We have a local AHJ saying its mandatory!
NFPA-13 actually gives some direction on this...
IT IS NOT A REQUIREMENT of the NFPA Codes and Standards to have a AHJ witness any of the tests required. What it says is that the contractor should notify the AHJ of the date/ time of the test so the AHJ can witness the test, if they choose to do so.
The test is not required to be witnessed by the AHJ. A notification is a courtesy to them, so they can CHOOSE to witness it.
The test can be performed on the contractors' time and schedule, per the NFPA Codes and Standards. It should, however, be witnessed by the owner's representative, insurance rep (if needed), GC, etc. and the paperwork signed by everyone who witnessed the test to attest that the test was performed, and the results as indicated are accurate.
However, that being said, a lot of the local AHJ's REQUIRE they witness the test and that it must be scheduled with them on their time and schedule, not the contractor's time and schedule.
Should the AHJ be at every test we perform? Probably not. But somewhere along the way someone didn't do a required test at all, performed a test incorrectly, performed a test accurately but didn't record the data properly or at all, or falsified records, etc. (Like always, a few bad apples spoil it for everyone!)
It is extremely important that we, as contractors, understand the local AHJ's requirements and develop and keep a good relationship with them. We are on the same team (to saves lives and property) and we should work together to accomplish this goal as quickly and easily as we can.
You should never have an adversarial relationship with the AHJ's! If there is a disagreement, it should always be handled as a teaching moment, for either the AHJ or the contractor.
If the AHJ requires they witness a test, it is usually a local requirement. If that is the case, schedule it so they can witness it.