LECTURE NOTES For Environmental Health Science Students Engineering Drawing Wuttet Taffesse, Laikemariam Kassa Haramaya University In collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education 2005 Funded under USAID Cooperative Agreement No. 663-A-00-00-0358-00. Produced in collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education. Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. All copies must retain all author credits and copyright notices included in the original document. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. ©2005 by Wuttet Taffesse, Laikemariam Kassa All rights reserved. Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. PREFACE The problem faced today in the learning and teaching of engineering drawing for Environmental Health Sciences students in universities, colleges, health institutions, training of health center emanates primarily from the unavailability of text books that focus on the needs and scope of Ethiopian environmental students. This lecture note has been prepared with the primary aim of alleviating the problems encountered in the teaching of Engineering Drawing course and in minimizing discrepancies prevailing among the different teaching and training health institutions. It can also be used as a reference material for professional sanitarians. The graphics of engineering design and construction may very well be the most important course of all studies for an engineering or technical career. The indisputable reason why graphics or drawing is so extremely important is that it is the language of the designer, technician, sanitarian, and engineer, used to communicate designs and construction details to others. The language of graphics is written in the form of drawings that represent the shape, size, and specifications of physical objects. The language is read by interpreting drawings so that physical objects can be constructed exactly as originally conceived by the designer. i This lecture note is devoted to provide general aspects of graphic communication like geometric construction, orthographic projections, maps etc particularly for environmental sanitation works such as dry pit latrine construction, drainage or sewerage construction etc. Each chapter begins by specifying learning objectives. The text and the self-explanatory drawings are much helpful to understand the subject even for the beginners. More over, other subsidiary topics like sectioning, projection of points and lines are added to enable students acquire concrete knowledge and skill for their professional career. Finally, it contains a glossary, which summarizes important terminologies used in the text. For further reading, students are encouraged to refer books which are listed in the bibliography section. ii Acknowledgement We are delighted to express our thanks to the carter center for the financial, material and moral support with out which this material wouldn’t come to reality. We are also glad to extend our heart felt appreciation for Ato Esayas Alemayehu, Ato Muluken Eyayu, Ato Wossen Tafere and Ato Dagnew Engidaw for their critical and constructive comments that are found to be highly essential for this lecture note preparation. We are very happy to be members of the faculty of health sciences, Alemaya university for the fact that working with such faculty are really incomparable. iii TABLE OF CONTENTS Preface ............................................................................... i Acknowledgement ................................................................ iii General Objectives ............................................................... vii Chapter 1: Introduction to Graphic Communication ............ 1 1.1. Drawing .................................................................. 1 1.1.1 Artistic Drawings .......................................... 2 1.1.2. Technical Drawings ...................................... 3 Chapter 2: Drawing Equipments and Their Use .................. 11 2.1. Introduction ............................................................ 11 2.2. Important Drawing Equipments .................... 11 Chapter 3: Lettering and Lines ............................................ 22 3.1. Letter Styles ........................................................... 22 3.2. Technique Of Lettering ........................................... 24 3.2.1. .Guide Lines ................................................. 24 3.3. Spacing Of Letters ................................................. 30 3.4. Lettering In Maps ................................................... 31 3.5. Conventional Lines ................................................ 31 Chapter 4: Geometric Construction ..................................... 35 4.1. 1 Introduction ......................................................... 35 4.2. Geometric Nomeniclature ...................................... 36 4.3. Techniques of Geometric Constructions ................ 42 Chapter 5: Projection ......................................................... 66 5.1. Introduction ........................................................... 67 5.1.1. Isometric Drawing ........................................ 68 5.1.2. Orthographic Or Multi View Projection ......... 70 5.2. Theory Of Multi View Projections ........................... 72 5.2.1. Orthographic Projection ............................... 74 iv 5.2.2. Classification of Surfaces and Lines in Orthographic Projections ................................ 82 5.2.3. Precedence of Lines .................................... 89 5.3. Pictorial Projections .............................................. 90 5.3.1. Isometric Projection ..................................... 94 5.3.2. Isometric Drawing ........................................ 96 Chapter 6: Sectioning .......................................................... 101 6.1. Sectional Views .................................................... 101 6.2. How Sections Are Shown ..................................... 106 6.3. Multsection Views ................................................ 109 Chapter 7: Projection of Points, Lines and Planes .............. 116 7.1. Introduction .......................................................... 117 7.2. Reference Planes ................................................. 118 7.3. Projection of Point ................................................ 119 7.4. Lines in Space ...................................................... 120 7.4.1. Classification Of Lines In Orthographic Projections ................................................ 121 7.4.2 Orthographic Projection Of A Line ............... 124 7.4.3. True Size (Shape) Of An Oblique Plane .... 146 Chapter 8: Dimensioning ..................................................... 149 8.1. Introduction .......................................................... 149 8.2. Definitions ............................................................ 150 8.3. Steps in Dimensioning .......................................... 152 8.4. Where to Put Dimensions ..................................... 153 Chapter 9: Mapping ............................................................. 159 9.1. Introduction .......................................................... 159 9.2. Definition ............................................................. 160 9.3. Purpose ................................................................ 161 9.4. Classification of Maps .......................................... 162 9.5. Sketch Map .......................................................... 166 9.6. Materials Used In a Sketch Mapping For Field or Office Use ............................................................ 172 9.7. Procedures for Making a Sketch Map ................. 172 v Chapter 10: Building Drawing ............................................. 176 10.1. Introduction ........................................................ 176 10.2. Important Terms Used In Building Drawing ....... 177 10.3. Principles of Architecture .................................... 180 10.4. Basic Elements of Planning Residential Building 182 10.5. Principles of Planning Of Residential Building .... 175 10.6. Specification Used To Draw the Building Drawing 189 10.7. Methods of Making Line and Detailed Drawing .. 191 10.8. Tips to Draw Building Drawing ........................... 194 Chapter 11. Application of Engineering Drawing In Environmental Health Projects ....................... 206 Introduction ................................................................. 206 A. Sanitation Projects .................................................. 207 B. Water Projects ........................................................ 227 Bibliography ......................................................................... 231 vi GENERAL OBJECTIVES This lecture notes will enable the students to: I. Explain the concept of graphic communication, their type and their role in sanitary construction. II. Familiarize with different drawing equipment, technical standards and procedures for construction of geometric figures. III. Equipped with the skill that enables them to convert pictorial (3-D) drawings to orthographic (2-D) drawings and vice versa. IV. Explain the principle and application of sectioning. V. Well familiar with the purpose, procedures, materials and conventional symbols utilized to make sketch maps. vii CHAPTER ONE INTRODUCTION TO GRAPHIC COMMUNICATION Objectives: At the end of this chapter students should be able to: ♦ Define graphic communication ♦ Mention types of drawing ♦ Explain the difference between different types of drawings ♦ Mention some of the applications of technical drawings 1.1 Drawing A drawing is a graphic representation of an object, or a part of it, and is the result of creative thought by an engineer or technician. When one person sketches a rough map in giving direction to another, this is graphic communication. Graphic communication involves using visual materials to relate ideas. Drawings, photographs, slides, transparencies, and sketches are all forms of graphic communication. Any medium that uses a graphic image to aid in conveying a message, instructions, or an idea is involved in graphic communication. 1