Which temperature classification applies to sprinklers located under glass skylights exposed to direct sun?

Which temperature classification applies to sprinklers located under glass skylights exposed to direct sun?

• A. Low
• B. Medium
• C. High
• D. Intermediated

Answer: (D)

The key idea is how radiant heat from sunlight affects sprinkler temperature ratings. Sprinkler bulbs break at a specific temperature, so the surrounding heat environment determines when they activate. When a sprinkler sits under glass skylights with direct sun, the local temperature around the head rises due to solar gain. That extra heat isn’t the same as a normal indoor ceiling space, so you don’t want a low rating that could trigger prematurely from the sun, nor do you necessarily need the highest rating for every hot-fire scenario. The intermediate temperature classification is used in such situations because it accounts for the additional radiant heat from sun exposure—hotter than normal indoor ambient, but not as extreme as a true high-heat environment. This rating helps ensure activation in a real fire while reducing the risk of a false release caused by sunlit skylights.

The key idea is how radiant heat from sunlight affects sprinkler temperature ratings. Sprinkler bulbs break at a specific temperature, so the surrounding heat environment determines when they activate. When a sprinkler sits under glass skylights with direct sun, the local temperature around the head rises due to solar gain. That extra heat isn’t the same as a normal indoor ceiling space, so you don’t want a low rating that could trigger prematurely from the sun, nor do you necessarily need the highest rating for every hot-fire scenario. The intermediate temperature classification is used in such situations because it accounts for the additional radiant heat from sun exposure—hotter than normal indoor ambient, but not as extreme as a true high-heat environment. This rating helps ensure activation in a real fire while reducing the risk of a false release caused by sunlit skylights.