【国外标准】 Standard Test Method for Determining Atmospheric Chloride Deposition Rate by Wet Candle Method

3.1 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.3.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.