoCAD is capable of producing two

basic types of 3D model: wireframes and solid models. The mass properties in solid models are generally not needed for pipe drawings, so wireframes are preferred for this use. Wireframes are like models made from toothpicks with no interior properties. Because pipe models involve single lines, 3D coordinates can be used to create wireframes quickly and easily.

Drawing the Basic WireframeSee Figure 16-27 for a pipe system that

has been created as a wireframe. Follow these steps to create the wireframe drawing:

1. Set up a new fi le with drawing limits of 0,0 and 400,300. Set the grid interval to 10 and enter ZOOM All.

2. Begin the model by drawing the pipe segments on the front plane. To do that, change from the plan (top) view to the elevation (front) view of the drawing. From the View menu, select 3D Viewport and then select Front.

Figure 16-27

A wireframe model of a pipe system


START POINT(50,50,0)

@40

<270

@200<0

@60

<90 @36<0

3. To draw on the front, you must also change the UCS. Enter the UCS com-mand, enter V to activate the View option, and press Enter. Then reenter the UCS command, enter S to activate the Save option, and name the UCS Front. Note: Some versions of AutoCAD change the UCS automatically.

4. Begin the drawing at the top left front corner of the pipe system (see Figure 16-28). Enter the LINE command and enter the coordinates 50,50,0 as the start-ing point. Because the fi rst four line seg-ments remain the front plane, you can use 2D polar coordinates to defi ne them. Temporarily end the LINE command.

Now you need to draw a line straight back from the front plane of the drawing. For this, you can use XYZ coordinates. However, you must fi rst determine the exact location of the points you need to specify in 3D space. You can do this in several ways. One would be to map out all of the points before you begin the model. But it is often easier and quicker to calculate the points as you go. We will use this method here.

5. Reenter the LINE command and use the Endpoint object snap to snap to the end of the last segment you drew in step 4. Leave the cursor over this point and read the coordinate values at the bottom left corner of the screen. The coordinate value should be 286,70,0. The next point you need to enter is at exactly the same X and Y coordinates but at a different depth, or Z coordinate. The Z coordi-nate equals the distance from the currentpoint to the next point on the pipe sys-tem. Therefore, at the To point: prompt, enter 286,70,−75. (The Z value is nega-tive because the line is moving away from you.)

6. You cannot see the result of this operation while you are in the default view. To see the 3D model grow as you proceed and for easier point selection, choose 3D Viewport and SW Isometric from the View menu. Enter the ZOOM command and then 1 to see the entire drawing (see Figure 16-29).

7. The next point is located 40′ straight up. Therefore, the only value that changes is the Y value. Because the current XYZ coordinate is 286,70,−75, add 40 to the Y value to get the next point: 70 + 40 =110. Enter the LINE command, snap to

Figure 16-28

Draw the fi rst four segments in the front plane using polar coordinates.

Figure 16-29

Changing the view to SW Isometric allows you to see all of the pipe segments.

Viewpoint ToolbarWhen you are working on a

drawing in which you will frequently need to change the viewpoint, it is worthwhile to display the Viewpoint toolbar. From the View menu, select Toolbars... and scroll down until the Viewpoint item appears. Click in the box beside the name to activate the Viewpoint toolbar. You may also right-click on a toolbar that is already displayed and choose Viewpoint from the shortcut menu. The buttons on this toolbar allow you to switch among the preset views without navigating the View menu.


POINT ON POSITIVEY AXIS

POINT ON POSITIVEX AXIS

ORIGIN OFNEW UCS

Figure 16-30

The completed basis for the wireframe

the end of the pipe segment you drew in step 4, and enter the next coordinate value: 286,110,−75. Leave the LINE com-mand active from this point on to ensure that the lines connect at their endpoints.

8. A tee occurs along the next segment of pipe. The easiest way to create this part of the drawing is to draw the segment from the current point to the tee, create the side pipes, and then return to the main loop of the pipe system. From the draw-ing in Figure 16-27, you can determine that the tee is located 126′ to the left of the current point. Therefore, to fi nd the coordinate value, subtract 126 from the current X value: 286 − 126 = 160. The new coordinate is 160,110,−75.

9. Continue by changing the depth dimen-sion (Z value) to create the short length of pipe that goes back (away from you) 40′. Leave the X and Y values unchanged. The value is 160,110,−115. Draw the short lengths of pipe that extend down 12′ and to the left 42′, and end the LINE com-mand. Add the short line at the end that denotes a detachable connection. Then reenter the LINE command and create the line that goes to the oil return. The length of this line does not matter. Turn Ortho on to ensure that the line follows the correct angle, then pick a point to end the line at about the point shown in Figure 16-27.

10. Use the BREAK command to trim the oil return line as in Figure 16-27 to show that it is behind the other lines. Note: Do not use the TRIM command; lines that appear to cross in 3D do not actu-ally cross, so the result of the TRIM com-mand is unpredictable.

11. Return to the tee and continue creating the lines to fi nish the main body of the pipe system. When you fi nish, your drawing should look like the one in Figure 16-30.

Adding the SymbolsSymbols must be added to complete the

pipe system. Only two symbols are necessary in this drawing: a relief valve and a stop valve. Note that their exact placement along the pipeline is not important, but they must be in line with the appropriate pipes. To do this, you will create two new UCSs, one for each valve.

1. Enter the UCS command, enter N for New, and enter 3 for 3Points.

2. For the new origin, pick the point shown in Figure 16-31. For a point on the positive X axis, turn Ortho on and move the cursor to the right until a line starts to form. Pick a point as shown in Figure 16-31. For a point on the positive Y axis, pick the endpoint as shown in the fi gure. Save the UCS as Valve1.

Figure 16-31

Create a new UCS by picking points as shown here.


POINT ON POSITIVEX AXIS

ORIGIN OFNEW UCS

POINT ONPOSITIVEY AXIS

3. To draw on the new UCS effi ciently, go to its plan view. From the View menu, select 3D Viewpoint, Plan View, and Cur-rent UCS. The surface on which you need to draw the relief valve is now parallel to the screen.

4. Draw the relief valve, estimating sizes to make it look appropriate in the drawing (see Figure 16-32).

5. Return temporarily to the SW Isometric view.

6. Create another new UCS using the 3Point option. This time, choose the origin and positive X and Y values (see Figure 16-33). Save this UCS as Valve2.

7. Go to the plan view of the current UCS and draw the valve (see Figure 16-34).

8. Return to the SW Isometric view. The drawing should now be similar to the one in Figure 16-35.

Dimensioning the DrawingNow you must dimension the drawing.

Study the isometric drawing in Figure 16-36carefully. Notice that the extension lines run parallel to the isometric axes. This happens because the dimensions were created on the appropriate UCSs. Follow these steps to dimen-sion the drawing:

1. Set up the dimension style for this large drawing. Set the text height to 4, for exam-ple, and the arrow size to 3. You may need to experiment to fi nd the best settings.

2. Enter the UCS command and R for Restore. Type Front for the name of the UCS to restore.

Figure 16-33

Defi ne the Valve2 UCS by picking points as shown.

Figure 16-34

Create the symbol for the stop valve on the Valve2 UCS.

Figure 16-35

An isometric view of the wireframe with both valve symbols in place

Figure 16-32

Create the relief valve at an appropriate size for the drawing.


Figure 16-36

Place the 40.00 dimension on the front UCS.

3. Display the Dimension toolbar. Pick the Linear Dimension button, right-click to select an object to dimension, and pick the lower left leg of the pipe system (see Figure 16-36). Create the dimension as you would for any other drawing. Notice

that it lines up automatically with the isometric view. Repeat this procedure for the other two dimensions that lie in the front plane.

4. Restore the Valve1 UCS and complete the dimensions that lie in that plane.

5. On your own, create the appropriate new UCSs for the remaining dimensions. To work most effi ciently, create all of the dimensions that lie on one UCS before moving to another UCS. The fi nished drawing should look like the one in Figure 16-27.

Dimensions are often omitted from wire-frame models of pipe systems. Because the drawing is made at full size, the engineer or drafter can query the CAD software to fi nd the specifi c length of a given pipe segment. However, if dimensions are not included, the model must be drawn to scale.

Section 16.2 AssessmentAfter You Read

Self-Check

1. Name the two types of pipe drawings? 2. Identify the important components of

a pipe drawing. 3. Name the steps in preparing a basic

orthographic pipe drawing using board-drafting and CAD techniques.

4. Explain how to create a basic isomet-ric drawing using board-drafting or CAD techniques.

5. Describe how to prepare a 3D wire-frame model of a pipe system using CAD techniques.

Academic IntegrationEnglish Language Arts

6. As mentioned early in this section, pipe systems have been in use since ancient

times. Research the earliest uses of pipe systems for transportation and for structural purposes and explain how they are the same and different than pipe sys-tems in use today. You can outline your comparison in an essay or by using a graphic organizer or chart.

Drafting Practice 7. Position an A4-size drawing sheet hori-

zontally and make a double-line drawing of a 90° malleable-iron threaded elbow and tee for Ø1.00″ steel pipe. Refer to Appendix tables C-19 through C-23. Use metric sizes. Join the two fi ttings with a piece of Ø1.00″ × 4.00″ steel pipe. Esti-mate any sizes not given. Scale: 1:1.

Go to glencoe.com for this book’s OLC for help with this drafting practice.



Review and AssessmentChapter Summary

Section 16.1 Pipe systems are made from various metals or plastic and are used for transporting liquids and gases or for structural purposes.Pipes are joined together using welded or adhesive connections or by means of screw fi ttings.Valves are used to regulate the fl ow of liquids or gases in pipe systems.

•

•

•

Section 16.2 Single-line, or simplifi ed, pipe drawings are more widely used for construction purposes, while double-line drawings are used for presentation purposes. Pipe drawings use either orthographic or pictorial (isometric) projection, and incorporate symbols rather than actual representations of components.Orthographic pipe drawings are best suited for pipe systems in which the pipes are positioned in one plane. Pictorial pipe drawings are used for pipe systems that position pipes in more than one plane.In CAD, 3D wireframe models are often used to create single-line isometric pipe drawings.

•

•

•

•

•

Review Content Vocabulary and Academic Vocabulary 1. Use each of these content and academic vocabulary terms in a sentence or drawing.

Content Vocabularypipe drawing (p. 551)nominal diameter (p. 551)pipe fi tting (p. 553)reduced fi tting (p. 553)

••••

screw fi tting (p. 554) gate valve (p. 556)check valve (p. 556)globe valve (p. 556) double-line drawing (p. 558)

•••••

single-line drawing (p. 559)

Academic Vocabularychemical (p. 551)schedule (p. 552)indicate (p. 560)

•

•••

Review Key Concepts2. List the various types of materials used for pipe components.3. Name the various kinds of pipe connections and fi ttings.4. Name the three types of valves used in pipe systems.5. Identify the various types of pipe drawings.6. Explain how to prepare a basic orthographic pipe drawing using board-drafting and CAD

techniques. 7. Outline the methods for creating pictorial drawings using board-drafting or CAD techniques.8. Describe how 3D wireframe models can be used to create pipe drawings in CAD.

16


Multiple Choice QuestionDirections Choose the letter of the best answer. Write the letter for the answer on a separate piece of paper. 12. A design engineer has a project that

calls for a pipe that will carry corrosive material at high pressure. Which of the following pipes is most appropriate?

a. cast iron c. seamless brass

b. plastic-lined steel d. copper tubing

Technology 9. The Information Age

Did you know that you are living in the Information Age? That is the name that has been given to the current economic era wherein the world’s economies have shifted focus away from producing physical goods and toward information management. Think about the technologies in your world that contribute to this shift. Then research the his-tory of two information technologies you use every day. Outline the steps that led to these technologies, either in an essay or by means of a graphic organizer such as a timeline.

10. EntrepreneurshipThink for a moment about the kind of work

environment you envision yourself working in after graduation. Are you suited for working for a drafting fi rm, in a partnership, or would you be better on your own? Review the mate-rial about entrepreneurship from Section 1.1, and, using other sources, research aspects of entrepreneurship, partnerships, and corpora-tions. Then make a chart organizing the posi-tive and negative aspects of each.

Mathematics 11. Adding Angles

Determine how many degrees there are in angle X.

Measuring Angles

When adding degrees and minutes, remem-ber that 60 minutes equals one degree.

TEST-TAKING TIP

When you take a test, do not use a mechanical, ink pen, or correction fl uid unless specifi cally asked to do so. Use a soft lead No. 2 pencil to mark your answers, and remove any answers you want to change with a good eraser.

Prep For

Win Competitive Events

13. Expectations of EmployersOrganizations such as SkillsUSA offer a

variety of architectural, career, and draft-ing competitions. Completing activities such as the one below will help you pre-pare for these events.

Activity Research those topics in pri-mary and secondary sources, and outline the information you fi nd. Read critically to distinguish fact from opinion. Then write two reports, one for your age group and another for people re-entering the workforce. Quote, paraphrase, and sum-marize your research accurately, and cite sources correctly. Vary your writing style, including vocabulary and sentence structure, for each audience.

Go to glencoe.com for this book’s OLC for more information about competitive events.13º 35’

12º 45’

X

Review and Assessment 571


Problems16

Drafting ProblemsThe drafting problems in this chapter are designed to be completed using

board drafting or CAD techniques.

45° REDUCINGELBOW

45° ELBOW

GLOBEVALVE

CROSSGATE VALVE

GATE VALVE

CAP

UNIONPLUG

ELBOWCHECKVALVE

TEE

TEE

ELBOW

TANK

REDUCER

Figure 16-37

1.

Convert the double-line pipe drawing shown in Figure 16-37 to a single-line drawing. Refer to Appendix B in your textbook for symbols. Pipe and fi ttings are 2″ except the smaller pipe between the 45° reducing elbow and the reducer, which is 1″. Mark the reducer and the 45° reducing elbow accordingly.


3'--6

6'--6 2'--81'--3

2'--

0

2'--

4

21

1'--9

2'--

01'

-81'

--6

TANKO1'--0 X 2'-4

12/

2. Convert the single-line pipe drawing in Figure 16-38 to a double-line drawing. Refer to Appendix B in your textbook for symbols. Pipe and fi ttings are 2″ except the smaller pipe to

the left of the reducer, which is 1½″. Label fi ttings and dimension the drawing if instructed

to do so. Scale: ¾″ = 1′-0.

Figure 16-38

Problems 573

CODE VALVE SERVICE A CHECK TANK 1 B GATE TANK 1 C GATE TANK 2 D GLOBE TANK 2 E CHECK RETURN LINES

TANK 1B

E

C

A

DTANK 2

4'--

3

RETURN LINE

TANK 1

B

C

A

DTANK 2

TANK 1

TANK 2

5'--

3 4'--

04'

--0

RETURN LINE

14'--0

8'--0

E

Problems16

3. Convert the three-view single-line pipe drawing in Figure 16-39 to a single-line isomet-ric pipe drawing. Pipe and fi ttings are Ø2.00, schedule 40, threaded. Label fi ttings and add

dimensions if instructed to do so. Estimate sizes not given. Scale: ¼″ = 1′-0.

Figure 16-39


Challenge Your Creativity

1. Design a seesaw to be constructed and used in your community park. Specify 2″-diameter pipe with threaded fi ttings for the main frame. The frame is to be anchored in concrete. The seesaw beam is to be made from 2″-diameter pipe with threaded caps on each end and wooden seats bolted in place. Design the beam so that it can be adjusted to balance with varying weight on each seat. The fi nished design should include the frame and three beams. Consider all safety issues in the design.

Teamwork

2. Design a scaffold for use in the construction and painting of houses. The design should involve Ø1″ pipe with threaded fi ttings. The overall size of the scaffold is to be 3′-0 deep, 10′-0 long, and 8′-0 high. Design it so that 2 × 12 planks can be placed at a height of 4′-0 or at 8′-0. Use pipe fl anges or casters on the base of each vertical member (leg). Each team member should develop design sketches of his or her design. Select the best ideas from each to fi nalize the team design. Prepare a fi nal set of working drawings with dimensions and pipe symbols.

Teamwork

3. Design an apparatus for bodybuilding. The team should fi rst list the specifi c types of exercises the apparatus is to accommo-date. Design the entire unit around steel pipe. Other materials may be used as nec-essary. Each team member should work on detailing a portion of the entire unit to accommodate a specifi c exercise. Then the team should work on integrating all of the designs into one fi nal unit.

Teamwork

4. Design a piece of playground equipment using mainly pipe with threaded fi ttings. Other materials can be used in a limited amount. Begin by brainstorming a list of activities that children would enjoy doing on this type of apparatus. Each team mem-ber should develop solutions for one or more item from the list. The team should then come together to develop the overall design. More than one structure might be necessary to accommodate all activities listed. All units are to be secured in con-crete. Prepare a fi nal set of working draw-ings with dimensions and a materials list.

Design ProblemsDesign problems have been prepared to challenge individual students or

teams of students. In these problems, you are to apply skills learned mainly in this chapter but also in other chapters throughout the text. They are designed to be completed using board drafting, CAD, or a combination of the two. Be creative and have fun!

Problems 575

Documents

16 Pipe Drafting - blogs · Pipe Systems Section 16.2 Creating Pipe Drawings 16 Pipe Drafting Chapter Objectives Describe various types of pipe and explain their uses. Identify pipe