Regulations don’t make a specific reference to safety chains, but I recall Australian Standards stipulating that there should be no article fitted to a fire (main) door to a Unit that could impede its full and proper closure; that’s why automatic closers are stipulated!
So with that emphasis on full and proper closure, an item such as a safety chain when fitted by Residents to such a door could, when unlatched and hanging down, become an “impediment” if it became wedged between the door and the jamb.
Unlikely maybe, but possible yes – so on that basis I think that your Plan’s Fire Inspection Contractor is correct, and even though those Residents who have fitted safety chains are not themselves breaking any Law, the fire rated (main) doors so affected don’t then comply with all aspects of the Standards upon which such legal compliance is assessed.
As mentioned, these doors are required to be fitted with a functioning automatic closer, so I’m wondering how it is that you and other residents are able to leave them ajar, but in any event it’s better for Residents’ fire safety for those safety chains to be removed and for entry doors to be kept fully closed for BOTH fire safety and Residents’ security.
As your Owners Corporation (O/C) owns those doors and is additionally responsible for the building’s fire safety, it in my opinion needs to write to all Residents advising that any items such as safety chains and door stops that could impede the proper closing of entry doors together with any keyed deadlocks that could impeded egress needs to be immediately removed, and that any such items that are still in place at the time of the next Fire Safety Inspection will be removed by the Contractor.
As for the costs, whilst the O/C could recover the Contractor’s costs of removing safety chains etc for those Residents who then haven’t, for something as important as fire safety I wouldn’t bother.
If in any doubt, your O/C should consider the consequences of a fire event occurring in the building at a time when even one fire rated (main) door to a Unit is ajar due to a safety chain, door stop, or something similar impeding its full and proper closure – when its been made aware of likely consequences.