Free Global Shipping. Description Pipe designers and drafters provide thousands of piping drawings used in the layout of industrial and other facilities. The layouts must comply with safety codes, government standards, client specifications, budget, and start-up date.
Pipe Drafting and Design, Second Edition provides step-by-step instructions to walk pipe designers and drafters and students in Engineering Design Graphics and Engineering Technology through the creation of piping arrangement and isometric drawings using symbols for fittings, flanges, valves, and mechanical equipment. The book is appropriate primarily for pipe design in the petrochemical industry.
More than illustrations and photographs provide examples and visual instructions. A unique feature is the systematic arrangement of drawings that begins with the layout of the structural foundations of a facility and continues through to the development of a 3-D model.
Advanced chapters discuss the customization of AutoCAD, AutoLISP and details on the use of third-party software to create 3-D models from which elevation, section and isometric drawings are extracted including bills of material. Covers drafting and design fundamentals to detailed advice on the development of piping drawings using manual and AutoCAD techniques 3-D model images provide an uncommon opportunity to visualize an entire piping facility Each chapter includes exercises and questions designed for review and practice.
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Need an account? Click here to sign up. Download Free PDF. Pipe Drafting and Design 2nd ed. Parisher, R. Rhea WW. Kenneth Orodoegbulem. A short summary of this paper. Download Download PDF. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher.
Parisher, Robert A. Rhea-2nd ed. Includes index. ISBN alk. Piping—Drawing—Handbooks, manuals, etc. Piping—Design and construction— Handbooks, manuals, etc.
Rhea, Robert A. P32 The publisher offers special discounts on bulk orders of this book. I could never say "Thank you" enough for what you have given me. Roy To Mary: Thank you for your help and support. Types of Projects! Joe Martinez: Technical Editing. Anthony W. Horn: Chapter 15 The material, applications, and routines presented in this book have been included for their instructional value. They have been tested for accuracy, but are not guaranteed for any particular purpose.
The publisher and authors do not offer any representations or warranties, nor do they accept any liabilities with respect to the material, applications, or routines. Patent and Trademark office by Autodesk, Inc. Autodesk provides this program "as is" and with all fault. Autodesk spe- cifically disclaims any implied warranty of merchantability or fitness for a particular use. Autodesk , Inc. Patent and Trademark office by Rebis, Inc.
It presents a step-by-step approach to the basic fundamentals students will need to begin a successful career in indus- trial drafting and design. Chapter One gives a quick overview of the many opportunities in drafting and design for those who master the basic skills pre- sented in the following chapters.
Then each chapter builds on the preceding one. It is necessary therefore to master the concepts in a given chapter before going on to the next one. Each chapter concludes with exercises and ques- tions designed to help students review and practice the concepts presented in that chapter. Parisher is a professor in the engineering design graphics depart- ment at San Jacinto College in Pasadena, Texas, where he has taught for over 20 years. Robert A. Rhea is a former associate professor of engineering technology at the University of Houston Downtown, Houston, Texas.
Facility design and layout must meet the cus- tomer's expectations as well as comply with safety codes, Many projects will be designed for construction in government standards, client specifications, budget, and other countries, offering the designer opportunities for start-up date.
Each project presents drafters and designers with The piping group has the main responsibility for the opportunities to expand their skills and knowledge of the design and layout of the facility.
During range for various companies. Many operating companies keep a small engi- construction of the facility while working under the neering staff in the home office or at the plant job site.
The Designers are exposed to the day-to-day operations of the designer is often called upon to make small design facility and follow the construction of small projects. This changes resulting from mistakes discovered during the situation may require that the designer have a broad range construction phase or as customers dictate changes. At the of knowledge and skills, as he or she often may be asked completion of the project, drawings are updated to reflect me man to design and lay out the complete project.
The design y changes made during construction, These may prepare foundation, steel, and piping drawings as drawings are called or referred to as "as-built" needed, and may even do some electrical and instrumen- drawings, tation design when required. These may include multi-story drawings must be prepared. These drawings give detailed office buildings, hospitals, condominiums, shopping dimensions from which welders can fabricate the pipe, The drafter who malls, or other similar structures.
In addition to the indus- prepares these drawings will not be trial piping components such as those found in a typical required to have an extensive background in plant layout, boiler room, supplementary piping systems must be however, the position provides the drafter with valuable designed for plumbing, HVAC, and drainage systems that experience in materials and material science, are also required in these structures.
As stu- for advancement to other departments within the engi- dents advance, they will use a variety of sophisticated neering firms. These departments include not only the software packages, ranging from basic CAD software to drafting and design departments but also: 3D solid modeling. Line thickness also has an important The drafter must become familiar with the uses of fit- role on P1? This will require commonly used on major elements of the drawing such as time and effort to master the recognition of symbol shapes P1?
Background components such as as well as research to find the dimensions needed to draw equipment, foundations, support structures, and dimen- sion lines are these items to scale. Often beginning drafters start out typically drawn with a.
This is where S importance of quality they acquire the skills and knowledge of piping that will line work and lettering. Manual drawings are constantly slid in and out of the flle drawers and run throu h blue allow them to advance to the position of piping designer.
This requires that lettering and line work or welders find this real world experience valuable. Many engineering companies require Students should not neglect their speaking, writing, their designers to know and use several different CAD and math skills. Every company appraises future employ- software tools. Engineering companies must be pre- ees during the interview process, not only for technical pared to accommodate the client's preference of CAD skills, but also for the personal skills needed to interact programs.
In today's marketplace, the pipe drafter and with the engineering team. This interaction is a must for designer should learn how to use AutoCAD and the team in order to complete the job with a minimal MicroStation.
These two CAD programs are widely amount of mistakes. Honesty, reliability, dedication to used by engineering firms in the United States and improving skills, and a positive attitude contribute much throughout the world to the successful career of the designer. You may work with people ware programs on the market today. Engineering firms from countries all over the world. Getting along with fel- must be reSpOnsive to the needs and preferences of their low workers has much to do with successful yearly eval- dients Software developers steadily develop, revise, and nations and compensation for your efforts.
Often clients will dictate that all bid packages sub- mitted for a project shall be completed using a particular Manual drafters use a variety of triangles, plastic tern- piping software program.
Most piping software packages plates circle and ellipse , and scales to layout piping provide the end user with the ability to develop three drawings. While electric erasers are not necessary, they dimensional computer models of the completed facility, make the job of erasing much easier and faster. Ingenuity gave birth to inven- with certain characteristics. These characteristics include tion and the pipe was born. Using the natural resources strength, wall thickness, corrosion resistance, and tem- available, early humans probably fashioned the first pipe perature and pressure limitations.
For example, pipes from bamboo. Needing to move larger amounts of water, having the same wall thickness but manufactured by dif- they later hollowed out logs.
Egyptian and Aztec civiliza- ferent methods may vary in strength and pressure limits. The first metallic pipes were The manufacturing methods we will mention include made by the Greeks and Romans from lead and bronze. The use of iron as a material to manufacture pipe came Seamless pipe is formed by piercing a solid, near-molten, about with the invention of gun powder. Gun powder, of steel rod, called a billet, with a mandrel to produce a pipe course, is not used to make the iron, but gun powder that has no seams or joints.
Figure depicts the manu- necessitated the invention of stronger gun barrels. Iron facturing process of seamless pipe. Eventually exotic metals were developed, and pipe became the highly specialized prod- uct it is today. Seamless pipe. Applied in a general sense, pipe is a term used to des- ignate a hollow, tubular body used to transport any com- Butt-welded pipe is formed by feeding hot steel plate modity possessing flow characteristics such as those through shapers that will roll it into a hollow circular found in liquids, gases, vapors, liquefied solids, and fine shape.
Forcibly squeezing the two ends of the plate powders. Figure A comprehensive list of the materials used to manu- shows the steel plate as it begins the process of forming facture pipe would be quite lengthy.
Some of the materi- butt-welded pipe. With such a broad range of materials available, selecting one to fit a particular need can be confusing.
A thorough under- standing of the pipe's intended use is essential. Each material has limitations that may make it inappropriate for a given application. Throughout this text we will base our discussion on carbon steel pipe, the most common material used in the piping industry. Figure Butt-welded pipe.
Steel Pipe 5 Least common of the three methods is spiral-welded uses of pipe, the continuous welded method is the most pipe. Spiral-welded pipe is formed by twisting strips of economical.
Seamless pipe is produced in single and dou- metal into a spiral shape, similar to a barber's pole, then ble random lengths. Single random lengths vary from welding where the edges join one another to form a seam. Pipe 2" and below is found in dou- This type of pipe is restricted to piping systems using low ble random lengths measuring 35'-0" to 40'-0" long.
Figure shows spiral- welded pipe as it appears before welding. Pipe is identified by three different size categories: nominal pipe size, outside diameter, and inside diameter see Figure Spiral-welded pipe.
Carbon steel pipe. Pipe diameters. Figure shows the three pipes previously described in their final form. Each of the three methods for producing pipe has its advantages and disadvantages.
Butt-welded pipe, for Nominal pipe size NFS is used to describe a pipe by example, is formed from rolled plate that has a more uni- name only. In process piping, the term nominal refers to form wall thickness and can be inspected for defects prior the name of the pipe, much like the name 2 x 4 given to a to forming and welding. This manufacturing method is piece of lumber.
The lumber does not actually measure particularly useful when thin walls and long lengths are 2" x 4", nor does a 6" pipe actually measure 6" in diame- needed. Because of the welded seam, however, there is ter. It's just an easy way to identify lumber and pipe. Pressure Piping Code B 31 was written to govern side diameter equal to its nominal pipe size.
In particular, code B This method achieves the desired strength necessary Generally, wider wall thicknesses are produced by the for pipe to perform its intended function while operating seamless method.
However, for the many low-pressure under various temperatures and pressures. Wall thickness is a term used to describe the thickness It is simply a convenient method to use when referring to of the metal used to make a pipe.
Wall thickness is also pipe. As a piping drafter, you should be aware however, commonly referred to as a pipe's weight. Originally man- pipe 14" and larger is identified by its actual outside mea- ufactured in weights known as standard, extra strong, and surement.
The chart in Table shows typical pipe diam- double extra strong, pipe has since increased in complex- eters and wall thicknesses. Now called schedules, these Before selecting pipe, careful consideration must be additional wall thicknesses allow a pipe to be selected to given to its material, temperature and pressure allow- meet the exact requirements needed for safe operation.
Buying and install- An example of this variance in wall thickness is shown in ing pipe that does not meet the minimum requirements Figure Using pipe that far exceeds what is required to do the job can result in tremendous cost overruns. The three methods we will focus on are those most widely used in piping systems made of carbon steel, as shown in Figure Later in the chap- Figure Pipe thickness.
MM IN. MM 2 Otherwise, the root gap would not be considered at all. Figure shows the Vie" root gap and the resulting butt-weld joint. Pipe joints. Butt-Weld Connections A butt-weld joint is made by welding the beveled ends oi pipe together. Beveled ends BE indicate that the ends oi the pipe are not cut square, but rather are cut or ground tc Figure Butt-weld joints.
In preparation for the welding process, a welder will separate two pieces of pipe by a Vie" space, known as a root gap. If twc pieces of pipe 3'-0" long were welded together in this man- Another common means of joining pipe is the threaded ner, the result would be a total length of 6'-0". Typically used on pipe 3" and However, sometimes a back-up ring is used in critical smaller, threaded connections are generally referred to as situations. The back-up ring is used when there is a need screwed pipe.
With tapered grooves cut into the ends of a to prevent the formation of weld icicles inside the pipe. In this situation, the ring does not allow of attachment. Male threads square, or perpendicular to, the long axis, unlike butt- are cut into the outside of a pipe or fitting, while female weld fittings that have beveled ends, threads are cut into the inside of the fitting. This connection WHO! When drawing and dimensioning screwed pipe, a piping drafter must be Not all piping systems require pipe designed to with- aware of this lost length of pipe.
Residential, commercial, and industrial Socket-Weld Connections facilities routinely are built with some form of gravity flow systems. The corrosion resistance properties of cast The third method of joining carbon steel pipe is socket iron pipe make it the ideal product for permanent below- welding. When assembling pipe with socket-weld fit- ground gravity flow installations. Cast irons are primarily alloys of iron that contain placed end-to-end.
Cast iron, lar that prevents the pipe from being inserted too deeply like steel, does corrode. What makes cast iron different is into the fitting. As cast iron corrodes, an insoluble As with screwed connections, a short amount of pipe layer of graphite compounds is produced. The density and is lost when the socket-weld connections are made. In steel through 3" in diameter. Unable to to allow for heat expansion during the welding procedure. Water will not leak out and, when used penetrated the pipe wall.
Considering the low cost of raw underground, roots cannot grow through the joints. See manufacturing materials and the relative ease of manu- Figure These benefits make cast iron the choice application in environments that demand good corrosion resistance. Joining Cast Iron Pipe Cast iron pipe is grouped into two basic categories: hub and spigot, and hubless. The hub, or bell, and spigot joint uses pipe with two different end types.
The hub end of the pipe has an enlarged diameter, thus resembling a bell. The spigot end of the adjoining pipe has a flat or plain-end shape. The spigot is inserted into the bell to establish a joint. Two methods of preventing leaks on bell and spigot joints are compression and lead and oakum.
The com- pression joint uses a one-piece rubber gasket to create a leak-proof seal. As shown in Figure , when the spigot Figure Lead and oakum joint. The method of joining these pipe and or failure. Hubless cast iron pipe is made in only one wall and root-proof joint. When the molten lead is poured over thickness and ranges in diameter from IVi" to 10".
Figure the waterproof oakum fiber, which is a loose, oil laden, depicts the hubless cast iron pipe joint. Compression joint. Hubless pipe coupling. The latest entry into the materials list for manufactur- Joints made with solvent cement have proven more reli- ing pipe is plastic. Not originally thought of as a product able. Though, once hardened, cemented joints cannot be capable of performing in the environs of a piping process disassembled.
They offer good resistance to abrasive chem- facility, plastic has emerged as a reliable, safe, and cost- ical and high-pressure commodities and are available in a effective alternative material. There is a broad range of large selection of fittings without the need of threads. Heat plastic compounds being developed today. Pipe can either be butt- fluoroplastics and thermoplastics. Fluoroplastics are joined or socket-joined. As a group, fluoroplastics perform burst pressure of the pipe. Thermoplastics are those separation.
For this reason they cannot be disassembled. Though fabrication with plastic may sound simple, cau- These plastics can be welded or injection molded into tion must be exercised when using plastic pipe. The effec- shapes for machining into piping system components. Four important use plastics.
Pipes made from plastic are replacing tradi- variables must be evaluated: chemical resistance, pressure tional, expensive materials like glass or ceramic-lined limitations, temperature limitations, and stress. The various pipe. Hazardous prove in Taber Abrasion Tests to be five to ten times bet- mixtures must be avoided. Pressure and temperature limita- ter in this regard than Stainless Steel.
The Taber tions must be established for obvious reasons. Pipe that is Abrasion Test cycles an abrasive wheel over the face of a overheated or pressurized beyond capacity can rupture, plate made of the material being tested. After 1, split, or burst. Stress, as applied to pipe, entails physical cycles of the wheel, the plate is measured to determine demands such as length of service, resistance to expansion the amount of weight loss.
Table lists the results. Excessive stresses in the form of restricted expansion Table and contraction, and frequent or sudden changes in internal Taber Abrasion Tester pressure and temperature must be avoided. Single-line drawings are used to identify the center- CTFE 13 line of the pipe. Double lines are used to represent the PS pipe's nominal size diameter. Typically hand drawn, single-line pipe is drawn PTFE with a. Plastic pipe can be joined by one of the following meth- Double-line pipe uses standard line widths to draw the ods: threading, solvent cement, or fusion.
Threading plastic pipe's nominal size diameter. A centerline is used on all pipe is not a viable option because it is expensive. Heavy double pipe to allow for the placement of dimensions. Steel Pipe 11 Figure provides several representations of pipe as it represent the pipe on a drawing. Drawings created with may appear on a drawing. Piping software When pipe is represented on a drawing, typically the programs draw with such accuracy that pipe is drawn pipe's nominal size dimension is used to identify pipe using the actual outside diameter.
Be aware that drawings created with a piping soft- There are certain applications, however, when the ware program use actual outside dimensions and will differ pipe's true outside diameter dimension is used to slightly from manual and AutoCAD generated drawings.
Pipe representations. Name three methods of manufacturing carbon steel pipe. Name the three most commonly used end preparations for joining pipe.
What is meant by the term nominal size pipel 4. Which diameter of pipe varies as the wall thickness changes?
What is the most common material used in the manufacture of pipe? When drawing pipe, which pipe sizes are drawn single line and which sizes are drawn double line?
How long is the gap between two lengths of pipe when a back-up ring separates them? What is the name for the amount of pipe "lost" when screwed connections are used? What is the standard drawing scale used on piping drawings? Name three-methods for joining carbon steel and plastic pipe.
Pipe Fittings Fittings are fabricated pieces of pipe that are used to connections. These specifications, or specs, as they are make changes of direction elbow , branch from a main more commonly called, may also require pipe smaller pipe tee , or make a reduction in line size reducer see than 3" to have screwed or socket-weld connections. For Figure However, this is not to ing to the pipe to which they are being attached. Fittings, say this is the only spec that can be written.
There may like pipe, are manufactured and classified according to be cases where small bore pipe is butt-welded, while their wall thickness. There are many more wall thick- larger sizes may be screwed or socket-welded, nesses of pipe however than there are thicknesses of fittings. Fittings are commercially manufactured in stan- oniuc dard weight, extra strong, Schedule , and double extra tLBUWo strong.
In the petrochemical industry, most companies have Of all the fittings, the elbow is the one most often guidelines known as piping specifications that state used. Simply put, the elbow, or ell, is used when a pipe pipe 3" and larger will be fabricated with butt-welded changes direction. Elbows can turn up, turn down, turn Figure When determining the length of an elbow, one must the manufacturer of the fitting.
Manufacturers issue dimensioning charts containing lengths for a particular establish the center-to-end dimension. The center-to-end fitting. The dimensional charts used to establish sizes of dimension is the measurement from the centerline of the fittings discussed in this text are listed on the Welded Fit- fitting to the end of the fitting see Figure As a refer- Notice the relationship between the nominal size and ence, portions of that chart are used throughout this the length of the fitting.
The fitting's length is equal to the chapter when fitting measurements are needed. Using the nominal pipe size plus one-half of the nominal size. The measurement labeled A represents dimension easy to remember. To find the fitting's length in inches, locate the appropriate nominal pipe size nal pipe size or: Figure Center-to-end dimension of a Figure Long radius elbow. Welded Fittings-Flanges Chart.
Pipe Fittings 15 in the row labeled Nominal Pipe Sizes. Follow across the shows how the elbow might appear if it were welded to a chart to find the desired pipe size.
Below that size, in the piece of pipe. The double-line long-radius elbow. Figure shows the To better visualize the long-radius elbow, we have steps using manual drafting techniques and Figure attached a piece of pipe to each end of the fitting.
This shows those steps using AutoCAD commands. Manual drafting solutions. Step 1. Mark off the distance from the center of the fitting to Step 3. Extend the ends of the fitting down and across the end of the fitting.
This is the A dimension from the respectively until they intersect. This will be the centerpoint Welded Fittings-Flanges Chart.
Use a circle tern- plate or com Step 2. Determine the nominal size of pipe and mark off Pass to draw the arcs' one-half of its size on each side of the fitting's centerline. Step 4. Remember, for fittings 12" and below, only the arc representing the elbow's centerline is drawn when creating single-line symbols.
AutoCAD commands. Drawing set-up. Step 2. The 21" radius should be measured above PT. Use the LINE command to draw the ends of elbow. Pipe Fittings 11 NOTE: The step-by-step instructional procedures presented using computer-aided drafting techniques presume each student has a comprehensive knowledge of basic AutoCAD commands. These self-instructional steps provide a simple method to create each fitting. They are not intended to restrict the student to any par- ticular commands.
Each student is encouraged to exper- iment with new commands that may achieve the same result. Center-to-end dimension of the short- see Figure Conversely, the short-radius ell also radius elbow.
The drawing symbols for a short-radius elbow are shown in Figure The mitered elbow is not an actual fitting, but instead is a manufactured turn in the piping system. This elbow is made by making angular cuts in a straight run of pipe and then welding the cuts together after they have been rolled to a different angle see Figure The mitered ell may be classified as one, two, three, or four weld miters. The number of welds used depends on the smoothness of flow required through the turn.
A two- weld miter will create more turbulence within the pipe than will a four-weld miter. Long-radius and short radius elbows. Drafting Symbols for Mitered Elbows Figure shows the double-line drafting symbols for two-weld and three-weld mitered elbows.
Unlike the pre- vious ells, the weld lines in the adjacent views of the A simple formula can be used to calculate the center- mitered elbow are represented by ellipses. The length of the fitting is equal to the nominal pipe of sight. Short-radius elbow symbols Figure Mitered elbows. Pipe Fittings 19 Figure Miter elbows drafting symbols. This elbow considerable savings. Because the P1? Figures and describe two manual methods for constructing the elbow.
Pipe Fittings 21 Figure Using construction lines, duplicate the procedure Step 3. Alternative manual solution. Step 3. Determine one-half of the pipe's diameter and mark this Step 2. This will estabhsh the OD of tne e Welded Fittings-Flanges Chart, mark off this length along P'P - each construction line beginning at the point of intersection. Use a circle template to draw the inside and outside arcs representing the elbow.
Draw an arc to represent the elbow's centerline. ERASE the two long-radius elbow. Use LINE to draw the two ends of the elbow. In some orthographic views, these elbows will appear at an angle to our line of sight.
In those views where the open end of the elbow appears at WELD TEE an angle to our line of sight, ellipses must be used to rep- resent the end of the fittings.
It is a three-way fitting used to make perpen- dicular connections to a pipe see Figure Lines that connect to the main run of pipe are known as branches.
The main run of pipe is often called the header. Figure shows a pipe header with two branch connections. Drafting Symbols for the Weld Tee Notice that the weld tee requires three welds be made to install the fitting.
Figure shows the drawing symbols for straight and reducing tees. A callout is required on the reducing tee to identify the header and branch sizes. The header Figure Pipe Fittings 23 Figure Weld tee. Header and branch connections. Weld tee symbols. Pipe Fittings 25 Figure Using the 11" C dimension found on the chart, draw Step 3.
Measure 7" one-half the header pipe size on either side of the centerline to draw the sides of the tee. Measure 7" one-half the branch pipe size on either side of the perpendicular line to draw the branch of the tee. Draw and darken the sides and weld lines of the tee. When drawin Step 1. Add break symbols. ZOOM, Extents. These dimensions are required to determine the Another method of making a branch connection is center-to-end length of the header and the length of the called a stub-in.
The stub-in is most commonly used as branch end. If a straight tee is being used, the C dimen- an alternative to the reducing tee. The stub-in is not an sion found on the Welded Fittings-Flanges Chart in actual fitting but rather a description of how the branch Figure must be added twice to find the total length connection is created.
A hole is bored into the header of the fitting. On a straight tee, the C dimension is also pipe, either the size of the OD or ID of the branch, and used as the length of the branch end. If a reducing tee is the branch is then stubbed into it. The two pipes are fitted being drawn, the M dimension must be substituted as together and then welded.
Although the branch connec- the length of the branch end. The M dimension is found tion can be the same pipe size or smaller as the header, on the Taylor Forge Seamless Welding Fittings Chart in it cannot be larger. Figure depicts the attachment Appendix A. Figures and provide the manual of a stub-in. Figure provides the single-line and and AutoCAD steps for drawing the tee. Stub-in connections. Stub-in symbols.
Pipe Fittings 27 How close stub-ins are made is an important consider- drawing representations of reinforcing pads and ation. A general rule is to allow a minimum of 3" between saddles. Purchased fittings, o-lets have one end between the outsides of branches made from a common shaped to the contour of the header and the other end header, and a header should be attached no closer than 3" to manufactured to accept the type of end connections a fitting. Figure provides the minimum measurements being used on the branch.
Weldolets are manufac- allowed between branches and fittings on an 18" header. Sockolets are made for socket-weld fittings. And threadolets are available Stub-in Reinforcements for screwed fittings.
Figure shows a typical threadolet. Figure gives drawing symbols for Even though the use of the stub-in is limited by the weldolets, sockolets, and threadolets.
Its chief Other o-lets are manufactured to be used to make con- advantage over the tee is cost. Figure shows a purchasing a fitting be avoided, but the stub-in requires latrolet and the elbolet. Used primarily f for connecting small-bore the header. Three remforcmg alternat. Resembling a metal washer that y where instrument , 0 ,been has Qr, K bent. T plate ,. The coupling rests on the external surface of the pipe the branch connection.
It is slipped onto the branch header and is welded from the outside. A purchased reinforcing pad, the accept the OD of the coupling. The coupling is welding saddle has a short neck designed to give inserted into the hole and is then welded. Figure additional support to the branch. Figure shows shows the coupling in use.
Welding minimums for stub-ins. Reinforcing pads and saddles. Latrolet and elbolet. Because pipe supports When the piping designer wants to reduce the diameter within a piperack are of the same elevation, a pipe must of a straight run of pipe, a reducing fitting must be used.
Using a concen- styles as shown in Figure Concentric—having a common centerline. Eccentric reducers are also used on pump suction noz- Eccentric—having offset centerlines.
By The concentric reducer maintains the same centerline keeping a flat on top FOT surface, vapor pockets can be at both the large and small ends of the fitting. Figure shows the centerlines of the The eccentric reducer has offset centerlines that will eccentric reducer in its FOT and FOB orientations.
Couplings as branches. Eccentric and concentric reducer. A quicker, though less accurate method, is to take one- half the difference between the two outside diameters. Drawing the Reducers Drafting Symbols for the Concentric and Eccentric Reducer Prior to drawing the reducer, the length of the fitting must be found on the Welded Fittings-Flanges Chart see The orthographic views for the concentric and eccen- Figure The H dimension will provide the end-to- tric reducers are shown in Figure No matter the size end length for either the concentric or eccentric reducer.
Always use the H dimension of the large end to determine Notice the callouts that must be included with the eccen- the fitting length. The large end is always listed first, no matter Figures and provide the manual and the direction of flow, and the flat side must be indicated. AutoCAD steps for drawing the reducer. Eccentric reducers.
Concentric and eccentric drawing symbols. Using the H dimension found on the chart, draw a Step 3. Connect the opposite ends of the fitting by drawing centerline 14" long. Measure 8" one-half the large end size on either Step 4. Darken the sides and weld lines of the reducer, side of the centerline on one end and 7" on either side of the centerline on the opposite end.
Pipe Fittings 31 Figure Place note as required. The last weld fitting we will discuss is the weld cap. It Welding one fitting directly to another is called fitting- is used to seal an open end of pipe.
When dimensioning make-up see the examples in Figure The cap will be system require the designer to use pipe of various lengths welded to the end and need not be included in the length between the fittings.
In these cases, pipe is cut to the dimension of the run of pipe. When fittings are not assem- ble-line symbol for all sizes of pipe.
By maintaining this to construct the round end of the fitting. Notice the weld dot on the single line see Rgure 3. Remember, all welds must be shown on We will now look at how each fitting relates to other fit- drawings. Use weld dots on single-line pipe symbols and tings when used in the design of various piping systems. Pipe should be dimensioned from center of fitting to and placement of dimensions. At the present time, we the end of pipe are only concerned with butt-weld fittings.
The general rules-of-thumb for placing dimensions on a drawing are Figure provides some examples for placing as follows: dimensions on drawings. Weld cap drawing symbols. Fitting make-up. Minimum pipe lengths. There are, however, be disassembled for inspection, repair, or replacement. Screwed and Manufactured for screwed and socket-weld applications, the socket-weld fittings are normally reserved for installa- union is represented on drawings as shown in Figure Screwed and socket- Unions should be positioned in locations that will weld fittings are also available in cast iron, malleable facilitate the easy removal of critical pieces of equipment.
Cast iron and malleable iron fittings Figure shows how unions are placed in a configura- are typically used on low pressure and temperature lines tion to allow easy removal of the valves.
Lines containing high pressure and temperature Plug commodities, which are subject to movement and vibration, require fittings made of forged steel. Forged The plug, like a cap, is designed to close off the end of steel screwed and socket-weld fittings are manufac- a run of pipe. Plugs are manufactured for screwed fittings tured in two pressure classes— and Figure shows the drawing symbols tings are provided in Appendix A.
These dimensioning for the plug. Figures and provide a sample of the Coupling dimension charts for screwed and socket-weld fittings found in Appendix A. Although this fitting is used in butt-welding applica- Most screwed fittings are manufactured with internal, tions as a branch connection, its primary use is to connect female threads per American Standard and API thread lengths of screwed and socket-weld pipe together.
Some guidelines see Figure Some fittings, such as plugs clients may stipulate, however, that all socket-weld pipe and swages, however, are manufactured with external must be connected with a butt weld, rather than a coupling.
Even though screwed fittings can be seal welded if necessary, strength of the fitting is By design, screwed and socket-weld fittings cannot be decreased when the threads are cut during the manufac- assembled by placing one fitting directly in contact with turing process.
Socket-weld fittings can be easily fitted another fitting. Screwed fittings are manufactured with and welded without the need of special clamps or tack- threads on the inside of the fitting, and socket-weld fit- welds, which are often required to hold a butt-weld tings have an internal socket that prevents fitting makeup fitting in place before the final weld is made see assembly.
To facilitate the assembly of screwed and Figure Pipe nipples can vary in length depending upon the distance required to fabricate the pipe configuration. A close nipple is one that provides the minimum length of pipe between fittings. Remember, Like butt-weld fittings, screwed and socket-weld fit- screwed and socket-weld fittings have a certain amount of tings are used to make similar configurations in a piping lost pipe due to thread engagement and socket depth.
Screwed and socket-weld fittings differ in size Therefore, each size pipe has a different minimum length and shape, but they achieve the same purpose as the butt- for the dimension of a close nipple.
Figure provides examples of some Many companies will use 3" as the standard minimum screwed and socket-weld fittings. This length will accommodate the Screwed and socket-weld fittings are drawn with amount of pipe lost inside the fitting on each end as well square corners using short hash marks to represent the as provide sufficient wrench clearance during assembly ends of the fitting see Figure Placement of dimensions.
Screwed fittings dimensioning chart. Pipe Fittings 35 Figure Socket-weld fittings dimensioning chart. Internal and external threads. Socket-weld fittings. Screwed and socket-weld fittings. Swage One exception to the standard 3" minimum rule is the swage nipple. Swages are functionally similar to reduc- ers, but are specifically designed for screwed and socket- weld pipe. Screwed swages have male external threads and can be connected to other screwed fittings without the use of a pipe nipple.
They are used to make reductions in the line size on a straight run of pipe. Swages, like reduc- ers, are available in either a concentric or eccentric shape. Figure shows varying lengths and sizes of screwed Figure Screwed and socket-weld pipe and swage nipples. Pipe Fittings 37 Figure Union Figure Positioning of unions. Union drawing symbols. Plug drawing symbols. Screwed swages will have thread ends TE , Figure depicts the concentric swage. Notice the socket-weld swages plain ends PE , and butt-weld end preparation combinations on the examples.
Because socket-weld Figure shows the drawing symbols for swages. Swages are also manufactured with different preparations on the two ends. When speci- Flanged fittings perform functions similar to other fit- fying a swage, use the following abbreviations: tings of the same type. The major difference is their method of connection. The connection joint for flanged BBE—bevel both ends fittings is made by bolting two specially designed metal TBE—thread both ends surfaces together.
A gasket to prevent leaks is sandwiched between the two surfaces. Flange types will be discussed PBE—plain both ends at great length in the following chapter. Pipe and swage nipples. Swage drawing symbols. Because molten cast iron can be easily man- ufactured into many unique shapes that cannot be attained Figure Concentric swages. All the standard fitting shapes vices. The physical appearance of pipe routing con- are available: elbows, tees, reducers, couplings, unions, figurations made of cast iron fittings is quite different etc.
Plastic fittings are manufactured for either screwed, from pipe routed with forged steel fittings because of the socket, or butted assembly. Plastic screwed and socket fit- large assortment of fittings available and the method in tings are available in sizes through 4" in diameter. Butt fit- which these configurations are assembled. Above-ground tings are manufactured for sizes 6"". Typically, pipe smaller than 3" in diameter is manufactured as having or end connections.
What is the most common fitting used? What are the four classifications of elbows? What is the formula for calculating the center-to-end dimension for LR and SR elbows? Describe a mitered elbow. When configuring tee connections, what is the main run of pipe called?
Name the two types of tees. What are some alternate methods to a tee fitting when fabricating branch connections? Which fitting is used to make a reduction in the line size of a run of pipe? Name the two types of reducers.
Define fitting make-up. What are the two pressure classifications for screwed and socket-weld fittings? What type of fittings must be bolted together? What is the typical installation service for cast iron pipe?
Name the three types of plastic fitting end types manufactured. Thefittingsdepicted in Figure will be used to complete. To complete the exer- Create icon from block geometry radio button, cises, draw the symbols below using the following guidelines. These required symbols into the appropriate locations. NOTE: The pipe break symbol is created with ellipses. DO NOT include text with the elliptical arc on the pipe break as necessary. AutoCAD drawing symbols and File names.
They are , , system components used throughout the piping system. Cast iron flanges Flanged connections are used as an alternative to welding have pound ratings of 25 , , , and Flanged the commodity within the pipe, are used to select the connections are preferred over threaded connections appropriate size, rating, and type of flange. The flange is an important component used in a number of different applications.
For example, a of any piping system. These joints may include join- same flange could be used for PSIG. When equipment is manufactured with at least one outlet called temperature decreases the allowable pressure increases, a nozzle. The nozzle is the point where, via the flange, the and vice versa. Pound ratings are also used to establish piping system is connected to the equipment. From this the outside diameter and thickness of a flange. Typically flange, the piping system is begun.
Figure shows how as pound ratings increase, so will the flange's diameter a nozzle and flange are used to connect the piping system and thickness. The face is usually machined to create a smooth surface. This smooth surface will help assure a leak-proof seal when two flanges are bolted together with a gasket sandwiched between. Although numerous types of flange faces are pro- Figure Nozzle and flange.
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