With GPR we can evaluate the contents of block walls. This can be very important for prisons as the concrete masonry units themselves are easy to chip through or break, but the high PSI concrete poured inside is next to impossible to chip through so it is very critical that every cell is filled. This is also important in buildings such as data centers with a gas-pressurized fire suppression system. In these types of buildings if a large area of voids are found this could lead to a blow out of the structure wall. Finding voids can be done very quickly making it possible to examine large sections of the wall in a very short amount of time.