One of my customers has an 8" PVC C-900 fire line and we need to positively locate, it does not have a trace wire. This is in an industrial plant with large storm drains, underground telephone and underground eletrical in the same area. The fire line is buried at around 8 to 10 feet (fill dirt was brought in after another project). They built a new addition to the plant and the corner of the building is sitting on the 10" loop fire line that I will need to relocate from under the building. There is an 8" run-in into another building that we need to locate. The old prints show how it is susposed to be, but it is not.
I can turn the water off with a couple of sectional valves and gain access to the 8" from inside of the building. What would be needed to run through the inside of the pipe to locate it at a maximum of 10 foot. This would be around 180 feet of pipe. Worst case would be two 8" MJ 90* with in four feet of each other at the very begining of the locate (this is where it comes into the building).