What is the typical temperature rating for 'Ordinary' sprinkler heads?

What is the typical temperature rating for 'Ordinary' sprinkler heads?

• A. 100-150 F
• B. 135-170 F
• C. 50-90 F
• D. 200-250 F

Answer: (B)

The main idea is that sprinkler head temperature ratings indicate the ambient heat level at which the head will activate to release water. Ordinary-rated heads are designed for typical indoor conditions, so they use a mid-range temperature, about 135–170 °F. This range strikes a balance: it won’t trip in normal room temperatures or during modest heat, but it will respond in a fire when the environment heats up. Other ranges are either too low for ordinary spaces (they would activate too easily) or too high for normal indoor fire protection. That’s why 135–170 °F is the best match for ordinary heads.

The main idea is that sprinkler head temperature ratings indicate the ambient heat level at which the head will activate to release water. Ordinary-rated heads are designed for typical indoor conditions, so they use a mid-range temperature, about 135–170 °F. This range strikes a balance: it won’t trip in normal room temperatures or during modest heat, but it will respond in a fire when the environment heats up.

Other ranges are either too low for ordinary spaces (they would activate too easily) or too high for normal indoor fire protection. That’s why 135–170 °F is the best match for ordinary heads.