Hi Imogen,
I believe most buildings would have a ‘False Fire Alarm’ by law.
Our buildings by law says “…the power to recover from the responsible owner, all false alarm charges imposed by the NSW Fire Brigade…”
In your case, if your building had a similar by law you could demand payment from the owner, not the tradesperson, as the OC has not employed the tradesperson, the owner has.
The owner may them make a claim against the tradesperson.