1、BRITISH STANDARD BS ISO 11907-2:1995 Implementation of ISO 11907-2:1995 Plastics Smoke generation Determination of the corrosivity of fire effluents Part 2: Static method ICS 13.220.40; 83.080BSISO 11907-2:1995 This British Standard, having been prepared under the directionof the Sector Board forMat
2、erials and Chemicals, waspublished under the authorityof the Standards Boardand comes into effect on 15March1996 BSI 04-2000 The following BSI references relate to the work on this standard: Committee reference PRI/26 Draft for comment 94/300398 DC ISBN 0 580 25530 1 Committees responsible for this
3、British Standard The preparation of this British Standard was entrusted to Technical Committee PRI/26, Burning behaviour of plastics, upon which the following bodies were represented: Association of Building Component Manufacturers British Apparel and Textile Confederation British Cable Makers Confe
4、deration British Electrical Systems Association (BEAMA) Ltd. British Plastics Federation British Railways Board British Telecommunications plc Civil Aviation Authority Department of the Environment (Building Research Establishment) Electrical and Electronic Insulation Association (BEAMA Ltd.) ERA Te
5、chnology Ltd. GAMBICA (BEAMA) Ltd. Home Office Institute of Materials Ministry of Defence Queen Mary and Westfield College RAPRA Technology Ltd. Society of British Aerospace Companies Limited Society of Motor Manufacturers and Traders Limited University of Ulster Co-opted members Amendments issued s
6、ince publication Amd. No. Date CommentsBSISO 11907-2:1995 BSI 04-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword iii Text of ISO 11907-2 1BSISO 11907-2:1995 ii BSI 04-2000 National foreword This British Standard reproduces verbatim ISO11907-2:1995 and imp
7、lements it as the UK national standard. This British Standard is published under the direction of the Sector Board for Materials and Chemicals whose Technical Committee PRI/26 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enqu
8、iries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, BSI, 389 Chiswick Hi
9、gh Road, London W44AL. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages T
10、his document comprises a front cover, an inside front cover, pagesi andii, theISO title page, pagesii toiv, pages1 to11 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front co
11、ver.ISO11907-2:1995(E) ii BSI 04-2000 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Principles 1 5 Apparatus 2 6 Test specimens 2 7 Procedure 3 8 Cleaning procedure 3 9 Expression of results 4 10 Post-exposure of test specimen (optional) 4 11 Precision 4 12 Test rep
12、ort 4 Annex A (informative) Typical test apparatus 5 A.1 General 5 A.2 Test chamber 5 A.3 Ignition source 5 A.4 Condensation device 6 A.5 Humidification unit 6 Annex B (informative) Variability in the corrosivity values (R COR ) measured by the static procedure 11 Figure A.1 General layout of test a
13、pparatus 7 Figure A.2 Plan view of typical test apparatus 8 Figure A.3 Typical test chamber arrangement 9 Figure A.4 Typical ignition source 10 Figure A.5 Typical PWB corrosion detector holder with cooling system attached 10 Table B.1 Repeatability and reproducibility of corrosivity values (R COR )
14、11ISO11907-2:1995(E) BSI 04-2000 iii 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
15、interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotech
16、nical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote.
17、International Standard ISO11907-2 was prepared by Technical Committee ISO/TC61, Plastics, SubcommitteeSC4, Burning behaviour. ISO 11907 consists of the following parts, under the general title Plastics Smokegeneration Determination of the corrosivity of fire effluents: Part 1: Guidance; Part 2: Stat
18、ic test; Part 3: Dynamic decomposition method using a travelling furnace; Part 4: Dynamic decomposition method using a conical radiant heater. At the time of publication of this part of ISO11907, the other parts were at various stages of preparation. Annex A andAnnex B of this part of ISO11907 are f
19、or information only.iv blankISO11907-2:1995(E) BSI 04-2000 1 1 Scope 1.1 This part of ISO11907 specifies a test method using a small-scale laboratory apparatus for the determination of the corrosive effects of combustion products liberated by burning plastics. Although the method is applicable to al
20、l combustible materials which might constitute a corrosion risk in the event of their burning, the size and nature of the test specimen is such that the test is not directly applicable to end-use assessment of corrosion hazard. 1.2 The test method makes it possible to produce a ranking of materials
21、in the order of the corrosivity of their combustion products under specific test conditions with regard to combustion temperature, available oxygen, ventilation and different humidity levels. NOTE 1In order to assess the risk of corrosion when materials burn, the ranking of materials by corrosivity
22、should be combined with their heat and flame response characteristics (e.g.ignitability, surface spread of flame, rate of heat release). The assessment of risk of corrosion in the event of fire requires consideration of many factors including fuel load, intensity of burning, ventilation conditions,
23、humidity levels and the nature of the exposed surfaces. Although the method described in this part of ISO11907 refers only to copper corrosion, the test can be applied to other metallic and non-metallic materials in a variety of detector forms. NOTE 2Additives and fillers have been shown to influenc
24、e the test results. 1.3 It is emphasized that this standard method of test is intended to be used to evaluate the relative degree of possible corrosive effects of fire gases to exposed materials and products under controlled laboratory conditions, and should not be considered, or used, for describin
25、g or appraising the corrosion risk of materials, products or systems under actual fire conditions. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO11907. At the time of publication, the editions indicat
26、ed were valid. All standards are subject to revision, and parties to agreements based on this part of ISO11907 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid Internation
27、al Standards. ISO/IEC Guide 52:1990, Glossary of fire terms and definitions. IEC 695-5-1:1993, Fire hazard testing Part5: Assessment of potential corrosion damage by fire effluent Section1: General guidance. 3 Definitions For the purposes of this part of ISO11907, the definitions given by ISO/IECGui
28、de52 apply, together with the following definitions. 3.1 corrosion the reaction of a metallic material with its environment, resulting in a measurable change of the material and possibly in an impairment of the functioning of a metal part or of an entire system NOTE 3In most cases, the reaction is e
29、lectrochemical. In others, however, it may be chemical (non-electrochemical) or physical. 3.2 corrosion damage the extent of the physical damage or impaired function caused by the chemical action of fire effluents 3.3 fire effluent decay characteristics the chemical and physical changes in fire effl
30、uents with time and during transport 3.4 fire model means for the decomposition and/or combustion of test specimens under defined conditions to representa) known stage(s) of fire in order to generate fire effluents for corrosivity assessments. (This term is also used by the fire science community in
31、 the mathematical simulation of fire characteristics.) 3.5 corrosion detector a standardized test piece made up to represent an electrical circuit or other material which can fail by corrosive effects 4 Principles 4.1 One of the basic principles of the test is expressed by the sequence: combustion c
32、ondensation corrosion, which is observed in real fires when humid effluents condense out on to cooler structures and components which may have escaped direct thermal damage. This may produce conditions conducive to corrosion. The test chamber for measuring the corrosiveness of effluents has been des
33、igned in order to reproduce the above conditions in a small-scale test.ISO11907-2:1995(E) 2 BSI 04-2000 The method primarily measures corrosion under conditions such that the sample is subject to condensation of water from the atmosphere and from the combustion products. It is also able to measure c
34、orrosion produced under conditions of low relative humidity, or where the detector temperature is above the dew point. 4.2 Under high relative humidity conditions, the combustion products are made to condense out on to a target substrate. This corrosion detector is a printed wiring board (PWB) (see5
35、.3), which is typically kept at constant temperature below the dew point of the effluents in the chamber. 4.3 In order to induce condensation, it is necessary to have a certain minimum relative humidity within the test chamber. Moreover, for a given atmosphere at a given temperature and relative hum
36、idity, condensation on a surface will occur only if its temperature lies at or below the dew point for that atmospheric condition. NOTE 4Moisture may be adsorbed on to the detector surface at temperatures above the dew point if hygroscopic chemical species have been deposited on to the surface of th
37、e corrosion detector. 4.4 If the desired temperature and relative humidity are known, it is possible to calculate the absolute humidity, i.e.the number of grams of water per cubic metre, necessary to produce condensation on the corrosion detector. 4.5 Constant temperature and relative humidity in th
38、e test chamber are established at the time of ignition (although the combustion of the specimen produces a temporary increase in the temperature of the test atmosphere). Once ignition has taken place, the repeatability of the test results depends on having a constant temperature of condensation at t
39、he detector. The detector temperature determines the residual relative humidity in the test chamber and also the reliability of the measurements of the electrical resistance of the detector, since this varies with temperature. 5 Apparatus 5.1 Test chamber The test chamber shall consist of a cylindri
40、cal sealed enclosure with a total volume of approximately20litres and a diameter of approximately 300mm (a typical test apparatus is described inAnnex A). The chamber shall be maintained at a constant temperature, e.g.by heating elements around its external surface. The test chamber doors shall be d
41、esigned to provide a gas-tight seal adequate for the purpose of maintaining a constant relative humidity within the test chamber for the duration of the test. The materials of construction of the test chamber shall have sufficiently low permeability to water vapour to permit the maintenance of a con
42、stant relative humidity of (65 2)% at the test temperature of50 C 2 C for the duration of the test. All materials within the chamber, with the exception of the corrosion target, shall be chemically inert to the combustion products or shall be protected from contact with the combustion products by me
43、ans of a surface coating or other device. The interior surfaces of the chamber are thermostatted uniformly at50 C 2 C to avoid formation of cold spots. 5.2 Ignition source 5.2.1 The ignition source consists of an inert crucible containing a resistance wire heater: a typical arrangement is shown inFi
44、gure A.4. 5.2.2 A dispensing device shall be provided, capable of placing the specimen in the crucible after the required ignition temperature has been reached. 5.3 Corrosion detector The corrosion detector shall be a resistance etched on a copper-plated laminated base. The detector shall be constru
45、cted of36 conductor tracks each52mm 1mm long, 0,3mm 0,02mm wide and174m 1 4m thick, on a laminated epoxy-resin base-plate (seeFigure A.5). Condensed products react with the copper if they are corrosive and the corrosivity shall be assessed by measurement of the resistance variation due to attack on
46、the copper circuit. 6 Test specimens A minimum sample quantity of3g shall be provided to allow five tests to be carried out on individual specimens of600mg 2mg of material. The specimens shall be in the form of granules or chips to ensure intimate contact with the ignition source. Prior to use, new
47、equipment shall be calibrated for relative humidity and temperature within the exposure chamber, and for the temperature of the ignition source, in accordance with the procedures recommended by the equipment manufacturer. These calibrations shall be carried out for maintenance purposes after every50
48、runs at least. Dimensions: PWB (40 1) mm (80 1) mm Base-plate (70 2) mm (140 2) mm Resistance: 8,0 7 0,5 7ISO11907-2:1995(E) BSI 04-2000 3 7 Procedure 7.1 Condensing mode 7.1.1 Place a test specimen in the dispensing device(5.2.2). 7.1.2 Prepare the PWB by cleaning with a pumice-based acidic powder
49、formulation. Rub the PWB with a piece of moist cotton wool containing the cleaning powder. Thoroughly wash the PWB with excess deionized water and carefully wipe it dry. NOTE 5By this method, copper surfaces are cleaned chemically as well as physically. The acidic chemical cleaning action removes oxides and wets the PWB surface. No residual film remains after rinsing and drying. Circuits which have been subjected to this treatment show no sign of corrosion in simple condensation tests. 7.1.3 Ensure that t
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