ASTM D7584-16(2021)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7584 − 16 (Reapproved 2021)
Standard Test Method for
Evaluating the Resistance of the Surface of Wet Blue and
Wet White to the Growth of Fungi in an Environmental
Chamber
This standard is issued under the fixed designation D7584; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D3273TestMethodforResistancetoGrowthofMoldonthe
Surface of Interior Coatings in an Environmental Cham-
1.1 This environmental chamber method measures the re-
ber
sistance of the treated Wet Blue and Wet White to the
E177Practice for Use of the Terms Precision and Bias in
germinationofsporesandsubsequentvegetativegrowthovera
ASTM Test Methods
period of four weeks. The test method is useful in estimating
E691Practice for Conducting an Interlaboratory Study to
the performance of fungicides and should assist in the predic-
Determine the Precision of a Test Method
tion of storage time of Wet Blue and Wet White before fungal
growth begins. The apparatus is designed so it can be easily
3. Terminology
built or obtained by any interested party and duplicate the
natural environment in which Wet Blue and Wet White is
3.1 Definitions:
inoculated with fungal spores. Spores that germinate on un- 3.1.1 fungi—chemoorganotrophic eukaryotic organisms liv-
treated or treated Wet Blue and Wet White can produce fungal
ing mainly under aerobic conditions and generating energy by
growth, resulting in disfigurement or discoloration, or both, of the oxidation of organic materials.
the Wet Blue and Wet White.
3.1.2 mold—a macroscopic discoloration of the surface of
wet blue. Mold also a sign of the presence of microscopic
1.2 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this fungal growth in the form of usually clear to white fungal
hyphae, spores of various colors, and other structures. Colored
standard.
spots, probably due to the presence of a colored pigment
1.3 This standard does not purport to address all of the
produced by the fungus, have been observed on the surface of
safety concerns, if any, associated with its use. It is the
wet blue in places where fungal growth has occurred and then
responsibility of the user of this standard to establish appro-
stopped. Fungal structures such as hyphae and spores may be
priate safety, health, and environmental practices and deter-
viewed by simply using a 10× hand lens.
mine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accor- 3.1.3 Wet Blue—hide or skin, or split of a hide or skin,
tanned with basic chromium sulfate, containing approximately
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 50% moisture and an acidic pH.
Development of International Standards, Guides and Recom-
3.1.4 Wet White—hide or skin that has been processed with
mendations issued by the World Trade Organization Technical
tanning as the terminal step by using organic or non-organic
Barriers to Trade (TBT) Committee.
tanning agents. Chromium or iron containing agents and
vegetable extracts will be excluded from use in Wet White.
2. Referenced Documents
3.1.5 Fungi of Importance in the Tannery:
2.1 ASTM Standards:
3.1.5.1 Filamentous Fungi:
(1)A wide variety of fungi have been identified in the
tannery, but commonly encountered species include Aspergil-
ThistestmethodisunderthejurisdictionofASTMCommitteeD31onLeather
lus spp., Paecilomyces spp., and Penicillium spp.
and is the direct responsibility of Subcommittee D31.02 on Wet Blue.
(2)Aspergillus niger produces black spores and Penicil-
Current edition approved Sept. 1, 2021. Published October 2021. Originally
lium luteum produces yellow-green colored spores.
approved in 2010. Last previous edition approved in 2016 as D7584 – 16. DOI:
10.1520/D7584-16R21.
(3)Trichoderma viride produces green spores.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.1.5.2 Yeast—Many yeasts are cream colored, but pig-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
mented ones may also be encountered including Rhodotorula
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. spp. which is pigmented red.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7584 − 16 (2021)
3.1.5.3 Factors Favoring the Growth of Fungi in the Tan- 5.2 After incubation for seven days, the entire surface area
nery: of the grain and flesh sides of the test specimen are examined
(1)Wet Blue andWetWhite contain nutrients beneficial to visually,firstoneside,forexample,thegrainside,andthenthe
fungal growth. other, for example, the flesh side, for the presence of fungal
(2)Favorable environmental factors include a slightly growth and rated using a numerical scale from 10 (clean or
acidic pH, a high moisture content, and warm temperatures. withoutanysignoffungalgrowth)to0(completelycoveredby
(3)Fungal spores are transported by air or on hides and fungal growth).
skins into the tannery and distributed within the tannery by
5.3 StepBisrepeatedonceperweekuntilratingshavebeen
physical contact or air currents to favorable substrates for
completed for all samples at 14, 21, and 28 days of environ-
growth including Wet Blue and Wet White.
mental chamber exposure.
5.4 Afterthefourthweeklyreadingiscompleted,areportof
4. Personal Protective Equipment
theresultsispreparedanddeliveredtothepartyrequestingthe
4.1 Fungi are opportunistic organisms. For this reason,
evaluation.
rubber gloves or powder-free latex examination gloves, safety
glasses, and a laboratory coat should be worn whenever
6. Significance and Use
handling samples with fungal growth are encountered.
6.1 The environmental chamber method is an accelerated
4.2 Adust mask or respirator should be worn whenever the
test for determining the resistance of Wet Blue and Wet White
environmental chamber is open or whenever samples with
to the growth of fungi, the causal agent of mold. See Test
fungal growth are encountered.
3,4
Method D3273.
4.2.1 Dust Mask—Examples, 3M 8210 and 3M 9322 Res-
6.2 Theenvironmentalchambermethodisusefulinestimat-
pirators.
4.2.2 Half-Mask Respirator—Equipped with a filter ap- ing the performance of fungicides and should assist in the
prediction of storage time before fungal growth begins.
proved 99.97% efficient against solid or liquid particulates
including oil-based particles: For example, the North 7700
Series Half-Mask Respirator equipped with Cartridge PI 00
Filter. 3
Didato, Dean T., Bowen, Judith R., and Hurlow, Elton L., Microorganism
Control During Leather Manufacture, Leather Technologists Pocket Book, Chapter
5. Summary of Method of Evaluation 20, Editor M. K. Leafe, The Society of Leather Technologists and Chemists,
Withernsea, East Yorkshire, UK, 1999.
5.1 Wet Blue or Wet White is suspended in a chamber with 4
Leather Technologists Pocket Book, The Society of Leather Technologists and
a warm, moist environment.
Chemists, Withernsea, East Yorkshire, UK, 1999, p. 405.
FIG. 1 Environmental Chamber
D7584 − 16 (2021)
6.3 Theenvironmentalchambermethodduplicatesthenatu- 7.2 Limit the sunlight entering the chamber room and only
ral environment in whichWet Blue orWetWhite is inoculated have room lights on when working in the room to prevent the
with fungal spores and subsequently disfigured or discolored growth of algae.
by fungi.
8. Apparatus (see Figs. 1 and 2)
6.4 The environmental chamber method measures the resis-
8.1 Atypical environmental chamber will have the follow-
tance of the treated Wet Blue or Wet White to the germination
ing components (all measurements rounded to the nearest
of spores and subsequent vegetative growth that spreads over
whole centimeter and may vary in dimensions from one
the surface of a comparatively large Wet Blue or Wet White
chamber design to another):
specimen over a period of four weeks.
8.1.1 The chamber is raised above floor level, made mobile
6.5 Theenvironmentalchambercanbekeptinoculatedwith
by setting it on a steel platform with casters, and built strong
fungi representative of those found in tanneries by adding
enough to support the weight of the chamber, soil, water, and
samples of Wet Blue and Wet White with fungal growth from
samples.Atypicalplatformmeasures97cminlengthby66cm
currently operating tanneries.
in width and height with steel legs and casters that elevate the
chamber an additional 36 cm above the floor.
6.6 Control specimens of Wet Blue and Wet White without
8.1.2 Arectangularshapedtankisusedtocontainthewater,
fungicide treatment can be added to the chamber periodically
soil, and samples.
to increase levels of fungal growth in the chamber.
8.1.2.1 Atypicaltankmeasures94cminlengthby62cmin
6.7 Leaching of fungicide from the test specimen into the
width by 62 cm in height with a wall thickness of l cm. The
agar often causes a zone of inhibition of fungal growth in the
tankisbuilttobewatertight.Theinsidedimensionsofthetank
Petri dish test, but in the environmental chamber any leaching
are 91 cm in length by 61 cm in width and height. The water
of fungicide from the test specimen drips into the water
level in the bottom of the tank is maintained at a height of 8 to
contained in the chamber and thus does not cause the types of
17 cm.
false readings observed in the Petri dish test.
8.1.2.2 The tank has an offset shoulder at the top rim. This
serves to support the chamber cover when in the closed
7. Interferences
position,tocontainwaterdrippingfromthechambercoverand
7.1 Acommon interference is contamination of samples by to divert the water back to the bottom of the tank without
unwanted organisms, for example arthropods—including cul- drippingontheWetBlueorWetWhitesamples.Therimgives
ture mites and fungus gnats—that enter the environmental the top of the tank an extended length of 104 cm, an extended
width of 72 cm, and a raised outside wall of 3.8 cm in height.
chamberontestspecimensorfromthelaboratoryenvironment.
Theinsideoftherimdrops3.6cmbelowthesurfaceofthetop
7.1.1 Culture Mites (Acari including Tyroglyphus and Tar-
of the tank to a horizontal shelf measuring 5 cm in width with
sonemus):
a curving waterfall that diverts water toward the bottom of the
7.1.1.1 Culture mites invade the environmental chamber
tank.
eating the funga hyphae on the test specimens, infecting them
8.1.3 Arectangular shaped soil tray is used to hold the soil
with bacteria, and moving from one test specimen to another
mix and inoculum. See Figs. 3 and 4.
contaminating them.
8.1.3.1 The soil tray is seated on top of a table for the
7.1.1.2 Mites thrive in environments with high temperature
purpose of elevating the tray above the level of the water.
and humidity.
8.1.3.2 The dimensions of the soil tray are 82 cm in length
7.1.1.3 Mites are attracted by the odor of fungi and can be
by 56 cm in width by 5 cm in height.
also be brought into the environmental chamber on the bodies
8.1.3.3 The bottom of the tray consists of a sheet of
of flies, organic material, soil, and even test specimens.
corrosion-resistant metal mesh. One layer of plastic or fiber-
7.1.1.4 Generalhygieneandpreventiveprecautionsmustbe
glass screening may be placed over the metal mesh to hold the
taken to control mites, including examining all new materials
soil in place if necessary.
entering the laboratory and maintaining separate rooms for
8.1.3.4 The primary purpose of the soil tray is to help keep
initial handling of new samples for testing and a clean room to
the chamber evenly moist.
house the environmental chamber.
8.1.4 Arectangular shaped supporting frame is located near
7.1.2 Fungus Gnats (Sciaroidea—including the dark winged
the top of the chamber and serves to hold the rods from which
fungus flies, Sciaridae):
the Wet Blue or Wet White samples hang. See Fig. 5. This
7.1.2.1 Larvae of fungus gnats are known to live wherever
particular frame will provide enough rod space to hang 100 or
fungi grow.
more Wet Blue or Wet White samples. Chambers may be
7.1.2.2 The same general hygiene and preventive precau-
designed to provide space for exposure of greater numbers of
tions that are used to control mites apply to the control of
samples to suit the needs of the testing laboratory.
fungus gnats, especially keeping the room containing the
environmental chambers clean.
The sole source of supply of the complete chamber known to the committee at
7.1.3 Ifculturemitesorfungusmitesbecomeestablishedin
this time is Indelco Custom Products, 32 Flicker St., Memphis, TN 38182-0183. If
anenvironmentalchamber,terminateworkinprogress,remove
you are aware of alternative suppliers, please provide this information to ASTM
all samples and soil, disinfect all hard surfaces, and begin the
International Headquarters. Your comments will receive careful consideration at a
chamber startup process again. meeting of the responsible technical committee, which you may attend.
D7584 − 16 (2021)
FIG. 2 Environmental Chamber Diagram
FIG. 3 Rectangular Shaped Soil Tray
FIG. 4 Soil Tray
8.1.4.1 The frame measures 90 cm in length by 58 cm in
width by 8 cm in height and is 2 cm in thickness.
8.1.4.2 Four L-shaped brackets hold the frame in place, and modatedinthechamber.Asanalternativetousingrodstohang
each bracket measures 5 cm in length by 2 cm in width by 0.6 thesampleson,useawirestrungacrossthetopofthechamber.
cm in thickness on each side. The brackets are fastened to the 8.1.4.5 Plastic insulated solid copper wire of 14 gauge (3
chamber wall using stainless steel fittings. mm diameter) is useful in making hangers for Wet Blue and
8.1.4.3 The top side of the frame on both sides of the Wet White samples. The wire is bendable into a suitable “S”
chamber running the length of the chamber has U-shaped shape for hanging test samples and retains its shape for
valleys cut into the top side to hold the rods in place and at a multiple uses.
right angle to the sides of the chamber. The U-shaped valleys 8.1.5 The top of the environmental chamber is constructed
are cut to a maximum depth of 0.6 cm and a width of 1.1 cm. of acrylic plastic and is designed to have straight sides and a
8.1.4.4 The rods measure 57 cm in length and 1.2 cm in pitched top so that moisture condensation will run down the
diameter. Ten rods holding 10 to 15 Wet Blue and Wet White sidesandberecirculatedinsteadofdrippingontotheWetBlue
samples hung at right angles to the rod can easily be accom- andWetWhite samples.The top features a handle at the front,
D7584 − 16 (2021)
FIG. 5 Chamber with Rods FIG. 6 Heater Conduit Boc Installed on Tank
hinges at the rear, and support struts on each side to allow the
lid to be propped in the open position. Typical dimensions
include:
8.1.5.1 Sides—Two sheets of acrylic cut to 99 cm at base
witha6cm vertical rise and then at an angle of 40 degrees for
64 cm on each side to the peak.
8.1.5.2 Front and Rear—Bottom sheet 69 cm wide by 6 cm
on sides rising vertically and attaching to a sheet rising at an
angleof40degreesmeasuring69cmwideby64cminlength.
8.1.5.3 The handle is mounted on the front sheet. The base
of the handle measures 3 cm in thickness by 3 cm in width by
30 cm in length and is used to attach the handle (30 cm in
length by 5 cm in width by 1 cm in thickness).
8.1.5.4 Singleordoublesupportstrutsareusedandmeasure
69 cm in length by 7 cm in width by 1 cm in thickness.
8.2 The environmental chamber must be capable of main- FIG. 7 TC Heater Installed in Tank Exterior
taining a relative humidity of 95 to 98% at a temperature of
approximately 32 °C (90 °F) while providing a continuous
inoculation of the surface of the test specimens with fungal
spores.
8.2.1 Maintaining the room temperature at approximately
24 °C is required so that heat loss from the cabinet is
insignificant and a relative humidity of 95 to 98% is readily
obtainable in the chamber. Alternatively, the cabinet must be
insulated with suitable material to minimize heat loss.
8.2.2 An electric water heat
...