6184/3 nternational Standard (TSO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXAYHAPOAHAR OPIAHW3AUWA NO CTAHAAPTW3AUWWORGANISATION INTE RNATIONALE DE NORMALISATION Explosion protection systems Part 3 : Determination of explosion indices of fuel/air mixtures other than dust/air and gas/air mixtures Systemes de protection contre les explosions - Partie 3: Determination des indices d'explosion des melanges de combustibles et d'air autres que les melanges air/poussiere et air/gaz First edition - 1985-11-15 ISO 6184/3-1985 (E) UDC 614.835 Ref. No. ISO 6184/3-1985 (E) Descriptors : explosion proofing, dust, air, gas mixtures, tests, explosion index. Price based on 4 pages Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (Iso member bodies). The work of preparing International Standards is normally carried out through ISo technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the Iso Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 6184/3 was prepared by Technical Committee ISO/TC 21, Equipment for fire protection and fire fighting. Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. ? International OrganizationforStandardization,1985 Printed in Switzerland INTERNATIONAL STANDARD ISO 6184/3-1985 (E) Explosion protection systems Part 3: Determination of explosion indices of fuel/air mixtures other than dust/air and gas/air mixtures O Introduction Two extremes of turbulence commonly encountered in in- dustrial plants are: 0.1 The assessment of measures required to provide protec- a) quiescent turbulence conditions prevailing in storage tion against explosion hazards involving fuel/air mixtures vessels; requires prior determination of the potential explosion severity b) high turbulence conditions prevailing in the region of an of such mixtures, by the measurement of explosion indices. Conversely, the measurement of the effectiveness and perfor- extraction fan. mance of explosion protection systems requires that they should be tested against explosions of known severity. It shouid be realized that turbulence can arise in two ways : a) turbulence intrinsictothe plant, under normal The severity of a fuel/air explosion is a function of the follow- operating conditions, as a consequence of perturbations to ing : the air-flow ; a) the physical and chemical properties of the fuel; b) turbulence induced by obstructions within an instal- b) the concentration of the fuel in the fuel/air mixture; lation on a gas which expands as the result of an explosion. c) the homogeneity and turbulence of the fuel/air mix- ture; d) the type, energy, and location of the ignition source; 7 Scope e the geometry of the container; This part of ISO 6184 specifies a method for the determination f) the temperature, and pressure of the fuel/air mixture. of the explosion indices of fuels in air(otherthandust/airand gas/air mixtures) in an enclosed space. Fuel/air mixtures may be, for example, gas/air/dust mixtures and vaporized liquid/air 0.2 This part of ISO 6184 is one of a series dealing with ex- mixtures. It gives the criteria by which results obtained using plosionprotectionsystems.Theotherpartsareasfollows: other test procedures can be correlated to yield explosion in- dices as determined by the method specified in this part of Part 1 : Determi