How does a heat detector differ from a smoke detector in response to fire?

• A. A heat detector responds to temperature rise or sustained high temperature, while a smoke detector responds to smoke particles from combustion
• B. A heat detector detects flames
• C. A heat detector uses smoke particles
• D. They respond identically

Answer: (A)

Heat detectors respond to temperature changes, either a rapid rise or reaching a fixed high temperature. Smoke detectors respond to the presence of smoke particles produced by combustion. This means heat detectors will alarm due to heat even if there isn’t smoke, while smoke detectors will alarm when particles of smoke are present, regardless of the temperature rise. In practice, smoke detectors often react faster to many fires (especially smoldering ones with visible smoke), whereas heat detectors are less prone to nuisance alarms in dusty or humid environments and are used in areas where smoke detectors might be triggered too easily (like kitchens or garages).