System Testing Flashcards

What is the minimum pressure used during a high-pressure leak test of a medical gas pipeline system per NFPA 99?

Answer: 150 psig

NFPA 99 requires a high-pressure leak test at 150 psig (or 20% above the system's maximum operating pressure) for medical gas pipelines.

During a cross-connection test, all zone valve boxes are closed and a test gas is introduced. What should the reading be at each outlet if the system is free of cross-connections?

Answer: Zero pressure at every outlet in the zone being tested

With zone valves closed, pressure should be zero at all outlets in the isolated zone if there are no cross-connections feeding gas from another source.

Which gas is typically used to perform the initial pressure test of a newly installed medical gas pipeline before purging?

Answer: Nitrogen

Dry nitrogen (or oil-free dry air) is used for initial pressure testing because it is inert, non-flammable, and avoids introducing combustion-supporting gas into an untested system.

When conducting a standing pressure test on a medical gas system, how long must pressure be maintained without loss to pass?

Answer: 24 hours

NFPA 99 requires the standing pressure test to be maintained for a minimum of 24 hours without pressure loss to confirm the integrity of the piping system.

What does a positive result on an odor test during medical gas system verification indicate?

Answer: Contamination is present in the pipeline

An unusual odor detected during outlet testing indicates contamination such as oil, solvent, or purge gas residue still present in the pipeline.

During a pipeline purity test, what maximum level of contamination (particulate) is generally acceptable for a medical gas system?

Answer: No visible particulate on a white filter paper after 30 seconds of flow

NFPA 99 requires that no discoloration appear on a white filter after flowing gas through it for 30 seconds, confirming freedom from particulate contamination.

Which of the following best describes the purpose of the 'piping purge' step performed before final system testing of a medical gas pipeline?

Answer: To remove debris, moisture, and residual test gases from the pipeline

Purging blows high-velocity gas through the pipeline to physically remove construction debris, moisture, and any residual gases before purity and cross-connection testing.