A couple of references spring to mind - BS 9999: 2017 see 32.1.6.1 (Self-closing devices). Also Approved Document M clauses 2.9 and 2.26 (if this building is in England).
Assuming that this door is part of the normal circulation routes, then I'd have thought timer settings / closing forces etc should have been sorted as a general H&S issue - you wouldn't want frail occupants knocked off their feet if the door closes on them? If it's OK in normal use, then it should be OK as a fire exit.
Obviously if there are electronic security locks on the doors then you'd need to consider BS 7273-4.
So long as the closing force is no more than is recommended, then I'd suggest that the timer setting is pretty immaterial. As Colin rightly points out, if there's no need for the door to be F/R then it can stay open for as long as you like, in an evacuation.