w. Bartknecht Explosions Course Prevention Protection With 259 Figures, Some in Color and 34 Tables Translation from the German by H. Burg and T. Almond Springer-Verlag Berlin Heidelberg New York 1981
Dr. Wolfgang Bartknecht c/o CIBA-GEIGY AG, Zentraler Sicherheitsdienst CH -4002 Basel Translators: H. Burg and T. Almond CIBA-GEIGY AG, CH-4002 Basel Revised translation of the second edition of "Explosionen. Ablauf und SchutzmaBnahmen" ISBN-13 :978-3-642-67749-6 Springer-Verlag Berlin Heidelberg New York 1980 ISBN-13 :978-3-642-67749-6 e-isbn -13 :978-3-642-67747-2 DOl: 10.1007/978-3-642-67747-2 Library of Congress Cataloging in Publication Data. Bartknecht. Wolfgang. Explosions, course, prevention, protection. Rev. translation of the 2d ed. of Explosionen, Ablauf und SchutzmaBnabmen. Includes bibliographical references and index. 1. Explosions - Safety measures. 2. Explosions. I. Title. QD516.B3613. 660.2'804. 80-22159 ISBN-13 :978-3-642-67749-6(U.S.) This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. by Springer-Verlag Berlin Heidelberg 1981 Softcover reprint of the hardcover 1st edition 1981 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Elsner & Behrens GmbH, Oftersheim. 2152/3140-543210
Preface The hazards of explosions to human beings and to material values can hardly be overrated. These hazards are aggravated since powders and gas mixtures with a tendency to explode in general do not signal their inherent danger. But there is one powder whose name already indicates the hazard it represents. This substance is gunpowder. Whoever handles it is conscious of the danger to which he is exposed. He also knows that it is he, himself, who can trigger the explosion, he also can keep the hazard under control. In this respect, gunpowder has become one of the more harmless substances. Names and information indicating danger will create hazard consciousness in man which is a necessary condition for the institution of measures to protect himself and his material values. Gunpowder is only one of innumerable powders or dusts with an inherent dust explosion hazard. Technical development leads to an ever growing number of solids in the form of dust. Important properties of solids can only be put to use if they are present in the form of dusts. Only in the form of dust can flour be used for food, concrete for structures. No medicinal tablets could be made without pharmaceutical products in powder form. These are only a few examples of powders being of vital importance to men. Their number could be increased at will. Thus, products in the form of powders must be made, transported, stored in large numbers and also in large quantities. There is an important principle in powder technology: Dust creates finer dust. The finer the dust, the higher the explosion hazard. Dust is a particularly hazardous form of solid substances. By no means smaller are the hazards inherent to gaseous mixtures. To investigate, describe and master these hazards has been chosen by the author of this book as his task for life. The book consists of three main chapters in which are described the conditions for and the course of explosions, as well as the measures to prevent them or to protect against their effects. It covers the full span from scientific knowledge to the technical consequences to be derived therefrom. On the basis of comprehensive knowledge, a book
VI Preface has been written which presents in understandable form a field of technology of particular importance for technical development in general, that facilitates and thus also accelerates practical application. This book does more than just close a gap in technical literature. Primarily, it contributes to the technically safer handling of powders and gaseous substances. By means of this book, technology can be made a little safer, man can be given even better protection. For technical academies, this book illustrates that an important area of safety technology has been developed so far that it can now be taught and learnt. Heinz Brauer Professor of technology Technical University of Berlin
Contents Part I The Course of Explosions 1 Introduction... 3 2 Explosions in Closed Vessels................. 4 2.1 Flammable Gases........................ 4 2.1.1 Explosion Limits... 4 2.1.2 Explosion Pressure - Violence of Explosion... 7 Flammable Gas (Vapour)/Air Mixtures.......... 7 Flammable Gas/Oxygen Mixtures... 23 Chlorine/Hydrogen Mixtures................. 25 2.2 Combustible Dusts....................... 27 2.2.1 Preliminary Remarks...................... 27 2.2.2 Explosion Limits... 27 2.2.3 Explosion Pressure - Violence of Explosion... 27 2.2.4 Lowest Minimum Ignition Energy............. 44 2.3 Hybrid Mixtures......................... 49 2.3.1 Preliminary Remarks...................... 49 2.3.2 Explosion Limits... 49 2.3.3 Explosion Pressure - Explosion Violence... 50 2.3.4 Lowest Minimum Ignition Energy..... 53 2.4 Conclusions............................ 55 3 Explosions - Detonations in Pipelines... 56 3.1 Preliminary Remarks...................... 56 3.2 Flammable Gases................... 57 3.3 Combustible Dusts.................... 65 3.4 Conclusions............................ 69 4 References... 70
VIII Contents Part II Protective Measures to Prevent Explosions or to Control Their Effects 1 Preliminary Remarks...................... 75 2 Measures to Prevent Explosions............... 77 2.1 Inerting... 77 2.1.1 Preliminary Remarks...................... 77 2.1.2 Flammable Gases...................... 77 2.1.3 Combustible Dusts................... 83 2.1.4 Conclusions............................ 86 3 Safety Measures Against the Effects of Explosions Within Enclosures or Rooms................. 87 3.1 Preliminary Remarks...................... 87 3.2 Explosion Resistant Construction... 87 3.2.1 Pressure Vessels... 87 3.2.2 Pressure Shock Resistant Vessels.............. 87 3.2.3 Conclusions............................ 89 3.3 Explosion Relief Venting................... 89 3.3.1 Preliminary Remarks...................... 89 3.3.2 Description of Relief Venting................ 89 Relief Venting of Vessels................... 89 Relief Venting of Rooms................... 90 3.3.3 Design and Properties of Relief Venting Devices.... 91 Preliminary Remarks...................... 91 Bursting Discs... 93 Bursting Discs Made of Brittle, Non-Deformable Material... 93 Bursting Discs Made of Defonnable Material... 93 Auxiliary Activation Bursting Discs... 100 Explosion Plates......................... 101 Self Closing Relief Devices.................. 102 Exposion Doors......................... 102 Spring Loaded Relief Devices................ 104 Conclusions... " 104 3.3.4 Sizing of Relief Areas... 105 Preliminary Remarks...................... 105 Flammable Gases........................ 106 Combustible Dusts... 113 Safe Discharge of Pressure Wave, Flames and Gases.. 115 Elongated Vessels (Silos)................... 119 3.3.5 Limits of Applicability... 124 3.4 Explosion Suppression..................... 125 3.4.1 Preliminary Remarks...................... 125 3.4.2 Description of Method..................... 125
Contents IX 3.4.3 3.4.4 3.4.5 3.4.6 3.4.7 3.4.8 3.5 Selection of the Sensor System............... 125 Description of the Extinguishing Systems... 129 Selection of the Best Extinguishing Medium... 130 Limits of Applicability... 137 Extinguishing Agent Requirement............. 140 Special Application Problems............. 144 The Influence ofinitial Pressure... 144 Suppression of Explosions of Organic Peroxides.... 144 Conclusions............................ 144 4 Safety Measures Against the Effects of Explosions in Pipelines............................ 146 4.1 Flame Barriers.......................... 146 4.1.1 Preliminary Remarks...................... 146 4.1.2 Mechanical Flame Barriers................ 154 Preliminary Remarks...................... 154 Explosion Barriers... 154 Long Time Flame Barriers... 158 Detonation Barriers....................... 161 4.1.3 Automatic Extinguishing Barrier.............. 162 4.2 Explosion Relief Venting................... 168 4.2.1 Preliminary Remarks...................... 168 4.2.2 Relief Venting Device for the End of a Pipeline... 171 Bursting Discs, Activated Discs... 171 Explosion Doors... 172 Spring Loaded Valves... 176 4.3 Rapid Action Valves.................... " 177 4.4 Conclusions............................ 181 5 6 Summary... 182 References... 183 Part III 1 2 2.1 2.1.1 2.1.2 2.1.3 Practical Applications of Protective Measures on Technical Equipment Preliminary Remarks...................... 189 Protective Measures for Equipment... 191 Grinders.,............................ 191 Preliminary Remarks...................... 191 Parameters Influencing the Pressure vs. Time Course of Explosions........................... 191 Conclusions............................ 195
x Contents 2.2 Bag Slitting Machines... 195 2.2.1 Preliminary Remarks...................... 195 2.2.2 The Application of Combined Protective Measures.. 195 2.3 Fluid Bed Driers and Granulators.............. 198 2.3.1 Preliminary Remarks...................... 198 2.3.2 The Application of Secondary Protective Measures.. 200 Basic Requirements of the Apparatus........... 200 Square Shape........................... 200 Round Shape........................... 201 Conclusions............................ 203 Explosion Relief Venting................... 203 Relief on Product Side of Filter............... 203 Relief on Clean Side of Filter... 208 Explosion Suppression..................... 211 Additional Requirements................... 213 2.4 Dust Separation Filters... 215 2.4.1 Preliminary Remarks...................... 215 2.4.2 Pocket Filters........................... 217 Application of Explosion Relief Venting......... 217 Conclusions............................ 220 2.4.3 Hose Filters............................ 221 Application of Explosion Relief Venting......... 221 The Location of the Ignition Source Within the Filter Housing.......................... 221 Explosion Propagation from a Pipeline.......... 224 Application of Explosion Suppression... 228 2.4.4 Conclusions............................ 228 3 Safeguards on Combined Equipment... 229 3.1 Preliminary Remarks...................... 229 3.2 Grinding Installations... 229 3.2.1 Protection by Inerting..................... 229 3.2.2 Protection by Relief Venting... 232 3.2.3 Protection by Explosion SuppreSSion........... 232 3.3 Spray Drying Installations... 235 3.3.1 Protection by Inerting..................... 237 3.3.2 Protection by Explosion Relief Venting... 238 3.3.3 Protection by Explosion Suppression........... 240 3.4 Conclusions............................ 241 4 Closing Remarks......................... 242 5 References... 244 Subject Index... 247