Compartment Fires and Tactical Ventilation', Is "Compartment Fires" Attempts to Address What Available From: Firefighters Need to Know About Compartment Fires
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Issued under the authority of the Home Office (Fire and Emergency Planning Directorate) FIRE SERVICE COLLEGE LIBRARY & INFORMATION RESOURCE CENTRE Fire Service Manual RETURN OR RENEW ON, OR BEFORE, THE LAST DATE STAl'1PED BELOW (2 RENEWALS MAX.) FINES ARE PAYABLE ON Al~Y ITEMS RETURNED LATE Volume 2 ~\ho\o~ Fire Service Operations \e:> I'Z/ 64- /5 I--r-I 0 S- 111"t ~ t. ~ .\o~ Compartment Fires ~~ LS.I.b&\' e and '5.2. 1(:) ~() ~ Tactical Ventilation l. to I THE FIRE SERVICE COLLEGE LIBRARY MORETON-IN-MARSH GLOUCESTERSHIRE GL560RH 01608 812050 [email protected] The Fire Service College 00119966 HM Fire Service Inspectorate Publications Section London: The Stationery Office Compartment Fires and CD Crown Copyright 1997 Published with the permission of the Home Office Tactica Ventila ion on behalf of the Controller of Her Majesty's Stationery Office Applications for reproduction should be made in writing to The Copyright Unit, Her Majesty's Stationery Office, St. Clements House, 2-16 Calegate, Norwich, NR3 IBQ Preface ISBN 0 11 3411758 This book replaces Part 3, Book 12 of The Manual physics involved. Much of the operational experi of Firemanship, and the two supplements "The ence originates in the United States, but this book Behaviour of Fire - Compartment Fires" and "The is intended to place this experience in the appro Behaviour of Fire - Tactical Ventilation of priate United Kingdom firefighting context. Buildings & Structures". It contains and updates the information previously given in those publications. The Home Office is indebted to all those who have helped in the preparation of this work. If readers wish to go into more detail they should refer to the relevant text books. A brief bibliogra Trai ing Video phy is given at the back. The Home Office produced a three-part training Part 1 - Compartment Fires video covering the above. The video, titled 'Compartment Fires and Tactical Ventilation', is "Compartment Fires" attempts to address what available from: firefighters need to know about compartment fires. It tries to summarise, without going into theory, • The College Shop, Fire Service CoIJege, what is understood about the early stages in the Moreton-in-Marsh, Glos GL56 ORH growth of a fire in a compartment, leading to a flashover and possibly backdraught, and the effect • Viewpoint Presentations Ltd of ventilation. Oddfellows Hall, London Road, Chipping Norton, Oxford OX7 5AR The definition of "backdraught" and "flashover" in this book are based on the state of knowledge in • The Stationery Office 1995, rather than British Standard 4422: 1987. "Compartment Fires" supplements Books I and II of The Manual ofFiremanship. Part 2 - Tactical Ventilation This Part attempts to bring together all the existing advice available on the use of ventilation. Very often, this advice is based on firefighters' experi ence, and has yet to be supported by experimental verfication. Nevertheless, it is based on good fire fighting practice, and a sound understanding of the Printed in the United Kingdom far The Stationery Office 130027 11/97 C50 13110 Compartment Fires and Tactical Ventilation 111 Compartment Fires and Tactical Ventilation Contents Part 1: Compartment Fire 1 Chapter 1 The Fire 3 1 Combustion 3 2 Fire Growth 4 3 The Effects of Water 4 4 The Effect of Walls and the Ceiling on the Plume 4 5 Actions by Firefighters 5 6 The Effect of Ventilation 5 Chapter 2 Backdraught 7 1 Reducing the Oxygen Supply to a Fire 7 2 The Definition of a Backdraught 7 3 Possible Backdraught Scenarios 7 4 Signs and Symptoms of a Backdraught 9 5 Actions by Firefighters 10 Aide Memoire 1 11 Illustration of build up to Backdraught 12 Chapter 3 Flashovers 13 1 Fire Spread 13 2 Definition of a Flashover 14 3 Signs and Symptoms of a Flashover 14 4 Actions by Firefighters 14 Aide Memoire 2 15 lJlustration of build up to Flashover 16 Chapter 4 Firefighter Awareness 17 Bibliography 17 Part 2: Tactical Ventilation 19 Chapter 1 Introduction 21 1 Ventilation 21 2 Smoke 21 3 The Value of Ventilation 22 4 When to Use Ventilation 22 5 The Effect of Wind 22 6 Tactical Ventilation Techniques 22 7 Operational Command 23 Compartment Fires and Tactical Ventilation V e hapter 2 Asses iog the eed for Ventilation 25 Chapter 9 Ventilation cenario 53 1 General 25 1 Single Storey WarehouselIndustrialBuilding/Sports Hall 53 2 Where Ventilation May Be of Benefit 27 (a) Construction 53 3 Assessing The Risks 28 (b) Special Hazards 53 4 How Ventilation Is to Be Achieved 28 (c) Fire against End Wall 53 (d) Fire in Centre of Building 53 Chapter 3 Horizontal Ventilation 31 (e) Unidentified Fire Location 54 2 1\vo-Storey WarehouselIndustrial Building/Sports Hall 54 1 General 31 (a) Construction 2 The Physical Principles Involved 31 54 (b) Fire on Ground Floor 3 The Principles of Horizontal Ventilation 31 54 (c) Fire on Upper Floor 4 Methods of Making Vents 32 54 3 Small Commercial Units 54 Chapter 4 Vertical Ventilation 35 (a) Construction 54 (b) Fire Confined to Shop Unit 54 1 General 35 4 Low Rise Apartment Buildings 55 2 Vertical Ventilation Safety 35 e (a) Construction 55 3 Methods of Making Vents 36 (b) Fires in Accommodation Units 55 4 Offensive and Defensive Vertical Ventilation 37 5 Two-Storey Residential House 55 (a) Construction 55 Chapter 5 Forced Ventilation 39 (b) Fire on Upper Level 55 (c) Fire on Lower Level 1 General 39 55 2 Positive Pressure Ventilation 40 3 Negative Pressure Ventilation 40 hapter 10 Ba ernent, nderground tructure and Tunnels 57 (a) Fans 40 1 Introduction 57 (b) Hoseline Branches 41 2 Basements 57 4 Heating, Ventilation and Air Conditioning 42 3 Tunnels 58 5 Powered Smoke and Heat Exhaust Ventilation Systems 42 (a) General Considerations 58 6 Safety Considerations 42 (b) Smoke Movement in nmnels 58 (c) Fires on Trains or Vehicles in Motion 58 Chapter 6 Po itive Pres. ure Ventilation 43 (d) Tunnels under Construction 58 1 Introduction 43 (e) Ventilation Options 59 2 Basic Fan Performance 43 3 Positioning the Fan 45 Chapter 11 High Rise Building and all 61 4 Fighting an Opposing Wind 45 1 Introduction 61 5 Size and Location of the Fire Compartment 47 2 The Stack Effect 62 6 The Effect of Opening Vents 47 3 Firefighting in High-Rise Structures 63 7 The Use of Multiple Fans 47 4 Built-In Smoke Ventilation Systems 64 5 The Effects of Wind 64 Chapter 7 Tactica Option with PP , - Defen ive 49 6 Ventilation below the Fire 64 1 Post Fire Smoke Clearance and Damping Down 49 7 Ventilation above the Fire 65 8 Ventilation of the Fire Floor 65 2 Smoke Clearance as Part of Firefighting 50 Chapter 8 Ta tira) Options with PPV - Offensive :1 Chapter 12 urnrnary 67 1 Domestic Premises 51 Aide Memoire 3 68 2 Stairwells 51 Glossary of Terms 69 3 Corridors 51 4 Cellars 51 Further Reading 71 5 Small Workshops and Stores 52 6 Large Volumes 52 VI Fire Service Manual Compartment Fires and Tactical Ventilation VII • Part 1 Co a ment ires e' Compartment Fires 1 Compartment Fires Chapt r Chapter 1 - The Fire 1 Combustion in wood. Eventually, if they get hot enough, the remaining solids, such as charcoal in the case of When a candle burns, the wax melts. The liquid is wood, will themselves start to bum. drawn up the wick, where it turns into a flammable vapour. It is this vapour which burns, forming the These gases rise in a plume (Figure 1.1), and mix flame. with air. If the gas/air mixture is correct, any given ignition source (eg a flame or spark) will trigger In the same way, in a fire in a compartment, it is the combustion process which will rapidly become useful to think of all the combustible materials (the self-sustaining. The reactions which occur fuel) as being sources of flammable gases. These between the flammable gases and the oxygen in gases, which need not necessarily ignite, are gen the air, generate large amounts of energy. This erated when the fuel is heated. Initially the gases energy causes a rise in the temperature of the gases result from the boiling off and decomposition produced in the reaction (the products of combus (pyrolysation) of hydrocarbons, such as the resin tion) and also appears as thermal radiation (heat) and visible radiation (flame). The high gas temperatures cause a vigorous upward movement driven by buoyancy; this induces mixing with the surrounding air by a process known as entrainment. Low down in the plume, the centre will be rich in flammable gases and this will be surrounded by an envelope of flame. In the upper part of the plume, there is no flame. It is a rising column of smoke which consists of large amounts of entrained air, together with non-flam mable products of combustion (mainly carbon dioxide and water), unburnt flammable gases and minute particles (soot). The flammable gases in the Thermal Thermal upper part of the fire are at too Iowa concentration Radiation Radiation to burn. The upper part of the flame is basically unstable, producing the well-known flickering associated with fires. In general, though, the average flame height depends on the heat generated by the fire. The hot plume radiates down on to the fuel, heat ing it, and so permitting the generation of flamma Figure 1.1 The Fire Plume ble gases to continue. In general, there will be suf- Compartment Fires 3 • ficient heat generated for the fire to spread as long at 100°C. The amount of energy necessary to do If the fire is at a wall, the plume may attach itself growth.