I was at a trade show recently for companies and professionals working in the Public Works sector. Most of the folks there were familiar with EM locators and primarily used that piece of equipment to locate underground utilities. Some expressed frustration with this equipment because they often had clay sewer pipes or PVC irrigation pipes that could NOT be located with the EM locator. They mentioned that despite having the power, water, and gas located, excavations would still damage other existing infrastructure.
I let the in on a secret, there is another piece of equipment out there that compliments EM locators. It was called Ground Penetrating Radar (GPR), and the utility did not have to be able to hold a current to be located. All it had to have was a different material than the soil it was buried in.
Many of the people at this trade show found this information inspiring! One individual said that the pipes they needed to locate were made of clay and the soil that they were buried in was also clay. This was an astute observation and a very important question to handle since this often is one of the objections that people have to the effectiveness of GPR. I told these folks that I actually didn’t even have to locate the pipe itself, but rather I could just locate the air in the pipe. As long as air is still different from clay, the GPR technology should still be able to detect the location of the pipe.
Some of the people in that group found this fascinating and wanted to try it out. One individual, however, was still skeptical and burst out laughing. As he walked away shaking his head saying to no one “I don’t believe it,” I smiled. It was one of the most fun reactions I have EVER had to a discussion about electromagnetic waves.