Active Standard ASTM G140 | Developed by Subcommittee: G01.04
Book of Standards Volume: 03.02
Historical (view previous versions of standard)
Significance and Use
This test method is capable of generating quantitative values of atmospheric chloride deposition specifying milligrams of chloride ions per square metre per day (or other units derived from such values).
Note 1—Chlorides in the atmosphere exist as a suspension of liquid droplets or solid particles. They are transported to solid surfaces by gravity, wind, or brownian motions. These transport mechanisms are direction-sensitive so that a vertical cylinder will not necessarily receive the same flux as a horizontal plate, or objects with different sizes and orientations. Therefore, the use of this approach to provide an indication of the deposition of chlorides on objects in atmospheric exposures may not be quantitatively accurate; however, this technique has been successful in classifying the severity of exposure in a variety of marine locations.
The sites where samples are to be taken and the sampling time periods should be established. A continuous program of monthly or 30-day exposures is recommended for site characterization. Seasonal monitoring may be performed if there are specific periods of interest.
1.1 This test method covers a wet candle device and its use in measuring atmospheric chloride deposition (amount of chloride salts deposited from the atmosphere on a given area per unit time).
1.2 Data on atmospheric chloride deposition can be useful in classifying the corrosivity of a specific area, such as an atmospheric test site. Caution must be exercised, however, to take into consideration the season because airborne chlorides vary widely between seasons.
1.3 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.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1193 Specification for Reagent Water
D4458 Test Method for Chloride Ions in Brackish Water, Seawater, and Brines
G92 Practice for Characterization of Atmospheric Test Sites
ISO StandardISO9225 Corrosion of Metals and Alloys. Aggressivity of Atmospheres--Methods of Measurement of Pollution Data Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
ICS Number Code 71.040.50 (Physicochemical methods of analysis); 77.060 (Corrosion of metals)