What is the temperature rating for Red color coded sprinkler systems?

• A. 325 - 375
• B. 175 - 225
• C. 135 - 170
• D. 250 - 300

Answer: (A)

Sprinkler activation temperature is the heat level at which a sprinkler head will release water. Color coding helps inspectors and installers identify the rating at a glance. Red color coded sprinkler heads have the highest commonly used temperature rating: 325–375°F (163–191°C). This means they stay closed in lower heat and only activate when the surrounding temperature reaches a very high level, which is useful in areas with higher heat exposure. The rating comes from the thermal element inside the head—either a glass bulb or fusible link—that fails at that temperature, triggering water discharge. Lower color codes correspond to cooler ratings, so the red codes indicate a high-temperature option suitable for hotter environments.