A new instrument developed by Christopher White, a research chemist at the National Institute of Standards and Technology (NIST), located in Gaithersburg, Maryland, will help in testing the sealants.
The sealants are used in buildings to prevent both the escape of heat outside and the seeping of water inside. The difficult task that can be daunting for most builders is to forecast the failure of sealants.
Currently, sealants are tested utilizing static methods such as keeping them outdoors for longer durations and to assess their endurance to hot, cold and humid conditions. According to White, though the sealants react to normal conditions they react differently when used with materials such as glass and steel. He explained that the steel frame or a glass window will expand and contract at diverse rates intone with the changes in weather conditions. The changes in sealants cause stress and finally fail and crack.
White and his colleagues utilized simple materials such as wood, PVC pipe, toilet flanges and steel supporting frames to develop the required instrument to examine the sealants under normal conditions. Among the two devices developed for the purpose, one is used to maintain the sealants under tension and the other is used to put them in compression mode under cold conditions.
The instrument continually monitors the changes in displacement and load by utilizing sensors and follows the environmental changes with a local weather station. White says that the sealants actually impact the movement under normal working conditions. Currently, two companies working with NIST have developed the instruments and deployed them for sealant testing.
Source: http://www.nist.gov/