ASTM G29-96(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:G29–96(Reapproved2002)
Standard Practice for
Determining Algal Resistance of Plastic Films
This standard is issued under the fixed designation G29; 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.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 4. Apparatus
1.1 This practice covers the determination of the suscepti- 4.1 Propagation Tank (see Fig. 1):
bility of plastic films to the attachment and proliferation of 4.1.1 A small fish tank (10 gal) is used to contain a
surface-growing algae. simulated cooling tower, made of redwood slats, over which
1.2 The values in SI units are to be regarded as the standard. culturemediumisrecirculatedthroughaplastictubewithholes
The inch-pound units given in parentheses are for information punched in the bottom. This design was developed in order to
only. provide ideal conditions for propagation of the algae that serve
1.3 This standard does not purport to address all of the as inocula for each test. Three redwood slats are joined by two
safety concerns, if any, associated with its use. It is the supports in such a way that water cascades over each slat in
responsibility of the user of this standard to establish appro- turn from a distributor tube above the upper slat.Asmall, fully
priate safety and health practices and determine the applica- immersed recirculating pump rests on the bottom of the tank
bility of regulatory limitations prior to use. and operates continuously to deliver the tank contents to the
distributor tube. The light required for algal propagation is
2. Summary of Practice
provided by a 100-W bulb placed 300 mm (12 in.) away from
2.1 In this practice, test strips of plastic film are suspended
the redwood slats. A timing device turns the light on for 12 h
in glass jars maintained at room temperature.The test strips are each day.
exposed to fluorescent light and in direct contact with a
4.1.2 The propagation tank, that is used as the permanent
standardized inoculum of the filamentous blue-green alga source of inoculum, is filled to approximately one-third capac-
Oscillatoria in culture medium. The sample test jars are
ity with the culture medium. Heavy growth of Oscillatoria
reinoculated with fresh alga every second or third day. A
rapidly develops on the redwood tower and, at different phases,
control using untreated plastic film is used as a basis of this growth appears light green, dark green, or black.
comparison. The inoculum is prepared with the help of a
4.2 Test Chambers (see Fig. 2):
propagation apparatus made from a small fish tank. The test is 4.2.1 One-litre (1-qt) wide-mouth glass jars, 170 mm (6 ⁄4
terminated at the end of two weeks, or whenever the test film
in.) high by 76 mm (3 in.) in inside diameter serve as test
shows dense algal growth. chambers wherein water containing an inoculum of the algal
organisms and strips of the plastic film are maintained in
3. Significance and Use
contact.
3.1 Bodies of water, such as swimming pools, artificial
4.2.2 The jars in 4.2.1 are placed in a 38-L (10-gal) fish
ponds, and irrigation ditches often are lined with plastic films.
tank, 508 by 267 by 305 mm (20 by 10 ⁄2 by 12 in.) high, that
Algae tend to grow in such bodies of water under the proper
is illuminated by four 20-W “cool white” fluorescent bulbs,
atmospheric conditions, and they can produce slimy and
arranged two on each long side of the tank, at the level of the
unsightly deposits on the film. The method described herein is
growing algae in the jars. The lamps are mounted on a bracket
useful in evaluating the degree and permanency of protection
that holds the outer surface of the bulbs 25 mm (1 in.) from the
against surface growth of algae afforded by various additives
wall of the tank. The tank is filled with water to within 25 mm
incorporated in the film.
1 2
This practice is under the jurisdiction ofASTM Committee G03 on Weathering The redwood tower should be soaked in water before use, until the water is
and Durability and is the direct responsibility of Subcommittee G03.04 on colorless. Water is changed daily.
Biological Deterioration. Model 1 MA manufactured by the Little Giant Corp., 3800 N. Tulsa Ave.,
Current edition approved Jan. 10, 2002. Published May 2002. Originally Oklahoma City, OK 73107, has been found suitable for this purpose.
approved in 1971. Last previous edition approved in 1996 as G29 – 96. DOI: Culture medium in the propagation tank is discarded, and the tank is refilled
10.1520/G0029-96R02. with fresh medium at monthly intervals.
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G29–96 (2002)
where such specifications are available. Other grades may be
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references
to water shall be understood to mean distilled water or water of
equal purity.
5.3 Culture Medium for Propagation Apparatus—Prepare
this medium by dissolving in 15 L of water the designated
amounts of the following reagents:
Arnon’s trace metal solution (see Note 1)15mL
Ethylenediamine t
...