Comparison of Precipitation Rates of Airborne Salts Obtained by Doken Tank Method and Dry Gauze Method

Abstract

In assessment of the applicability of weathering steel bridge in a building site, precipitation rate of airborne salts is usually compared with reference value of that. To analyze the precipitation rate of airborne salts at building sites, either Doken tank method (Public Works Research Institute method) or dry gauze method are generally employed. This study compared quantities of airborne salts sampled by Doken tank and dry gauze in order to examine the consistency between the methods with Doken tank and dry gauze. While Doken tank has one window to obtain airborne salts, the dry gauze has back and front sides, both of which can obtain airborne salts. Precipitation rate of salts obtained by the dry gauze facing East and West is higher than average of those by two Doken tanks facing East and West, suggesting that the dry gauze effectively catches airborne salt relative to Doken tank. Considering that the reference value was measured by the method with dry gauze, we had better to discuss the applicability of weathering steel bridge on the basis of precipitation rate of airborne salts obtained by dry gauze.