Here is some background information;
Usually home and office based fire detectors work on heat and smoke, not IR/UV there is probably a reason for that.
Wikipedia lists applications of UV/IR sensors as;
- Hydrogen stations.[5]
- Gas-fueled cookers
- Industrial heating and drying systems
- Domestic heating systems
- Industrial gas turbines
Fire systems detect fires in zones. Trying to get one to triangulate a fire sounds tricky. Using CCTV to determine the exact location after the alarm is raised may be the best bet.