ASTM G160-12(2019)

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: G160 − 12 (Reapproved 2019)
Standard Practice for
Evaluating Microbial Susceptibility of Nonmetallic Materials
By Laboratory Soil Burial
This standard is issued under the fixed designation G160; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
1.1 This practice is limited to the method of conducting an
mine the applicability of regulatory limitations prior to use.
evaluation of a nonmetallic material’s microbiological suscep-
1.6 This international standard was developed in accor-
tibilitywhenincontactwiththenaturalenvironmentofthesoil
dance with internationally recognized principles on standard-
under use conditions. This practice is intended for use on solid
ization established in the Decision on Principles for the
material test specimens that are no larger than approximately
2 2 Development of International Standards, Guides and Recom-
2 cm(0.79 in.)thickand100 cm (15.5 in. )oronfilmforming
mendations issued by the World Trade Organization Technical
materials such as coatings which may be tested in the form of
Barriers to Trade (TBT) Committee.
films at least 50 by 50 mm (2 by 2 in.) in size. This practice
may be applied to articles that do not spend the majority of
2. Referenced Documents
their service life in soil.
2.1 ASTM Standards:
1.2 A wide variety of properties may be affected by micro-
G154 Practice for Operating Fluorescent Ultraviolet (UV)
bial attack depending on material or item characteristics.
Lamp Apparatus for Exposure of Nonmetallic Materials
Standard methods (where available) should be used for each
G155 Practice for Operating XenonArc LightApparatus for
different property to be evaluated. This practice does not
Exposure of Non-Metallic Materials
attempt to enumerate all of the possible properties of interest
nor specify the most appropriate test for those properties. Test
3. Significance and Use
methods must, however, be appropriate to the material being
3.1 These results may be used to compare the susceptibility
tested.
of materials when exposed to this test procedure.
1.3 Materials intended for use in soil burial applications are
3.2 Microbiological susceptibility may be reflected by a
often subjected to periods of exposure to solar radiation and
numberofchangesincludingstaining,weightloss,orreduction
otherelementsofweatherforsometimebeforetheyareburied.
in tensile or flexural strength.
Because these exposures may alter the ability of a material to
3.3 This practice may be considered an inoculation with a
resist the effects of soil-borne microorganisms, it is recom-
mended that this practice be combined with appropriate envi- mixed culture of fungi and bacteria.
ronmentalexposures(forexample,solarsimulatingweathering
4. Soil
devices, the hydrolytic effects of extended aqueous contact, or
extraneous nutrients) or fabrication into articles (for example,
4.1 Composition—Soil shall be composed of equal parts of
adhesive bonding of seams) which may promote microbiologi-
fertile topsoil (soil with a high clay content should not be
cal susceptibility during the service life of the material.
used), well-rotted and shredded horse manure, and coarse sand
(10 to 40 mesh).
1.4 The values stated in SI units are to be regarded as
standard. The values given in parentheses are provided for
4.2 Mixing—Thesoilcompositionof4.1shouldbeprepared
information purposes only.
by simple mixing and sifting through ⁄4 in. mesh screen.
1.5 This standard does not purport to address all of the
4.3 Aging—The mixture is aged for three months and
safety concerns, if any, associated with its use. It is the
resifted twice at four-week intervals during the three months.
Afterthreemonths,aviabilitycontrolofuntreatedcottoncloth,
This practice is under the jurisdiction ofASTM Committee G03 on Weathering
and Durability and is the direct responsibility of Subcommittee G03.04 on
Biological Deterioration. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 15, 2019. Published March 2019. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1998. Last previous edition approved in 2012 as G160 – 12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/G0160-12R19. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G160 − 12 (2019)
2 2
400 to 475 g⁄m (12 to 14 oz⁄yd ), buried in the soil shall have various stages of fungal attack will be variable. The ASTM
a tensile strength loss of at least 50 % after five days. Manual 7 may be used as a guide.
NOTE 1—The soil mixture may be used for sequential tests as long as
the cotton cloth control degrades within the specified time period.
7. Solar-Simulating Weathering Devices
7.1 For those soil burial applications in which the materials
4.4 pH—The soil shall have a pH between 6.5 to 7.5,
checked periodically, and maintained by the addition of ground are expected to be exposed to environmental conditions,
including solar radiation, it is recommended that they be
limestone to raise the pH or flowers of sulfur to lower the pH.
The soil pH may be taken by dispersing 1 weight part soil in exposed in a laboratory accelerated weathering device prior to
soil burial. The type and duration of exposure shall be agreed
20 parts of water, shaking or stirring, then allowing the mix to
upon by interested parties. The duration shall be of sufficient
settle for 1 h. The pH is measured with indicator paper,
electrodes, or by titration. length, known by previous experience to have reduced the
resistance of some materials to the effects of soil-borne
4.5 Moisture—The soil shall be maintained at between 20
microorganisms. If used, the type and duration of exposure
and 30 % moisture, based on the dry weight of the soil. (The
shall be completely described in the Test Report.
percent moisture is calculated by weighing approximately
7.2 The two types of weathering devices described in the
50 mL of a representative portion and taking the portion to
Practices listed below have been used historically prior to
constant weight by placing the soil in an oven at a temperature
evaluation of the microbial susceptibility of nonmetallic mate-
of 101 to 106 °C.) Water lost during use as a result of
rials by laboratory soil burial. Because of differences in the
evaporationshallbereplacedwithoutdeformingthesoilbed.If
spectral power distributions of the exposure sources as well as
the surrounding atmosphere is maintained at 85 to 95 %
the other conditions in the two types of laboratory weatherin
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