ASTM F1738-96(1999)
(Test Method)Standard Test Method for Determination of Deposition of Aerially Applied Oil Spill Dispersants
Standard Test Method for Determination of Deposition of Aerially Applied Oil Spill Dispersants
SCOPE
1.1 This test method covers the measurement of the deposition of an aerially applied dispersant on the surface of the ground or water. The test method of obtaining these measurements is described, and the analysis of the results, in terms of dispersant use, is considered. There are a number of techniques that have been developed, and this test method outlines their application. These measurements can be used to confirm or verify the specifications of a given equipment set, its proper functioning, and use.
1.2 This test method is applicable to systems used with helicopters or airplanes.
1.3 This test method is one of four related to dispersant application systems. Guide F 1413 covers design, Practice F 1460 covers calibration, Test Method F 1738 covers deposition, and Guide F 1737 covers the use of the systems. Familiarity with all four standards is recommended.
1.4 There are some exposure and occupational health concerns regarding the methods described. These are not discussed in this test method since they are a function of dispersant formulation. Anyone undertaking such experiments should consult the occupational health experts of the dispersant manufacturer regarding the precautions to be used.
1.5 The values stated in SI units are to be regarded as the standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:F1738–96(Reapproved 1999)
Standard Test Method for
Determination of Deposition of Aerially Applied Oil Spill
Dispersants
This standard is issued under the fixed designation F 1738; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope ment: Boom and Nozzle Systems
F 1460 Practice for Calibrating Oil Spill Dispersant Appli-
1.1 This test method covers the measurement of the depo-
cation Equipment Boom and Nozzle Systems
sition of an aerially applied dispersant on the surface of the
F 1737 Guide for Use of Oil-Spill Dispersant Application
ground or water. The test method of obtaining these measure-
Equipment During Spill Response: Boom and Nozzle
ments is described, and the analysis of the results, in terms of
Systems
dispersant use, is considered.There are a number of techniques
that have been developed, and this test method outlines their
3. Significance and Use
application. These measurements can be used to confirm or
3.1 The deposition of an aerially applied dispersant is
verify the specifications of a given equipment set, its proper
defined as the amount of an aerially applied dispersant that
functioning, and use.
contacts the surface; whereas, application dosage (frequently
1.2 This test method is applicable to systems used with
referred to as application rate) is the amount of material that is
helicopters or airplanes.
released per unit area by the delivery system. The units of
1.3 This test method is one of four related to dispersant
deposition are litres per hectare or U.S. gallons per acre. The
application systems. Guide F 1413 covers design, Practice
deposition may differ from the application dosage (volume of
F 1460 covers calibration, Test Method F 1738 covers deposi-
material per unit area) for many reasons, such as, the effects of
tion, and Guide F 1737 covers the use of the systems. Famil-
wind on the spray and the evaporation of the dispersant after it
iarity with all four standards is recommended.
has been released from the aircraft.
1.4 There are some exposure and occupational health con-
3.2 This test method describes the measurement of the
cernsregardingthemethodsdescribed.Thesearenotdiscussed
ability of a spray system to deposit a dispersant on oil. It is not
in this test method since they are a function of dispersant
intended that this test method be used at the time of a spill.
formulation. Anyone undertaking such experiments should
These techniques are intended to determine the equipment
consult the occupational health experts of the dispersant
performance during the development of new systems and after
manufacturer regarding the precautions to be used.
the repair or significant modification of a system.
1.5 The values stated in SI units are to be regarded as the
3.3 The data obtained from the use of this test method can
standard.
be directly related to the deposition of dispersant on an oil
1.6 This standard does not purport to address all of the
slick, and thus can serve to determine both the dispersant
safety concerns, if any, associated with its use. It is the
deposition and the droplet size.
responsibility of the user of this standard to establish appro-
3.4 Dispersant deposition and droplet size data can be used
priate safety and health practices and determine the applica-
as a technical basis for the optimization of dispersant applica-
bility of regulatory limitations prior to use.
tion equipment and its use.
2. Referenced Documents
4. Apparatus and Materials
2.1 ASTM Standards:
4.1 The basic concept is to provide a collection surface on
F 1413 Guide for Oil-Spill Dispersant Application Equip-
which the aerially applied material is deposited.The amount of
material and the deposition pattern and its droplet size can be
measured using this surface. Several systems and methods
This test method is under the jurisdiction of ASTM Committee F20 on
have been developed, and each has its own advantages and
Hazardous Substances and Oil Spill Response and is the direct responsibility of
disadvantages.
Subcommittee F20.13 on Treatment.
Current edition approved Oct. 10, 1996. Published December 1996.
4.2 Thesemeasurementsrequirealarge,flatopenarea(such
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
as a field or an airport) which is suitable for low-level flying
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and maneuvering. The location should be away from human
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1738–96 (1999)
habitations or environmentally sensitive areas in order to about an order of magnitude of concentration. From these sets
minimize problems due to noise and drifting spray. of data, the amount of material deposited on the surface in any
4.3 These field programs should be conducted under low- units required, such as litres/hectare (U.S. gal/acre), can be
wind conditions in order to minimize drift. Near-surface calculated.
turbulence due to thermal gradients or atmospheric instability
5.1.2 Metal Troughs—Avariation of the sampling dish is a
cancontributetoavariationintheresults.Thesemeasurements
V-shaped metal trough, divided into sections and placed
cannot be carried out in the presence of precipitation or in
perpendicular to the flight path. Each section is about two
heavy concentrations of dust.
metres long with a cross section of about 6 cm. A number of
4.4 All tests are to be conducted with the flight path in an
troughs, connected end-to-end, are used to cover a length of
upwind direction. The upwind direction is chosen to simplify
about25 %greaterthanthetotalspraywidth.Afterasprayrun,
the interpretation of the data and to conform with typical field
the troughs are washed with a solvent, such as methanol or
practice. It may be necessary to alter the flight path slightly for
hexane, and the eluent from each section is collected for
changes in wind direction during the course of an experimental
analysis. The concept is similar to that of the glass dishes, but
program.
this system has the advantage of sampling the total spray
4.5 It is common practice to use a dye, soluble in the
width, and providing an average dose over the discrete section.
dispersant, which will assist in the detection of the dispersant
Onemajoradvantageofthetroughsisthattheyremaininplace
by the analysis system. Oil Red B and Rhodamine WP have
during a number of experimental runs, thus reducing the time
been used at concentrations of 0.1 to 2.0 %. The sensitivity of
between runs. This allows for more runs per day.
current detection systems allows the use of concentrations at
5.1.3 String Measurement—Another method uses a cord or
the 0.1 % level or less.
string that is either stretched across the width of the spray or is
4.6 The area used will become covered with dispersant
supported on a series of stands. Except for very narrow-width
spray, and it is suggested that the area not be used for
application systems, the string is supported about every two
agricultural purposes at least until any evidence of the dispers-
metres by a stand.The dispersant is collected by the string, and
ant or dye is no longer observable. The length of time depends
thustheneededdataareobtained.Sincethecrosssectionofthe
on the weather conditions, especially precipitation that occurs
string is much smaller than that of the Petri dish or trough,
after the spray program has been completed.
more dye may be needed in the sprayed dispersant. The string
is then allowed to dry. The amount of material that the string
5. Deposition Measurement Methods
collected is determined by a fluorometric or colormetric
5.1 These techniques involve the use of a collecting surface
technique. This method measures the relative deposition only,
of known area and the measurement of the amount and
and not the absolute deposition.
character of the dispersant deposited on this area. A variety of
5.1.4 Data Determination—The data collected from these
systems may be used, such as the following:
types of measurements is the same in character. The amount of
5.1.1 GlassPetriDishesorSimilarContainers—Flatdishes
dispersant that reaches the ground is measured as a function of
of known area are placed in a line perpendicular to the flight
the position along the swath of the spray. From this, spray
path, and extending over a distance 25 % greater than the
patterns can be determined and plotted. Data gathered using
expected swath width. Dishes of a diameter of 120 to 140 mm
dishes and the metal troughs can be used to compute the actual
are typically used. There should be about twenty dishes placed
deposition.
across the flight path in order to have an adequate number of
sampling points. In a typical experimental setup, the distance
6. Drop-Size Determination
between sampling dishes should be greater than one metre and
6.1 While the techniques of Section 5 provide an accurate
less than
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