1、Designation: D3274 09 (Reapproved 2017)Standard Test Method forEvaluating Degree of Surface Disfigurement of Paint Filmsby Fungal or Algal Growth, or Soil and Dirt Accumulation1This standard is issued under the fixed designation D3274; the number immediately following the designation indicates the y
2、ear oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. D
3、epartment of Defense.1. Scope1.1 Fungal growth, frequently referred to as mildew in thepaint industry, causes defacement of paint film exposed out-doors. The visual rating of paint surface disfigurement due tofungal or algal attack is required in order to compare theperformance of different coatings
4、.1.2 This method of rating mildew evaluation is intended tobe used on exterior exposed paint films. This method may beused to rate interior fungal or algal growth, but it should benoted that the growth patterns on interior surfaces are differentthan exterior due to the lack of weathering influences.
5、 It isprimarily intended for test specimens, but can also be sued forrating mildew growth on larger structures such as entirehouses. If this is used for large areas, the project should bebroken down into smaller sections.1.3 This method is intended for field use for the macrorating of surface disfig
6、urement only. The visual scales aremeant to be used by the unaided eye to rate algal, fungal, or dirtdisfigurement on larger surface areas such as test panels, sidingboards, or entire buildings. Techniques are included for thedifferentiation of soil and dirt.1.4 Fungi will grow on most paint films e
7、xposed outdoorsthat are located in conditions favorable to growth. Test proce-dures such as Practices D1006, D3456, and G7 are availabledescribing natural exposure tests that can be used to exposepaint films, in order to create fungal or algal growth.1.5 The pictorial references available for use wi
8、th this testmethod provide a numerical basis for rating the degree offungal or algal growth on paint films.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety,
9、health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of Inte
10、rnational Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1006 Practice for Conducting Exterior Exposure Tests ofPaints on WoodD3456 Practice for Determining by Exterior Exposure Test
11、sthe Susceptibility of Paint Films to MicrobiologicalAttackD4610 Guide for Determining the Presence of and Remov-ing Microbial (Fungal or Algal) Growth on Paint andRelated CoatingsG7 Practice for Atmospheric Environmental Exposure Test-ing of Nonmetallic Materials3. Terminology3.1 Types of Fungal Gr
12、owthDuring examination of a paintfilm, it may be possible to distinguish between the severaltypes of fungal or algal growth. If required, it may be necessaryto note the type of fungal or algal growth found. Undermagnification, and with some identification training, it ispossible to be able to distin
13、guish growth types. The followingdefinitions are some growth types that may be found.3.2 hyphae, nthread-like, tubular fungal filaments thatcompose the mycelium.3.3 mildew, na popular term for the conglomerations offungi that grow on and disfigure paint films.3.4 mycelium, nvegetative mass of hyphae
14、 forming thebody of a fungus.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, andApplications and is the direct responsibility ofSubcommittee D01.28 on Biodeterioration.Current edition approved Dec. 1, 2017. Published December 2017. Originall
15、yapproved in 1973. Last previous edition approved in 2013 as D3274 09 (2013).DOI: 10.1520/D3274-09R17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards
16、Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision
17、on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.5 sporean asexual reproductive cell capable of develop-ing into a mature fungus without fusion with another cell.3.5.1 Discuss
18、ionSpores tend to be spherical in morphol-ogy and are observed singly or in clusters. Spores may or maynot be associated with fungal mycelia and can range in a widevariety of colors. Although primarily gray or black, somespores are green in color and have been mistaken as terrestrialalgae.4. Signifi
19、cance and Use4.1 The growth of fungi in and on the surface of paint filmsrepresents a major cause of discoloration or disfigurement ofpainted surfaces. Because of their dark pigmentation, it isfrequently difficult to distinguish fungi from dirt or soilparticles.4.2 Use of Pictorial Standards:4.2.1 T
20、he pictorial references that are part of this testmethod are for illustration purposes and may be used for visualcomparisons.4.2.2 The diagrams represent an idealized schematic ofvarious growth levels on paint films. they are intended as arepresentation only, but will serve as a useful guideline toe
21、stablish amount and type of growth.4.2.3 The diagrams represented in Fig. 1 are not derivedfrom a linear scale. The scale is intended to provide for morediscrimination at the earlier stages of fungal or algal growth. Itis at these levels that greater discernment is necessary.4.2.4 Comparisons made o
22、n dark colored substrates will bemuch more difficult, and will therefore require much more careand attention. It must be noted that because it is difficult todistinguish mild fungal or algal growth on the very darksubstrates, there may be a tendency to under-rate thosespecimens.5. Soil or Dirt Parti
23、cles5.1 Fungal or algal ratings can be made more difficult by thepresence of dirt and soil particles. The distinction between dirtaccumulation and surface mildew is sometimes difficult todistinguish to the naked eye.5.2 Use visual evaluation under high power binocular mag-nification to assist in det
24、ermining whether the particle is soil,dirt, or mildew.(a)FIG. 1 Early Stages of Fungal GrowthD3274 09 (2017)2NOTE 1After experience has been gained in a certain geographiclocation, recognition of mildew becomes easier and can often be achievedwithout the aid of magnification.5.3 In some cases it is
25、necessary to place a drop of 5 %sodium hypochlorite (common household bleach) on the paintsurface to determine if the defacement is biological in accor-dance with Guide D4610.5.3.1 The bleach will remove the coloration from any livingorganic matter, therefore if the color of the “particles” underthe
26、 bleach drop do not change color, that object is probablyeither dirt or soil.5.4 The addition of a drop of bleach is an invasive anddestructive test. The future growth of organisms on that spotand in the immediate surrounding area will be inhibited for along time after the addition. Do not use bleac
27、h unless abso-lutely necessary, and make a note on the report form if used.6. Visual Evaluations6.1 Whenever fungal or algal growth is being rated visuallyit should be done without the aid of magnification. The ratingshould be made as it appears to the naked eye. Up to 10magnification can be used to
28、 assist in the identification ofmildew and to clarify the rating. Magnification will also help todistinguish between dirt attachment and mildew growth. Ifmagnification is used, it should be noted on the report.6.2 View the paint film under good illumination conditions,either in a controlled light bo
29、oth under daylight light source, oroutside in the shade. Occasionally it may be necessary to viewthe paint film under strong sunlight.6.3 Rate the specimen using one of the following methods.Under most field use conditions, comparison to the drawingsprovides a satisfactory numerical rating. Use a tr
30、ansparent gridscale to determine percent area coverage for more accurateratings as described in 6.3.3.6.3.1 There are three different growth patterns described inthis standard:Description DesignationSpot Growth SNon Uniform Spread PComplete Coverage G6.3.2 Determine which growth pattern most closely
31、 matchesthat seen on the specimen. See Fig. 1 a through c, for visualrepresentation of these patterns.6.3.3 Compare the growth to the drawings. Estimate whichpictorial reference most closely matches the actual test speci-men being evaluated. Rate the number and type of growth(b)FIG. 1 Early Stages o
32、f Fungal Growth (continued)D3274 09 (2017)3pattern. Derive the numerical rating directly from the ratingscales shown in Table 1. Include the growth pattern type asdetermined from Fig. 1 a through c. Actual photographs offungal or algal surface growth are shown in Fig. 2.6.4 Rating ScalesRate the mil
33、dew growth using either anestimate of the percentage of the surface covered, or byapplying a descriptive term to the general appearance. Thecross-reference of these three items is detailed in Table 1.6.4.1 The odd numbered ratings not shown in Table 1 maybe applied by interpolation. Odd numbered rat
34、ings are shownin Fig. 1 a through c. No pictures for 10 or zero ratings areshown in the figures.6.5 When the growth is found to be concentrated in one areaof the test surface, enter a note in the report to this effect. Statewhere the concentration was found, and what type of growthwas most prevalent
35、.6.6 Ignore the area around the outer edge of the test surfaceif the mildew growth extends all the way to the edge. Themildew growth here may be due to other influences andtherefore not necessarily reflect the true resistance of the paintfilm. If there is growth occurring along one edge that hasinva
36、ded other areas on the surface, originating typically at thebottom, report this as a special note.6.7 If there are two growth types, for example, Spot andNon-Uniform, report the coverage and type for both types. It ispossible that the type of coverage might change during thecourse of the exposure, t
37、ypically from Spot to Non-Uniform orComplete Coverage.6.8 IdentificationIf the fungal or algal species is known,indicate on the report the name of the organism and the methodby which the identification was made.7. Report7.1 The report should include the numerical rating value,plus any notes regardin
38、g uniformity or other morphology.7.2 Use a report format as agree upon between the contrac-tual parties. As a minimum, report the following criteria. Notethat all the following information may not be available if theexposure is carried out by an independent testing agency.7.2.1 Unique reference numb
39、er to identify test series.7.2.2 Paint panel identification.(c)FIG. 1 Early Stages of Fungal Growth (continued)TABLE 1 Rating ScalesRating Coverage % Description10 0 No Fungal Growth9 0.03 Trace8 0.1 Slight6 1 Moderate4 10 Pronounced2 33 Severe0 50 Complete CoverageD3274 09 (2017)4Slight MildewFIG.
40、2 Examples of Paint Disfigurement through Fungal or Algal GrowthD3274 09 (2017)5Moderate MildewFIG. 2 Examples of Paint Disfigurement through Fungal or Algal Growth (continued)D3274 09 (2017)6Severe MildewFIG. 2 Examples of Paint Disfigurement through Fungal or Algal Growth (continued)D3274 09 (2017
41、)77.2.3 Date of report.7.2.4 Date of exposure.7.2.5 Location of exposure.7.2.6 Numerical fungus rating.7.2.7 Any notes about morphology or uniformity.8. Precision and Bias38.1 The precision of this test method has been tested bysubcommittee D01.28 by means of round robin testing. Re-peatability of e
42、valuations by the same inspector has beenshown to improve when using the pictorial references evenwith little or no training. Overall variability between users ofthis standard is 62.4 rating points without training and 61.6points with training. When removing high and low values andcorrecting for ind
43、ividual biases, the overall variability can bereduced to 61.1 rating points. This was measured using 12individuals, rating 20 specimens, at 2 different time periods.8.1.1 The use of this rating method to rank specimens isextremely reliable and repeatable. The ranking of the speci-mens by these indiv
44、iduals was repeatable at R = 0.99 using theSpearman Rank Coefficient to compare the ranking at each ofthe two rating times.8.2 Bias cannot be determined due to the lack of a standardreference to be used for comparison. This is a highly subjectivemethod of evaluation, but some individual biases can b
45、edetermined by frequent intercomparisons amongst groups ofraters.9. Keywords9.1 disfigurement; fungus; mildew; pictorial standardsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard a
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