Someday before I was invited by my colleagues to attend presentation from one of NDT company that offer us a new method of inspection. They called it Magnetic Tomography Method (MTM).
Generally it is used to inspect the unpiggable line, but it is not limited to that purpose only I suppose.
Lets discuss this method by looking on term Magnetic Tomography. Magnetic is obviously using magnet, meanwhile tomograph is image created by some kind of energy. So, magnetic tomography method is the method that use magnetic field to create an image of stress distribution. These stresses indicate cracks, bends or other defects.
Application of this equipment is by putting on magnetometer to the top of the pipe or other equipments that you want to inspect. Usually need 2 operators to operate this machine: 1 for collecting the data via magnetometer and other one is to give direction by using GPS (if some equipments are buried). It can detect up to 20xD maximum distance from equipments to be inspected and magnetometer.
How far the stresses are acceptable? These informations they said include in their so called "black box". Up until I wrote down this post I still don't understand what is the mechanism of this black box or what is the standard used is it ASME, API or other else? These questions can't be answered during presentation because they said that data during inspections will be transfered to Russia for further analysis.
After analysis done, reports come with results matrix of severity. We could know where are the area that have damage more severe than others. Basically it is a screening equipment, so when you want to know an accurate results of inspection should be another way to cover the screening such as when you inspect buried pipeline it should excavate or if the equipments are insulated you need to remove insulation to inspect it further more.
