What is the color code for a heat detector rated at 250°F?

• A. Red
• B. Blue
• C. Green
• D. Yellow

Answer: (B)

Heat detectors use a fixed temperature rating, and each rating is identified by a color so you can tell at a glance what activation temperature a detector has. For a detector that activates around 250°F, the color used is blue. This helps ensure you install the right device for hot environments, reducing nuisance alarms while still providing protection if a true heat event occurs. The other colors correspond to different ratings, so the blue color tells you this one is the higher 250°F rating.