52. Corrosion Identification of Gas Pipe Risers in Buildings Using Advanced Ultrasonic Guided Waves

In modern cities, natural gas is a major source of fuel that is needed in each resident’s daily life. Gas pipe risers are used to distribute natural gas to each household unit. They penetrate into each unit through concrete walls to connect the main outdoor gas pipe to the indoor residential gas pipes. After long periods of operation, part of the pipe riser embedded in concrete is prone to corrosion due to the combined effect of corrosive materials in concrete and humid environment. If the deterioration caused by the riser corrosion is ignored, pipe rupture and poisonous gas leaks are possible. In the worst-case scenario, catastrophic gas explosions can lead to human fatalities. Therefore, there is an urgent need for effective and reliable non-destructing testing methods that could enable the identification of corrosion in in-service through-wall riser so that the safety and proper maintenance of pipeline system in building can be guaranteed. This paper presents the application of advanced ultrasonic guided waves for this purpose. The problems and difficulties involved in the inspection including construction of transduction system and signal analysis of complex reflection wave signals will be identified and discussed. The experiments will be conducted to demonstrate the effectiveness of developed techniques. With the help of all of the achievements, the building is expected to become safer to live and hundreds of million dollars per year will be saved by avoiding potential gas explosions.