1、DEUTSCHE NORM October 1997 Evaluation of the action of microorganisms on plastics (IS0 846 : 1997) English version of DIN EN IS0 846 DIN EN IS0 846 - ICs 07.100.99; 83.080.01 Descriptors: Plastics, pest resistance, testing. Supersedes DIN 53739, November 1984 edition. Kunststoffe - Bestimmung der Ei
2、nwirkung von Mikroorganismen auf Kunststoffe (IS0 846 : 1997) European Standard EN IS0 846 : 1997 has the status of a DIN Standard. A comma is used as the decimal marker. National foreword This standard has been published in accordance with a decision taken by CEN/TC 249 to adopt, without alteration
3、, International Standard IS0 846 as a European Standard. The responsible German body involved in its preparation was the Normenausschu Kunststoffe (Plastics Technology Standards Committee), Technical Committee Verhalten gegen Umgebungseinflsse. DIN EN IS0 291 *) and DIN IEC 68-2-1 O are the standard
4、s corresponding to International Standards IS0 291 and IEC 68-2-10, respectively, referred to in clause 2 of the EN. Amendments DIN 53739, November 1984 edition, has been superseded by the specifications of EN IS0 846 : 1997. Previous edition DIN 53739: 1984-1 1. National Annex NA Standard referred
5、to (and not included in Normative references) DIN EN IS0 291 Plastics - Standard atmospheres for conditioning and testing (ISO/DIS 291 : 1996)*) *) At present at the stage of draft. EN comprises 25 pages. O No pari of this standard may be reproduced without the prior permission of Ref. No. DIN EN IS
6、0 846 : 1997-1 O DIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, D10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group O9 Sales No. II09 04.98 EUROPEAN STANDARD NORME EUROPENNE EUROPAISCHE NORM EN IS0 846 June 1997 ICs 07.100.01; 83
7、.080.01 Descriptors: Plastics, pest resistance, testing. English version Plastics Evaluation of the action of microorganisms (IS0 846 : 1997) Plastiques - valuation de laction des micro-organismes (IS0 846 : 1997) Kunststoffe - Bestimmung der Einwirkung von Mikroorganismen auf Kunststoffe (IS0 846 :
8、 1997) This European Standard was approved by CEN on 1997-05-1 5. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical r
9、eferences concerning such national stand- ards may be obtained on application to the Central Secretariat or to any CEN member. The European Standards exist in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN memb
10、er into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norwa
11、y, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1997. CEN - All rights of exploitation in any form and by any means res
12、erved worldwide for CEN national members. Ref. No. EN IS0 846 : 1997 E Page 2 EN IS0 846 : 1997 Foreword International Standard IS0 846 : 1997 Plastics - Evaluation of the action of microorganisms, which was prepared by ISO/TC 61 Plastics of the International Organization for Standardization, has be
13、en adopted by Technical Committee CEN/TC 249 Plastics, the Secretariat of which is held by IBN, as a European Standard. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, and conflicting national standards withdrawn,
14、 by December 1997 at the latest. In accordance with the CENKENELEC Internal Regulations, the national standards organizations of the follow- ing countries are bound to implement this European Standard: Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland,
15、 Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. Endorsement notice The text of the International Standard IS0 846 : 1997 was approved by CEN as a European Standard without any modification. Contents Introduction 1 2 3 4 5 6 7 8 9 10 11 12 13
16、 Scope Normative references Definitions Principle . Apparatus and materials Test specimens . Preparation of specimens Procedu res Assessment . Expression of results . Accuracy of the measurements . Test report . Bibliography . Annexes A Detemination of the water content and water-holding capacity of
17、 a soil B Precision C Information on test fungi Page 3 4 5 5 5 6 10 11 12 17 19 20 20 21 22 24 25 Page 3 EN IS0 846 : 1997 Introduction Under certain climatic and environmental conditions, microorganisms may settle on and colonize the surface of plastics or plastics products. Their presence and/or t
18、heir metabolic products may not only damage the plastic itself, but may also affect the serviceability of building materials and systems containing plastic parts. The tests and test conditions specified in this International Standard are empirical and cover most- but not all- potential applications.
19、 For specific applications and for long-term tests, procedures should be agreed upon which reflect performance under actual conditions. The actions of microorganisms on plastics are influenced by two different processes: a) direct action: the deterioration of plastics which serve as a nutritive subs
20、tance for the growth of the microorganisms; b) indirect action: the influence of metabolic products of the micro- organisms, e.g. discolouration or further deterioration. This International Standard deals with both of these two processes, as well as their combined action. Page 4 EN IS0 846 : 1997 WA
21、RNING - Handling and manipulation of microorganisms which are potentially hazardous requires a high degree of technical competence and may be subject to current national legislation and regulations. Only personnel trained in microbiological techniques should carry out such tests. Codes of practice f
22、or disinfection, sterilization and personal hygiene must be strictly observed. It is recommended that workers consult IEC 68-2-10:1988, appendix A “Danger to personnel”, and IS0 721 8:1996, Microbiology of food and animal feeding stuffs - General rules for microbiological examinations. 1 Scope This
23、International Standard specifies methods for determining the deterioration of plastics due to the action of fungi and bacteria and soil microorganisms. The aim is not to determine the biodegradability of plastics. The type and extent of deterioration may be determined by a) visual examination andlor
24、 b) changes in mass and/or c) changes in other physical properties. The tests are applicable to all articles made of plastic that have an even surface and that can thus be easily cleaned. The exceptions are porous materials, such as plastic foams. This International Standard uses the same test fungi
25、 as IEC68-2-10. The IEC method, which uses so-called “assembled specimens”, calls for inoculation of the specimens with a spore suspension, incubation of the inoculated specimens and assessment of the fungal growth as well as any physical attack on the specimens. The volume of testing and the test s
26、trains used will depend on the application envisaged for the plastic. These parameters should therefore be agreed upon before the tests and should be stated in the test report. Page 5 EN IS0 846 : 1997 2 Normative references The following standards contain provisions which, through reference in this
27、 text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent
28、editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. IS0 291 :-I), Plastics - Standard atmospheres for conditioning and testing. IEC 68-2 - 10:1988, Basic environmental testing procedures - Part 2: Tests - Test J and guidanc
29、e: Mould growth. 3 Definitions For the purposes of this International Standard, the following definitions apply: 3.1 biodeterioration: A change in the chemical or physical properties of a material due to the action of a microorganism. 3.2 fungistatic effect: The antimycotic effect of an antimicrobia
30、l treatment which prevents a given material from being overgrown by fungi under moist conditions. 3.3 biodegradation: The term “biodegradation“ is being discussed by TC 61 /SC 5MIG 22, Biodegradability, and the official definition will be included here when it is available. 4 Principle 4.1 The test
31、involves exposing test specimens of plastic to the action of selected test strains of fungi and bacteria (or, in the case of the soil-burial test, to microbially active soil) for specified or agreed periods of time under specified conditions of temperature and humidity. At the end of the exposure, t
32、he test specimens are assessed before and/or after cleaning by visual examination and/or any change in mass or other physical properties is determined. The results obtained with the specimens exposed to biological attack (batch i) are compared with those obtained from untreated specimens (batch O) o
33、r sterile specimens (batch S) kept under the same conditions. 4.2 Short descriptions of the test methods used to determine the resistance of plastics to fungi (method A) or the fungistatic effects (methods B and B), resistance to bacteria (method C) and resistance to soil microorganisms (method D) a
34、re given below. 4.2.1 Resistance to fungi 4.2.1.1 Method A: Fungai-growth test Test specimens are exposed to a mixed suspension of fungus spores in the presence of an incomplete nutritive medium (without a carbon source). The fungi can only grow at the expense of the material. If the specimens conta
35、in no nutritive component, the fungi cannot develop mycelia and there is no deterioration of the plastic. 1) To be published. (Revision of IS0 291:1977) Page 6 EN IS0 846 : 1997 Method A is suitable for the assessment of the inherent resistance of plastics to fungal attack in the absence of other or
36、ganic matter. It is recommended that, when method A is carried out, methods B and B are also carried out to assist in the interpretation of the results. 4.2.1.2 Methods B and B: Determination of fungistatic effects Test specimens are exposed to a mixed suspension of fungus spores in the presence of
37、a complete medium, .e. with a carbon source. Even if the plastic does not contain any nutritive elements, the fungi can grow over the specimens and their metabolic products can attack the material. Any inhibition of the growth either on the plastic or in the growth medium (zone of inhibition) shows
38、fungistatic activity of the plastic or the presence of a fungicidal treatment. In method B, the specimens are not placed on the nutritive medium until it is completely overgrown. MethodsB and 8 are used when Surface contamination is expected. In order to save time, and for a better understanding of
39、the phenomenon, it is recommended that the two methods are carried out simultaneously. 4.2.2 Method C: Resistance to bacteria The action of bacteria on test specimens is assessed using an incomplete medium. If there is no growth in the agar round the specimen, then the specimen does not contain any
40、nutritive components. 4.2.3 Method D: Resistance to microbially active soil (soil-burial test) Test specimens are completely buried in natural soil with a known water-holding capacity and a specified moisture content (see annex A). The soil-burial test has been included in this International Standar
41、d because many plastics are used in permanent contact with soil and exposed to high humidities. 4.3 Choice of properties for assessment of biodeterioration The choice of the properties to be determined depends on the aim of the test. A visual assessment of biological attack should preferably always
42、be made as the first stage in assessing the resistance of the plastic. The measurement of changes in mass is recommended, especially for those plastics that contain biologically degradable substances, such as plasticizers, lubricants and stabilizers (as in plasticized PVC, for instance). The measure
43、d loss is, in this case, often lower than the actual loss as the biologically degradable substance is only partly utilized and the metabolic products often remain in the plastic. When, above all, the surface is affected, it is recommended that determinations be made of those properties which clearly
44、 indicate surface changes, such as surface gloss, flexural properties, impact resistance and hardness. 5 Apparatus and materials 5.1 For all tests 5.1.1 Incubators That used for tests involving fungal and bacterial attack shall be capable of controlling the temperature to fl OC at any temperature fr
45、om 20 “C to 35 “C at a relative humidity of 90 30 or greater. Page 7 EN IS0 846 : 1997 That used for soil-burial tests shall be capable of controlling the temperature to +1 OC at 29 “C at a relative humidity of 95% or greater. NOTE - Experience has shown that it is preferable to use two incubators:
46、one for Petri dish tests and another for soil-burial tests. 5.1.2 Oven, capable of controlling the temperature at 45 OC for drying test specimens and at between 103 OC and 105 OC for determining the water-holding capacity of soil. 5.1.3 Desiccator, capable of maintaining standard temperature and hum
47、idity conditions (23 “C and 50 % R.H.) for the conditioning of test and control specimens. 5.1.4 Autoclave, capable of maintaining a temperature and pressure of 120 “C and 2 bar, respectively, for sterilizing Petri dishes and soil. 5.1.5 Analytical balance, accurateto 0,l mg. 5.1.6 Laboratory centri
48、fuge. 5.1.7 Stereoscopic microscope, magnification x 50. 5.1.8 Glass or plastic disposable Petri dishes, of suitable size for exposing test specimens. 5.1.9 Glass containers, with a volume of about 1 litre (height 16 cm; diameter 11 cm), for example preserving jars with covers. 5.1.10 Distilled or d
49、eionized water. The water used for the preparation of all solutions and nutritive media and for all determinations shall be distilled or deionized and have a conductivity of 95 % relative humiditye) Page 13 EN IS0 846 : 1997 8.2.1 Fungal-growth test (method A) 8.2.1.1 Filling the Petri dishes After sterilization, pour incomplete agar medium (5.2.3.4) into sterile Petri dishes to give a depth of about 5 mm. It solidifies on cooling. 8.2.1.2 Arrangement of test specimens Place the specimens separately, as flat as possible, on the solidified medium, avoiding any contact betwee
