Standard and non-standard work within the ambit of the strata management agreement is whatever you want it to be. You can include a schedule of what constitutes standard work, it has nothing to do with the construction industry of the WHS legislation.
The issue here is that the strata manager is issuing work orders at the behest of one owner. I am not completely familiar with community associations but I assume the same principle applies in relation to work orders, i.e. that one person is not authorised to instruct the strata manager to issue work orders, or to engage contractors etc. If you don’t want that to happen tell the manager that he should not act on the instructions of that owner.