1、BRITISH STANDARD BS3900-G6: 1989 Methods of Test for paints Part G6: Assessment of resistance to fungal growth This Part is to be read in conjunction with BS3900-0, issued separately UDC 667.613:620.193.82:614.8BS3900-G6:1989 This British Standard, having been prepared under the directionof the Pigm
2、ents, Paints and Varnishes Standards Committee, was published under the authority of the Board of BSI and comes into effect on 31 July1989 BSI07-1999 The committees responsible for thisBritish Standard are shown inBS3900-0 The following BSI references relate to the work on this standard: Committee r
3、eferencePVC/10 Draft for comment86/52086DC ISBN 0 580 17153 1 Foreword This Part of BS3900 has been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee. It is one of a series of standards in Group G of BS3900 which is concerned with environmental testing of paint f
4、ilms. This Part describes a method for assessing the resistance to fungal growth and has been developed as a result of an extensive series of international co-operative experiments conducted under the auspices of the International Biodeterioration Research Group. The results of the cooperative study
5、, which were published in1984 A F Bravery, S Barry, M Pantke and W Worley, J. Oil Colour Chemists Association,1984,67(1),2), showed that close agreement between and within the different laboratories could be achieved by experienced microbiologists. It is assumed in the drafting of this standard that
6、 it will be used and applied by those who are appropriately qualified and experienced. The procedures described in this standard are intended to be carried out by suitably trained and/or supervised personnel. The substances and procedures described may be injurious to health if inadequate precaution
7、s are taken. This standard refers only to its technical suitability and does not absolve the user from statutory obligations relating to health and safety. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their
8、correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyr
9、ight date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS3900-G6:1989 BSI 07-1999 i Contents Page Foreword Inside front cover 1 Scope 1 2 Definitions 1 3 Suppleme
10、ntary information 1 4 Principle 1 5 Materials and apparatus 1 6 Preparation of test panels 1 7 Microbiological tests 2 8 Test report 4 Appendix A Biological safety precautions 5 Appendix B Test tank (incubator) 5 Appendix C Cultures of fungi 6 Appendix D Control paint 6 Appendix E Preconditioning of
11、 coated test panels 6 Appendix F Preparation of mixed inoculum of the test fungi 7 Appendix G Preparation of soiling medium 7 Figure 1 Test tank (incubator) 5 Table 1 Composition of mixed inoculum 3 Table 2 Rating scale for assessment of fungal growth 3 Table 3 Fungal species that may be used in add
12、itional tests 4 Table 4 Control paint 6 Publications referred to Inside back coverii blankBS3900-G6:1989 BSI 07-1999 1 1 Scope This Part of BS3900 describes a method for assessing the fungal (mould) resistance of paints, varnishes and lacquers with or without fungicidal additives, applied either as
13、part of a multi-coat system or separately. In addition to the information given in the method certain supplementary information detailed in clause3 is necessary before this method can be used. WARNING When carrying out this method it is essential to avoid inhalation of spores by the operator and con
14、tamination by the spores of the laboratory. Guidance on precautions is given in Appendix A and attention is drawn to BS2011-2.2J for more detailed advice. NOTE 1The method has been prepared to assess the resistance to fungal growth of paints applied in the laboratory to specified panels. The princip
15、le may also be applied to production applied coatings on sheet materials having established a criterion for assessment but a claim to comply with this Part of BS3900 cannot be made. NOTE 2The titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions F
16、or the purposes of this Part of BS3900, the definitions given in BS2015 apply. 3 Supplementary information For any particular application or product, the following supplementary information shall be provided for this method of test. This information shall be derived, partly or totally, from the prod
17、uct specification, British Standard or other documents relating to the product under test or, where appropriate, shall be the subject of agreement between the interested parties. a) The material, thickness and surface preparation of the test substrate (see5.1 and6.1). b) The method of application of
18、 the test coating to the test substrate (see6.3). c) The duration and conditions of drying the coating (or conditions of storing and ageing, if applicable) or conditioning before testing (see6.4). d) The inoculum mixture to be used including the name and strain number of any additional fungal specie
19、s against which the coating is to be tested (see7.7). e) Whether a soiling medium is to be used and, if so, whether it is natural or artificial (see7.2 and7.4). f) The duration of the test (see7.6). g) The wetting agent (seeF.1). 4 Principle Flat panels of wood, plaster, steel or other relevant and
20、suitable substrates are painted, and then conditioned in a suitable environment before being inoculated with test organisms. The inoculated panels are incubated in a test cabinet under specified conditions and inspected at specified intervals for fungal growth. The extent of such growth is assessed
21、using a numerical scale, together with a written description of the nature of the growth and, where possible, photographs. 5 Materials and apparatus 5.1 Flat test panels, selected and prepared as described in6.1. NOTEThe choice of test panel material depends on the intended field of use of the paint
22、s under test (see clause3). 5.2 Apparatus for application of mixed inoculum (see7.3). 5.3 Apparatus for application of soiling medium (see7.4). 5.4 Test tank (incubator) (see Appendix B and Figure 1). 5.5 Cultures of appropriate test fungi species, grown on suitable media (see Appendix C). 5.6 Micro
23、scope, enabling inspection of the painted surface to be carried out at a magnification of 25to 30 and a spore count to be carried out at a magnification of approximately 200. NOTEA camera attachment suitable for taking photographs at 25 to 30 is desirable but not essential. 5.7 Haemocytometer comply
24、ing with BS748, or similar device for determining the concentration of spores in a suspension. 5.8 Ancillary apparatus, and facilities for mycological testing. 5.9 Control paint, (see Appendix D). 5.10 Distilled water, of at least grade3 of BS3978. 5.11 Petroleum spirit,60 C to80 C boiling range. 6
25、Preparation of test panels 6.1 Test panel substrates 6.1.1 General. Test panels shall be approximately100mm 75 mm with a hole2mm to3mm in diameter drilled91mm from the mid-point of one of the75mm sides. The edges of porous substrates shall be presealed with an inert sealant.BS3900-G6:1989 2 BSI 07-1
26、999 After preparation depending on the substrate (see below) the panels shall be conditioned at23 2 C and505% r.h. for at least7 days before coating. 6.1.2 Wood panels. Test panels shall be10 1mm thick, (see clause3) and cut from straight-grained stock with the grain in the100mm direction. When exam
27、ined using normal or corrected vision without magnification, they shall be free from knots, stains, excess resin or other defects. Ensure that the panels do not contain residual chemicals from anti-sap-stain treatments often applied before shipping. The sapwood of Scots pine (Pinus sylvestris) shall
28、 be used as the standard reference timber, if other species are used for the test panels this shall be clearly stated in any report. Lightly sand the faces and edges of the panels with a fine-grade sand paper. 6.1.3 Plaster panels. From a mixture of3 parts (by mass) of calcium sulphate hemi-hydrate
29、(CaSO 4 .H 2 O) and2 parts (by mass) of distilled water(5.10), cast plaster test panels10 1mm thick (see clause3). Form the panels in suitable moulds, with a level and smooth finish and then leave to set at room temperature for17 1 h, usually overnight. Carefully remove the panels from the moulds. 6
30、.1.4 Metal panels. Cut metal panels, from mild steel sheet or from other metal or alloy sheet if specified (see clause3), of approximately1mm thickness. Lightly roughen the surfaces with fine-grade sand or carborundum paper. Clean and degrease the panels with petroleum spirit(5.11). NOTEBS3900-A3 sp
31、ecifies metal standard test panels that may also be suitable for use in connection with this Part of BS3900. 6.1.5 Other materials. e.g.mineral building boards, wood composite board. Cut panels from material at least5mm thick (see clause3). If the boards contain cement type materials reduce the pH t
32、o approximately7 by exposure to carbon dioxide atmosphere in sealed polyethylene bags. Test for the pH value of the surface using a moistened wide range indicator paper. 6.2 Paint samples Take representative samples of each paint as described in BS3900-A1. Examine and prepare each sample as describe
33、d in BS3900-A2. 6.3 Application of the paint 6.3.1 General. During the painting and drying operations and conditioning (see6.4), keep the test laboratory as free from dust and spores as practicable. Maintain the test atmosphere at23 2 C and at505% r.h. Prepare at least two coated test panels for eac
34、h paint under test and the control paint (see Appendix D). 6.3.2 Test paints. Apply by brushing, dipping or spraying a uniform coat of the thoroughly mixed paint (see6.2) to all surfaces of the prepared test panel (see6.1). In accordance with the manufacturers or other specified instructions (see cl
35、ause3) allow the coated panels to dry and, if required, re-coat. NOTEIt is recommended that the first coat of a water-borne test paint should be thinned with water and that only subsequent coats of the paint are applied as received. 6.3.3 Control paint. Apply a coat of the control paint (see Appendi
36、x D) by brush to a substrate of the same material as that to which the test paint has been applied in the same test procedure. Allow the coated test panel to dry for24h and then apply a second coat by brush. 6.4 Conditioning of coated test panels NOTEFor paints for special purposes, special pre-trea
37、tments other than or as well as the conditioning described in6.4.1 and6.4.2 may be required and details should be recorded in the test report. Examples of two alternative procedures are given in Appendix E. 6.4.1 Paint for interior use. Allow panels coated with solvent-borne paint to condition for21
38、 days and the panels coated with water-borne paint to condition for2 days under the specified conditions (see6.3.1). 6.4.2 Paints for exterior use. Allow panels coated with a paint for exterior use to condition for7 days under the specified conditions (see6.3.1). Then expose the panels for250h in an
39、 artificial weathering machine of the type described in BS3900-F3 unless otherwise specified (seeclause3). At the end of the exposure period remove the panels and allow them to condition for at least24h under the specified conditions (see6.3.1). 6.4.3 Control paint. Allow panels prepared as describe
40、d in6.3.3 to dry for at least24h and then condition for21 days under the specified laboratory conditions (see6.3.1). 7 Microbiological tests 7.1 Preparation of the mixed inoculum 7.1.1 The mixed inoculum shall consist of a mixture of all the species given in Table 1. A well-sporulating culture of ea
41、ch of the species grown on a sloped medium in a sterile glass tube shall be used.BS3900-G6:1989 BSI 07-1999 3 7.1.2 Prepare the mixed inoculum using the method described in Appendix F. 7.2 Preparation of soiling medium Prepare the material and artificial soil using the appropriate method described i
42、n Appendix G. Table 1 Composition of mixed inoculum 7.3 Inoculation of coated test panels After preconditioning the coated panels (see6.4) place the panels horizontally and spray each on one side with1mL of the mixed inoculum to give as uniform a coverage as possible. If the panels are to be tested
43、without further treatment allow to dry for31h before use. If the panels are to be further treated with a soiling medium proceed direct to7.4. 7.4 Application of soiling medium to inoculated panels NOTESoiling is appropriate to paints for exterior use and to those for certain interior uses where a hi
44、gh soiling hazard may be found such as kitchens, breweries and bakeries. Weigh approximately0.03g of the appropriate soiling medium (see7.2). Whilst the inoculum is still wet, apply this quantity as uniformly as possible to the inoculated surface using a coarse spray. 7.5 Incubation 7.5.1 Place the
45、treated test and control panels randomly in an operating test tank (seeB.2). If the test tank does not contain compartments there shall be at least25mm between the nearest faces of adjacent panels and inoculated surfaces shall not face each other. Continue the incubation ensuring that the conditions
46、 specified inB.2 are maintained and avoiding washing of the inoculum from the panels. 7.6 Assessment 7.6.1 Control panels. After14 days incubation examine the control panels using the microscope(5.6) and assess the fungal (mould) growth using the scale given in Table 2. Optimum fungal growth conditi
47、ons in the cabinet are indicated if the rating at this stage is2 to3. Return the control panels to the tank and continue the incubation for a further14 days at which time the rating assessment of the control panels indicating optimum conditions, will be4 to5. if these ratings have not been achieved
48、the test shall be abandoned and repeated with reinoculated panels. If the ratings are satisfactory replace the control panels and proceed to7.6.2. Table 2 Rating scale for assessment offungal growth 7.6.2 Test panels. Examine the test panels using the microscope(5.6). Assess the fungal growth using
49、the scale given in Table 2 and report the rating for each at28 days(4weeks) incubation. Replace the test panels and continue the incubation repeating the assessment after2 and8 week periods further incubation, and report the ratings at6 and12 weeks. NOTE 1If all the panels in a particular test show a rating of5 at any of the interim assessments the test should be discontinued at that stage. NOTE 2It is recommended that photographs of the test panels at each assessment should be taken for record purposes. Species Strain number Aspergillus vers
