1、Designation: D7584 10Standard 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 oforiginal adoption or, i
2、n 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 treated wet blue
3、 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 soit can be easily bu
4、ilt 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 blue1.2 The values stated
5、 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-priate safety and h
6、ealth 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 onthe Surface of Interior Coatings in an EnvironmentalChamberE177 Practice for Use of the Terms Precision and Bias inA
7、STM 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 acidic pH.3.1.2 fungic
8、hemoorganotrophic 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 usually clear to whit
9、e 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 as hyphae and spores
10、may beviewed by simply using a 103 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) Aspergillus niger pro
11、duces 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 Favoring the Growth of
12、 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 distributed within the
13、 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 should be worn wheneverh
14、andling samples with fungal growth are encountered.1This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.02 on Wet Blue.Current edition approved May 1, 2010. Published June 2010.2For referenced ASTM standards, visit the ASTM
15、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
16、States.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 Dust 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
17、liquid particulatesincluding oil-based particles: For example, the North 7700Series Half-Mask Respirator equipped with Cartridge PI 00Filter.5. Summary of Method of Evaluation5.1 Wet blue is suspended in a chamber with a warm, moistenvironment.5.2 After incubation for seven days, the entire surface
18、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 the presence of fungalgrowth and rated using a numerical scale from 10 (clean orwithout any sign of fungal growth) to 0 (comple
19、tely 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 exposure.5.4 After the fourth weekly reading is completed, a report ofthe results is prepared and delivered to the party requesting the
20、evaluation.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 agent of mold. See Test Method D3273.3,46.2 The environmental chamber method is useful in estimat-ing the performance of fungicide
21、s 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 is inoculated with fungalspores and subsequently disfigured or discolored by fungi.6.4 The environmental chamber method measures
22、 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 specimen over a period of fourweeks.6.5 The environmental chamber can be kept inoculated withfungi representative of those found in tan
23、neries by addingsamples of wet blue with fungal growth currently operatingtanneries.6.6 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
24、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 types offalse readings observed in the Petri dish test.7. Interferences7
25、.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 Culture Mites (Acari including Tyroglyphus and Tar-sonemus):7.1.1.1
26、 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 temperatureand humidity.7.1.1.3 Mites are attracted by the odor of
27、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 examining all new materialsentering the laboratory and maintaining separat
28、e 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 live whereverfungi grow.7.1.2.2 The same general hygiene and preventiv
29、e 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 chamber, terminate work in progress, removeall samples and soil, disi
30、nfect all hard surfaces, and begin thechamber 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 compone
31、nts (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 setting it on a steel platform with casters, and built strongenough to support the weight of the chamber, soil, wate
32、r, 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.3Didato, Dean T., Bowen, Judith R., and Hurlow, Elton L., MicroorganismControl During Leather Manufacture, Leather Technologist
33、s 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. 405.5The sole source of supply of the c
34、omplete chamber known to the committee atthis time is Plastico, 32 Flicker St., Memphis, TN 38182-0183. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technic
35、al committee,1which you may attend.D7584 1028.1.2 Arectangular 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. TheFIG. 1 Environmental ChamberFIG. 2 Environmental Chamber Diag
36、ramD7584 103tank is built to be watertight. The inside dimensions of the tankare 91 cm in length by 61 cm in width and height. The 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 cov
37、er when in the closedposition, to contain water dripping from the chamber cover andto divert the water back to the bottom of the tank withoutdripping 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
38、 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 curvingwaterfall 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
39、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 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. On
40、e 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 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 hol
41、d the rods from whichthe wet blue samples hang. See Fig. 5. This particular framewill provide enough rod space to hang 100 or more wet bluesamples. 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 measure
42、s 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 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 fittin
43、gs.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 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
44、.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 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 insula
45、ted solid copper wire of 14 gauge (3mm diameter) is useful in making hangers for wet bluesamples. The wire is bendable into a suitable “S” shape 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
46、 to have straight sides and apitched top so that moisture 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 positio
47、n. Typical dimensions include: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 o
48、f 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 3 cm in width byFIG. 3 Rectangular Shaped Soil TrayFIG. 4 Soil TrayFIG. 5 Chamber with RodsD7584 10430 cm in length and is used to attach the han
49、dle (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.8.2.1 Maintaining the room temperature at approximately24C is required so that heat loss from the cabinet is insignifi-cant and a relative humidity of 95 to 98 % is r
