1、Designation: G140 02 (Reapproved 2014)Standard Test Method forDetermining Atmospheric Chloride Deposition Rate by WetCandle Method1This standard is issued under the fixed designation G140; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revi
2、sion, the year of 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 a wet candle device and its usein measuring atmospheric chloride deposition
3、(amount ofchloride salts deposited from the atmosphere on a given areaper unit time).1.2 Data on atmospheric chloride deposition can be usefulin classifying the corrosivity of a specific area, such as anatmospheric test site. Caution must be exercised, however, totake into consideration the season b
4、ecause airborne chloridesvary widely between seasons.1.3 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 o
5、f regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4458 Test Method for Chloride Ions in Brackish Water,Seawater, and BrinesG92 Practice for Characterization of Atmospheric Test Sites2.2 ISO Standard:ISO 9225 Corrosion of Metals and
6、 Alloys. Aggressivity ofAtmospheresMethods of Measurement of PollutionData33. Significance and Use3.1 This test method is capable of generating quantitativevalues of atmospheric chloride deposition specifying milli-grams of chloride ions per square metre per day (or other unitsderived from such valu
7、es).NOTE 1Chlorides in the atmosphere exist as a suspension of liquiddroplets or solid particles. They are transported to solid surfaces bygravity, wind, or brownian motions. These transport mechanisms aredirection-sensitive so that a vertical cylinder will not necessarily receivethe same flux as a
8、horizontal plate, or objects with different sizes andorientations. Therefore, the use of this approach to provide an indicationof the deposition of chlorides on objects in atmospheric exposures may notbe quantitatively accurate; however, this technique has been successful inclassifying the severity
9、of exposure in a variety of marine locations.3.2 The sites where samples are to be taken and thesampling time periods should be established. A continuousprogram of monthly or 30-day exposures is recommended forsite characterization. Seasonal monitoring may be performed ifthere are specific periods o
10、f interest.4. Apparatus4.1 ComponentsThe components needed to construct onewet candle device are as follows:4.1.1 Erlenmeyer Flask, narrow mouth, 500 mL, (glass orpolypropylene). Other size flasks may be used, but dimensionsin Fig. 1 will have to be adjusted accordingly.NOTE 2Polypropylene flasks ar
11、e recommended during threat offreezing weather.4.1.2 Glass Test Tube, general purpose, 16 by 150-mmlength.4.1.3 Solid Rubber or Neoprene Stopper, No. 7, diameter top38 mm, bottom 30 mm.4.1.4 Cotton Bandage Gauze, strip, 50 mm wide and ap-proximately 1500 mm long.NOTE 3The overall length of the gauze
12、 may vary with installation.4.1.5 Type IV Reagent Water, 1 L, 200 mL CHOH(CH2OH2) (glycerin) and 20 drops CH3(CH2)6COOH (oc-tanoic acid) should be added to prevent freezing, if necessary(See Specification D1193).4.1.6 Gloves, vinyl, one pair.NOTE 4Poly(vinyl chloride) (PVC) is recommended. Latex glo
13、ves arenot acceptable, as their chloride content is reported to be comparable tothat of human hands.4.2 Support StandAsuitable support stand shall be erectedat the site where the atmosphere is to be sampled. A treated1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of Me
14、tals and is the direct responsibility of Subcommittee G01.04 onAtmospheric Corrosion.Current edition approved Nov. 1, 2014. Published November 2014. Originallyapproved in 1996. Last previous edition approved in 2008 as G14002 (2008). DOI:10.1520/G0140-02R14.2For referenced ASTM standards, visit the
15、ASTM website, www.astm.org, orcontact 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 National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10
16、036, http:/www.ansi.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1wood post (100 by 100 by 2250 mm) or galvanized pipe(42-mm diameter by 2250-mm length) with an attached plateon top is suitable, with 750 mm in the ground and 150
17、0 mmabove the ground on which the apparatus to hold the candle canbe mounted (see Fig. 1). The apparatus shall be mounted sothat the arms supporting the rain cover do not shield the gauzefrom a known source of chloride.4.3 Assembly of the Wet Candle Apparatus (see Fig. 1):4.3.1 The rubber stopper mu
18、st be modified.4.3.1.1 In the center, bore a hole 15 mm in diameter throughthe stopper.4.3.1.2 On opposite sides of the conical surface of thestopper, cut or grind a channel or flat, from top to bottom,sufficiently wide (;25 mm) for the gauze to pass freelybetween the stopper and the neck of the fla
19、sk when the stopperis installed tightly in the flask (see Fig. 1).4.3.2 Insert the test tube upward through the hole in therubber stopper so that the lip of the tube is at the bottom of thesmall end of the stopper.4.3.2.1 The flask and tube/stopper assembly should berinsed withType IVreagent water t
20、o remove any contaminants.4.3.3 Cover bare hands with gloves (PVC or other plastic(see Note 4). With freshly opened bandage gauze (50 mmwide), start with a wick 150 mm in length, pass through onechannel in the stopper and tightly wrap all the exposed area ofthe tube. Using overlapping turns, move up
21、 the tube coveringthe top, then back down the tube to the stopper, pass the gauzethrough the other channel in the stopper, leaving anothersection of the gauze approximately equal in length to the first(150 mm).NOTE 5The total area of exposed gauze will be approximately 0.01m2.4.3.4 Rinse gauze with
22、Type IV reagent water and fill theflask with 350 mL of Type IV reagent water (see 4.1.5).4.3.5 Insert wick ends of gauze into flask and press stopper/tube assembly firmly into flask.4.3.6 Care while handling and transporting candles is ofutmost importance to prevent contamination by perspiration oro
23、ther means. It is good practice to cover the assembled candle,either before or after filling the flask, with a protective shield toprevent accidental contamination during storage and transport,and also following retrieval for analysis. A polyethylene bagapproximately 75 mm (3 in.) by 230 mm (9 in.)
24、or plastic wraphas been found satisfactory. If a bag is used, it can be securedto the flask with a rubber band.5. Procedure5.1 Exposure of Wet Candle:5.1.1 Place a wetted candle in the support stand. Removethe protective shield, and if not previously filled, handling theNOTE 1Dimensions are in milli
25、metres (mm).FIG. 1 Wet Candle Chloride ApparatusG140 02 (2014)2tube and stopper by the protective shield, remove the stopperand wick from the flask sufficiently to add 350 mL of Type IVreagent water. Replace the stopper. Record the exposure timeand date, and any other pertinent conditions of the exp
26、osure.5.1.2 A predetermined exposure period shall have beenestablished (see 3.2). The exposure period may require that thewater be replenished due to evaporation. If to be exposed tofreezing conditions, see instructions in Section 4.NOTE 6The collection efficiency of a frozen wick will not be the sa
27、meas a wet wick. Therefore, measurements will be invalid even if the flaskdoes not break.5.2 Removal of Wet Candle:5.2.1 Remove complete candle assembly for analysis. Be-fore or immediately after removal, identify the candle with itslocation and any other identifying data, as well as date and timeof
28、 removal.5.2.2 If continuous monitoring is desired, candles may beemplaced sequentially on a periodic basis (that is, monthly)with the new candle installed when the exposed one isremoved.5.2.3 Transport wet candle immediately to a laboratory orlocation equipped to conduct the chemical analysis, exer
29、cisingcaution to prevent spillage or contamination. A protectiveshield, as described in 4.3.6 is strongly recommended.5.3 Preparing Candle Assembly for Analysis:5.3.1 Reverse the procedure in 4.3.3, again using gloves,then remove (unwind) the gauze from the test tube and placeinto a 600-mL beaker. P
30、our the contents of the flask into thebeaker. Rinse test tube and flask with Type IV reagent waterand add to beaker. Bring contents of beaker to approximately500 mL. Cover and let stand for 24 h.NOTE 7If more than one wet candle is being evaluated, properlyseparate and identify each beaker.5.3.2 Aga
31、in using gloves, remove the gauze from the beakerand wring it out, letting the water drain from the gauze, andtransfer the liquid to a 500-mL flask. Bring the volume to 500mL by adding Type IV reagent water.5.4 Determination of Chloride Content from Wet Candle:5.4.1 The chemical procedure for determ
32、ination of thechloride concentration is described in Test Method D4458.This test method is based upon the titration of chloride withsilver nitrate.5.4.2 Alternative chloride analysis procedures include theuse of ion chromatography or the mercurimetric titrationmethod of ISO 9225.5.4.3 A blank gauze
33、sample, the same size as stated in 4.3.3and from the same lot, should be tested for chlorides. If theblank shows no chlorides present, then no further blanks fromthat batch need be tested. It is strongly recommended that theblank testing be done before the wet candles are assembled.6. Calculation6.1
34、 Calculate the contents of the water in accordance withTest Method D4458 as follows:mg Cl2/L 5mL AgNO3used 2 B! 3T 31000mL sample(1)where:T = titre, mgCl/mL of AgNO3, andB = indicator blank.6.2 Calculate results in terms of mg Cl/m2/day using thefollowing relationship:mg Cl2/m2/day 5 mg Cl2/L (2)2At
35、where:t = time of exposure, days, andA = exposed area of gauze, determined as follows:A 5 DD11! (3)where:D = test tube diameter, m,1 = test tube length exposed, m, andA = exposed area, m2.7. Report7.1 The format for reporting data obtained by this testmethod and other pertinent information can be fo
36、und inPractice G92.NOTE 8It may be desired to report atmospheric chloride deposition asNaCl rather than chlorides. The factor for converting from chlorides toNaCl is 1.65.8. Precision and Bias8.1 PrecisionThe precision of this wet candle test methodfor measuring atmospheric chloride deposition rate
37、is beingdetermined. In this procedure, only the repeatability can bedetermined because the conditions at any exposure site areunique in any time period.8.2 BiasThe atmospheric chloride deposition rate as mea-sured by the wet candle method has no bias because the valueof wet candle atmospheric deposi
38、tion is defined only in termsof this test method.The resulting deposition is quantitative, andthe chloride deposition found on the candle gauze does notnecessarily correlate with chloride deposition obtained on othergeometries or techniques, nor with actual atmospheric chloridecontent.9. Keywords9.1
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