1、FUNDAMENTALS OF GAS APPLIANCE VENTING AND VENTILATION FOURTH EDITION MANUAL AND WORKBOOK COMBINED PREPARED BY Roger Carson Enterprises, Inc. FOR AMERICAN GAS ASSOCIATION 400 N. Capitol Street N.W. Washington, DC 20001 Catalog No. XH0201 Copyright 2002 by American Gas Association Fourth Printing 2002
2、 Printed in United States of America iDISCLAIMER The AGA (together with its members) disclaims liability for any personal injury, property or other damages of any nature whatsoever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the publication, use o
3、f, or reliance on this document or whether based on information contained in or omitted from this document. All warranties, express or implied, are disclaimed, including without limitation, any and all warranties concerning the accuracy of the information, its fitness or appropriateness for a partic
4、ular purpose or use, its merchantability and its non-infringement of any third partys intellectual property rights. AGA (together with its members) expressly disclaims any and all responsibilities for the accuracy or completeness of the information and makes no representations or warranties regardin
5、g the informations compliance with any applicable statute, rule or regulation. In issuing and making this document available, the AGA (together with its members) is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is the AGA undertaking to perfor
6、m any duty owed by any person or entity to someone else. Anyone using this document is doing so at the users own discretion and at its own risk. The user should seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. This manual is not d
7、esigned to provide installation, repair or maintenance instructions. Equipment should be installed, repaired or maintained in compliance with manufacturers instructions, applicable building codes and regulations and national standards. This manual is not intended to take the place of those documents
8、. ii FOREWORD The first edition of this manual was originally prepared under the direction of the American Gas Association and Gas Appliance Manufacturers Association Joint Committee for Customer Service. It was written by Douglas W. DeWerth, Senior Research Engineer and J. Fred Parr, Manager of Eng
9、ineering Services, American Gas Association, Laboratories, Cleveland, Ohio. The 2002 edition was edited and prepared by James W. Freeman and Mary S. Carson, Consultants, Roger Carson Enterprises, Inc. This edition combines the manual and the workbook. The purpose of the manual is to provide a text f
10、or self-study. Hopefully, it will become a useful general education tool to vocational-technical schools, appliance service and repairmen, and utility customer service programs. The text has been prepared so that only a moderate knowledge of mathematics and science is required for understanding. In
11、an effort to assist in the reinforcement of the material found in the text, this edition updates and combines the text of the Fundamentals of Gas Appliance Venting and Ventilation, Catalog No. XH9303 manual and the Fundamentals of Gas Venting and Ventilation Work Book, Catalog No. XH9403. Answers to
12、 all chapter reviews can be found listed in numerical order in each chapter review page and correct answers can be found beginning on pages 134 of this manual. Comments in this manual may differ from local building codes and construction practices. This manual does not provide installation, repair o
13、r maintenance instructions. Equipment should be installed, repaired or maintained in compliance with manufacturers instructions, applicable building codes and regulations and national standards. Venting Tables from the National Fuel Gas Code (NFGC) 2002 Edition have been referenced. Remember: Many s
14、tates and communities have adopted the International Fuel Gas Code (IFGC). The IFGC venting guidelines are the same as the National Fuel Gas Code. Other fundamental texts in this series cover the following subject areas: Combustion Electricity Appliance Controls Gas Appliances Customer Service At th
15、e end of the text is a glossary of terms used in venting and ventilation. It is suggested that the student should be familiar with these terms so that the text material will be meaningful. Words, which appear in the text in bold-faced type, appear in the glossary. The fourth edition has been updated
16、 to include provisions of the 2002 edition of the NFGC. Appliance Venting. Notes are from NFGC 2002. Please refer to the pages of the Venting Tables for reference to the exact sections of the NFGC Venting Tables. iii iv CONTENTS I. HISTORY OF VENTING AND VENTILATION 1 CHAPTER REVIEW.3 II. THE PURPOS
17、E OF GAS APPLIANCE VENTING AND VENTILATION. 5 CHAPTER REVIEW. 8 III. BASIC THEORY OF VENTING SYSTEM OPERATION . 10 Motive Force in Vents . 10 Need to Remove Water Vapor. 10 Factors That Affect Venting System Design and Operation . 11 Vent Gas Temperature . 11 Heat Loss . 11 Vent Height 11 Vent Syste
18、m Capacity 11 Restrictions to Flow . 11 Ambient Temperature 11 CHAPTER REVIEW. 13 IV. TYPES OF GAS VENTS 16 Chimneys . 16 Type B Vents . 16 Type B-W Vents 17 Type L Vents 17 Single-Wall Metal Pipe Vents . 17 Plastic Pipe Vents 17 CHAPTER REVIEW. 18 V. VENTING SYSTEMS. 19 Appliance Categorization. 19
19、 Single Appliance Natural Draft Type Vent Systems . 20 Multiple Appliance Natural Draft Type Vent Systems 20 Direct Vent Systems 21 Special Venting Systems 21 Power Venting . 21 Manifold Venting. 22 Multiple Venting Systems 23 Multi-Story Vents 23 Exhaust System Venting 24 High-Efficiency Appliance
20、Vents 24 CHAPTER REVIEW.26 v VI. CODE REQUIREMENTS FOR VENTING .33 Appliances Subject to Venting.33 Equipment Not Required to be Vented (Unvented Appliances)33 Vent Materials34 Clearance Requirements 35 Sizing Requirements 36 Installation Standards.36 Pitch .36 Length 36 Support and Location.37 Chim
21、ney Connection .37 Fireplace.38 Dampers .38 Protection Against Fire Hazards 38 Prohibited Installations 39 CHAPTER REVIEW.42 VII. VENT SIZING AND DESIGN .48 Venting Into a Masonry Chimney48 Single Appliance Natural Draft Vent.49 Multiple Appliance Vent Systems .53 How to Size a Multiple Vent System.
22、53 Multi-Story Vent Systems55 Determining Size of Common Vent 55 Precautions in Designing Multi-Story Vent Systems 55 Power Venting .57 Manifold Connectors .57 Direct Vent Systems 58 Termination of Type B Vents 58 Miscellaneous Design Specifications 60 Effects of Joints and Turns 60 Single-Wall Vent
23、s60 Outside Vents.61 Vents in High Altitude Locations 61 CHAPTER REVIEW.62 VIII. AIR FOR COMBUSTION AND VENTILATION.64 Required Volume of Indoor Air.64 CHAPTER REVIEW.68 IX. INSTALLATION OF VENTS 70 Vents and Vent Fittings .70 Roof Flashing.70 Storm Collar.70 “Y” Fitting .71 “Siamese” Folding .71 Ve
24、nt Terminals (Vent Caps) 71 Installing Vents and Vent Connectors .72 Joint Connectors.72 vi Draft Hood Connections 72 Support.72 General Precautions .72 Minimize Lateral Runs 72 Avoid Internal Vent Obstructions73 Provide Proper Clearances.73 Install Firestops73 Provide Adequate Air 73 Do Not Run Ven
25、t Through Existing Ducts73 Protection of Vents 74 Placing the Appliance Vent in Operation 74 Check for Water Leaks 74 Check Overall Appearance 74 Check Air Supply.74 Test for Proper Draft74 Direct Vent Systems 75 CHAPTER REVIEW.76 X. TROUBLESHOOTING.79 Chronic Pilot Outage79 Condensation 79 Leaking
26、Flue Gases80 Rusting or Corrosion of Burners, Draft Hoods or Vent Pipes .80 Spillage of Combustion Products.81 Incorrectly Sized Vent System.81 Incorrectly Sized Vent Cap81 Excessive Lateral Run81 Too Many Elbows81 Improper Pitch to Lateral Runs82 Exhaust Systems or Furnace Blowers82 Improper Seal B
27、etween Furnace and Return Air Duct 82 Restriction of the Vent System 82 Wind Conditions at the Vent Cap 82 Appliances Attached to Multiple Vent 82 High-Efficiency Appliances.83 Discoloration of Room Walls or Vent System 83 Surface Salt Deposits Outside Masonry Chimneys .83 Unvented Appliance Problem
28、s 83 Condensation on Walls, Windows or Baseboards .84 Carbon Deposits.84 CHAPTER REVIEW.85 XI. SIZING OF CATEGORY I VENTING SYSTEMS AND TABLES88 CHAPTER REVIEW.126 REFERENCE SOURCES127 GLOSSARY 128 ANSWERS TO CHAPTER REVIEW 134 vii REVISED FUNDAMENTALS OF GAS APPLIANCE VENTING AND VENTILATION INSTRU
29、CTIONS 1. Read one complete chapter of the training manual. 2. Read the questions based on the chapter you have read. Each question should be read and an answer formed in your mind before completing the blank spaces provided. Write your answer down. In the small frame to the right of the page you wi
30、ll find an answer choice for each blank space in the question. Correct answers are provided, but are in random order for you to select from. In the back of the workbook is an answer sheet for each chapter. 3. After you have answered all of the questions in a chapter, check the answers on the answer
31、sheet in the back of the workbook. 4. If you are not correct, review the section of the manual that pertains to this question. The number in the parenthesis in the lower right hand corner of each question frame is the manual page number where the information appears. 5. After all of the incorrect re
32、sponses in a chapter are corrected, and appropriate material reviewed, then go on to the next chapter. 2002 AMERICAN GAS ASSOCIATION ALL RIGHTS RESERVED viii I. History of Venting and Ventilation When early man first took fire into his shelter, it surely did not take him long to realize that somehow
33、 he had to let the smoke out. As time passed and more and more time was spent inside a house, a better vent system was needed. This took the form of a fireplace and chimney. Early chimneys were made of stone or brick. The fuel used in the fireplace usually was wood, coal or peat (solid fuels). Thus,
34、 when natural gas was first used extensively in homes for heating and cooking purposes (about 1930), most of the homes were already equipped with a masonry chimney. To utilize existing structures, the gas-fired appliances were simply connected to the masonry chimneys. It did not take long to find ou
35、t that brick and masonry chimneys built for solid fuels were not always good vents for the products of combustion of gas appliances. The chimneys were usually too large and unlined. Deterioration of the inside caused by water vapor condensing out of the flue gases occasionally resulted in blockage t
36、hat prevented the flue gases from reaching the outside. The first vent*for fires was probably a hole in the roof of a shelter. Man also, no doubt, soon learned that the vent would not work if the shelter opening was covered preventing fresh air from entering his living space. Venting, the process of
37、 removing gases produced by burning, took place through the roof; while ventilation, the process of replacement of air consumed by the fire and air carried out with the hot gases, took place through the entrance. The American Indians who lived on the Western Plains vented their tents in much the sam
38、e manner. They built fires on the ground at the center of the teepee and had a flap at the peak that could be opened to let the smoke escape to the outdoors. Ventilation air entered at the entrance flap and through cracks in the teepee. The teepee was actually a single-walled vent and an Indian fami
39、ly lived in their “vent pipe.” This venting system was not perfect and teepee occupants probably suffered in a continuously smoky atmosphere. 1*Words that appear in the text in boldface type are defined in the Glossary. industry, the construction industry and municipal building inspection authoritie
40、s, that properly engineered and installed vent systems, were needed throughout the country. Thus, in most cities, towns and other incorporated communities, a part of the building code is devoted to venting gas appliances. In the early days of venting gas appliances, no common vent construction or si
41、zing was used. Vent pipes of many designs, made of various materials were used to create passageways for combustion products to the outside. Rusted or corroded vent pipes, damaged walls, discolored furnishings, and in some instances fatal accidents resulted from poorly designed and installed vent sy
42、stems. It became obvious to the gas See Chapter VI of this manual for discussion for code requirements for venting.2 CHAPTER REVIEW I. HISTORY OF VENTING AND VENTILATION This review is designed to be a reinforcement of the information supplied in each chapter. Instructions: Read one chapter of the m
43、anual and read the questions in the Chapter Review. Read question and provide an answer in your mind before completing the blank spaces provided. The answers to each page are provided in the column to the far right; however, they are not in order. It is your job to select the correct word or words a
44、nd fill-in the blanks. The correct answers are listed by the numbers at the end of the manual. If you are not correct, review the section of the manual that pertains to that question. QUESTIONS ANSWERS 1. Venting is the process of removing gases produced by burning; early man vented through a hole i
45、n the roof of the shelter. 1. _ is the process of replacing air consumed by the fire and air carried out with the 2. _ _; took place through the shelter opening. (p. 1) BUILDING CODE CHIMNEY FATAL ACCIDENTS 2. As time passed and more and more time was spent indoors, a better vent system was needed.
46、This took the form of a fireplace and _. (p. 1) HOT GASES VENTILATION3. Rusted or corroded vent pipes can permit flue products to escape which can damage walls, discolor furnishings and in some instances caused _ _. (p. 1) 4. In most cities, towns and other incorporated communities, a part of the lo
47、cal _ _is devoted to rules for venting gas appliances. (p. 2) 3QUESTIONS ANSWERS 5. Masonry chimneys built for solid fuels were not always good vents for gas appliances because they were often: 1. _ _ and 2._. Deterioration of the inside occasionally resulted in 3. _ which prevented 4. _ _ from reac
48、hing the outside atmosphere. (p. 1) BLOCKAGE FLUE GASES TOO LARGE UNLINED 4II. The Purpose of Gas Appliance Venting and VentilationA properly designed and installed appliance venting and ventilation system will serve the following important purposes: Conveys all the hot combustion gases to the outside atmosphere; Protects the building structure from fire hazards due to overheating walls or other surfaces; Prevents damage to walls and furnishings due to the escape and condensation of hot combustion gases; and Provides for g
