1、Designation: G 140 02Standard Test Method forDetermining Atmospheric Chloride Deposition Rate by WetCandle Method1This standard is issued under the fixed designation G 140; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes a wet candle device and itsuse in measuring atmospheric chloride deposition (amount ofch
3、loride 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 because airbo
4、rne 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 of regulatory
5、 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 4458 Test Method for Chloride Ions in Brackish Water,Seawater, and Brines2G 92 Practice for Characterization of Atmospheric TestSites32.2 ISO Standard:ISO 9225 Corrosion of Metals and Alloys.
6、 Aggressivity ofAtmospheresMethods of Measurement of PollutionData43. 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 values).NOTE
7、 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 horizont
8、al 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 of expos
9、ure 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 of intere
10、st.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 are recomm
11、ended 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, diametertop 38 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 may var
12、y 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 D 1193).4.1.6 Gloves, vinyl, one pair.NOTE 4Poly(vinyl chloride) (PVC) is recommended. Latex gloves are
13、not acceptable, as their chloride content is reported to be comparable tothat of human hands.4.2 Support StandA suitable support stand shall beerected at the site where the atmosphere is to be sampled. Atreated wood post (100 by 100 by 2250 mm) or galvanized pipe(42-mm diameter by 2250-mm length) wi
14、th an attached plateon top is suitable, with 750 mm in the ground and 1500 mm1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and is the direct responsibility of Subcommittee G01.04 onAtmospheric Corrosion.Current edition approved June 10, 2002. Published July
15、2002. Originallypublished as G 140 96. Last previous edition G 140 96.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 03.02.4Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbo
16、r Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.above 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
17、 the Wet Candle Apparatus (see Fig. 1):4.3.1 The rubber stopper must 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 t
18、he gauze to pass freelybetween the stopper and the neck of the flask 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 an
19、d tube/stopper assembly should berinsed with Type IV reagent water to 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 wr
20、ap all the exposed area ofthe tube. Using overlapping turns, move up 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 o
21、f exposed gauze will be approximately 0.01m2.4.3.4 Rinse gauze with 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
22、 is ofutmost importance to prevent contamination by perspiration orother 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 analys
23、is. A polyethylene bagapproximately 75 mm (3 in.) by 230 mm (9 in.) 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
24、 if not previously filled, handling thetube and stopper by the protective shield, remove the stopperand wick from the flask sufficiently to add 350 mL of Type IVNOTE 1Dimensions are in millimetres (mm).FIG. 1 Wet Candle Chloride ApparatusG 1402reagent water. Replace the stopper. Record the exposure
25、timeand date, and any other pertinent conditions of the exposure.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 6Th
26、e collection efficiency of a frozen wick will not be the sameas 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
27、 and any other identifying data, as well as date and timeof 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
28、 orlocation equipped to conduct the chemical analysis, exercisingcaution 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) th
29、e gauze from the test tube and placeinto a 600-mL beaker. Pour 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 eva
30、luated, properlyseparate and identify each beaker.5.3.2 Again 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 Cont
31、ent from Wet Candle:5.4.1 The chemical procedure for determination of thechloride concentration is described in Test Method D 4458.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 me
32、rcurimetric titrationmethod of ISO 9225.5.4.3 A blank gauze 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
33、 done before the wet candles are assembled.6. Calculation6.1 Calculate the contents of the water in accordance withTest Method D 4458 as follows:mg Cl2/L 5mL AgNO3used 2 B! 3 T 3 1000mL sample(1)where:T = titre, mgCl/mL of AgNO3, andB = indicator blank.6.2 Calculate results in terms of mg Cl/m2/day
34、using thefollowing relationship:mg Cl2/m2/day 5 mg Cl2/L2At (2)where:t = time of exposure, days, andA = exposed area of gauze, determined as follows:A 5pDD 1 1! (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 obta
35、ined by this testmethod and other pertinent information can be found inPractice G 92.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 can
36、dle test methodfor measuring atmospheric chloride deposition rate 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 me
37、thod has no bias because the valueof wet candle atmospheric deposition 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 tec
38、hniques, nor with actual atmospheric chloridecontent.9. Keywords9.1 atmospheric chloride deposition rate; wet candlemethodG 1403ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are
39、 expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not r
40、evised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you
41、 may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).G 1404
