The discharge size of the Inspector's Test connection should be equal to which sprinkler size?

• A. Equal to the largest sprinkler
• B. Proportional to sprinkler count
• C. Independent of sprinkler sizes
• D. Equal to the smallest sprinkler in the system

Answer: (D)

The test discharge is sized to match the smallest sprinkler in the system because the Inspector’s Test is meant to simulate the flow that a single head would require during operation. Using the smallest head as the reference ensures the test reflects the minimum demand a sprinkler could present, so the water supply and valve operation are evaluated under a realistic, worst-case single-head scenario without overloading the system. If you used the largest sprinkler, you’d be testing with a flow that never corresponds to a single head’s demand, which can mask problems or place unnecessary stress on the system during testing. Sprinkler count or a size independent of head sizes wouldn’t accurately represent the actual hydraulic demand of the system. Thus, matching the discharge to the smallest sprinkler keeps the test representative and conservative.