1、Designation: D3274 09 (Reapproved 2013)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 Depart
3、ment 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.1.2
4、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. It i
5、sprimarily 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 disfigureme
6、nt 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 expose
7、d 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 with th
8、is 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 and he
9、alth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1006 Practice for Conducting Exterior Exposure Tests ofPaints on WoodD3456 Practice for Determining by Exterior Exposure Teststhe Susceptibility of Paint Films to Microb
10、iologicalAttackD4610 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 GrowthDuring examination of a paintfilm, it ma
11、y 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 distinguish growth types. The followingdefinitions
12、 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 forming thebody of a fungus.3.5 sporean ase
13、xual reproductive cell capable of develop-ing into a mature fungus without fusion with another cell.3.5.1 DiscussionSpores 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 wide1This test method is un
14、der 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 Oct. 1, 2013. Published October 2013. Originallyapproved in 1973. Last previous edition approved in
15、2009 as D3274 091. DOI:10.1520/D3274-09R13.2For 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 Document Summary page onthe ASTM website.Copyright ASTM Int
16、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1variety of colors. Although primarily gray or black, somespores are green in color and have been mistaken as terrestrialalgae.4. Significance and Use4.1 The growth of fungi in and on the surface of paint
17、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 The pictorial references that are part of this testmethod are for ill
18、ustration 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 toestablish amount and type of growth.4.2.3 The diagrams represented in
19、 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 on dark colored substrates will bemuch more difficult, and will there
20、fore 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 Particles5.1 Fungal or algal ratings can be made more difficult by thepre
21、sence 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 determining whether the particle is soil,dirt, or mildew.NOTE 1After ex
22、perience 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 necessary to place a drop of 5 %sodium hypochlorite (common household bleach) on the paintsurface to determine if the defac
23、ement 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 bleach drop do not change color, that object is probablyeither dirt or soil.5.4 The addition of a drop of bleach is an inv
24、asive anddestructive test. The future growth of organisms on that spot(a)FIG. 1 Early Stages of Fungal GrowthD3274 09 (2013)2and in the immediate surrounding area will be inhibited for along time after the addition. Do not use bleach unless abso-lutely necessary, and make a note on the report form i
25、f 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 assist in the identification ofmildew and to clarify the rating. Ma
26、gnification 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 booth under daylight light source, oroutside in the shade. Occasionall
27、y 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 transparent gridscale to determine percent area coverage for more accu
28、rateratings 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 matchesthat seen on the specimen. See Fig. 1 a through c, for visua
29、lrepresentation 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 growthpattern. Derive the numerical rating directly from the ratingscales shown in Table 1. Includ
30、e 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 mildew growth using either anestimate of the percentage of the surface covered, or by(b)FIG. 1 Early Stages of Fungal Growth (continued)D3
31、274 09 (2013)3applying 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 ratings are shownin Fig. 1 a through c. No pictures for 10 or zero rati
32、ngs 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.6.6 Ignore the area around the outer edge of the test surfaceif the
33、 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 hasinvaded other areas on the surface, originating typically at thebottom,
34、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, typically from Spot to Non-Uniform orComplete Coverage.6.8 Identifica
35、tionIf 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 regarding uniformity or other morphology.7.2 Use a report format as agree up
36、on 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 number to identify test series.7.2.2 Paint panel identification.7.2.3 Da
37、te 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.(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
38、10 Pronounced2 33 Severe0 50 Complete CoverageD3274 09 (2013)4Slight MildewFIG. 2 Examples of Paint Disfigurement through Fungal or Algal GrowthD3274 09 (2013)5Moderate MildewFIG. 2 Examples of Paint Disfigurement through Fungal or Algal Growth (continued)D3274 09 (2013)6Severe MildewFIG. 2 Examples
39、 of Paint Disfigurement through Fungal or Algal Growth (continued)D3274 09 (2013)78. 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 evaluations by the same inspector has beenshown to improve when using
40、 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 individual biases, the overall variability can bereduced to 61.1 rating
41、 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 individuals was repeatable at R = 0.99 using theSpearman Rank Coefficient
42、 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 bedetermined by frequent intercomparisons amongst groups ofraters.9.
43、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 are expressly advised that determination of the validity of any such
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