Explosion suppression systems
1 Scope
This standard describes the basic requirements for the design and application of explosion suppression systems. This standard also specifies a method for evaluating the effectiveness and the scale up of explosion suppression systems against defined explosions. It gives the criteria for alternative test apparatus used to undertake explosion suppression efficacy tests and criteria to be applied in defining the safe operating regime of an explosion suppression system. It covers:
——general requirements for explosion suppression components;
——evaluating the effectiveness of an explosion suppression system;
——evaluating the scale up of an explosion suppression system;
——evaluation and development of design tools for explosion suppression systems;
——instructions for installation of an explosion suppression system;
——maintenance instructions for an explosion suppression system.
This standard is applicable only to explosion suppression systems intended for the protection of closed, or essentially closed, enclosures in which an explosion may result as a consequence of ignition of an explosible mixtures, e.g. dust-air mixtures, gas (vapour)-air mixtures, dust-gas (vapour)-air mixtures and mists.
This standard is not applicable for explosions of materials listed below, or for mixtures containing some of those materials:
——unstable materials that are liable to dissociate;
——explosive materials;
——pyrotechnic materials;
——pyrophoric materials.
Note: For the listed materials expert advice is required.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document applies.
GB/T 15605 Guide for pressure venting of dust explosions (GB/T 15605-2008, NEQ VDI 3673-1:2002)
GB/T 16425 Determination for minimum explosive concentration of dust clouds
GB/T 16426 Determination for maximum explosion pressure and maximum rate of pressure rise of dust cloud (GB/T 16426-1996, eqv ISO/DIS 6184-1)
GB/T 2900.35 Electrotechnical terminology—Equipment for explosive atmospheres (GB/T 2900.35-2008, IEC 60050-426:2008, IDT)
GB 25285.1 Explosive atmospheres—Explosion prevention and protection—Part 1: Basic concepts and methodology
EN 13673-1 Determination of the maximum explosion pressure and the maximum rate of pressure rise of gases and vapours — Part 1: Determination of the maximum explosion pressure
EN 13673-2 Determination of maximum explosion pressure and the maximum rate of pressure rise of gases and vapours — Part 2: Determination of the maximum explosion pressure rise
EN 14034-4 Determination of explosion characteristics of dust clouds—Part 4: Determination of the limiting oxygen concentration LOC of dust clouds
EN 14994 Gas explosion venting protective systems
EN 26184-3 Explosion protection systems — Part 3: Determination of explosion indices of fuel/air mixtures other than dust/air and gas/air mixtures
3 Terms and definitions
For the purposes of this standard, the terms and definitions given in GB 25285.1, GB/T 2900.35 and the following apply.
3.1
HRD-suppressor
appliance containing an explosion suppressant, which can be expelled by the action of internal pressure
Note 1: This pressure may be stored pressure, or may be obtained by a chemical reaction such as the activation of an explosive or pyrotechnic device.
Note 2: HRD is the abbreviation of High Rate Discharge.
3.2
suppressant
substance contained in the HRD-suppressor which, when dispersed into a volume to be protected, can arrest or prevent a developing explosion in that volume
Note: Three categories of suppressants are in general use, separately or in combination:
——powder suppressant;
——powder suppressant;
——chemical suppressant.
3.2.1
powder suppressant
powder with recognised flame extinguishing properties such as products based on monoammonium phosphate, potassium bicarbonate or sodium bicarbonate
Note: Such suppressants may contain additives to improve their flow properties and their effectiveness.
3.2.2
water suppressant
water, cold or hot, used as an explosion suppressant
Note: Additives may be included to provide frost protection, and/or to improve the suppressant effectiveness.
3.2.3
chemical suppressants
chemical suppressants with recognised flame-extinguishing properties
3.3
dispersion agent pressure
ps
maintained pressure in a stored pressure-type suppressor at which the suppressant is dispersed, e.g. dry gas, chemical reaction or the application of heat
3.4
suppressant charge
Ms
mass or volume of the suppressant contained within the suppressor
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Explosion suppression
5 General requirements for explosion suppression components
6 Requirements for the design of an explosion suppression system
7 Safety integrity of explosion suppression systems
8 Installation
9 Marking and packaging
Annex A (Informative) Development of nomograph type design guidelines
