What temperature range is covered by intermediate temperature-rated sprinklers?

• A. 151°F to 200°F
• B. 50°F to 100°F
• C. 101°F to 150°F
• D. 1°F to 50°F

Answer: (C)

The main idea here is that sprinkler temperature ratings indicate the ambient temperature at which the head will activate, not the temperature of the water. Sprinklers are categorized by how hot the surrounding air must be for the fusible element (or glass bulb) to release water. The intermediate temperature-rated sprinklers are designed for a middle range of ambient temperatures—hotter than the very low ratings but not as hot as the high ratings.

For this question, the intermediate range is 101°F to 150°F. This places it between the lower end (low-temperature category) and the higher end (high-temperature category). So, in spaces where ambient temperatures can reach roughly between 101°F and 150°F, the intermediate rating ensures reliable activation.

The other ranges correspond to the other ratings: ranges like 50–100°F or 1–50°F are low-temperature ratings, and 151–200°F is a high-temperature rating.