At the end of a pneumatic test for a Halon 1301 system, the pressure drop shall not exceed ___ of the test pressure.

• A. 5%
• B. 10%
• C. 20%
• D. 30%

Answer: (C)

During a pneumatic test of a Halon 1301 system, the goal is to verify the piping’s integrity by pressurizing it and watching for leaks. The key acceptance criterion is how much pressure is lost during the test. The pressure drop shall not exceed twenty percent of the test pressure. This standard gives a clear threshold: the end pressure must be at least 80% of the start pressure. For example, if you apply 200 psi as the test pressure, the pressure at the end should not drop below 160 psi. A drop greater than 20% signals leaks or weak joints that require repair and re-testing. The smaller percentages would be too stringent for typical workmanship and instrument tolerances, while a larger threshold would risk missing significant leaks.