Engineering Drawing

DOE-HDBK-1016/1-93 JANUARY 1993

DOE FUNDAMENTALS HANDBOOK ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Volume 1 of 2

U.S. Department of Energy Washington, D.C. 20585

FSC-6910

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN37831. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE93012220

DOE-HDBK-1016/1-93 ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS

ABSTRACT The Engineering Sym bology, Prints, and Drawings Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and technical staff with the necessary fundamentals training to ensure a basic understanding of engineering prints, their use, and their function. The handbook includes information on engineering fluid drawings and prints; piping and instrument drawings; major symbols and conventions; electronic diagrams and schematics; logic circuits and diagrams; and fabrication, construction, and architectural drawings. This information will provide personnel with a foundation for reading, interpreting, and using the engineering prints and drawings that are associated with various DOE nuclear facility operations and maintenance.

Key Words: Training Material, Print Reading, Piping and Instrument Drawings, Schematics, Electrical Diagrams, Block Diagrams, Logic Diagrams, Fabrication Drawings, Construction Drawings, Architectural Drawings

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FOREWORD The Departm ent of Energy (DOE) Fundam entals Handbooks consist of ten academic subjects, which include Mathematics; Classical Physics; Thermodynamics, Heat Transfer, and Fluid Flow; Instrumentation and Control; Electrical Science; Material Science; Mechanical Science; Chemistry; Engineering Symbology, Prints, and Drawings; and Nuclear Physics and Reactor Theory. The handbooks are provided as an aid to DOE nuclear facility contractors. These handbooks were first published as Reactor Operator Fundamentals Manuals in 1985 for use by DOE category A reactors. The subject areas, subject matter content, and level of detail of the Reactor Operator Fundamentals Manuals were determined from several sources. DOE Category A reactor training managers determined which materials should be included, and served as a primary reference in the initial development phase. Training guidelines from the commercial nuclear power industry, results of job and task analyses, and independent input from contractors and operations-oriented personnel were all considered and included to some degree in developing the text material and learning objectives. The DOE Fundam entals Handbooks represent the needs of various DOE nuclear facilities' fundamental training requirements. To increase their applicability to nonreactor nuclear facilities, the Reactor Operator Fundamentals Manual learning objectives were distributed to the Nuclear Facility Training Coordination Program Steering Committee for review and comment. To update their reactor-specific content, DOE Category A reactor training managers also reviewed and commented on the content. On the basis of feedback from these sources, information that applied to two or more DOE nuclear facilities was considered generic and was included. The final draft of each of the handbooks was then reviewed by these two groups. This approach has resulted in revised modular handbooks that contain sufficient detail such that each facility may adjust the content to fit their specific needs. Each handbook contains an abstract, a foreword, an overview, learning objectives, and text material, and is divided into modules so that content and order may be modified by individual DOE contractors to suit their specific training needs. Each handbook is supported by a separate examination bank with an answer key. The DOE Fundam entals Handbooks have been prepared for the Assistant Secretary for Nuclear Energy, Office of Nuclear Safety Policy and Standards, by the DOE Training Coordination Program. This program is managed by EG&G Idaho, Inc.

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OVERVIEW The Departm ent of Energy Fundam entals Handbook entitled Engineering Sym bology, Prints, and Drawings was prepared as an information resource for personnel who are responsible for the operation of the Department's nuclear facilities. A basic understanding of engineering prints and drawings is necessary for DOE nuclear facility operators, maintenance personnel, and the technical staff to safely operate and maintain the facility and facility support systems. The information in the handbook is presented to provide a foundation for applying engineering concepts to the job. This knowledge will improve personnel understanding of the impact that their actions may have on the safe and reliable operation of facility components and systems. The Engineering Sym bology, Prints, and Drawings handbook consists of six modules that are contained in two volumes. The following is a brief description of the information presented in each module of the handbook. Volume 1 of 2 Module 1 - Introduction to Print Reading This module introduces each type of drawing and its various formats. It also reviews the information contained in the non-drawing areas of a drawing. Module 2 - Engineering Fluid Diagrams and Prints This module introduces engineering fluid diagrams and prints (P&IDs); reviews the common symbols and conventions used on P&IDs; and provides several examples of how to read a P&ID. Module 3 - Electrical Diagrams and Schematics This module reviews the major symbols and conventions used on electrical schematics and single line drawings and provides several examples of reading electrical prints.

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OVERVIEW (Cont.)

Volume 2 of 2 Module 4 - Electronic Diagrams and Schematics This module reviews electronic schematics and block diagrams. It covers the major symbols used and provides several examples of reading these types of diagrams. Module 5 - Logic Diagrams This module introduces the basic symbols and common conventions used on logic diagrams. It explains how logic prints are used to represent a component's control circuits. Truth tables are also briefly discusses and several examples of reading logic diagrams are provided. Module 6 - Engineering Fabrication, Construction, and Architectural Drawings This module reviews fabrication, construction, and architectural drawings and introduces the symbols and conventions used to dimension and tolerance these types of drawings. The information contained in this handbook is by no means all encompassing. An attempt to present the entire subject of engineering drawings would be impractical. However, the Engineering Sym bology, Prints, and Drawings handbook does present enough information to provide the reader with a fundamental knowledge level sufficient to understand the advanced theoretical concepts presented in other subject areas, and to improve understanding of basic system operation and equipment operations.

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Department of Energy Fundamentals Handbook

ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Module 1 Introduction to Print Reading

Introduction To Print Reading

DOE-HDBK-1016/1-93

TABLE OF CONTENTS

TABLE OF CONTENTS LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

v

INTRODUCTION TO PRINT READING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Introduction . . . . . . . Anatomy of a Drawing The Title Block . . . . . Grid System . . . . . . . Revision Block . . . . . Changes . . . . . . . . . . Notes and Legend . . . Summary . . . . . . . . .

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1 2 2 5 6 7 8 9

INTRODUCTION TO THE TYPES OF DRAWINGS, VIEWS, AND PERSPECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Categories of Drawings . . . . . . . . . . . . . . . . . . . . . Piping and Instrument Drawings (P&IDs) . . . . . . . . . Electrical Single Lines and Schematics . . . . . . . . . . . Electronic Diagrams and Schematics . . . . . . . . . . . . Logic Diagrams and Prints . . . . . . . . . . . . . . . . . . . Fabrication, Construction, and Architectural Drawings Drawing Format . . . . . . . . . . . . . . . . . . . . . . . . . . Views and Perspectives . . . . . . . . . . . . . . . . . . . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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10 10 11 13 14 14 16 19 22

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LIST OF FIGURES

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LIST OF FIGURES Figure 1 Title Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Figure 2 Example of a Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3 Revision Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 4 Methods of Denoting Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 5 Notes and Legends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 6 Example P&ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 7 Example of a Single Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 8 Example of a Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 9 Example of an Electronic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 10 Example of a Logic Print . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 11 Example of a Fabrication Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 12 Example of a Single Line P&ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 13 Example Pictorial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 14 Example of an Assembly Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Figure 15 Example of a Cutaway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 16 Example Orthographic Projection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 17 Orthographic Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 18 Example of an Isometric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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LIST OF TABLES

LIST OF TABLES NONE

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REFERENCES

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REFERENCES ANSI Y14.5M - 1982, Dimensioning and Tolerancing, American National Standards Institute. ANSI Y32.2 - 1975, Graphic Symbols for Electrical and Electronic Diagrams, American National Standards Institute. Gasperini, Richard E., Digital Troubleshooting, Movonics Company; Los Altos, California, 1976. Jensen - Helsel, Engineering Drawing and Design, Second Ed., McGraw-Hill Book Company, New York, 1979. Lenk, John D., Handbook of Logic Circuits, Reston Publishing Company, Reston, Virginia, 1972. Wickes, William E., Logic Design with Integrated Circuits, John Wiley & Sons, Inc, 1968. Naval Auxiliary Machinery, United States Naval Institute, Annapolis, Maryland, 1951. TPC Training Systems, Reading Schematics and Symbols, Technical Publishing Company, Barrington, Illinois, 1974. Arnell, Alvin, Standard Graphical Symbols, McGraw-Hill Book Company, 1963. George Mashe, Systems Summary of a Westinghouse Pressurized Water Reactor, Westinghouse Electric Corporation, 1971. Zappe, R.W., Valve Selection Handbook, Gulf Publishing Company, Houston, Texas, 1968.

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OBJECTIVES

TERMINAL OBJECTIVE 1.0

Given an engineering print, READ and INTERPRET the information contained in the title block, the notes and legend, the revision block, and the drawing grid.

ENABLING OBJECTIVES 1.1

STATE the five types of information provided in the title block of an engineering drawing.

1.2

STATE how the grid system on an engineering drawing is used to locate a piece of equipment.

1.3

STATE the three types of information provided in the revision block of an engineering drawing.

1.4

STATE the purpose of the notes and legend section of an engineering drawing.

1.5

LIST the five drawing categories used on engineering drawings.

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Introduction to Print Reading

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INTRODUCTION TO PRINT READING

INTRODUCTION T O PRINT READING A through knowledge of the information presented in the title block, the revision block, the notes and legend, and the drawing grid is necessary before a drawing can be read. This information is displayed in the areas surrounding the graphic portion of the drawing. EO 1.1

STATE the five types of information provided in the title block of an engineering drawing.

EO 1.2

STATE how the grid system on an engineering drawing is used to locate a piece of equipment.

EO 1.3

STATE the three types of information provided in the revision block of an engineering drawing.

EO 1.4

STATE the purpose of the notes and legend section of an engineering drawing .

Introduction The ability to read and understand information contained on drawings is essential to perform most engineering-related jobs. Engineering drawings are the industry's means of communicating detailed and accurate information on how to fabricate, assemble, troubleshoot, repair, and operate a piece of equipment or a system. To understand how to "read" a drawing it is necessary to be familiar with the standard conventions, rules, and basic symbols used on the various types of drawings. But before learning how to read the actual "drawing," an understanding of the information contained in the various non-drawing areas of a print is also necessary. This chapter will address the information most commonly seen in the non-drawing areas of a nuclear grade engineering type drawing. Because of the extreme variation in format, location of information, and types of information presented on drawings from vendor to vendor and site to site, all drawings will not necessarily contain the following information or format, but will usually be similar in nature. In this handbook the terms print, drawing, and diagram are used interchangeably to denote the complete drawing. This includes the graphic portion, the title block, the grid system, the revision block, and the notes and legend. When the words print, drawing, or diagram, appear in quotes, the word is referring only to the actual graphic portion of the drawing.

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Anatomy of a Drawing A generic engineering drawing can be divided into the following five major areas or parts. 1. 2. 3. 4. 5.

Title block Grid system Revision block Notes and legends Engineering drawing (graphic portion)

The information contained in the drawing itself will be covered in subsequent modules. This module will cover the non-drawing portions of a print. The first four parts listed above provide important information about the actual drawing. The ability to understand the information contained in these areas is as important as being able to read the drawing itself. Failure to understand these areas can result in improper use or the misinterpretation of the drawing.

The Title Block The title block of a drawing, usually located on the bottom or lower right hand corner, contains all the information necessary to identify the drawing and to verify its validity. A title block is divided into several areas as illustrated by Figure 1.

First Area of the Title Block The first area of the title block contains the drawing title, the drawing number, and lists the location, the site, or the vendor. The drawing title and the drawing number are used for identification and filing purposes. Usually the number is unique to the drawing and is comprised of a code that contains information about the drawing such as the site, system, and type of drawing. The drawing number may also contain information such as the sheet number, if the drawing is part of a series, or it may contain the revision level. Drawings are usually filed by their drawing number because the drawing title may be common to several prints or series of prints.

Second Area of the Title Block The second area of the title block contains the signatures and approval dates, which provide information as to when and by whom the component/system was designed and when and by whom the drawing was drafted and verified for final approval. This information can be invaluable in locating further data on the system/component design or operation. These names can also help in the resolution of a discrepancy between the drawing and another source of information.

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Figure 1 Title Block

Third Area of the Title Block The third area of the title block is the reference block. The reference block lists other drawings that are related to the system/component, or it can list all the other drawings that are cross-referenced on the drawing, depending on the site's or vendor's conventions. The reference block can be extremely helpful in tracing down additional information on the system or component. Other information may also be contained in the title block and will vary from site to site and vendor to vendor. Some examples are contract numbers and drawing scale.

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Drawing Scale All drawings can be classified as either drawings with scale or those not drawn to scale. Drawings without a scale usually are intended to present only functional information about the component or system. Prints drawn to scale allow the figures to be rendered accurately and precisely. Scale drawings also allow components and systems that are too large to be drawn full size to be drawn in a more convenient and easy to read size. The opposite is also true. A very small component can be scaled up, or enlarged, so that its details can be seen when drawn on paper. Scale drawings usually present the information used to fabricate or construct a component or system. If a drawing is drawn to scale, it can be used to obtain information such as physical dimensions, tolerances, and materials that allows the fabrication or construction of the component or system. Every dimension of a component or system does not have to be stated in writing on the drawing because the user can actually measure the distance (e.g., the length of a part) from the drawing and divide or multiply by the stated scale to obtain the correct measurements.

The scale of a drawing is usually presented as a ratio and is read as illustrated in the following examples.

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1" = 1"

Read as 1 inch (on the drawing) equals 1 inch (on the actual component or system). This can also be stated as FULL SIZE in the scale block of the drawing. The measured distance on the drawing is the actual distance or size of the component.

3/8" = 1'

Read as 3/8 inch (on the drawing) equals 1 foot (on the actual component or system). This is called 3/8 scale. For example, if a component part measures 6/8 inch on the drawing, the actual component measures 2 feet.

1/2" = 1'

Read as 1/2 inch (on the drawing) equals 1 foot (on the actual component or system). This is called 1/2 scale. For example, if a component part measures 1-1/2 inches on the drawing the actual component measures 3 feet.

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Grid System Because drawings tend to be large and complex, finding a specific point or piece of equipment on a drawing can be quite difficult. This is especially true when one wire or pipe run is continued on a second drawing. To help locate a specific point on a referenced print, most drawings, especially Piping and Instrument Drawings (P&ID) and electrical schematic drawings, have a grid system. The grid can consist of letters, numbers, or both that run horizontally and vertically around the drawing as illustrated on Figure 2. Like a city map, the drawing is divided into smaller blocks, each having a unique two letter or number identifier. For example, when a pipe is continued from one drawing to another, not only is the second drawing referenced on the first drawing, but so are the grid coordinates locating the continued pipe. Therefore the search for the pipe contained in the block is much easier than searching the whole drawing.

Figure 2

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Example of a Grid

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Revision Block As changes to a component or system are made, the drawings depicting the component or system must be redrafted and reissued. When a drawing is first issued, it is called revision zero, and the revision block is empty. As each revision is made to the drawing, an entry is placed in the revision block. This entry will provide the revision number, a title or summary of the revision, and the date of the revision. The revision number may also appear at the end of the drawing number or in its own separate block, as shown in Figure 2, Figure 3. As the component or system is modified, and the drawing is updated to reflect the changes, the revision number is increased by one, and the revision number in the revision block is changed to indicate the new revision number. For example, if a Revision 2 drawing is modified, the new drawing showing the latest modifications will have the same drawing number, but its revision level will be increased to 3. The old Revision 2 drawing will be filed and maintained in the filing system for historical purposes.

Figure 3 Revision Block

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Changes There are two common methods of indicating where a revision has changed a drawing that contains a system diagram. The first is the cloud method, where each change is enclosed by a hand-drawn cloud shape, as shown in Figure 4. The second method involves placing a circle (or triangle or other shape) with the revision number next to each effected portion of the drawing, as shown in Figure 4. The cloud method indicates changes from the most recent revision only, whereas the second method indicates all revisions to the drawing because all of the previous revision circles remain on the drawing.

Figure 4 Methods of Denoting Changes

The revision number and revision block are especially useful in researching the evolution of a specific system or component through the comparison of the various revisions.

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Notes and Legend Drawings are comprised of symbols and lines that represent components or systems. Although a majority of the symbols and lines are self-explanatory or standard (as described in later modules), a few unique symbols and conventions must be explained for each drawing. The notes and legends section of a drawing lists and explains any special symbols and conventions used on the drawing, as illustrated on Figure 5. Also listed in the notes section is any information the designer or draftsman felt was necessary to correctly use or understand the drawing. Because of the importance of understanding all of the symbols and conventions used on a drawing, the notes and legend section must be reviewed before reading a drawing.

Figure 5 Notes and Legends

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Summary The important information in this chapter is summarized below.

Introduction to Print Reading Summary The title block of a drawing contains: the drawing title the drawing number location, site, or vendor issuing the drawing the design, review, and approval signatures the reference block The grid system of a drawing allows information to be more easily identified using the coordinates provided by the grid. The coordinate letters and/or numbers break down the drawing into smaller blocks. The revision block of a drawing provides the revision number, a title or summary of the revision, and the date of the revision, for each revision. The notes and legend section of a drawing provides explanations of special symbols or conventions used on the drawing and any additional information the designer or draftsman felt was necessary to understand the drawing.

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INTRODUCTION TO THE TYPES DOE-HDBK-1016/1-93 OF DRAWINGS, VIEWS, AND PERSPECTIVES


INTRODUCTION T O T HE T YPES OF DRAWINGS, VIEWS, AND PERSPECTIVE S To read a drawing correctly, the user must have a basic understanding of the various categories of drawings and the views and perspectives in which each drawing can be presented. EO 1.5

LIST the five drawing categories used on engineering drawings.

Categories of Drawings The previous chapter reviewed the non-drawing portions of a print. This chapter will introduce the five common categories of drawings. They are 1) piping and instrument drawings (P&IDs), 2) electrical single lines and schematics, 3) electronic diagrams and schematics, 4) logic diagrams and prints, and 5) fabrication, construction, and architectural drawings.

Piping and Instrument Drawings (P&IDs) P&IDs are usually designed to present functional information about a system or component. Examples are piping layout, flowpaths, pumps, valves, instruments, signal modifiers, and controllers, as illustrated in Figure 6.

Figure 6 Example P&ID

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DOE-HDBK-1016/1-93 INTRODUCTION TO THE TYPES OF DRAWINGS, VIEWS, AND PERSPECTIVES

As a rule P&IDs do not have a drawing scale and present only the relationship or sequence between components. Just because two pieces of equipment are drawn next to each other does not indicate that in the plant the equipment is even in the same building; it is just the next part or piece of the system. These drawings only present information on how a system functions, not the actual physical relationships. Because P&IDs provide the most concise format for how a system should function, they are used extensively in the operation, repair, and modification of the plant.

Electrical Single Lines and Schematics Electrical single lines and schematics are designed to present functional information about the electrical design of a system or component. They provide the same types of information about electrical systems that P&IDs provide for piping and instrument systems. Like P&IDs, electrical prints are not usually drawn to scale. Examples of typical single lines are site or building power distribution, system power distribution, and motor control centers. Figure 7 is an example of an electrical single line. Electrical schematics provide a more detailed level of information about an electrical system or component than the Figure 7 Example of a Single Line single lines. Electrical schematic drawings present information such as the individual relays, relay contacts, fuses, motors, lights, and instrument sensors. Examples of typical schematics are valve actuating circuits, motor start circuits, and breaker circuits.

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Figure 8 is an example of a motor start circuit schematic. Electrical single lines and schematics provide the most concise format for depicting how electrical systems should function, and are used extensively in the operation, repair, and modification of the plant.

Figure 8 Example of a Schematic

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Electronic Diagra ms and Schematics Electronic diagrams and schematics are designed to present information about the individual components (resistors, transistors, and capacitors) used in a circuit, as illustrated in Figure 9. These drawings are usually used by circuit designers and electronics repair personnel.

Figure 9 Example of an Electronic Diagram

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Logic Diagra ms and Prints Logic diagrams and prints can be used to depict several types of information. The most common use is to provide a simplified functional representation of an electrical circuit, as illustrated in Figure 10. For example, it is easier and faster to figure out how a valve functions and responds to various inputs signals by representing a valve circuit using logic symbols, than by using the electrical schematic with its complex relays and contacts. These drawings do not replace schematics, but they are easier to use for certain applications.

Figure 10 Example of a Logic Print

Fabrication, Construction, and Architectural Drawings Fabrication, construction, and architectural drawings are designed to present the detailed information required to construct or fabricate a part, system, or structure. These three types of drawings differ only in their application as opposed to any real differences in the drawings themselves. Construction drawings, commonly referred to as "blueprint" drawings, present the detailed information required to assemble a structure on site. Architectural drawings present information about the conceptual design of the building or structure. Examples are house plans, building elevations (outside view of each side of a structure), equipment installation drawings, foundation drawings, and equipment assembly drawings. Fabrication drawings, as shown in Figure 11, are similar to construction and architectural drawing but are usually found in machine shops and provide the necessary detailed information for a craftsman to fabricate a part. All three types of drawings, fabrication, construction, and architectural, are usually drawn to scale.

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Figure 11 Example of a Fabrication Drawing

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Drawing Format P&IDs, fabrication, construction, and architectural drawings can be presented using one of several different formats. The standard formats are single line, pictorial or double line, and cutaway. Each format provides specific information about a component or system.

Single Line Drawings The single line format is most commonly used in P&IDs. Figure 12 is an example of a single line P&ID. The single line format represents all piping, regardless of size, as single line. All system equipment is represented by simple standard symbols (covered in later modules). By simplifying piping and equipment, single lines allow the system's equipment and instrumentation relationships to be clearly understood by the reader.

Figure 12 Example of a Single Line P&ID

Pictorial or Double Line Drawings Pictorial or double line drawings present the same type information as a single line, but the equipment is represented as if it had been photographed. Figure 13 provides an example illustration of a pictorial drawing. This format is rarely used since it requires much more effort to produce than a single line drawing and does not present any more information as to how the system functions. Compare the pictorial illustration, Figure 13, to the single line of the same system shown in Figure 12. Pictorial or double line drawings are often used in advertising and training material.

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DOE-HDBK-1O16/1-93 INTRODUCTION TO THE TYPES OF DRAWINGS, VIEWS, AND PERSPECTIVES

Figure 13 Example Pictorial

Assembly Drawings Assembly drawing are a special application of pictorial drawings that are common in the engineering field. As seen in Figure 14, an assembly drawing is a pictorial view of the object with all the components shown as they go together. This type pictorial is usually found in vendor manuals and is used for parts identification and general information relative to the assembly of the component.

Figure 14 Example of an Assembly Drawing

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INTRODUCTION TO THE TYPES DOE-HDBK1016/1-93 OF DRAWINGS, VIEWS, AND PERSPECTIVES


Cutaway Drawings A cutaway drawing is another special type of pictorial drawing. In a cutaway, as the name implies, the component or system has a portion cut away to reveal the internal parts of the component or system. Figure 15 is an illustration of a cutaway. This type of drawing is extremely helpful in the maintenance and training areas where the way internal parts are assembled is important.

Figure 15 Example of a Cutaway

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Views and Perspectives In addition to the different drawing formats, there are different views or perspectives in which the formats can be drawn. The most commonly used are the orthographic projection and the isometric projection.

Orthographic Projections Orthographic projection is widely used for fabrication and construction type drawings, as shown in Figure 16. Orthographic projections present the component or system

through the use of three views, These are a top view, a side view, and a front view. Other views, such as a bottom view, are used to more fully depict the component or system when necessary.

Figure 16 Example Orthographic Projection

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Figure 17 shows how each of the three views is obtained. The orthographic projection is typically drawn to scale and shows all components in their proper relationships to each other. The three views, when provided with dimensions and a drawing scale, contain information that is necessary to fabricate or construct the component or system.

Figure 17 Orthographic Projections

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Isometric Projection The isometric projection presents a single view of the component or system. The view is commonly from above and at an angle of 30°. This provides a more realistic threedimensional view. As shown on Figure 18, this view makes it easier to see how the system looks and how its various portions or parts are related to one another. Isometric projections may or may not be drawn to a scale.

Figure 18 Example of an Isometric

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Drawing Types, Views, and Perspectives Summary •

The five engineering drawing categories are: P&IDs Electrical single lines and schematics Electronic diagrams and schematics Logic diagrams and prints Fabrication, construction, and architectural drawings

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ENGINEERING SYM BOLOGY, PRINTS, AND DRAW INGS M odule 2 Engineering Fluid Diagrams and Prints

Engineering Fluid Diagrams and Prints

DOE-HDBK-1016/1-93

TABLE OF CONTENTS

TABLE OF C ONTENTS

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

v

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii ENGINEERING FLUIDS DIAGRAMS AND PRINTS . . . . . . . . . . . . . . . . . . . . . . . . Symbology . . . . . . . . . . . . . . . . . . Valve Symbols . . . . . . . . . . . . . . . . Valve Actuators . . . . . . . . . . . . . . . Control Valve Designations . . . . . . . Piping Systems . . . . . . . . . . . . . . . Instrumentation . . . . . . . . . . . . . . . Sensing Devices and Detectors . . . . . Modifiers and Transmitters . . . . . . . Indicators and Recorders . . . . . . . . . Controllers . . . . . . . . . . . . . . . . . . Examples of Simple Instrument Loops Components . . . . . . . . . . . . . . . . . . Miscellaneous P&ID Symbols . . . . . Summary . . . . . . . . . . . . . . . . . . .

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1 2 3 4 6 7 8 10 11 12 12 13 13 15 15

READING ENGINEERING P&IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

Standards and Conventions for Valve Status . . . . . . . . . . . . . . . . . . . . . . . . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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P&ID PRINT READING EXAMPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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TABLE OF C ONTENTS FLUID POWER P&IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fluid Power Diagrams and Schematics Pumps . . . . . . . . . . . . . . . . . . . . . . Reservoirs . . . . . . . . . . . . . . . . . . . . Actuator . . . . . . . . . . . . . . . . . . . . . Piping . . . . . . . . . . . . . . . . . . . . . . . Valves . . . . . . . . . . . . . . . . . . . . . . Reading Fluid Power Diagrams . . . . . Types of Fluid Power Diagrams . . . . . Summary . . . . . . . . . . . . . . . . . . . .

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LIST OF FIGURES

LIST OF FIGURES Figure 1 Valve Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Figure 2 Valve Actuator Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 3 Remotely Controlled Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 4 Level Control Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 5 Control Valves with Valve Positioners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 6 Control Valve Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 7 Piping Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 8 More Piping Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 9 Detector and Sensing Device Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 10 Transmitters and Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 11 Indicators and Recorders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 12 Controllers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 13 Signal Conditioners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 14 Instrumentation System Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 15 Symbols for Major Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 16 Miscellaneous Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 17 Valve Status Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 18 Exercise P&ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 19 Fluid Power Pump and Compressor Symbols . . . . . . . . . . . . . . . . . . . . . . . 23 Figure 20 Fluid Power Reservoir Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Figure 21 Symbols for Linear Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

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LIST OF FIGURES (Cont.) Figure 22 Symbols for Rotary Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 23 Fluid Power Line Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 24 Valve Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 25 Valve Symbol Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Figure 26 Fluid Power Valve Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Figure 27 Simple Hydraulic Power System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Figure 28 Line Diagram of Figure 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Figure 29 Typical Fluid Power Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Figure 30 Pictorial Fluid Power Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Figure 31 Cutaway Fluid Power Diagram

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Figure 32 Schematic Fluid Power Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

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LIST OF TABLES

LIST OF TABLES Table 1 Instrument Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

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REFERENCES

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REFERENCES

ANSI Y14.5M - 1982, Dimensioning and Tolerancing, American National Standards Institute. ANSI Y32.2 - 1975, Graphic Symbols for Electrical and Electronic Diagrams, American National Standards Institute. Gasperini, Richard E., Digital Troubleshooting, Movonics Company; Los Altos, California, 1976. Jensen - Helsel, Engineering Drawing and Design, Second Ed., McGraw-Hill Book Company, New York, 1979. Lenk, John D., Handbook of Logic Circuits, Reston Publishing Company, Reston, Virginia, 1972. Wickes, William E., Logic Design with Integrated Circuits, John Wiley & Sons, Inc, 1968. Naval Auxiliary Machinery, United States Naval Institute, Annapolis, Maryland, 1951. TPC Training Systems, Reading Schematics and Symbols, Technical Publishing Company, Barrington, Illinois, 1974. Arnell, Alvin, Standard Graphical Symbols, McGraw-Hill Book Company, 1963. George Mashe, Systems Summary of a Westinghouse Pressurized Water Reactor, Westinghouse Electric Corporation, 1971. Zappe, R.W., Valve Selection Handbook, Gulf Publishing Company, Houston, Texas, 1968.

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DOE-HDBK-1016/1-93

OBJECTIVES


Given an engineering print, READ and INTERPRET facility engineering Piping and Instrument Drawings.

ENABLING OBJECTIVE S 1.1

IDENTIFY the symbols used on engineering P&IDs for the following types of valves:

a. b. c. d. e. f. 1.2

Globe valve Gate valve Ball valve Check valve Stop check valve Butterfly valve

g. h. i. j. k. l.

Relief valve Rupture disk Three-way valve Four-way valve Throttle (needle) valve Pressure regulator

IDENTIFY the symbols used on engineering P&IDs for the following types of valve

operators: a. b. c. d. e. f.

Diaphragm valve operator Motor valve operator Solenoid valve operator Piston (hydraulic) valve operator Hand (manual) valve operator Reach-rod valve operator

1.3

IDENTIFY the symbols used on engineering P&IDs for educators and ejectors.

1.4

IDENTIFY the symbols used on engineering P&IDs for the following lines:

a. b. c. d. e. f. g.

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Process Pneumatic Hydraulic Inert gas Instrument signal (electrical) Instrument capillary Electrical

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OBJECTIVES

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ENABLING OBJECTIVES (cont.) 1.5

IDENTIFY the symbols used on engineering P&IDs for the following basic types of instrumentation:

a. b. c. d. e. f. g. 1.6

Differential pressure cell Temperature element Venturi Orifice Rotometer Conductivity or salinity cell Radiation detector

IDENTIFY the symbols used on engineering P&IDs to denote the location, either local

or board mounted, of instruments, indicators, and controllers. 1.7

IDENTIFY the symbols used on engineering P&IDs for the following types of instrument signal controllers and modifiers:

a. b. c. d. 1.8

Proportional Proportional-integral Proportional-integral-differential Square root extractors

IDENTIFY the symbols used on engineering P&IDs for the following types of system

components: a. b. c. d. e. f. g.

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Centrifugal pumps Positive displacement pumps Heat exchangers Compressors Fans Tanks Filters/strainers

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OBJECTIVES

ENABLING OBJECTIVES (cont.) 1.9

STATE how the following valve conditions are depicted on an engineering P&ID:

a. b. c. d. e. f. g. h. i.

Open valve Closed valve Throttled valve Combination valves (3- or 4-way valve) Locked-closed valve Locked-open valve Fail-open valve Fail-closed valve Fail-as-is valve

1.10

Given an engineering P&ID, IDENTIFY components and DETERM INE the flowpath(s) for a given valve lineup.

1.11

IDENTIFY the symbols used on engineering fluid power drawings for the following

components: a. b. c. d. e. f. 1.12

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Pump Compressor Reservoir Actuators Piping and piping junctions Valves

Given a fluid power type drawing, DETERM INE the operation or resultant action of the stated component when hydraulic pressure is applied/removed.

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Engineer Fluid Diagrams and Prints


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DOE-HDBK-1016/1-93 ENGINEERING FLUIDS DIAGRAMS AND PRINTS

ENGINEERING FLUIDS DIAGRAMS AND PRINTS To read and understand engineering fluid diagrams and prints, usually referred to as P&IDs, an individual must be familiar with the basic symbols. EO 1.1

IDENTIFY the symbols used on engineering P&IDs for the following types of valves: a. b. c. d. e. f.

EO 1.2

g. h. i. j. k. l.

Relief valve Rupture disk Three-way valve Four-way valve Throttle (needle) valve Pressure regulator

IDENTIFY the symbols used on engineering P&IDs for the following types of valve operators: a. b. c. d. e. f.

Diaphragm valve operator Motor valve operator Solenoid valve operator Piston (hydraulic) valve operator Hand (manual) valve operator Reach rod valve operator

EO 1.3

IDENTIFY the symbols used on engineering P&IDs for educators and ejectors.

EO 1.4

IDENTIFY the symbols used on engineering P&IDs for the following lines: a. b. c. d.

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Globe valve Gate valve B all valve Check valve Stop check valve Butterfly valve

Process Pneumatic Hydraulic Inert gas

e. f. g.

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Instrument signal (electrical) Instrument capillary Electrical

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EO 1.5


IDENTIFY the symbols used on engineering P&IDs for the following basic types of instrum entation: a. b. c. d.

Differential pressure cell Tem perature element Venturi Orifice

e. f. g.

Rotometer Conductivity or salinity cell Radiation detector

EO 1.6

IDENTIFY the symbols used on engineering P&IDs to denote the location, either local or board mounted, of instruments, indicators, and controllers.

EO 1.7

IDENTIFY the symbols used on engineering P&IDs for the following types of instrument signal modifiers: a. b. c. d.

EO 1.8

Proportional Proportional-integral Proportional-integral-differential Square root extractors

IDENTIFY the symbols used on engineering P&IDs for the following types of system components: a. b. c. d.

Centrifugal pum ps Positive displacement pumps Heat exchangers Compressors

e. f. g.

Fans Tanks Filters/strainers

Symbology To read and interpret piping and instrument drawings (P&IDs), the reader must learn the meaning of the symbols. This chapter discusses the common symbols that are used to depict fluid system components. When the symbology is mastered, the reader will be able to interpret most P&IDs. The reader should note that this chapter is only representative of fluid system symbology, rather than being all-inclusive. The symbols presented herein are those most commonly used in engineering P&IDs. The reader may expand his or her knowledge by obtaining and studying the appropriate drafting standards used at his or her facility.

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Valve Symbols Valves are used to control the direction, flow rate, and pressure of fluids. Figure 1 shows the symbols that depict the major valve types. It shoud be noted that globe and gate valves will often be depicted by the same valve symbol. In such cases, information concerning the valve type may be conveyed by the component identification number or by the notes and legend section of the drawing; however, in many instances even that may not hold true.

Figure 1 Valve Symbols

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Valve Actuators Some valves are provided with actuators to allow remote operation, to increase mechanical advantage, or both. Figure 2 shows the symbols for the common valve actuators. Note that although each is shown attached to a gate valve, an actuator can be attached to any type of valve body. If no actuator is shown on a valve symbol, it may be assumed the valve is equipped only with a handwheel for manual operation.

Figure 2 Valve Actuator Symbols

The combination of a valve and an actuator is commonly called a control valve. Control valves are symbolized by combining the appropriate valve symbol and actuator symbol, as illustrated in Figure 2. Control valves can be configured in many different ways. The most commonly found configurations are to manually control the actuator from a remote operating station, to automatically control the actuator from an instrument, or both. In many cases, remote control of a valve is accomplished by using an intermediate, small control valve to operate the actuator of the process control valve. The intermediate control valve is placed in the line supplying motive force to the process control valve, as shown in Figure 3. In this example, air to the process air-operated control valve is controlled by the solenoid-operated, 3-way valve in the air supply line. The 3-way valve may supply air to the control valve's diaphragm or vent the diaphragm to the atmosphere. Figure 3 Remotely Controlled Valve

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Note that the symbols alone in Figure 3 do not provide the reader with enough information to determine whether applying air pressure to the diaphragm opens or closes the process control valve, or whether energizing the solenoid pressurizes or vents the diaphragm. Further, Figure 3 is incomplete in that it does not show the electrical portion of the valve control system nor does it identify the source of the motive force (compressed air). Although Figure 3 informs the reader of the types of mechanical components in the control system and how they interconnect, it does not provide enough information to determine how those components react to a control signal. Control valves operated by an instrument signal are symbolized in the same manner as those shown previously, except the output of the controlling instrument goes to the valve actuator. Figure 4 shows a level instrument (designated "LC") that controls the level in the tank by positioning an air-operated diaphragm control valve. Again, note that Figure 4 does not contain enough information to enable the reader to determine how the control valve responds to a change in level.

Figure 4 Level Control Valve

An additional aspect of some control valves is a valve positioner, which allows more precise control of the valve. This is especially useful when instrument signals are used to control the valve. An example of a valve positioner is a set of limit switches operated by the motion of the valve. A positioner is symbolized by a square box on the stem of the control valve actuator. The positioner may have lines attached for motive force, instrument signals, or both. Figure 5 shows two examples of valves equipped with positioners. Note that, although these examples are more detailed than those of Figure 3 and Figure 4, the reader still does not have sufficient information to fully determine response of the control valve to a change in control signal.

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Figure 5 Control Valves with Valve Positioners

In Example A of Figure 5, the reader can reasonably assume that opening of the control valve is in some way proportional to the level it controls and that the solenoid valve provides an override of the automatic control signals. However, the reader cannot ascertain whether it opens or closes the control valve. Also, the reader cannot determine in which direction the valve moves in response to a change in the control parameter. In Example B of Figure 5, the reader can make the same general assumptions as in Example A, except the control signal is unknown. Without additional information, the reader can only assume the air supply provides both the control signal and motive force for positioning the control valve. Even when valves are equipped with positioners, the positioner symbol may appear only on detailed system diagrams. Larger, overall system diagrams usually do not show this much detail and may only show the examples of Figure 5 as air-operated valves with no special features.

Control Valve Designations A control valve may serve any number of functions within a fluid system. To differentiate between valve uses, a balloon labeling system is used to identify the function of a control valve, as shown in Figure 6. The common convention is that the first letter used in the valve designator indicates the parameter to be controlled by the valve. For example: F = flow T = temperature L = level P = pressure H = hand (manually operated valve) The second letter is usually a "C" and identifies the valve as a controller, or active component, as opposed to a hand-operated valve. The third letter is a "V" to indicate that the piece of equipment is a valve.

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Figure 6 Control Valve Designations

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Piping Systems The piping of a single system may contain more than a single medium. For example, although the main process flow line may carry water, the associated auxiliary piping may carry compressed air, inert gas, or hydraulic fluid. Also, a fluid system diagram may also depict instrument signals and electrical wires as well as piping. Figure 7 shows commonly used symbols for indicating the medium carried by the piping and for differentiating between piping, instrumentation signals, and electrical wires. Note that, although the auxiliary piping symbols identify their mediums, the symbol for the process flow line does not identify its medium.

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Figure 7 Piping Symbols

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The diagram may also depict t h e i n d i v i d u al f i t t i n g s comprising the piping runs depending on its intended use. Figure 8 shows symbols used to depict pipe fittings.

Instrumentation One of the main purposes of a P&ID is to provide functional information about how instrumentation in a system or piece of equipment interfaces with the system or piece of equipment. Because of this, a large amount of the symbology appearing on P&IDs depicts instrumentation and instrument loops. The symbols used to represent instruments and their loops can Figure 8 More Piping Symbols be divided into four categories. Generally each of these four categories uses the component identifying (labeling) scheme identified in Table 1. The first column of Table 1 lists the letters used to identify the parameter being sensed or monitored by the loop or instrument. The second column lists the letters used to indicate the type of indicator or controller. The third column lists the letters used to indicate the type of component. The fourth column lists the letters used to indicate the type of signals that are being modified by a modifier.

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TAB LE 1 Instrument Identifiers Sensed Parameter F T P I L V Z

= = = = = = =

flow temperature pressure current level voltage position

Type of Indicator or Controller

Type of Component

Type of signal

T = transmitter M = modifier E = element

I = current V = voltage P = pneumatic

R = recorder I = indicator C = controller

The first three columns above are combined such that the resulting instrument identifier indicates its sensed parameter, the function of the instrument, and the type of instrument. The fourth column is used only in the case of an instrument modifier and is used to indicate the types of signals being modified. The following is a list of example instrument identifiers constructed from Table 1. FIC FM PM TE TR LIC

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flow indicating controller flow modifier pressure modifier temperature element temperature recorder level indicating controller

TT PT FE FI TI FC

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= = = = = =

temperature transmitter pressure transmitter flow element flow indicator temperature indicator flow controller

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Sensing Devices and Detectors The parameters of any system are monitored for indication, control, or both. To create a usable signal, a device must be inserted into the system to detect the desired parameter. In some cases, a device is used to create special conditions so that another device can supply the necessary measurement. Figure 9 shows the symbols used for the various sensors and detectors.

Figure 9 Detector and Sensing Device Symbols

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M odifiers and Transmitters Sensors and detectors by themselves are not sufficient to create usable system indications. Each sensor or detector must be coupled with appropriate modifiers and/or transmitters. The exceptions are certain types of local instrumentation having mechanical readouts, such as bourdon tube pressure gages and bimetallic thermometers. Figure 10 illustrates various examples of modifiers and transmitters. Figure 10 also illustrates the common notations used to indicate the location of an instrument, i.e., local or board mounted. Transmitters are used to convert the signal from a sensor or detector to a form that can be sent to a remote point for processing, controlling, or monitoring. The output can be electronic (voltage or current), pneumatic, or hydraulic. Figure 10 illustrates symbols for several specific types of transmitters. The reader should note that modifiers may only be identified by the type of input and output signal (such as I/P for one that converts an electrical input to a pneumatic output) rather than by the monitored parameter (such as PM for pressure modifier).

Figure 10 Transmitters and Instruments

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Indicators and Recorders Indicators and recorders are instruments that convert the signal generated by an instrument loop into a readable form. The indicator or recorder may be locally or board mounted, and like modifiers and transmitters this information is indicated by the type of symbol used. Figure 11 provides examples of the symbols used for indicators and recorders and how their location is denoted.

Controllers Controllers process the signal from an instrument loop and use it to position or manipulate some other system component. Generally they are denoted by placing a "C" in the balloon after the controlling parameter as shown in Figure 12. There are controllers that serve to process a signal and create a new Figure 11 Indicators and Recorders signal. These include proportional controllers, proportional-integral controllers, and proportional-integral-differential controllers. The symbols for these controllers are illustrated in Figure 13. Note that these types of controllers are also called signal conditioners.

Figure 12 Controllers

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Figure 13 Signal Conditioners

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Exa mples of Simple Instrument Loops Figure 14 shows two examples of simple instrument loops. Figure 14 (A) shows a temperature transmitter (TT), which generates two electrical signals. One signal goes to a boardmounted temperature recorder (TR) for display. The second signal is sent to a proportional-integral-derivative (PID) controller, the output of which is sent to a current-to-pneumatic modifier (I/P). In the I/P modifier, the electric signal is converted into a pneumatic signal, commonly 3 psi to 15 psi, which in turn operates the valve. The function of the complete loop is to modify flow based on process fluid temperature. Note that there is not enough information to determine how flow and temperature are related and what the setpoint is, but in some instances the setpoint is stated on a P&ID. Knowing the setpoint and purpose of the system will usually be sufficient to allow the operation of the instrument loop to be determined. Figure 14 Instrumentation System Examples

The pneumatic level transmitter (LT) illustrated in Figure 14 (B) senses tank level. The output of the level transmitter is pneumatic and is routed to a board-mounted level modifier (LM). The level modifier conditions the signal (possibly boosts or mathematically modifies the signal) and uses the modified signal for two purposes. The modifier drives a board-mounted recorder (LR) for indication, and it sends a modified pneumatic signal to the diaphragm-operated level control valve. Notice that insufficient information exists to determine the relationship between sensed tank level and valve operation.

Components Within every fluid system there are major components such as pumps, tanks, heat exchangers, and fans. Figure 15 shows the engineering symbols for the most common major components.

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Figure 15 Symbols for Major Components

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Miscellaneous P&ID Symbols In addition to the normal symbols used on P&IDs to represent specific pieces of equipment, there are miscellaneous symbols that are used to guide or provide additional information about the drawing. Figure 16 lists and explains four of the more common miscellaneous symbols.

Figure 16 Miscellaneous Symbols


Engineering Fluids Diagra ms and Prints Summary In this chapter the common symbols found on P&IDs for valves, valve operators, process piping, instrumentation, and common system components were reviewed.

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READING ENGINEERING P&IDs

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READING ENGINEERING P&IDs Standards and conventions have been developed to provide consistency from drawing to drawing. To accurately interpret a drawing, these standards and conventions must be understood. EO 1.9

STATE how the following valve conditions are depicted on an engineering P& ID drawing: a. b. c. d.

Open valve Closed valve Throttled valve Com bination valves (3- or 4- way valve)

e. f. g. h. i.

Locked-closed valve Locked-open valve Fail-open valves Fail-closed valve Fail-as-is valve

Standards and Conventions for Valve Status Before a diagram or print can be properly read and understood, the basic conventions used by P&IDs to denote valve positions and failure modes must be understood. The reader must be able to determine the valve position, know if this position is normal, know how the valve will fail, and in some cases know if the valve is normally locked in that position. Figure 17 illustrates the symbols used to indicate valve status. Unless otherwise stated, P&IDs indicate valves in their "normal" position. This is usually interpreted as the normal or primary flowpath for the system. An exception is safety systems, which are normally shown in their standby or non-accident condition.

Figure 17 Valve Status Symbols

3-way valves are sometimes drawn in the position that they will fail to instead of always being drawn in their "normal" position. This will either be defined as the standard by the system of drawings or noted in some manner on the individual drawings.

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Reading Engineering P&IDs Summary This chapter reviewed the basic symbology, common standards, and conventions used on P&IDs, such as valve conditions and modes of failure. This information, with the symbology learned in the preceding chapter, provides the information necessary to read and interpret most P&IDs.

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P&ID PRINT READING EXAMPLE

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P&ID PRINT READING E XAMPLE The ability to read and understand prints is achieved through the repetitive reading of prints.

EO 1.10

Given an engineering P&ID, IDENTIFY components and DETERM INE the flowpath(s) for a given valve lineup.

Exa mple At this point, all the symbols for valves and major components have been presented, as have the conventions for identifying the condition of a system. Refer to Figure 18 as necessary to answer the following questions. The answers are provided in the back of this section so that you may judge your own knowledge level.

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Figure 18 Exercise P&ID

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1.

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Identify the following components by letter or number. a. b. c. d. e. f. g. h. i. j. k. l. m. n. o. p. q.

Centrifugal pump Heat exchanger Tank Venturi Rupture disc Relief valve Motor-operated valve Air-operated valve Throttle valve Conductivity cell Air line Current-to-pneumatic converter Check valve A locked-closed valve A closed valve A locked-open valve A solenoid valve

2.

What is the controlling parameter for Valves 10 and 21?

3.

Which valves would need to change position in order for Pump B to supply flow to only points G and H?

4.

Which valves will fail open? Fail closed? Fail as is?

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Answers for questions on Figure 18 1.

a. b. c. d. e. f. g. h. i. j. k. l. m. n. o. p. q.

2.

Temperature as sensed by the temperature elements (TE)

3.

Open 18 and/or 19 Shut 13 and 25

4.

Fail Open: Fail Closed: Fail as is:

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A or B C or D E 31 1 8 or 17 2,3,7 or 16 10, 21 12 or 24 26 32 28 5 or 14 18 or 19 18 or 19 4 11 or 23

2 and 3 10 and 21 7 and 16

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P&ID Print Reading Exa mple Summary This chapter provided the student with examples in applying the material learned in Chapters 1 and 2.

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FLUID POWER P&IDs

FLUID P OWER P&IDs Fluid power diagrams and schematics require an independent review because they use a unique set of symbols and conventions. EO 1.11

IDENTIFY the symbols used on engineering fluid power drawings for the following components: a. Pum p b. Com pressor c. Reservoir

EO 1.12

d. Actuators e. Piping and piping junctions f. Valves

Given a fluid power type drawing, DETERM INE the operation or resultant action of the stated component when hydraulic pressure is applied/removed.

Fluid Power Diagra ms and Schematics Different symbology is used when dealing with systems that operate with fluid power. Fluid power includes either gas (such as air) or hydraulic (such as water or oil) motive media. Some of the symbols used in fluid power systems are the same or similar to those already discussed, but many are entirely different. Fluid power systems are divided into five basic parts: pumps, reservoirs, actuators, valves, and lines.

Pumps In the broad area of fluid power, two categories of pump symbols are used, depending on the motive media being used (i.e., hydraulic or pneumatic). The basic symbol for the pump is a circle containing one or more arrow heads indicating the direction(s) of flow with the points of the arrows in contact with the circle. Hydraulic pumps are shown by solid arrow heads. Pneumatic compressors are represented by hollow arrow heads. Figure 19 provides common symbols used for pumps (hydraulic) and compressors (pneumatic) in fluid power diagrams.

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Figure 19 Fluid Power Pump and Compressor Symbols

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Reservoirs Reservoirs provide a location for storage of the motive media (hydraulic fluid or compressed gas). Although the symbols used to represent reservoirs vary widely, certain conventions are used to indicate how a reservoir handles the fluid. Pneumatic reservoirs are usually simple tanks and their symbology is usually some variation of the cylinder shown in Figure 20. Hydraulic reservoirs can be much more complex in terms of how the fluid is admitted to and removed from the tank. To convey this information, symbology conventions have been developed. These symbols are in Figure 20.

Figure 20 Fluid Power Reservoir Symbols

Actuator An actuator in a fluid power system is any device that converts the hydraulic or pneumatic pressure into mechanical work. Actuators are classified as linear actuators and rotary actuators. Linear actuators have some form of piston device. Figure 21 illustrates several types of linear actuators and their drawing symbols.

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Figure 21 Symbols for Linear Actuators

Rotary actuators are generally called motors and may be fixed or variable. Several of the more common rotary symbols are shown in Figure 22. Note the similarity between rotary motor symbols in Figure 22 and the pump symbols shown in Figure 19. The difference between them is that the point of the arrow touches the circle in a pump and the tail of the arrow touches the circle in a motor.

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Figure 22 Symbols for Rotary Actuators

Piping The sole purpose of piping in a fluid power system is to transport the working media, at pressure, from one point to another. The symbols for the various lines and termination points are shown in Figure 23.

Figure 23 Fluid Power Line Symbols

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FLUID POWER P&IDs

Valves Valves are the most complicated symbols in fluid power systems. Valves provide the control that is required to ensure that the motive media is routed to the correct point when needed. Fluid power system diagrams require much more complex valve symbology than standard P&IDs due to the complicated valving used in fluid power systems. In a typical P&ID, a valve opens, closes, or throttles the process fluid, but is rarely required to route the process fluid in any complex manner (three- and four-way valves being the common exceptions). In fluid power systems it is common for a valve to have three to eight pipes attached to the valve body, with the valve being capable of routing the fluid, or several separate fluids, in any number of combinations of input and output flowpaths. The symbols used to represent fluid power valves must contain much more information than the standard P&ID valve symbology. To meet this need, the valve symbology shown in the following figures was developed for fluid power P&IDs. Figure 24, a cutaway view, provides an example of the internal complexity of a simple fluid power type valve. Figure 24 illustrates a four-way/three-position valve and how it operates to vary the flow of the fluid. Note that in Figure 24 the operator of the valve is not identified, but like a standard process fluid valve the valve could be operated by a diaphragm, motor, hydraulic, solenoid, or manual operator. Fluid power valves, when electrically operated by a solenoid, are drawn in the de-energized position. Energizing the solenoid will cause the valve to shift to the other port. If the valve is operated by other than a solenoid or is a multiport valve, the information necessary to determine how the valve operates will be provided on each drawing or on its accompanying legend print.

Figure 24 Valve Operation

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Refer to Figure 25 to see how the valve in Figure 24 is transformed into a usable symbol.

Figure 25 Valve Symbol Development

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Figure 26 shows symbols for the various valve types used in fluid power systems.

Figure 26 Fluid Power Valve Symbols

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Reading Fluid Power Diagra ms Using the symbology previously discussed, a fluid power diagram can now be read. But before reading some complex examples, let's look at a simple hydraulic system and convert it into a fluid power diagram.

Using the drawing in Figure 27, the left portion of Figure 28 lists each part and its fluid power symbol. The right side of Figure 28 shows the fluid power diagram that represents the drawing in Figure 27.

Figure 27 Simple Hydraulic Power System

Figure 28 Line Diagram of Simple Hydraulic Power System

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FLUID POWER P&IDs

With an understanding of the principles involved in reading fluid power diagram, any diagram can be interpreted. Figure 29 shows the kind of diagram that is likely to be encountered in the engineering field. To read this diagram, a step-by-step interpretation of what is happening in the system will be presented.

Figure 29 Typical Fluid Power Diagram

The first step is to get an overall view of what is happening. The arrows between A and B in the lower right-hand corner of the figure indicate that the system is designed to press or clamp some type of part between two sections of the machine. Hydraulic systems are often used in press work or other applications where the work piece must be held in place.

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With the basic function understood, a detailed study of the diagram can be accomplished using a step-by-step analysis of each numbered local area in the diagram. LOCAL AREA NUMBER 1 Symbol for an open reservoir with a strainer. The strainer is used to clean the oil before it enters the system. LOCAL AREA NUMBER 2 Fixed displacement pump, electrically operated. This pump provides hydraulic pressure to the system. LOCAL AREA NUMBER 3 Symbol for a relief valve with separate pressure gage. The relief valve is spring operated and protects the system from over pressurization. It also acts as an unloader valve to relieve pressure when the cylinder is not in operation. When system pressure exceeds its setpoint, the valve opens and returns the hydraulic fluid back to the reservoir. The gage provides a reading of how much pressure is in the system. LOCAL AREA NUMBER 4 Composite symbol for a 4-way, 2-position valve. Pushbutton PB-1 is used to activate the valve by energizing the S-1 solenoid (note the valve is shown in the de-energized position). As shown, the high pressure hydraulic fluid is being routed from Port 1 to Port 3 and then to the bottom chamber of the piston. This drives and holds the piston in local area #5 in the retracted position. When the piston is fully retracted and hydraulic pressure builds, the unloader (relief) valve will lift and maintain the system's pressure at setpoint. When PB-1 is pushed and S-1 energized, the 1-2 ports are aligned and 3-4 ports are aligned. This allows hydraulic fluid to enter the top chamber of the piston and drive it down. The fluid in the bottom chamber drains though the 3-4 ports back into the reservoir. The piston will continue to travel down until either PB-1 is released or full travel is reached, at which point the unloader (relief) valve will lift. LOCAL AREA NUMBER 5 Actuating cylinder and piston. The cylinder is designed to receive fluid in either the upper or lower chambers. The system is designed so that when pressure is applied to the top chamber, the bottom chamber is aligned to drain back to the reservoir. When pressure is applied to the bottom chamber, the top chamber is aligned so that it drains back to the reservoir.

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FLUID POWER P&IDs

Types of Fluid Power Diagra ms Several kinds of diagrams can be used to show how systems work. With an understanding of how to interpret Figure 29, a reader will be able to interpret all of the diagrams that follow. A pictorial diagram shows the physical arrangement of the elements in a system. The components are outline drawings that show the external shape of each item. Pictorial drawings do not show the internal function of the elements and are not especially valuable for maintenance or troubleshooting. Figure 30 shows a pictorial diagram of a system.

Figure 30 Pictorial Fluid Power Diagram

A cutaway diagram shows both the physical arrangement and the operation of the different components. It is generally used for instructional purposes because it explains the functions while showing how the system is arranged. Because these diagrams require so much space, they are not usually used for complicated systems. Figure 31 shows the system represented in Figure 30 in cutaway diagram format and illustrates the similarities and differences between the two types of diagrams.

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Figure 31 Cutaway Fluid Power Diagram

A schematic diagram uses symbols to show the elements in a system. Schematics are designed to supply the functional information of the system. They do not accurately represent the relative location of the components. Schematics are useful in maintenance work, and understanding them is an important part of troubleshooting. Figure 32 is a schematic diagram of the system illustrated in Figure 30 and Figure 31.

Figure 32 Schematic Fluid Power Diagram

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Fluid Power P&IDs Summary This chapter reviewed the most commonly used symbols on fluid power diagrams and the basic standards and conventions for reading and interpreting fluid power diagrams.

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ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Module 3 Electrical Diagrams and Schematics

Electrical Diagrams and Schematics

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TABLE OF CONTENTS

TABLE OF C ONTENTS

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ii

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

v

ELECTRICAL DIAGRAMS AND SCHEMATICS . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Symbology . . . . . . . . . . . . . . . . . . . . . . . . . . . Transformers . . . . . . . . . . . . . . . . . . . . . . . . . Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fuses and Breakers . . . . . . . . . . . . . . . . . . . . . Relays, Contacts, Connectors, Lines, Resistors, and Miscellaneous Electrical Components Large Components . . . . . . . . . . . . . . . . . . . . . Types of Electrical Diagrams or Schematics . . . . Reading Electrical Diagrams and Schematics . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ELECTRICAL WIRING AND SCHEMATIC DIAGRAM READING EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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LIST OF FIGURES

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LIST OF FIGURES

Figure 1 Basic Transformer Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Figure 2 Transformer Polarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Figure 3 Switches and Switch Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Figure 4 Switch and Switch Status Symbology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 5 Fuse and Circuit Breaker Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 6 3-phase and Removable Breaker Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 7 Common Electrical Component Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 8 Large Common Electrical Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 9 Comparison of an Electrical Schematic and a Pictorial Diagram . . . . . . . . . . . . . 9 Figure 10 Comparison of an Electrical Schematic and a Wiring Diagram . . . . . . . . . . . . 10 Figure 11 Wiring Diagram of a Car's Electrical Circuit . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 12 Schematic of a Car's Electrical Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 13 Example Electrical Single Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 14 Examples of Relays and Relay Contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 15 Ganged Switch Symbology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 16 Three-Phase Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Figure 17 Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 18 Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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LIST OF TABLES

LIST OF TABLES Table 1 Comparison Between Wiring and Schematic Diagrams . . . . . . . . . . . . . . . . . . .

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OBJECTIVES


Given an electrical print, schematics.

READ and INTERPRET facility electrical diagrams and

ENABLING OBJECTIVE S 1.1

IDENTIFY the symbols used on engineering electrical drawings for the following

components: a. b. c. d. e. f. g. h. i. j. k. l.

Single-phase circuit breaker (open/closed) Three-phase circuit breaker (open/closed) Thermal overload "a" contact "b" contact Time-delay contacts Relay Potential transformer Current transformer Single-phase transformer Delta-wound transformer Wye-wound transformer

m. n. o. p. q. r. s. t. u. v. w. x. y.

Electric motor Meters Junctions In-line fuses Single switch Multiple-position switch Pushbutton switch Limit switches Turbine-driven generator Motor-generator set Generator (wye or delta) Diesel-driven generator Battery

1.2

Given an electrical drawing of a circuit containing a transformer, DETERMINE the direction of current flow, as shown by the transformer's symbol.

1.3

IDENTIFY the symbols and/or codes used on engineering electrical drawings to depict

the relationship between the following components: a. b. c.

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Relay and its contacts Switch and its contacts Interlocking device and its interlocked equipment

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ENABLING OBJECTIVES (Cont.) 1.4

STATE the condition in which all electrical devices are shown, unless otherwise noted on the diagram or schematic.

1.5

Given a simple electrical schematic and initial conditions, DETERMINE the condition of the specified component (i.e., energized/de-energized, open/closed).

1.6

Given a simple electrical schematic and initial conditions, IDENTIFY the power sources and/or loads and their status (i.e., energized or de-energized).

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DOE-HDBK-1016/1-93 ELECTRICAL DIAGRAMS AND SCHEMATICS

ELECTRICAL DIAGRAMS AND SCHEMATICS To read and interpret electrical diagrams and schematics, the basic symbols and conventions used in the drawing must be understood. This chapter concentrates on how electrical components are represented on diagrams and schematics. The function of the individual electrical components and the theory behind their operation is covered in more detail in the Electrical Science Handbook. EO 1.1 IDENTIFY the symbols used on engineering electrical drawings for the following components: a. b. c. d. e. f. g. h. i. j. k. l.

Single-phase circuit breaker (open/closed) Three-phase circuit breaker (open/closed) Therm al overload "a" contact "b" contact Tim e-delay contacts Relay Potential transformer Current transformer Single-phase transformer Delta-wound transform er W ye-wound transform er

m. n. o. p. q. r. s. t. u. v. w. x. y.

Electric motor Meters Junctions In-line fuses Single switch Multiple-position switch Pushbutton switch Limit switches Turbine-driven generator Motor-generator set Generator (wye or delta) Diesel-driven generator Battery

EO 1.2 Given an electrical drawing of a circuit containing a transform er, DETERM INE the direction of current flow, as shown by the transform er's symbol. EO 1.3 IDENTIFY the symbols and/or codes used on engineering electrical drawings to depict the relationship between the following components: a. Relay and its contacts b. Switch and its contacts c. Interlocking device and its interlocked equipment EO 1.4 STATE the condition in which all electrical devices are shown, unless otherwise noted on the diagram or schematic. EO 1.5 Given a sim ple electrical schematic and initial conditions, DETERM INE the condition of the specified component (i.e., energized/de-energized, open/closed).

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Symbology To read and interpret electrical diagrams and schematics, the reader must first be well versed in what the many symbols represent. This chapter discusses the common symbols used to depict the many components in electrical systems. Once mastered, this knowledge should enable the r eader t o successf ul l y understand most electrical diagrams and schematics. The information that follows provides details on the basic symbols used to represent components in electrical transmission, switching, control, and protection diagrams and schematics.

Transformers Figure 1 Basic Transformer Symbols The basic symbols for the various types of transformers are shown in Figure 1 (A). Figure 1 (B) shows how the basic symbol for the transformer is modified to represent specific types and transformer applications.

In addition to the transformer symbol itself, polarity marks are sometimes used to indicate current flow in the circuit. This information can be used to determine the phase relationship (polarity) between the input and output terminals of a transformer. The marks usually appear as dots on a transformer symbol, as shown in Figure 2.

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Figure 2 Transformer Polarity

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On the primary side of the transformer the dot indicates current in; on the secondary side the dot indicates current out. If at a given instant the current is flowing into the transformer at the dotted end of the primary coil, it will be flowing out of the transformer at the dotted end of the secondary coil. The current flow for a transformer using the dot symbology is illustrated in Figure 2.

Switches Figure 3 shows the most common types of switches and their symbols. The term "pole," as used to describe the switches in Figure 3, refers to the number of points at which current can enter a switch. Single pole and double pole switches are shown, but a switch may have as many poles as it requires to perform its function. The term "throw" used in Figure 3 refers to the number of circuits that each pole of a switch can complete or control.

Figure 3 Switches and Switch Symbols

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Figure 4 provides the common symbols that are used to denote automatic switches and explains how the symbol indicates switch status or actuation.

Figure 4 Switch and Switch Status Symbology

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Fuses and Breakers Figure 5 depicts basic fuse and circuit breaker symbols for single-phase applications. In addition to the graphic symbol, most drawings will also provide the rating of the fuse next to the symbol. The rating is usually in amps.

Figure 5 Fuse and Circuit Breaker Symbols

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When fuses, breakers, or switches are used in three-phase systems, the three-phase symbol combines the single-phase symbol in triplicate as shown in Figure 6. Also shown is the symbol for a removable breaker, which is a standard breaker symbol placed between a set of chevrons. The chevrons represent the point at which the breaker disconnects from the circuit when removed.

Figure 6 Three-phase and Removable Breaker Symbols

Relays, Contacts, Connectors, Lines, Resistors, and Miscellaneous Electrical Components Figure 7 shows the common symbols for relays, contacts, connectors, lines, resistors, and other miscellaneous electrical components.

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Figure 7 Common Electrical Component Symbols

Large Components The symbols in Figure 8 are used to identify the larger components that may be found in an electrical diagram or schematic. The detail used for these symbols will vary when used in system diagrams. Usually the amount of detail will reflect the relative importance of a component to the particular diagram.

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Figure 8 Large Common Electrical Components

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Types of Electrical Diagra ms or Schematics There are three ways to show electrical circuits. They are wiring, schematic, and pictorial diagrams. The two most commonly used are the wiring diagram and the schematic diagram. The uses of these two types of diagrams are compared in Table 1.

TAB LE 1 Comparison Between Wiring and Schematic Diagra ms Wiring Diagrams

Schematic Diagrams

1. Emphasize connections between elements of a circuit or system

1. Emphasize "flow" of system 2. Use horizontal and vertical lines to show system flow

2. Use horizontal and vertical lines to represent the wires

3. Use symbols that indicate function of equipment, but the symbols do not look like the actual equipment

3. Use simplified pictorials that clearly resemble circuit/system components 4. Place equipment and wiring on drawing to approximate actual physical location in real circuit

The pictorial diagram is usually not found in engineering applications for the reasons shown in the following example. Figure 9 provides a simple example of how a schematic diagram compares to a pictorial equivalent. As can be seen, the pictorial version is not nearly as useful as the schematic, especially if you were trying to obtain enough information to repair a circuit or determine how it operates.

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4. Drawing layout is done to show the "flow" of the system as it functions, not the physical layout of the equipment

Figure 9 Comparison of an Electrical Schematic and a Pictorial Diagram

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Figure 10 provides an example of the relationship between a schematic diagram (Figure 10A) and a wiring diagram (Figure 10B) for an air drying unit. A more complex example, the electrical circuit of an automobile, is shown in wiring diagram format in Figure 11 and in schematic format in Figure 12. Notice that the wiring diagram (Figure 11), uses both pictorial representations and schematic symbols. The schematic (Figure 12) drops all pictorial representations and depicts the electrical system only in symbols.

Figure 10 Comparison of an Electrical Schematic and a Wiring Diagram

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Figure 11 Wiring Diagram of a Car's Electrical Circuit

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Figure 12 Schematic of a Car's Electrical Circuit

When dealing with a large power distribution system, a special type of schematic diagram called an electrical single line is used to show all or part of the system. This type of diagram depicts the major power sources, breakers, loads, and protective devices, thereby providing a useful overall view of the flow of power in a large electrical power distribution system. On power distribution single lines, even if it is a 3-phase system, each load is commonly represented by only a simple circle with a description of the load and its power rating (running power consumption). Unless otherwise stated, the common units are kilowatts (kW). Figure 13 shows a portion of an electrical distribution system at a nuclear power plant.

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Figure 13 Example Electrical Single Line

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Reading Electrical Diagra ms and Schematics To read electrical system diagrams and schematics properly, the condition or state of each component must first be understood. For electrical schematics that detail individual relays and contacts, the components are always shown in the de-energized condition (also called the shelfstate). To associate the proper relay with the contact(s) that it operates, each relay is assigned a specific number and/or letter combination. The number/letter code for each relay is carried by all associated contacts. Figure 14 (A) shows a simple schematic containing a coil (M1) and its contact. If space permits, the relationship may be emphasized by drawing a dashed line (symbolizing a mechanical connection) between the relay and its contact(s) or a dashed box around them as shown in Figure 14 (B). Figure 14 (C) illustrates a switch and a second set of contacts that are operated by the switch.

Figure 14 Examples of Relays and Relay Contacts

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When a switch is used in a circuit, it may contain several sets of contacts or small switches internal to it. The internal switches are shown individually on a schematic. In many cases, the position of one internal switch will effect the position of another. Such switches are called ganged switches and are symbolized by connecting them with a dashed line as shown in Figure 15 (A). In that example, closing Switch 1 also closes Switch 2. The dashed line is also used to indicate a mechanical interlock between two circuit components. Figure 15 (B) shows two breakers with an interlock between them.

Figure 15 Ganged Switch Symbology

In system single line diagrams, transformers are often represented by the symbol for a singlephase air core transformer; however, that does not necessarily mean that the transformer has an air core or that it is single phase. Single line system diagrams are intended to convey only general functional information, similar to the type of information presented on a P&ID for a piping system. The reader must investigate further if more detail is required. In diagrams

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depicting three-phase systems, a small symbol may be placed to the side of the transformer primary and secondary to indicate the type of transformer windings that are used. Figure 16 (A) shows the most commonly used symbols to indicate how the phases are connected in three-phase windings. Figure 16 (B) illustrates examples of how these symbols appear in a three-phase single line diagram.

Figure 16 Three-Phase Symbols

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Electrical Diagra ms and Schematics Summary This chapter covered the common symbols used on electrical diagrams and schematics to represent the basic electrical components. Polarity on a transformer is defined by dots placed on the primary and secondary windings. On the primary side, the dot indicates current in; on the secondary, the dot indicates current out. Switches, relays, and interlocked equipment commonly use dashed lines or boxes to indicate the relationship between them and other components. Electrical components, such as relays, are drawn in the de-energized state unless otherwise noted on the diagram.

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ELECTRICAL WIRING DOE-HDBK-1016/1-93 AND SCHEMATIC DIAGRAM READING EXAMPLES


ELECTRICAL WIRING AND SCHEMATIC DIAGRAM READING EXAMPLES This chapter contains several examples that will help to build, through practice, on the knowledge gained in reading electrical wiring and schematic diagrams. 1.6

Given a sim ple electrical schematic and initial conditions, IDENTIFY the power sources and/or loads and their status (i.e., energized or deenergized).

Exa mples To aid in understanding the symbology and diagrams discussed in this module refer to Figure 17 and Figure 18. Then answer the questions asked about each. The answers for each example are given on the page following the questions. Referring to Figure 17: 1.

What type of diagram is it?

2.

What is the rating on the fuses protecting the motor controller circuit?

Refer to the number at the far left to locate the following lines.

3.

What is the component labeled ITDR in line 13?

4.

Which lines contain limit switches?

5.

Which lines contain pushbutton switches?

6.

How many contacts are operated from relay 8CR?

7.

What component is represented by the symbol on the far right of line 4?

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DOE-HDBK-1016/1-93 ELECTRICAL WIRING AND SCHEMATIC DIAGRAM READING EXAMPLES

Figure 17 Example 1

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Answers to questions on Figure 17. 1.

Schematic

2.

10 amps

3.

A time delay closing switch

4.

Lines 7, 9, 11, 12, 14, and 15

5.

Lines 3, 4, 5, 6, and 18

6.

4.

7.

A green lamp

Figure 18 Example 2

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Referring to Figure 18.

1.

What type of diagram is Figure 18?

2.

How many current transformers are in the diagram?

3.

What type of circuit breakers are shown?

4.

What is the voltage on the main bus?

5.

What is the voltage entering the transformer in the lower left corner?

6.

Classify the transformer in the upper left corner.

7.

What is the component in the lower left corner?

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Answers to questions on Figure 18. 1.

System diagram

2.

3. If you said 4, the one in the upper right is a potential transformer.

3.

Drawout type.

4.

4.16 kV or 4160 V.

5.

480 V.

6.

Delta primary, grounded wye secondary.

7.

(Emergency) diesel generator

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Electrical Wiring and Schematic Diagra m Reading Exa mple Summary This chapter reviewed the material presented in this module through the practice reading examples.

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DOE-HDBK-1016/2-93 JANUARY 1993

DOE FUNDAMENTALS HANDBOOK ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Volume 2 of 2

U.S. Department of Energy Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited.

FSC-6910

This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information, P.O. Box 62, Oak Ridge, TN 37831. Available to the public from the National Technical Information Services, U.S. Department of Commerce, 5285 Port Royal., Springfield, VA 22161. Order No. DE93012181


ABSTRACT The Engineering Sym bology, Prints, and Drawings Handbook was developed to assist nuclear facility operating contractors in providing operators, maintenance personnel, and technical staff with the necessary fundamentals training to ensure a basic understanding of engineering prints, their use, and their function. The handbook includes information on engineering fluid drawings and prints; piping and instrument drawings; major symbols and conventions; electronic diagrams and schematics; logic circuits and diagrams; and fabrication, construction, and architectural drawings. This information will provide personnel with a foundation for reading, interpreting, and using the engineering prints and drawings that are associated with various DOE nuclear facility operations and maintenance.

Key Words: Training Material, Print Reading, Piping and Instrument Drawings, Schematics, Electrical Diagrams, Block Diagrams, Logic Diagrams, Fabrication Drawings, Construction Drawings, Architectural Drawings

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FOREWORD The Departm ent of Energy (DOE) Fundam entals Handbooks consist of ten academic subjects, which include Mathematics; Classical Physics; Thermodynamics, Heat Transfer, and Fluid Flow; Instrumentation and Control; Electrical Science; Material Science; Mechanical Science; Chemistry; Engineering Symbology, Prints, and Drawings; and Nuclear Physics and Reactor Theory. The handbooks are provided as an aid to DOE nuclear facility contractors. These handbooks were first published as Reactor Operator Fundamentals Manuals in 1985 for use by DOE category A reactors. The subject areas, subject matter content, and level of detail of the Reactor Operator Fundamentals Manuals were determined from several sources. DOE Category A reactor training managers determined which materials should be included, and served as a primary reference in the initial development phase. Training guidelines from the commercial nuclear power industry, results of job and task analyses, and independent input from contractors and operations-oriented personnel were all considered and included to some degree in developing the text material and learning objectives. The DOE Fundam entals Handbooks represent the needs of various DOE nuclear facilities' fundamental training requirements. To increase their applicability to nonreactor nuclear facilities, the Reactor Operator Fundamentals Manual learning objectives were distributed to the Nuclear Facility Training Coordination Program Steering Committee for review and comment. To update their reactor-specific content, DOE Category A reactor training managers also reviewed and commented on the content. On the basis of feedback from these sources, information that applied to two or more DOE nuclear facilities was considered generic and was included. The final draft of each of the handbooks was then reviewed by these two groups. This approach has resulted in revised modular handbooks that contain sufficient detail such that each facility may adjust the content to fit their specific needs. Each handbook contains an abstract, a foreword, an overview, learning objectives, and text material, and is divided into modules so that content and order may be modified by individual DOE contractors to suit their specific training needs. Each handbook is supported by a separate examination bank with an answer key. The DOE Fundam entals Handbooks have been prepared for the Assistant Secretary for Nuclear Energy, Office of Nuclear Safety Policy and Standards, by the DOE Training Coordination Program. This program is managed by EG&G Idaho, Inc.

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OVERVIEW The Departm ent of Energy Fundam entals Handbook entitled Engineering Sym bology, Prints, and Drawings was prepared as an information resource for personnel who are responsible for the operation of the Department's nuclear facilities. A basic understanding of engineering prints and drawings is necessary for DOE nuclear facility operators, maintenance personnel, and the technical staff to safely operate and maintain the facility and facility support systems. The information in the handbook is presented to provide a foundation for applying engineering concepts to the job. This knowledge will improve personnel understanding of the impact that their actions may have on the safe and reliable operation of facility components and systems. The Engineering Sym bology, Prints, and Drawings handbook consists of six modules that are contained in two volumes. The following is a brief description of the information presented in each module of the handbook. Volume 1 of 2 Module 1 - Introduction to Print Reading This module introduces each type of drawing and its various formats. It also reviews the information contained in the non-drawing areas of a drawing. Module 2 - Engineering Fluid Diagrams and Prints This module introduces engineering fluid diagrams and prints (P&IDs); reviews the common symbols and conventions used on P&IDs; and provides several examples of how to read a P&ID. Module 3 - Electrical Diagrams and Schematics This module reviews the major symbols and conventions used on electrical schematics and single line drawings and provides several examples of reading electrical prints.

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OVERVIEW (Cont.)

Volume 2 of 2 Module 4 - Electronic Diagrams and Schematics This module reviews electronic schematics and block diagrams. It covers the major symbols used and provides several examples of reading these types of drawings. Module 5 - Logic Diagrams This module introduces the basic symbols and common conventions used on logic diagrams. It explains how logic prints are used to represent a component's control circuits. Truth tables are also briefly discusses and several examples of reading logic diagrams are provided. Module 6 - Engineering Fabrication, Construction, and Architectural Drawings This module reviews fabrication, construction, and architectural drawings and introduces the symbols and conventions used to dimension and tolerance these types of drawings. The information contained in this handbook is by no means all encompassing. An attempt to present the entire subject of engineering drawings would be impractical. However, the Engineering Sym bology, Prints, and Drawings handbook does present enough information to provide the reader with a fundamental knowledge level sufficient to understand the advanced theoretical concepts presented in other subject areas, and to improve understanding of basic system operation and equipment operations.

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ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Module 4 Electronic Diagrams and Schematics

Electronic Diagrams and Schematics

DOE-HDBK-1016/2-93

TABLE OF CONTENTS

TABLE OF CONTENTS

ii

LIST OF FIGURES

iii

LIST OF TABLES REFERENCES

iv

OBJECTIVES

v

ELECTRONIC DIAGRAMS AND SCHEMATICS

1

Introduction Electronic Schematic Drawing Symbology Examples of Electronic Schematic Diagrams Reading Electronic Prints, Diagrams, and Schematics Block Drawing Symbology Examples of Block Diagrams Summary EXAMPLES

18

Example 1 Example 2 Summary

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1 2 5 7 12 12 17

18 22 23

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DOE-HDBK-1016/2-93

LIST OF FIGURES


LIST OF FIGURES Figure 1 Electronic Symbols

3

Figure 2 Electronic Symbols (Continued)

4

Figure 3 Example of an Electronic Schematic Diagram

5

Figure 4 Comparison of an Electronic Schematic Diagram and its Pictorial Layout Diagram

6

Figure 5 Transformer Polarity Markings

7

Figure 6 Schematic Showing Power Supply Connections

8

Figure 7 NPN Transistor-Conducting

9

Figure 8 NPN Transistor-Nonconducting

9

Figure 9 PNP Transistor

10

Figure 10 Diode

10

Figure 11 Bistable Symbols

11

Figure 1 2 Example Blocks

12

Figure 1 3 Example Block Diagram

13

Figure 14 Example of a Combined Drawing, P&ID, Electrical Single Line, and Electronic Block Diagram . Figure 15 Example Combination Diagram of Electrical Single Line, and Block Diagram

16

Figure 16 Example 1

19

Figure 17 Example 2

22

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DOE-HDBK-1016/2-93

LIST OF TABLES

LIST OF TABLES NONE

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REFERENCES

DOE-HDBK-1016/2-93


REFERENCES ANSI Y14.5M - 1982, Dimensioning and Tolerancing, American National Standards Institute. ANSI Y32.2 -1975, Graphic Symbols for Electrical and Electronic Diagrams, American National Standards Institute. Gasperini, Richard E., Digital Troubleshooting, Movonics Company; Los Altos, California, 1976. Jensen - Helsel, Engineering Drawing and Design, Second Ed., McGraw-Hill Book Company, New York, 1979. Lenk, John D., Handbook of Logic Circuits, Reston Publishing Company, Reston, Virginia, 1972. Wickes, William E., Logic Design with Integrated Circuits, John Wiley & Sons Inc, 1968. Naval Auxiliary Machinery, United States Naval Institute, Annapolis, Maryland, 1951. TPC Training Systems, Reading Schematics and Symbols, Technical Publishing Company, Barrington, Illinois, 1974. Arnell, Alvin, Standard Graphica1 Symbols, McGraw-Hill Book Company, 1963. George Mashe, Systems Summary of a Westinghouse Pressurized Water Reactor, Westinghouse Electric Corporation, 1971. Zappe, R. W., Valve Selection Handbook, Gulf Publishing Company, Houston, Texas, 1968. .

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DOE-HDBK-1016/2-93

OBJECTIVES


Given a block diagram, print, or schematic, IDENTIFY the basic component symbols as presented in this module.

ENABLING OBJECTIVES

1.1

IDENTIFY the symbols used on engineering electronic block diagrams, prints, and schematics, for the following components. a. b. c. d. e. f. g. h. i. j. k. 1. m. n.

1.2

. . .

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Fixed resistor Variable resistor Tapped resistor Fixed capacitor Variable capacitor Fixed inductor Variable inductor Diode Light emitting diode (LED) Ammeter Voltmeter Wattmeter Chassis ground Circuit ground

o. p. q. r. s. t. u. v. w. x. y. z. aa. bb.

Fuse Plug Headset Light bulb Silicon controlled rectifier (SCR) Half wave rectifier Full wave rectifier Oscillator Potentiometer Rheostat Antenna Amplifier PNP and NPN transistors Junction

STATE the purpose of a block diagram and an electronic schematic diagram.

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DOE-HDBK-1016/2-93 ELECTRONIC DIAGRAMS, PRINTS, AND SCHEMATICS

ELECTRONIC DIAGRAMS, PRINTS, AND SCHEMATICS To read and understand an electronic diagram or electronic schematic, the basic symbols and conventions must be understood.

EO 1.1

IDENTIFY the symbols used on engineering electronic block diagrams, prints, and schematics, for the following components. a. b.

Fixed resistor Variable resistor c. Tapped resistor d. Fixed capacitor e. Variable capacitor f. Fixed inductor g. Variable inductor h. Diode i. Light emitting diode (LED) j. Ammeter k. Voltmeter l. Wattmeter m. Chassis ground EO 1.2

n. o. p. q. r. s. t. u. v. w. x. y. z. aa. bb.

Circuit ground Fuse Plug Headset Light bulb Silicon controlled rectifier (SCR) Half wave bridge rectifier Full wave rectifier Oscillator Potentiometer Rheostat Antenna Amplifier PNP and NPN transistors Junction

STATE the purpose of a block diagram and an electronic schematic diagram.

Introduction Electronic prints fall into two basic categories, electronic schematics and block diagrams. Electronic schematics represent the most detailed category of electronic drawings. They depict every component in a circuit, the component's technical information (such as its ratings), and how each component is wired into the circuit. Block diagrams are the simplest type of drawing. As the name implies, block diagrams represent any part, component, or system as a simple geometric shape, with each block capable of representing a single component (such as a relay) or an entire system. The intended use of the drawing dictates the level of detail provided by

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each block. This chapter will review the basic symbols and conventions used in both types of drawings.

Electronic Schematic Drawing Symbology Of all the different types of electronic drawings, electronic schematics provide the most detail and information about a circuit. Each electronic component in a given circuit will be depicted and in most cases its rating or other applicable component information will be provided. This type of drawing provides the level of information needed to troubleshoot electronic circuits. Electronic schematics are the most difficult type of drawing to read, because they require a very high level of knowledge as to how each of the electronic components affects, or is affected by, an electrical current. This chapter reviews only the symbols commonly used in depicting the many components in electronic systems. Once mastered, this knowledge should enable the reader to obtain a functional understanding of most electronic prints and schematics. Figure 1 and Figure 2 illustrate the most common electronic symbols used on electronic schematics.

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Figure 1 Electronic Symbols

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Figure 2 Electronic Symbols (Continued)


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Examples of Electronic Schematic Diagrams Electronic schematics use symbols for each component found in an electrical circuit, no matter how small. The schematics do not show placement or scale, merely function and flow. From this, the actual workings of a piece of electronic equipment can be determined. Figure 3 is an example of an electronic schematic diagram.

Figure 3 Example of an Electronic Schematic Diagram

A second type of electronic schematic diagram, the pictorial layout diagram, is actually not so much an electronic schematic as a pictorial of how the electronic circuit actually looks. These drawings show the actual layout of the components on the circuit board. This provides a two-dimensional drawing, usually looking down from the top, detailing the components in their location. Shown in Figure 4 is the schematic for a circuit and the same circuit drawn in pictorial or layout format for comparison. Normally the pictorial layout would be accompanied by a parts list.

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Figure 4 Comparison of an Electronic Schematic Diagram and its Pictorial Layout Diagram

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Reading Electronic Prints, Diagrams and Schematics To properly read prints and schematics, the reader must identify the condition of the components shown and also follow the events that occur as the circuit functions. As with electrical systems, the relays and contacts shown are always in the de-energized condition. Modern electronic systems usually contain few, if any, relays or contacts, so these will normally play a minor role. Electronic schematics are more difficult to read than electrical schematics, especially when solid state devices are used (The Electronic Science Fundamental Handbook discusses electrical schematics in detail). Knowledge of the workings of these devices is necessary to determine current flow. In this section, only the basics will be covered to assist in reading skills. The first observation in dealing with a detailed electronic schematic is the source and polarity of power. Generally, power will be shown one of two ways, either as an input transformer, or as a numerical value. When power is supplied by a transformer, polarity marks will aid in determining current flow. In this convention, dots on the primary and secondary indicate current flow into the primary and out of the secondary at a given instant of time. In Figure 5, the current is into the top of the primary and out of the bottom of the secondary.

PRIMARY

SECONDARY

Figure 5 Transformer Polarity Markings

Generally, the electrical power source is indicated at the point where it enters a particular schematic. These values are stated numerically with polarity assigned (+15 volts, -15 volts). These markings are usually at the top and bottom of schematics, but not always. In the example shown in Figure 6, power is shown at both the top and bottom in a circuit using two power sources. Unless specified as an Alternating Current (AC) power source, the voltages can normally be assumed to be Direct Current (DC).

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Figure 6 Schematic Showing Power Supply Connections

In any circuit, a ground must be established to create a complete current path. Ground is usually depicted by the use of the ground symbol that was shown previously. The direction of current flow can be determined by observing the polarity of the power supplies. When polarities are shown, current flow can be established and ground may not always be shown. With the power sources located and the ground point established, operation of the devices can be determined. The most common semiconductor devices are the transistor and the diode. They are made from materials like silicone and germanium, and have electrical properties intermediate between conductors and insulators. The semiconductor will be one of two varieties, the PNP or NPN. The designation indicates the direction the electrons move through the device. The direction of

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the arrow indicates type, as shown in Figure 2. There are, however, many different ways to install a transistor to achieve different operational characteristics. These are too numerous to cover here, so only the most common and basic configuration (the common emitter) will be shown. Even though transistors contain multiple junctions of p- or n-type material, current flow is generally in the same direction. Using conventional current flow (i.e. from + to -), current will travel through the transistor from most positive to least positive and in the direction of the arrow on the emitter. In Figure 7, the transistor has a positive power supply with ground on the emitter. If the input is also positive, the transistor will conduct.

Figure 7 NPN Transistor-Conducting

If the input goes negative, as in Figure 8, the conduction of the device stops because the input, or in this case the base junction, controls the transistor condition. Notice that when current flows, it does so in the direction of the arrow.

Figure 8 NPN Transistor-Nonconducting

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Figure 9 uses a PNP transistor. The same rules apply as above except that this time polarities of power must change to allow current flow.

Figure 9 PNP Transistor

The same rules that apply to transistors hold true with diodes. However, diodes are simpler than transistors because they have only one junction and conduct in only one direction, as indicated in Figure 10. The diode symbol, like the transistor symbol, shows the direction of conduction by the direction of the arrow, which is from positive to negative.

Figure 10 Diode

Although these simple rules will not allow you to read all electronic schematics, they will aid in understanding some of the basic concepts.

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An item that may cause confusion when reading electronic prints or schematics is the markings used to show bistable operation. In most cases, bistables will be indicated by a box or circle, as shown in Figure 11 (A). The lines in or around these bistables not only mark them as bistables, but also indicate how they function.

Figure 11 Bistable Symbols

Figure 11 (B) shows the various conventions used to indicate bistable operation. Commonly, one circuit will interface with other circuits, which requires a method that allows the reader to follow one wire or signal path from the first drawing to the second. This may be done in many ways, but generally the line or conductor to be continued will end at a terminal board. This board will be labeled and numbered with the continuation drawing indicated (a separate drawing may exist for each line). With the next drawing in hand, only the terminal board that matches the previous number needs to be found to continue. In cases where terminal boards are not used, the conductor should end with a number (usually a single digit) and also the next drawing number. To assist in locating the continuation, coordinates are provided on some drawings that indicate the location of the continuation on the second drawing. The continuation point on the second drawing will also reference back to the first drawing and the coordinates of the continuation.

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Block Drawing Symbology Not all electronics prints are drawn to the level of detail depicting the individual resistors and capacitors, nor is this level of information always necessary. These simpler drawings are called block diagrams. Block diagrams provide a means of representing any type of electronic circuit or system in a simple graphic format. Block diagrams are designed to present flow or functional information about the circuit or system, not detailed component data. The symbols shown in Figure 12 are used in block diagrams.

Figure 12 Example Blocks

When block diagrams are used, the basic blocks shown above (Figure 12) can be used for almost anything. Whatever the block represents will be written inside. Note that block diagrams are presented in this chapter with electronic schematics because block diagrams are commonly found with complex schematic diagrams to help present or summarize their flow or functional information. The use of block diagrams is not restricted to electronic circuits. Block diagrams are used extensively to show complex instrument channels and other complex systems when only the flowpath of the signal is important.

Examples of Block Diagrams The block diagram is the most basic and easiest to understand of all the types of engineering prints. It consists of simple blocks that can represent as much, or as little, as desired. An example of a block diagram is shown in Figure 13. This particular block diagram represents an instrumentation channel used to measure the neutron flux, indicate the measured flux, and generate output signals for use by other systems.

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Figure 13 Example Block Diagram

Each block represents a stage in the development of a signal that is used to display on the meter at the bottom or to send to systems outside the bounds of the drawing. Notice that not all blocks are equal. Some represent multiple functions, while others represent only a simple stage or single bistable circuit in a larger component. The creator of the block diagram decides the content of each block based on the intended use of the drawing. Each of the type of drawing reviewed in this and previous modules is not always distinct and separate. In many cases, two or more types of drawings will be combined into a single print. This allows the necessary information to be presented in a clear and concise format.

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Figure 14 provides a sample illustration of how the various types of drawings can be combined. In this example, mechanical symbols are used to represent the process system and the valves controlled by the electrical circuit; electrical single line symbols are used to show the solenoid relays and contacts used in the system; and electronic block symbols are used for the controllers, summers, I/P converter, and bistables.

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Figure 15 illustrates the use of an electronic block diagram combined with an electrical single line diagram. This drawing represents a portion of the generator protection circuitry of a nuclear power generating plant.

Figure 15 Example Combination Diagram of Electrical Single Line, and Block Diagram

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Electronic Diagrams, Prints, and Schematics Summary This chapter covered the common symbols used to represent the basic electronic components used on electronic diagrams, prints, and schematics. A block diagram presents the flow or functional information about a circuit, but it is not a detailed depiction of the circuit. An electronic schematic diagram presents the detailed information about the circuit, each of its components, and how they are wired into the circuit.

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EXAMPLES This chapter provides several exercises to reinforce the material presented in this module.

Example 1 To assist in your understanding of reading symbols and schematics, answer the following questions concerning the following figures. The answers to each example are given on the page following the questions.

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EXAMPLES

Figure 16 Example 1

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Refer to Figure 16 to answer the following:

1.

List the number which corresponds to the listed component. a. b. c. d. e. f. g. h. . i. j. k.

coil or inductor PNP transistor diode positive power supply fixed resistor capacitor NPN transistor variable resistor negative power supply circuit ground potentiometer

2.

What is the value of R13? (Include units)

3.

With the input to Q1 at -15 volts, will the transistor be conducting or nonconducting? Why?

4.

What is the value of C1? (Include units)

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EXAMPLES

Answers to questions on Figure 16 g.1 h.6 i.8

j. 11 k. 5

1.

a.10 b.2 c.3

2.

3.3 kilo-ohm, or 3300 ohms.

3.

Nonconducting, because the potential of the base (-15 v) is not positive relative to the emitter (-15 v).

4.

50 microfarads or 0.000050 farads.

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Example 2

Figure 17 Example 2

Refer to Figure 17 to answer the following: a.

How many resistors are there in the circuit?

b.

How many transistors are there?

c.

What is CR4?

d.

How many power supplies are there feeding the circuit and its components?

e.

How many capacitors are in the circuit?

f.

Q2 will conduct when the output of U2 is a positive or negative voltage?

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, and are they PNP or NPN transistors?

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EXAMPLES

Answers to questions on Figure 17 a.

Seven resistors, R11, R13, R14, R20, R12, Rl, RL

b.

Two, both are NPN type transistors.

c.

Diode

d.

Two power supplies, a 1-5 VDC to the U2 amplifier and 24 VDC battery in the circuit.

e.

One, C7

f.

NPN transistors conduct when their base junction is positive


Exercise Summary This chapter reviewed the material presented in this module through practice print reading exercises.

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TABLE OF CONTENTS


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OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ENGINEERING LOGIC DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Introduction . . . . . . . . Symbology . . . . . . . . . Time Delays . . . . . . . . Complex Logic Devices Summary . . . . . . . . . .

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TRUTH TABLES AND EXERCISES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Truth Tables . Reading Logic Examples . . . Example 1 . . Example 2 . . Summary . . .

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LIST OF FIGURES

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Logic Diagrams

LIST OF FIGURES Figure 1 Example of a Pump Start Circuit Schematic Diagram . . . . . . . . . . . . . . . . . . . . 2 Figure 2 Example of Pump Start Circuit as a Logic Diagram . . . . . . . . . . . . . . . . . . . . . 3 Figure 3 Basic Logic Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 4 Conventions for Depicting Multiple Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 5 COINCIDENCE Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 6 EXCLUSIVE OR and EXCLUSIVE NOR Gates . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 7 Type One Time Delay Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 8 Type Two Time Delay Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 9 Type Three Time Delay Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 10 Symbols for Complex Logic Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 11 Truth Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 12 Logic Gate Status Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 13 Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 14 Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

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LIST OF TABLES

LIST OF TABLES NONE

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REFERENCES

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OBJECTIVES


Given a logic diagram, READ and INTERPRET the diagrams.


IDENTIFY the symbols used on logic diagrams to represent the following components: a. b. c. d. e. f. g.

AND gate NAND gate COINCIDENCE gate OR gate NOR gate EXCLUSIVE OR gate NOT gate or inverter

h. i. j. k. l. m.

Adder Time-delay Counter Shift register Flip-flop Logic memories

1.2

EXPLAIN the operation of the three types of time delay devices.

1.3

DEVELOP the truth tables for the following logic gates: a. b. c.

AND gate OR gate NOT gate

d. e. f.

NAND gate NOR gate EXCLUSIVE OR gate

1.4

IDENTIFY the symbols used to denote a logical 1 (or high) and a logical 0 (or low) as used in logic diagrams.

1.5

Given a logic diagram and appropriate information, DETERMINE the output of each component and the logic circuit.

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ENGINEERING LOGIC DIAGRAMS

ENGINEERING LOGIC DIAGRAMS This chapter will review the symbols and conventions used on logic diagrams.

EO 1.1

IDENTIFY the symbols used on logic diagrams to represent the following components: a. b. c. d. e. f. g.

EO 1.2

AND gate NAND gate COINCIDENCE gate OR gate NOR gate EXCLUSIVE OR gate NOT gate or inverter

h. i. j. k. l. m.

Adder Time-delay Counter Shift register Flip-flop Logic memories

EXPLAIN the operation of the three types of time delay devices.

Introduction Logic diagrams have many uses. In the solid state industry, they are used as the principal diagram for the design of solid state components such as computer chips. They are used by mathematicians to help solve logical problems (called boolean algebra). However, their principle application at DOE facilities is their ability to present component and system operational information. The use of logic symbology results in a diagram that allows the user to determine the operation of a given component or system as the various input signals change. To read and interpret logic diagrams, the reader must understand what each of the specialized symbols represent. This chapter discusses the common symbols used on logic diagrams. When mastered, this knowledge should enable the reader to understand most logic diagrams. Facility operators and technical staff personnel commonly see logic symbols on equipment diagrams. The logic symbols, called gates, depict the operation/start/stop circuits of components and systems. The following two figures, which use a common facility start/stop pump circuit as an example, clearly demonstrate the reasons for learning to read logic diagrams. Figure 1 presents a schematic for a large pump, and Figure 2 shows the same pump circuit using only logic gates. It is obvious that when the basic logic symbols are understood, figuring out how the pump operates and how it will respond to various combinations of inputs using the logic diagram is fast and easy, as compared to laboriously tracing through the relays and contacts of the schematic diagram for the same information.

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Figure 1 Example of a Pump Start Circuit Schematic Diagram


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Figure 2 Example of Figure 1 Pump Start Circuit as a Logic Diagram

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Symbology There are three basic types of logic gates. They are AND, OR, and NOT gates. Each gate is a very simple device that only has two states, on and off. The states of a gate are also commonly referred to as high or low, 1 or 0, or True or False, where on = high = 1 = True, and off = low = 0 = False. The state of the gate, also referred to as its output, is determined by the status of the inputs to the gate, with each type of gate responding differently to the various possible combinations of inputs. Specifically, these combinations are as follows. AND gate - provides an output (on) when all its inputs are on. When any one of the inputs is off, the gate's output is off. OR gate - provides an output (on) when any one or more of its inputs is on. The gate is off only when all of its inputs are off. NOT gate - provides a reversal of the input. If the input is on, the output will be off. If the input is off, the output will be on. Because the NOT gate is frequently used in conjunction with AND and OR gates, special symbols have been developed to represent these combinations. The combination of an AND gate and a NOT gate is called a NAND gate. The combination of an OR gate with a NOT gate is called a NOR gate. NAND gate - is the opposite (NOT) of an AND gate's output. It provides an output (on) except when all the inputs are on. NOR gate - is the opposite (NOT) of an OR gate's output. It provides an output only when all inputs are off. Figure 3 illustrates the symbols covering the three basic logic gates plus NAND and NOR gates. The IEEE/ANSI symbols are used most often; however, other symbol conventions are provided on Figure 3 for information.

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Figure 3 Basic Logic Symbols

The AND gate has a common variation called a COINCIDENCE gate. Logic gates are not limited to two inputs. Theoretically, there is no limit to the number of inputs a gate can have. But, as the number of inputs increases, the symbol must be altered to accommodate the increased inputs. There are two basic ways to show multiple inputs. Figure 4 demonstrates both methods, using an OR gate as an example. The symbols used in Figure 4 are used extensively in computer logic diagrams. Process control logic diagrams usually use the symbology shown in Figure 2.

Figure 4 Conventions for Depicting Multiple Inputs

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The COINCIDENCE gate behaves like an AND gate except that only a specific number of the total number of inputs needs to be on for the gate's output to be on. The symbol for a COINCIDENCE gate is shown in Figure 5. The fraction in the logic symbol indicates that the AND gate is a COINCIDENCE gate. The numerator of the fraction indicates the number of inputs that must be on for the gate to be on. The denominator states the total number of inputs to the gate. Two variations of the OR gate are the EXCLUSIVE OR and its opposite, the EXCLUSIVE NOR. The EXCLUSIVE OR and the EXCLUSIVE NOR are symbolized by adding a line on the back of the standard OR or NOR gate's symbol, as illustrated in Figure 6.

Figure 5 COINCIDENCE Gate

EXCLUSIVE OR - provides an output (on) when only one of the inputs is on. Any other combination results in no output (off). EXCLUSIVE NOR - is the opposite (NOT) of an EXCLUSIVE OR gate's output. It provides an output only when all inputs are on or when all inputs are off.

Figure 6 EXCLUSIVE OR and EXCLUSIVE NOR Gates

Time Delays When logic diagrams are used to represent start/stop/operate circuits, the diagrams must also be able to symbolize the various timing devices found in the actual circuits. There are three major types of timers. They are 1) the Type-One Time Delay Device, 2) the Type-Two Time Delay Device, and 3) The Type-Three Time Delay Device.

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Upon receipt of the input signal, the Type-One Time Delay Device delays the output (on) for the specified period of time, but the output will stop (off) as soon as the input signal is removed, as illustrated by Figure 7. The symbol for this type of timer is illustrated in Figure 7.

Figure 7 Type One Time Delay Device

The Type-Two Time Delay Device provides an output signal (on) immediately upon reciept of the input signal, but the output is maintained only for a specified period of time once the input signal (off) has been removed. Figure 8 demonstrates the signal response, and Figure 8 illustrates the symbol used to denote this type of timer.

Figure 8 Type Two Time Delay Device

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Upon reciept of an input signal, Type-Three Time Delay Devices provide an output signal for a specified period of time, regardless of the duration of the input. Figure 9 demonstrates the signal response and illustrates the symbol used to denote the timer.

Figure 9 Type-Three Time Delay Device

Complex Logic Devices In addition to the seven basic logic gates, there are several complex logic devices that may be encountered in the use of logic prints. Memory devices - In many circuits, a device that can "remember" the last command or the last position is required for a circuit to function. Like the AND and OR gates, memory devices have been designed to work with on/off signals. The two input signals to a memory device are called set and reset. Figure 10 shows the common symbols used for memory devices.

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Figure 10 Symbols for Complex Logic Devices

Flop-flop - As the name implies, a flip-flop is a device in which as one or more of its inputs changes, the output changes. A flip-flop is a complex circuit constructed from OR and NOT gates, but is used so frequently in complex circuits that it has its own symbol. Figure 10 shows the common symbol used for a flip-flop.

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This device, although occasionally used on component and system type logic diagrams, is principally used in solid state logic diagrams (computers). Binary counter - Several types of binary counters exist, all of which are constructed of flip-flops. The purpose of a counter is to allow a computer to count higher than 1, which is the highest number a single flip-flop can represent. By ganging flip-flops, higher binary numbers can be constructed. Figure 10 illustrates a common symbol used for a binary counter. Shift register - Is a storage device constructed of flip-flops that is used in computers to provide temporary storage of a binary word. Figure 10 shows the common symbol used for a shift register. Half adder - Is a logic circuit that is used in computer circuits to allow the computer to "carry" numbers when it is performing mathematical operations (for example to perform the addition of 9 + 2, a single 10s unit must be "carried" from the ones column to the tens column). Figure 10 illustrates the symbol used for a half adder.


Engineering Logic Diagrams Summary This chapter reviewed the seven basic symbols used on logic diagrams and the symbols used for six of the more complex logic devices. There are three types of time delay devices: Type One - delays the output signal for a specified period of time Type Two - only generates an output for the specified period of time Type Three - receipt of an input signal triggers the device to output a signal for the specified time, regardless of the duration of the input

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TRUTH TABLES AND EXERCISES

TRUTH TABLES AND EXERCISES Truth tables offer a simple and easy to understand tool that can be used to determine the output of any logic gate or circuit for all input combinations.

EO 1.3

DEVELOP the truth tables for the following logic gates: a. b. c.

AND gate OR gate NOT gate

d. e. f.

NAND gate NOR gate EXCLUSIVE OR gate

EO 1.4

IDENTIFY the symbols used to denote a logical 1 (or high) and a logical 0 (or low) as used in logic diagrams.

EO 1.5

Given a logic diagram and appropriate information, DETERMINE the output of each component and the logic circuit.

Truth Tables When a logic gate has only two inputs, or the logic circuit to be analyzed has only one or two gates, it is fairly easy to remember how a specific gate responds and determine the output of the gate or circuit. But as the number of inputs and/or the complexity of the circuit grows, it becomes more difficult to determine the output of the gate or circuit. Truth tables, as illustrated in Figure 11, are tools designed to help solve this problem. A truth table has a column for the input of each gate and column for the output of each gate. The number of rows needed is based on the number of inputs, so that every combination of input signal is listed (mathematically the number of rows is 2n, where n = number of inputs). In truth tables, the on and off status of the inputs and outputs is represented using 0s and 1s. As previously stated 0 = off and 1 = on. Figure 11 lists truth tables for the seven basic logic gates. Compare each gate's truth table with its definition given earlier in this module, and verify for yourself that they are stating the same thing.

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Figure 11 Truth Tables

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Reading Logic Diagrams When reading logic prints the reader usually must decide the input values to each gate. But occasionally the print will provide information as to the normal state of each logic gate. This is denoted by a symbol similar to the bistable symbol, as shown in Figure 12. The symbol is drawn so that the first part of the square wave indicates the normal state of the gate. The second part of the square wave indicates the off-normal state of the gate. Figure 12 also illustrates how this notation is applied.

Figure 12 Logic Gate Status Notation

Reading a logic diagram that does not provide information on the status of the gates is not any more difficult. It simply requires the reader to choose the initial conditions, determine the response of the circuits, and modify the inputs as needed. The following exercises will illustrate how to read some simple logic diagrams.

Examples To aid in understanding the material presented in this module, practice reading the following logic diagrams by answering the questions. The answers are on page 18.

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Example 1 Refer to Figure 13 to answer the following questions. Figure 13 illustrates a logic diagram of a simple fan start circuit.

Figure 13 Example 1

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1.

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Identify by number the following logic symbols: a.

AND

b.

OR

c.

Time delay

d.

Retentive-Memory

2.

How long must the safety signal be present before the time delay (1) will pass an output (on) signal to Gate 2?

3.

Under what conditions will Gate 2 turn on?

4.

Under what conditions will the low flow alarm (5) sound?

5.

Since the control switch is always in the AUTO position (due to the spring return feature), what logic gate keeps the continuous on signal that is generated by the control switch being in the AUTO position from starting the fan? What signal must also be present to allow the AUTO signal to start the fan?

6.

If 12 minutes after first receiving a safety signal, with the fan control switch in the AUTO position, the safety signal is removed (off), what will happen to the fan? Why?

7.

How many ways can the fan be started? How many ways can the fan be stopped?

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Example 2 Refer to Figure 14 to answer the following questions. Figure 14 illustrates a simple valve control circuit. Flow control valve (FCV) 1-147 is an air-operated valve, with its air controlled by flow solenoid valve (FSV) 1-147, which is shown in its de-energized position.

Figure 14 Example 2

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Identify by number the following logic symbols. a.

AND

b.

OR

c.

NOT

2.

As drawn, with the hand switch in the AUTO position and no safety signal present, what is the status of the two inputs to Gate 4, on or off?

3.

Since electrical components are drawn in their de-energized state, and using the answer from Question 2, is the flow solenoid valve (FSV-1-147) in its correct position? Why?

4.

How many ways can FSV-1-147 be energized? De-energized?

5.

If a safety signal is present, can FCV-1-147 (valve FSV-1-147 energized) be opened? Why?

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Answers to example 1. 1.

a. b. c. d.

2 3 1 4

2.

The safety signal must be received for greater than 10 minutes before it will pass through the time delay. If the safety signal is removed before 10 minutes has elapsed no signal will be passed to Gate 2.

3.

Gate 2 will turn on when the hand-switch is in the AUTO position and a safety signal has been received for greater than 10 minutes.

4.

If flow switch (FS) 30-38 senses less than 20,000 cfm, 45 seconds after the fan has started, or the same condition exists on the 1B-B fan, the alarm will sound.

5.

AND Gate 2 prevents the on signal from passing until a safety signal is also received (>10 minutes).

6.

Ten minutes after receiving the safety signal, the fan started. At 12 minutes, removing the safety signal only removes the continuous start signal to the fan. The fan will continue to run until the hand switch is placed in the stop position. Further, with the removal of the safety signal, the fan will remain stopped when the hand switch spring returns to the AUTO position. Note that if the hand switch is placed in the stop position while the safety signal is present, the fan will stop, but will restart as soon as the switch spring returns to the AUTO position.

7.

It can be started by two signals - START and AUTO plus a safety signal. It can be stopped by one signal - STOP (but will only remain stopped if no safety signal is present or the switch is held in the stopped position).

Answers to example number 2. 1.

a. 1 & 4 b. 2 c. 3

2.

Right input is - on - this is because the hand control switch is in the AUTO position, and the AUTO switch contacts are made up, resulting in an on signal. Therefore the handswitch CLOSE position contacts are open, resulting in an off signal. The off signal is reversed in the NOT gate and becomes an on signal.

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Left input is - off -. To determine this, the status of the gates feeding the left input must be determined. Looking at the OR gate (2) above it The right input to the OR gate is - off - because the hand control switch is in the AUTO position. The OPEN position contacts are not made up, resulting in an off signal. The left input to the OR gate comes from the AND gate (1) above it. Looking at the three inputs to the AND gate. The bottom input is - on - because the hand control switch is in the AUTO position and the AUTO contacts are made up, resulting in an on signal. The middle input to the AND gate is - on - because the NOT gate reverses the off safety signal. The top input is - off - because the valve is not fully open, resulting in the generation of an off signal. Note this is the signal that, once the valve has traveled to the fully open position, allows the valve to remain open after the hand switch is allowed to spring return to the AUTO position. Now that all the inputs are known, we can work back through the circuit to determine the status of the left input to the AND gate (4). Because the one input, the top, to the AND gate (1) is off, the output of the AND gate is off. Therefore, the left input into the OR gate (2) is off. Therefore, because both the left and right inputs to the OR gate (2) are off the output of the OR gate (1) is off. 3.

Yes, de-energized is correct because the left input of the AND gate (4) is off and its right input is on. But because it is an AND gate and both its inputs are not on, it will not pass an on signal to the solenoid to energize it.

4.

It can be energized one way - the hand switch can be momentarily placed in the OPEN position. It can be de-energized two ways - the hand switch can be placed in the CLOSE position, or, if the valve is open and a safety signal is received, the valve will automatically close.

5.

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Yes, the valve can be opened, but it will not remain open when the hand switch is allowed to spring return to the AUTO position. This is because the safety signal's NOT gate removes the on signal that allows the AND gate (1) to output an on signal and energize the solenoid.

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Truth Tables and Exercises Summary The normal and off-normal status of each logic gate can be symbolized by the use of a symbol similar to the bistable. The first part of the square wave indicates the normal state of the gate. The second part of the square wave indicates the off-normal state of the gate. This chapter presented the truth tables for each of the seven basic logic gates. This chapter reviewed several examples of how to read logic diagrams of simple pump and valve circuits.

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ENGINEERING SYMBOLOGY, PRINTS, AND DRAWINGS Module 6 Engineering Fabrication, Construction, and Architectural Drawings

DOE-HDBK-1016/2-93 Engineering Fabrication, Construction, and Architectural Drawings

TABLE OF CONTENTS


iv

OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dimensioning Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dimensioning and Tolerance Symbology, Rules, and Conventions Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWING, EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Examples . Example 1 Example 2 Example 3 Summary .

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LIST OF FIGURES


LIST OF FIGURES Figure 1 Example of a Fabrication Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Figure 2 Example of a Construction Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Figure 3 Example of an Architectural Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 4 Types of Dimensioning Lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 5 Example of Dimensioning Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 6 Symbology Used in Tolerancing Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Figure 7 Examples of Tolerance Symbology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 8 Example of Tolerancing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 9 Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Figure 10 Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 11 Example 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

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LIST OF TABLES

LIST OF TABLES NONE

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REFERENCES



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OBJECTIVES


Given an engineering fabrication, construction, or architectural drawing, READ and INTERPRET basic dimensional and tolerance symbology, and basic fabrication, construction, or architectural symbology.


STATE the purpose of engineering fabrication, construction, and architectural drawings.

1.2

Given an engineering fabrication, construction, or architectural drawing, DETERMINE the specified dimensions of an object.

1.3

Given an engineering fabrication, construction, or architectural drawing, DETERMINE the maximum and minimum dimensions or location of an object or feature from the stated drawing tolerance.

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Engineering Fabrication, Construction, and Architectural Drawings

DOE-HDBK-1016/2-93 ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWINGS

ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWINGS This chapter describes the basic symbology used in the dimensions and tolerances of engineering fabrication, construction, and architectural drawings. Knowledge of this information will make these types of prints easier to read and understand.

EO 1.1

STATE the purpose of engineering fabrication, construction, and architectural drawings.

EO 1.2

Given an engineering fabrication, construction, or architectural drawing, DETERMINE the specified dimensions of an object.

EO 1.3

Given an engineering fabrication, construction, or architectural drawing, DETERMINE the maximum and minimum dimensions or location of an object or feature from the stated drawing tolerance.

Introduction This chapter will describe engineering fabrication, construction, and architectural drawings. These three types of drawings represent the category of drawings commonly referred to as blueprints. Fabrication, construction, and architectural drawings differ from P&IDs, electrical prints, and logic diagrams in that they are drawn to scale and provide the component's physical dimensions so that the part, component, or structure can be manufactured or assembled. Although fabrication and construction drawings are presented as separate categories, both supply information about the manufacture or assembly of a component or structure. The only real difference between the two is the subject matter. A fabrication drawing provides information on how a single part is machined or fabricated in a machine shop, whereas a construction drawing provides the construction or assembly of large multi-component structures or systems. Fabrication drawings, also called machine drawings, are principally found in and around machine and fabrication shops where the actual machine work is performed. The drawing usually depicts the part or component as an orthographic projection (see module 1 for definition) with each view containing the necessary dimensions. Figure 1 is an example of a fabrication drawing. In this case, the drawing is a centering rest that is used to support material as it is being machined.

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DOE-HDBK-1016/2-93 ENGINEERING FABRICATION, CONSTRUCTION, Engineering Fabrication, AND ARCHITECTURAL DRAWINGS Construction, and Architectural Drawings

Figure 1 Example of a Fabrication Drawing

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Construction drawings are found principally at sites where the construction of a structure or system is being performed. These drawings usually depict each structure/system or portion of a structure/system as an orthographic projection with each view containing the necessary dimensions required for assembly. Figure 2 provides an example of a construction print for a section of a steel roof truss.

Figure 2 Example of a Construction Drawing

Architectural drawings are used by architects in the conceptual design of buildings and structures. These drawings do not provide detailed information on how the structure or building is to be built, but rather they provide information on how the designer wants the building to appear and how it will function. Examples of this are location-size-type of doors, windows, rooms, flow of people, storage areas, and location of equipment. These drawings can be presented in several formats, including orthographic, isometric, plan, elevation, or perspective. Figure 3 provides an example of an architectural drawing, of a county library.

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Figure 3 Example of an Architectural Drawing

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Dimensioning Drawings For any engineering fabrication, construction, or architectural drawing to be of value, exact information concerning the various dimensions and their tolerances must be provided by the drawing. Drawings usually denote dimensions and tolerances per the American National Standards Institute (ANSI) standards. These standards are explained in detail in Dimensioning and Tolerancing, ANSI Y14.5M - 1982. This section will review the basic methods of denoting dimensions and tolerances on drawings per the ANSI standards. Dimensions on a drawing can be expressed in one of two ways. In the first method, the drawing is drafted to scale and any measurement is obtained by measuring the drawing and correcting for the scale. In the second method, the actual dimensions of the component are specified on the drawing. The second method is the preferred method because it reduces the chances of error and allows greater accuracy and drawing flexibility. Because even the simplest component has several dimensions that must be stated (and each dimension must have a tolerance), a drawing can quickly become cluttered with dimensions. To reduce this problem, the ANSI standards provide rules and conventions for dimensioning a drawing. The basic rules and conventions must be understood before a dimensioned drawing can be correctly read.

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Dimensioning and Tolerance Symbology, Rules, and Conventions When actual dimensions are specified on a print, the basic line symbols that are illustrated by Figure 4 are used.

Figure 4 Types of Dimensioning Lines

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Figure 5 provides examples of the various methods used on drawings to indicate linear, circular and angular dimensions.

Figure 5 Example of Dimensioning Notation

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When a drawing is dimensioned, each dimension must have a tolerance. In many cases, the tolerance is not stated, but is set to an implied standard. An example is the blueprint for a house. The measurements are not usually given stated tolerances, but it is implied that the carpenter will build the building to the normal tolerances of his trade (1/8-1/4 inch), and the design and use of the blueprints allow for this kind of error. Another method of expressing tolerances on a drawing is to state in the title block, or in a note, a global tolerance for all measurements on the drawing. The last method is to state the tolerance for a specified dimension with the measurement. This method is usually used in conjunction with one of the other two tolerancing methods. This type of notation is commonly used for a dimension that requires a higher level of accuracy than the remainder of the drawing. Figure 6 provides several examples of how this type of tolerancing notation can appear on a drawing. Tolerances are applied to more than just linear dimensions, such as 1 + 0.1 inches. They can apply to any dimension, including the radius, the degree of out-of-round, the allowable out-ofsquare, the surface condition, or any other parameter that effects the shape and size of the object. These types of tolerances are called geometric tolerances. Geometric tolerances state the maximum allowable variation of a form or its position from the perfect geometry implied on the drawing. The term geometry refers to various forms, such as a plane, a cylinder, a cone, a square, or a hexagon. Theoretically these are perfect forms, but because it is impossible to produce perfect forms, it may be necessary to specify the amount of variation permitted. These tolerances specify either the diameter or the width of a tolerance zone within which a surface or the axis of a cylinder or a hole must be if the part is to meet the required accuracy for proper function and fit. The methods of indicating geometric tolerances by means of geometric characteristic symbols are shown in Figure 6. Examples of tolerance symbology are shown in Figure 7.

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Figure 6 Symbology Used in Tolerancing Drawings

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Figure 7 Examples of Tolerance Symbology

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Because tolerances allow a part or the placement of a part or feature to vary or have a range, all of an object's dimensions can not be specified. This allows the unspecified, and therefor nontoleranced, dimension to absorb the errors in the critical dimensions. As illustrated in Figure 8 (A) for example, all of the internal dimensions plus each dimension's maximum tolerance adds up to more than the specified overall dimension and its maximum tolerance. In this case the length of each step plus its maximum tolerance is 1 1/10 inches, for a maximum object length of 3 3/10 inches. However the drawing also specifies that the total length of the object cannot exceed 3 1/10 inches. A drawing dimensioned in this manner is not correct, and one of the following changes must be made if the part is to be correctly manufactured. To prevent this type of conflict, the designer must either specify different tolerances for each of the dimensions so that the length of each smaller dimension plus its maximum error adds up to a value within the overall dimension plus its tolerance, or leave one of the dimensions off, as illustrated in Figure 8 (B) (the preferred method).

Figure 8 Example of Tolerancing

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Engineering Fabrication, Construction, and Architectural Drawings Summary The purpose of a fabrication drawing is to provide the information necessary to manufacture and machine components. The purpose of construction drawings is to provide the information necessary to build and assemble structures and systems. The purpose of architectural drawings is to provide conceptual information about buildings and structures. This chapter reviewed the basic symbology used in dimensioning engineering fabrication, construction, and architectural drawings.

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DOE-HDBK-1016/2-93 ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWINGS, EXAMPLES

ENGINEERING FABRICATION, CONSTRUCTION, AND ARCHITECTURAL DRAWING, EXAMPLES The information presented in the previous chapter is reviewed in this chapter through the performance of reading drawing examples.

Examples To aid in understanding the material presented in this module, practice reading the following prints by answering the questions. The answers are on the page following the last example.

Example 1

Figure 9 Example 1

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DOE-HDBK-1016/2-93 ENGINEERING FABRICATION, CONSTRUCTION, Engineering Fabrication, AND ARCHITECTURAL DRAWINGS, EXAMPLES Construction, and Architectural Drawings

1.

What is the overall height of the structure?

2.

What is the width (front-to-back) of the structure?

3.

What is the difference between the width (front-to-back) and the width (side-to-side) of the base of the structure?

Example 2

Figure 10 Example 2

1.

What is the geometric characteristic being given a tolerance?

2.

What is the maximum diameter of the shaft?

3.

What is the minimum diameter of the shaft?

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Example 3

Figure 11 Example 3

1.

What is the geometric characteristic being given a tolerance?

2.

What is the maximum length of the cylinder?

3.

What is the minimum length of the cylinder?

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5' 6"

2.

4' 1"

3.

9" (4' 10" side-to-side distance - 4' 1" front-to-back distance)


Using Figure 6, the straight line in the geometric characteristic box indicates "straightness." This implies that the surface must be straight to with in 0.02 inches.

2.

16.00 inches

3.

15.89 inches


Using Figure 6, the circle with two parallel bars in the geometric characteristic box indicates "Cylindricity," or how close to being a perfect cylinder it must be (in this case 0.25 inches).

2.

4.15 inches. The nominal length of 4.1 plus the tolerance of 0.05.

3.

4.05 inches. The nominal length of 4.1 minus the tolerance of 0.05.

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Engineering Fabrication, Construction, and Architectural Drawing Exercise Summary This chapter reviewed the material on dimensioning and tolerancing engineering fabrication, construction, and architectural drawings.

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end of text. CONCLUDING MATERIAL Review activities:

Preparing activity:

DOE - ANL-W, BNL, EG&G Idaho, EG&G Mound, EG&G Rocky Flats, LLNL, LANL, MMES, ORAU, REECo, WHC, WINCO, WEMCO, and WSRC.

DOE - NE-73 Project Number 6910-0022

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Engineering Drawing

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