What percent of zones shall be tested at the outlet most remote from the source to verify the piping particulate test?

• A. 100%
• B. 75%
• C. 50%
• D. 25%

Answer: (D)

Testing the farthest outlet from the source in a representative subset of zones checks the longest run for particulates, which is the most demanding path for cleanliness. If that worst-case point meets the piping particulate criteria, it’s reasonable to infer that shorter runs in the other zones will too, provided the system design is consistent. Standards allow verifying the overall cleanliness by sampling a fraction of zones rather than every outlet, with a minimum of 25% to balance thoroughness and practicality. Choosing a higher percentage would be unnecessarily burdensome, while testing less than 25% could miss issues in some zones. Therefore, a quarter of the zones tested at their farthest outlets is the required approach.