Heat detectors should be used for the main part of garage fire detection.
1. After the car starts, it gives off soot-like exhaust gas. If smoke detector is installed, it will cause false alarm.
2. When a car catches fire, the fire spreads quickly, few smoke produced at initial time. So, heat detector is better for garage fire detection.
Smoke detectors should be used in garage stairwells, walkways and elevators.