1、Designation: F1738 15Standard Test Method forDetermination of Deposition of Aerially Applied Oil SpillDispersants1This standard is issued under the fixed designation F1738; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 test method covers the measurement of the depo-sition of an aerially applied dispersant surrogate, typically dy
3、edwater, on the surface of the ground or water. The test methodof obtaining these measurements is described, and the analysisof the results, in terms of dispersant use, is considered. Thereare a number of techniques that have been developed, and thistest method outlines their application. These meas
4、urements canbe used to confirm or verify the specifications of a givenequipment set, its proper functioning, and use.1.2 This test method is applicable to systems used withhelicopters or airplanes.1.3 This test method is one of four related to dispersantapplication systems. Guide F1413_F1413 covers
5、design, Prac-tice F1460/F1460M covers calibration, Test Method F1738covers deposition, and Guide F1737/F1737M covers the use ofthe systems. Familiarity with all four standards is recom-mended.1.4 There are some exposure and occupational health con-cerns regarding the methods described. These are not
6、 discussedin this test method since they are a function of dispersantformulation. Anyone undertaking such experiments shouldconsult the occupational health experts of the dispersantmanufacturer regarding the precautions to be used.1.5 The values stated in SI units are to be regarded asstandard. No o
7、ther units of measurement are included in thisstandard.1.6 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 health practices and determine the applica-bility
8、 of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E642 Practice for Determining Application Rates and Dis-tribution Patterns from Aerial Application EquipmentE1260 Test Method for Determining Liquid Drop SizeCharacteristics in a Spray Using Optical NonimagingLight-Sc
9、attering InstrumentsF1413_F1413 Guide for Oil Spill Dispersant ApplicationEquipment: Boom and Nozzle SystemsF1460/F1460M Practice for Calibrating Oil Spill DispersantApplication Equipment Boom and Nozzle SystemsF1737/F1737M Guide for Use of Oil Spill Dispersant Ap-plication Equipment During Spill Re
10、sponse: Boom andNozzle Systems2.2 ASAE/ASABE Standard:3ASAE/ASABE S561.1 (R2013) Procedure for MeasuringDrift Deposits from Ground, Orchard, andAerial Sprayers- Standard by The American Society of Agricultural andBiological Engineers3. Significance and Use3.1 The deposition of an aerially applied di
11、spersant isdefined as the amount of an aerially applied dispersant thatcontacts the surface; whereas, application dosage (frequentlyreferred to as application rate) is the amount of material that isreleased per unit area by the delivery system. The units ofdeposition are litres per hectare or U.S. g
12、allons per acre. Thedeposition may differ from the application dosage (volume ofmaterial per unit area) for many reasons, such as, the effects ofwind on the spray and the evaporation of the dispersant after ithas been released from the aircraft.3.2 This test method describes the measurement of theab
13、ility of a spray system to deposit a dispersant on oil. It is notintended that this test method be used at the time of a spill.These techniques are intended to determine the equipment1This test method is under the jurisdiction of ASTM Committee F20 onHazardous Substances and Oil Spill Response and i
14、s the direct responsibility ofSubcommittee F20.13 on Treatment.Current edition approved March 1, 2015. Published April 2015. Originallyapproved in 1996. Last previous edition approved in 2010 as F1738 10. DOI:10.1520/F1738-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orco
15、ntact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Agricultural and Biological Engineers(ASABE), 2950 Niles Road, St. Joseph, MI 49085, http:/www.asab
16、e.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1performance during the development of new systems and afterthe repair or significant modification of a system.3.3 The data obtained from the use of this test method canbe directly
17、related to the deposition of dispersant on an oilslick, and thus can serve to determine both the dispersantdeposition and the droplet size.3.4 Surrogate deposition and droplet size data can be usedas a technical basis for the optimization of dispersant applica-tion equipment and its use.3.5 The choi
18、ce of a dispersant surrogate may vary, typicallywater is chosen along with a marker dye.4. Apparatus and Materials4.1 The basic concept is to provide a collection surface onwhich the aerially applied material is deposited. The amount ofmaterial and the deposition pattern and its droplet size can bem
19、easured using this surface. Several systems and methodshave been developed, and each has its own advantages anddisadvantages.4.2 These measurements require a large, flat open area (suchas a field or an airport) which is suitable for low-level flyingand maneuvering. The location should be away from h
20、umanhabitation or environmentally sensitive areas in order tominimize problems due to noise and drifting spray.4.3 These field programs should be conducted under low-wind conditions in order to minimize drift. Near-surfaceturbulence due to thermal gradients or atmospheric instabilitycan contribute t
21、o a variation in the results. These measurementscannot be carried out in the presence of precipitation or inheavy concentrations of dust.4.4 All tests are to be conducted with the flight path in anupwind direction. The upwind direction is chosen to simplifythe interpretation of the data and to confo
22、rm with typical fieldpractice. It may be necessary to alter the flight path slightly forchanges in wind direction during the course of an experimentalprogram.4.5 It is common practice to use a surrogate, typically water,rather than the dispersant itself. Dye can be added to the waterto provide a mea
23、surement target. This dye should respond tothe analytical method used in Section 5. Special permissionwould be required to use a dispersant and permissions may alsobe required to apply a surrogate, and special precautions maybe required to protect and clean the area afterwards.5. Deposition Measurem
24、ent Methods5.1 These techniques involve the use of a collecting surfaceof known area and the measurement of the amount andcharacter of the dispersant deposited on this area. A variety ofsystems may be used, such as the following:5.1.1 Laser Measuring InstrumentationThe use of laser-based measuring t
25、echniques is becoming more common andcan provide both droplet size and deposition distribution. Thismethod employs laser scattering devices deployed in an arrayon a flat surface (Test Method E1260), the number of thesedevices depends on the specified horizontal range of thesedevices and the amount o
26、f surface coverage desired by the testgroup. The data are collected in the memory of the units andanalyzed and processed upon completion of the test. With someunits, it is possible to conduct multiple tests before recovery ofthe data as the data are time-stamped.5.1.2 Coated CardsStandard cards spec
27、ifically designedfor the purpose (for example, Kromekote cards) of known areaare placed in a line perpendicular to the flight path, andextending over a distance 25 % greater than the expected swathwidth. The cards typically have dimensions of 5 by 7 cm. Thereshould be about twenty cards placed acros
28、s the flight path inorder to have an adequate number of sampling points. In atypical experimental setup, the distance between samplingcards should be greater than one metre and less than threemetres. This criteria may require more or less than twenty cardsdepending on the spray system being tested.
29、Each card shouldbe identified by a unique label, indicating its place on thesampling line and the number of the spray pass. The markingshould be made in such a fashion that it will not be removed bythe dispersant surrogate, as well as Garrco Vision Pink dyemixed at a ratio of 1:400 to provide color
30、to the Kromekotecards. The cards are kept covered until just before the spray runto reduce the possibility of contamination. The cards are placein holders if wind can move these cards out of position. Theplacement, uncovering, and retrieval of these cards is laborintensive. After the spray run, the
31、cards are collected andanalyzed by machine (Practice E642, ASAE/ASABE S561.1(R2013). The cards may be used to provide both droplet size,spray width and deposition pattern. This method may also beused in combination with other methods to provide data.5.1.3 Glass Petri Dishes or Similar ContainersFlat
32、 dishesof known area are placed in a line perpendicular to the flightpath, and extending over a distance 25 % greater than theexpected swath width. Dishes of a diameter of 120 to 140 mmare typically used. There should be about twenty dishes placedacross the flight path in order to have an adequate n
33、umber ofsampling points. In a typical experimental setup, the distancebetween sampling dishes should be greater than one metre andless than three metres. This criteria may require more or lessthan twenty dishes depending on the spray system being tested.Each sampling dish should be identified by a u
34、nique label,indicating its place on the sampling line and the number of thespray pass. The marking should be made in such a fashion thatit will not be removed by the dispersant surrogate, or roughhandling. The sampling dishes are kept covered until justbefore the spray run to reduce the possibility
35、of contamination.The placement, uncovering, and retrieval of these dishes islabor intensive.After the spray run, the dishes are collected andwashed with a suitable solvent, such as methanol or hexane, tocollect the deposited material. The amount of dye present canbe determined by using a colorimeter
36、 sensitive to the dye used.The system must be calibrated using a sample of the dyedsurrogate and solvent mixture for that experimental pass. Forthese measurements, care must be taken to ensure that the samedilution factors are used for both the calibration and materialfrom the sampling dishes, since
37、 the measurement instrumentsare only linear over about an order of magnitude of concen-tration. From these sets of data, the amount of materialF1738 152deposited on the surface in any units required, such aslitres/hectare (U.S. gal/acre), can be calculated.5.1.4 Metal TroughsA variation of the sampl
38、ing dish is aV-shaped metal trough, divided into sections and placedperpendicular to the flight path. Each section is about twometres long with a cross section of about 6 cm. A number oftroughs, connected end-to-end, are used to cover a length ofabout 25 % greater than the total spray width.After a
39、spray run,the troughs are washed with a solvent, such as methanol orhexane, and the eluent from each section is collected foranalysis. The concept is similar to that of the glass dishes, butthis system has the advantage of sampling the total spraywidth, and providing an average dose over the discret
40、e section.One major advantage of the troughs is that they remain in placeduring a number of experimental runs, thus reducing the timebetween runs. This allows for more runs per day.5.1.5 String MeasurementThe string method is often usedto provide information on spray width and pattern. Thismethod us
41、es a cord or string that is either stretched across thewidth of the spray or is supported on a series of stands. Exceptfor very narrow-width application systems, the string is sup-ported about every two metres by a stand. The surrogate isRhodamine WT dye mixed with water at a ratio of about1:7500. T
42、he surrogate is collected by the string, and thus theneeded data are obtained. Since the cross section of the stringis much smaller than that of the Petri dish or trough, more dyemay be needed in the sprayed dispersant. The string is thenallowed to dry. The amount of material that the string collect
43、edis determined by a fluorometric or colormetric technique.Automated devices are available for this application. Thismethod measures the relative deposition only, and not theabsolute deposition.5.1.6 Data DeterminationThe data collected from thesetypes of measurements is the same in character. The a
44、mount ofdispersant that reaches the ground is measured as a function ofthe position along the swath of the spray. From this, spraypatterns can be determined and plotted. Data gathered usingdishes and the metal troughs can be used to compute the actualdeposition.6. Drop-Size Determination6.1 While th
45、e techniques of Section 5 provide an accuratemeasurement of the deposition, they do not give any indicationof the drop size or drop-size distribution except for the use forKromekote Cards as described in 5.1.2. Drop-size measure-ments are also required in order to characterize a dispersantapplicatio
46、n system. The basic principle of most drop-sizemeasurements is to capture the falling drops on a surface andthen measure the area of the drop. The surface must becalibrated so that the conversion factor from drop volume tosurface drop diameter is known.6.1.1 The analysis of such drop sizes is expres
47、sed as avolume median diameter (VMD). The VMD is the effectivediameter of a distribution of various drop sizes. It represents asingle parameter description of a spray-pattern droplet sizedistribution and is statistically based. Therefore, VMD cannotbe used to compute the terminal velocity of a drop
48、or itsmomentum. It is the momentum that is critical for thedispersant, since this determines the probability of the dropletpenetrating the slick.6.2 Most techniques developed for pesticide drop-size mea-surements fail since the deposition for dispersants is severalorders of magnitude greater than th
49、ose used for pesticides.When these techniques are used for dispersants, the flux ofdroplets are so dense that they overlap, and thus, individualparticles cannot be measured.6.3 There are a number of methods that have been used inthe measurement of drop size. One modern method is to uselaser particle instrumentation which can directly provide drop-let diameter along with statistics on these. Traditional methodsoften use paper as the absorbing material. One common systemuses specially coated cards (Kromekote). There are two prod-ucts that are typically used: a water-sensitive pa
