In many situations, the cost of accessing a pipe is much higher than the cost of inspection. This access cost can make repeat inspections with removable rings prohibitively expensive. The environmentally robust gPIMS® range of sensors has been developed to be easily bonded to the pipe, sealed and then left in place. A cable connects the gPIMS® sensor to a connection box that can be located in a convenient, easy to access location.By performing repeat inspections and comparing the results to previous inspections, operators can monitor for any change in the condition of the pipe. Frequent data collection significantly improves sensitivity and reduces false call rates compared to conventional guided wave testing.