1、Designation: D7584 16Standard Test Method forEvaluating the Resistance of the Surface of Wet Blue andWet White to the Growth of Fungi in an EnvironmentalChamber1This standard is issued under the fixed designation D7584; the number immediately following the designation indicates the year oforiginal a
2、doption 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.1. Scope1.1 This environmental chamber method measures the re-sistance of the tre
3、ated Wet Blue and Wet White to thegermination of spores and subsequent vegetative growth over aperiod of four weeks. The test method is useful in estimatingthe performance of fungicides and should assist in the predic-tion of storage time of Wet Blue and Wet White before fungalgrowth begins. The app
4、aratus is designed so it can be easilybuilt or obtained by any interested party and duplicate thenatural environment in which Wet Blue and Wet White isinoculated with fungal spores. Spores that germinate on un-treated or treated Wet Blue and Wet White can produce fungalgrowth, resulting in disfigure
5、ment or discoloration, or both, ofthe Wet Blue and Wet White.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the
6、responsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D3273 Test Method for Resistance to Growth of Mold on theSurface of Interior Coatings i
7、n an Environmental Cham-berE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 fungichemoorganotrophic eukaryotic organisms liv-ing mainly under ae
8、robic conditions and generating energy bythe oxidation of organic materials.3.1.2 molda macroscopic discoloration of the surface ofwet blue. Mold also a sign of the presence of microscopicfungal growth in the form of usually clear to white fungalhyphae, spores of various colors, and other structures
9、. Coloredspots, probably due to the presence of a colored pigmentproduced by the fungus, have been observed on the surface ofwet blue in places where fungal growth has occurred and thenstopped. Fungal structures such as hyphae and spores may beviewed by simply using a 10 hand lens.3.1.3 Wet Bluehide
10、 or skin, or split of a hide or skin,tanned with basic chromium sulfate, containing approximately50 % moisture and an acidic pH.3.1.4 Wet Whitehide or skin that has been processed withtanning as the terminal step by using organic or non-organictanning agents. Chromium or iron containing agents andve
11、getable extracts will be excluded from use in Wet White.3.1.5 Fungi of Importance in the Tannery:3.1.5.1 Filamentous Fungi:(1) A wide variety of fungi have been identified in thetannery, but commonly encountered species include Aspergil-lus spp., Paecilomyces spp., and Penicillium spp.(2) Aspergillu
12、s niger produces black spores and Penicil-lium luteum produces yellow-green colored spores.(3) Trichoderma viride produces green spores.3.1.5.2 YeastMany yeasts are cream colored, but pig-mented ones may also be encountered including Rhodotorulaspp. which is pigmented red.3.1.5.3 Factors Favoring th
13、e Growth of Fungi in the Tan-nery:(1) Wet Blue and Wet White contain nutrients beneficial tofungal growth.(2) Favorable environmental factors include a slightlyacidic pH, a high moisture content, and warm temperatures.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is
14、the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved June 1, 2016. Published June 2016. Originallyapproved in 2010. Last previous edition approved in 2015 as D7584 10(2015).DOI: 10.1520/D7584-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, or
15、contact 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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1(3) Fungal spores a
16、re transported by air or on hides andskins into the tannery and distributed within the tannery byphysical contact or air currents to favorable substrates forgrowth including Wet Blue and Wet White.4. Personal Protective Equipment4.1 Fungi are opportunistic organisms. For this reason,rubber gloves or
17、 powder-free latex examination gloves, safetyglasses, and a laboratory coat should be worn wheneverhandling samples with fungal growth are encountered.4.2 A dust mask or respirator should be worn whenever theenvironmental chamber is open or whenever samples withfungal growth are encountered.4.2.1 Du
18、st MaskExamples, 3M 8210 and 3M 9322 Res-pirators.4.2.2 Half-Mask RespiratorEquipped with a filter ap-proved 99.97 % efficient against solid or liquid particulatesincluding oil-based particles: For example, the North 7700Series Half-Mask Respirator equipped with Cartridge PI 00Filter.5. Summary of M
19、ethod of Evaluation5.1 Wet Blue or Wet White is suspended in a chamber witha warm, moist environment.5.2 After incubation for seven days, the entire surface areaof the grain and flesh sides of the test specimen are examinedvisually, first one side, for example, the grain side, and then theother, for
20、 example, the flesh side, for the presence of fungalgrowth and rated using a numerical scale from 10 (clean orwithout any sign of fungal growth) to 0 (completely covered byfungal growth).5.3 Step B is repeated once per week until ratings have beencompleted for all samples at 14, 21, and 28 days of e
21、nviron-mental chamber exposure.5.4 After the fourth weekly reading is completed, a report ofthe results is prepared and delivered to the party requesting theevaluation.6. Significance and Use6.1 The environmental chamber method is an acceleratedtest for determining the resistance of Wet Blue and Wet
22、 Whiteto the growth of fungi, the causal agent of mold. See TestMethod D3273.3,46.2 The environmental chamber method is useful in estimat-ing the performance of fungicides and should assist in theprediction of storage time before fungal growth begins.6.3 The environmental chamber method duplicates t
23、he natu-ral environment in which Wet Blue or Wet White is inoculatedwith fungal spores and subsequently disfigured or discoloredby fungi.3Didato, Dean T., Bowen, Judith R., and Hurlow, Elton L., MicroorganismControl During Leather Manufacture, Leather Technologists Pocket Book, Chapter20, Editor M.
24、K. Leafe, The Society of Leather Technologists and Chemists,Withernsea, East Yorkshire, UK, 1999.4Leather Technologists Pocket Book, The Society of Leather Technologists andChemists, Withernsea, East Yorkshire, UK, 1999, pp. 405.FIG. 1 Environmental ChamberD7584 1626.4 The environmental chamber meth
25、od measures the resis-tance of the treated Wet Blue or Wet White to the germinationof spores and subsequent vegetative growth that spreads overthe surface of a comparatively large Wet Blue or Wet Whitespecimen over a period of four weeks.6.5 The environmental chamber can be kept inoculated withfungi
26、 representative of those found in tanneries by addingsamples of Wet Blue and Wet White with fungal growth fromcurrently operating tanneries.6.6 Control specimens of Wet Blue and Wet White withoutfungicide treatment can be added to the chamber periodicallyto increase levels of fungal growth in the ch
27、amber.6.7 Leaching of fungicide from the test specimen into theagar often causes a zone of inhibition of fungal growth in thePetri dish test, but in the environmental chamber any leachingof fungicide from the test specimen drips into the watercontained in the chamber and thus does not cause the type
28、s offalse readings observed in the Petri dish test.7. Interferences7.1 A common interference is contamination of samples byunwanted organisms, for example arthropodsincluding cul-ture mites and fungus gnatsthat enter the environmentalchamber on test specimens or from the laboratory environment.7.1.1
29、 Culture Mites (Acari including Tyroglyphus and Tar-sonemus):7.1.1.1 Culture mites invade the environmental chambereating the funga hyphae on the test specimens, infecting themwith bacteria, and moving from one test specimen to anothercontaminating them.7.1.1.2 Mites thrive in environments with high
30、 temperatureand humidity.7.1.1.3 Mites are attracted by the odor of fungi and can bealso be brought into the environmental chamber on the bodiesof flies, organic material, soil, and even test specimens.7.1.1.4 General hygiene and preventive precautions must betaken to control mites, including examin
31、ing all new materialsentering the laboratory and maintaining separate rooms forinitial handling of new samples for testing and a clean room tohouse the environmental chamber.7.1.2 Fungus Gnats (Sciaroideaincluding the dark wingedfungus flies, Sciaridae):7.1.2.1 Larvae of fungus gnats are known to li
32、ve whereverfungi grow.7.1.2.2 The same general hygiene and preventive precau-tions that are used to control mites apply to the control offungus gnats, especially keeping the room containing theenvironmental chambers clean.7.1.3 If culture mites or fungus mites become established inan environmental c
33、hamber, terminate work in progress, removeall samples and soil, disinfect all hard surfaces, and begin thechamber startup process again.FIG. 2 Environmental Chamber DiagramD7584 1637.2 Limit the sunlight entering the chamber room and onlyhave room lights on when working in the room to prevent thegro
34、wth of algae.8. Apparatus (see Figs. 1 and 2)8.1 A typical environmental chamber5will have the follow-ing components (all measurements rounded to the nearestwhole centimeter and may vary in dimensions from onechamber design to another):8.1.1 The chamber is raised above floor level, made mobileby set
35、ting it on a steel platform with casters, and built strongenough to support the weight of the chamber, soil, water, andsamples.Atypical platform measures 97 cm in length by 66 cmin width and height with steel legs and casters that elevate thechamber an additional 36 cm above the floor.8.1.2 Arectang
36、ular shaped tank is used to contain the water,soil, and samples.8.1.2.1 Atypical tank measures 94 cm in length by 62 cm inwidth by 62 cm in height with a wall thickness of l cm. Thetank is built to be watertight. The inside dimensions of the tankare 91 cm in length by 61 cm in width and height. The
37、waterlevel in the bottom of the tank is maintained at a height of 8 to17 cm.8.1.2.2 The tank has an offset shoulder at the top rim. Thisserves to support the chamber cover when in the closedposition, to contain water dripping from the chamber cover andto divert the water back to the bottom of the ta
38、nk withoutdripping on the Wet Blue or Wet White samples. The rim givesthe top of the tank an extended length of 104 cm, an extendedwidth of 72 cm, and a raised outside wall of 3.8 cm in height.The inside of the rim drops 3.6 cm below the surface of the topof the tank to a horizontal shelf measuring
39、5 cm in width witha curving waterfall that diverts water toward the bottom of thetank.8.1.3 A rectangular shaped soil tray is used to hold the soilmix and inoculum. See Figs. 3 and 4.8.1.3.1 The soil tray is seated on top of a table for thepurpose of elevating the tray above the level of the water.8
40、.1.3.2 The dimensions of the soil tray are 82 cm in lengthby 56 cm in width by 5 cm in height.8.1.3.3 The bottom of the tray consists of a sheet ofcorrosion-resistant metal mesh. One layer of plastic or fiber-glass screening may be placed over the metal mesh to hold thesoil in place if necessary.8.1
41、.3.4 The primary purpose of the soil tray is to help keepthe chamber evenly moist.8.1.4 A rectangular shaped supporting frame is located nearthe top of the chamber and serves to hold the rods from whichthe Wet Blue or Wet White samples hang. See Fig. 5. Thisparticular frame will provide enough rod s
42、pace to hang 100 ormore Wet Blue or Wet White samples. Chambers may bedesigned to provide space for exposure of greater numbers ofsamples to suit the needs of the testing laboratory.8.1.4.1 The frame measures 90 cm in length by 58 cm inwidth by 8 cm in height and is 2 cm in thickness.8.1.4.2 Four L-
43、shaped brackets hold the frame in place, andeach bracket measures 5 cm in length by 2 cm in width by 0.6cm in thickness on each side. The brackets are fastened to thechamber wall using stainless steel fittings.8.1.4.3 The top side of the frame on both sides of thechamber running the length of the ch
44、amber has U-shapedvalleys cut into the top side to hold the rods in place and at a5The sole source of supply of the complete chamber known to the committee atthis time is Indelco Custom Products, 32 Flicker St., Memphis, TN 38182-0183. Ifyou are aware of alternative suppliers, please provide this in
45、formation to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.FIG. 3 Rectangular Shaped Soil TrayFIG. 4 Soil TrayFIG. 5 Chamber with RodsD7584 164right angle to the sides of the chamber. The U-sh
46、aped valleysare cut to a maximum depth of 0.6 cm and a width of 1.1 cm.8.1.4.4 The rods measure 57 cm in length and 1.2 cm indiameter. Ten rods holding 10 to 15 Wet Blue and Wet Whitesamples hung at right angles to the rod can easily be accom-modated in the chamber.As an alternative to using rods to
47、 hangthe samples on, use a wire strung across the top of the chamber.8.1.4.5 Plastic insulated solid copper wire of 14 gauge (3mm diameter) is useful in making hangers for Wet Blue andWet White samples. The wire is bendable into a suitable “S”shape for hanging test samples and retains its shape form
48、ultiple uses.8.1.5 The top of the environmental chamber is constructedof acrylic plastic and is designed to have straight sides and apitched top so that moisture condensation will run down thesides and be recirculated instead of dripping onto the Wet Blueand Wet White samples. The top features a han
49、dle at the front,hinges at the rear, and support struts on each side to allow thelid to be propped in the open position. Typical dimensionsinclude:8.1.5.1 SidesTwo sheets of acrylic cut to 99 cm at basewitha6cmvertical rise and then at an angle of 40 degrees for64 cm on each side to the peak.8.1.5.2 Front and RearBottom sheet 69 cm wide by 6 cmon sides rising vertically and attaching to a sheet rising at anangle of 40 degrees measuring 69 cm wide by 64 cm in length.8.1.5.3 The handle is mounted on the front sheet. The baseof the handle measures 3 cm in thickness by
