1、Designation: D7584 10 (Reapproved 2015)Standard Test Method forEvaluating the Resistance of the Surface of Wet Blue to theGrowth of Fungi in an Environmental Chamber1This standard is issued under the fixed designation D7584; the number immediately following the designation indicates the year oforigi
2、nal 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.1. Scope1.1 This environmental chamber method measures the re-sistance of th
3、e treated wet blue to the germination of spores andsubsequent vegetative growth over a period of four weeks. Thetest method is useful in estimating the performance of fungi-cides and should assist in the prediction of storage time of wetblue before fungal growth begins. The apparatus is designed soi
4、t can be easily built or obtained by any interested party andduplicate the natural environment in which wet blue is inocu-lated with fungal spores. Spores that germinate on untreated ortreated wet blue can produce fungal growth, resulting indisfigurement or discoloration, or both, of the wet blue.1.
5、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 theresponsibility of the user of this standard to establish appro-
6、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 in an Environmental Cham-berE177 Practice for Use of the Terms P
7、recision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 wet bluehide or skin, or split of a hide or skin,tanned with basic chromium sulfate, containing approximately50 % moisture and an a
8、cidic pH.3.1.2 fungichemoorganotrophic eukaryotic organisms liv-ing mainly under aerobic conditions and generating energy bythe oxidation of organic materials.3.1.3 molda macroscopic discoloration of the surface ofwet blue. Mold also a sign of the presence of microscopicfungal growth in the form of
9、usually clear to white fungalhyphae, spores of various colors, and other structures. 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
10、as hyphae and spores may beviewed by simply using a 10 hand lens.3.1.4 Fungi of Importance in the Tannery:3.1.4.1 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) A
11、spergillus niger produces black spores and Penicil-lium luteum produces yellow-green colored spores.(3) Trichoderma viride produces green spores.3.1.4.2 YeastMany yeasts are cream colored, but pig-mented ones may also be encountered including Rhodotorulaspp. which is pigmented red.3.1.4.3 Factors Fa
12、voring the Growth of Fungi in the Tan-nery:(1) Wet blue contains nutrients beneficial to fungal growth.(2) Favorable environmental factors include a slightlyacidic pH, a high moisture content, and warm temperatures.(3) Fungal spores are transported by air or on hides andskins into the tannery and di
13、stributed within the tannery byphysical contact or air currents to favorable substrates forgrowth including wet blue.4. Personal Protective Equipment4.1 Fungi are opportunistic organisms. For this reason,rubber gloves or powder-free latex examination gloves, safetyglasses, and a laboratory coat shou
14、ld be worn wheneverhandling samples with fungal growth are encountered.1This test method is under the jurisdiction ofASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved Dec. 1, 2015. Published December 2015. Originallyapproved in
15、2010. Last previous edition approved in 2010 as D7584 10. DOI:10.1520/D7584-10R15.2For 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 pag
16、e onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2 A dust mask or respirator should be worn whenever theenvironmental chamber is open or whenever samples withfungal growth are encountered.4.2.1 Dust MaskExamples,
17、 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 Method of Evaluat
18、ion5.1 Wet blue is suspended in a chamber with a warm, moistenvironment.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 example, the flesh side, for
19、 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 environ-mental chamber exposur
20、e.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 to the growth offungi, the causal ag
21、ent of mold. See Test Method 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 the natu-ral environment in which wet blue
22、is inoculated with fungalspores and subsequently disfigured or discolored by fungi.6.4 The environmental chamber method measures the resis-tance of the treated wet blue to the germination of spores andsubsequent vegetative growth that spreads over the surface ofa comparatively large wet blue specime
23、n over a period of fourweeks.6.5 The environmental chamber can be kept inoculated withfungi representative of those found in tanneries by addingsamples of wet blue with fungal growth currently operatingtanneries.3Didato, Dean T., Bowen, Judith R., and Hurlow, Elton L., MicroorganismControl During Le
24、ather Manufacture, Leather Technologists Pocket Book, Chapter20, Editor M. 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.
25、405.FIG. 1 Environmental ChamberD7584 10 (2015)26.6 Control specimens of wet blue without fungicide treat-ment can be added to the chamber periodically to increaselevels of fungal growth in the chamber.6.7 Leaching of fungicide from the test specimen into theagar often causes a zone of inhibition of
26、 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 types offalse readings observed in the Petri dish test.7. Interferences7.1 A common interference is contamin
27、ation 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 Culture Mites (Acari including Tyroglyphus and Tar-sonemus):7.1.1.1 Culture mites invade the environmen
28、tal 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 temperatureand humidity.7.1.1.3 Mites are attracted by the odor of fungi and can bealso be brought into
29、 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 examining all new materialsentering the laboratory and maintaining separate rooms forinitial handling of new s
30、amples 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 live whereverfungi grow.7.1.2.2 The same general hygiene and preventive precau-tions that are used to cont
31、rol 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 chamber, terminate work in progress, removeall samples and soil, disinfect all hard surfaces, and begin t
32、hechamber startup process again.7.2 Limit the sunlight entering the chamber room and onlyhave room lights on when working in the room to prevent thegrowth 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
33、 nearest5The 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 information to ASTMInternational Headquarters. Your comments will receive ca
34、reful consideration at ameeting of the responsible technical committee,1which you may attend.FIG. 2 Environmental Chamber DiagramD7584 10 (2015)3whole centimeter and may vary in dimensions from onechamber design to another):8.1.1 The chamber is raised above floor level, made mobileby setting it on a
35、 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 Arectangular shaped
36、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 waterlevel i
37、n 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 tank withoutdr
38、ipping on the wet blue samples. The rim gives the top of thetank an extended length of 104 cm, an extended width of 72cm, and a raised outside wall of 3.8 cm in height. The inside ofthe rim drops 3.6 cm below the surface of the top of the tankto a horizontal shelf measuring 5 cm in width with a curv
39、ingwaterfall that diverts water toward the bottom of the tank.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.8.1.3.2 The dimensions of
40、 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.8.1.3.4 The primary purpose
41、 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 samples hang. See Fig. 5. This particular framewill provide enough rod space to hang 100 or more wet bluesamp
42、les. Chambers may be designed to provide space forexposure of greater numbers of samples to suit the needs of thetesting 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-shaped brackets hold the frame in place, andeach b
43、racket 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 chamber has U-shapedvalleys cut into the top side to
44、 hold the rods in place and at aright angle to the sides of the chamber. The U-shaped 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 samples hung atright angles to the rod can easily
45、 be accommodated in thechamber. As an alternative to using rods to hang the sampleson, 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 bluesamples. The wire is bendable into a suitable “S” shap
46、e forhanging test samples and retains its shape for multiple uses.8.1.5 The top of the environmental chamber is constructedof acrylic plastic and is designed to have straight sides and aFIG. 3 Rectangular Shaped Soil TrayFIG. 4 Soil TrayFIG. 5 Chamber with RodsD7584 10 (2015)4pitched top so that moi
47、sture condensation will run down thesides and be recirculated instead of dripping onto the wet bluesamples. The top features a handle at the front, hinges at therear, and support struts on each side to allow the lid to bepropped in the open position. Typical dimensions include:8.1.5.1 SidesTwo sheet
48、s 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
49、.8.1.5.3 The handle is mounted on the front sheet. The baseof the handle measures 3 cm in thickness by 3 cm in width by30 cm in length and is used to attach the handle (30 cm inlength by 5 cm in width by 1 cm in thickness).8.1.5.4 Single or double support struts are used and measure69 cm in length by 7 cm in width by 1 cm in thickness.8.2 The environmental chamber must be capable of main-taining a relative humidity of 95 to 98 % at a temperature ofapproximately 32C (90F) while providing a continuousinoculation of the surface of the test specimens with fungalspores.
