Re: bonding monitoring system
Some ground check systems used in drag line and mining applications circulate a milliamp current through the ground wire and alarm or trip if continuity is lost. One of these might be retrofitted to your application.
But any monitoring system would probably need a completed isolated pipe. That may be more of a safety issue than a loose coupling.
Any system trying to monitor the joints would essentially be a big ohmmeter with leads connected at each end of the pipe. But the meter will also read the resistance of sneak circuits caused by the pipe touching the grounded pipe rack or building steel or by metallic objects in the pipe connected to grounded systems like control valves, thermocouples or pressure switches. The sneak circuits could mask a bad coupling joint.
Isolating the piping so the only current path is through the pipe could be a lot of work for little benefit. The pipe would probably have to be isolated at every pipe support.
The cost of isolating the pipe to allow accurate monitoring is probably more than the cost of installing small bonding jumpers on every coupling and grounding the heck out of the piping run to drain off any static charge.
Good luck solving an interesting problem.
