ASTM G140-2002(2008) Standard Test Method for Determining Atmospheric Chloride Deposition Rate by Wet Candle Method《用湿蜡法测定大气氯化物沉淀速率的标准试验方法》.pdf

《ASTM G140-2002(2008) Standard Test Method for Determining Atmospheric Chloride Deposition Rate by Wet Candle Method《用湿蜡法测定大气氯化物沉淀速率的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM G140-2002(2008) Standard Test Method for Determining Atmospheric Chloride Deposition Rate by Wet Candle Method《用湿蜡法测定大气氯化物沉淀速率的标准试验方法》.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: G 140 02 (Reapproved 2008)Standard 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 re

2、vision, the year of 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 covers a wet candle device and its usein measuring atmospheric chloride depositi

3、on (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 seaso

4、n because 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-bilit

5、y of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 4458 Test Method for Chloride Ions in Brackish Water,Seawater, and BrinesG92 Practice for Characterization of Atmospheric TestSites2.2 ISO Standard:ISO 9225 Corrosion of Metals

6、 and 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

7、values).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 a

8、s a 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 sever

9、ity 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 perio

10、ds of 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 flask

11、s are 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, 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 g

12、auze 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 D 1193).4.1.6 Gloves, vinyl, one pair.NOTE 4Poly(vinyl chloride) (PVC) is recommended. Late

13、x gloves arenot acceptable, as their chloride content is reported to be comparable tothat of human hands.1This 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 Ma

14、y 1, 2008. Published May 2008. Originallyapproved in 1996. Last previous edition approved in 2002 as G 14002.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the sta

15、ndards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Suppor

16、t 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) with an attached plateon top is suitable, with 750 mm in the ground and 1500 mmabove the ground on which

17、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 must be modified.4.3.1.1 In the

18、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 flask when the stopperis installe

19、d 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 to remove any contaminants.4.3.

20、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 the tube coveringthe top, the

21、n 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 Type IV reagent water and fill

22、 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 orother means. It is good practic

23、e 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.) or plastic wrapNOTEDimensions

24、are in millimetres (mm).FIG. 1 Wet Candle Chloride ApparatusG 140 02 (2008)2has 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

25、 previously filled, handling thetube 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 exposure.5.1.2 A predetermined exp

26、osure 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 sameas a wet wick. Therefore, mea

27、surements 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 removal.5.2.2 If continuous mo

28、nitoring 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, exercisingcaution to prevent spilla

29、ge 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. Pour the contents of the flask i

30、nto 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 Again using gloves, remove the gau

31、ze 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 determination of thechloride concentr

32、ation 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 mercurimetric titrationmethod of ISO 9225.5.4.3 A blank gauze sample, the same size as state

33、d 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 Calculate the contents of the

34、 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 using thefollowing relationship:mg Cl2/m2/day 5 mg Cl2/L2At (2)where:t = time of exposure,

35、 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 obtained by this testmethod and other pertinent information can be found inPractice G92.NOTE 8

36、It 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 is beingdetermined. In th

37、is 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 deposition is defined only in t

38、ermsof 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 atmospheric chloride dep

39、osition rate; wet candle methodG 140 02 (2008)3ASTM 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 expressly advised that determination of the validity of any such patent rights,

40、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 revised, either reapproved or withdrawn. Your comments are invited either for revi

41、sion 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 may attend. If you feel that your comments have not received a fair hearing you

42、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 140 02 (2008)4