During a negative-pressure leak test, leaks are tested upstream from the check valve, including vaporizers and flow controls. True or False?

During a negative-pressure leak test, leaks are tested upstream from the check valve, including vaporizers and flow controls. True or False?

• A. True
• B. False
• C. Only downstream
• D. Both upstream and downstream

Answer: (A)

The negative-pressure leak test checks the integrity of the gas-path components that lie upstream of the check valve. Since the check valve prevents backflow from the patient side into the fresh gas pathway, any leaks that could occur when the system is under negative pressure would be in the portion before that valve—things like vaporizers and flow-control valves. By applying negative pressure and observing whether the upstream portion holds pressure, you verify there are no leaks in those components. Leaks downstream from the check valve (toward the patient or scavenging system) are addressed by a different test that pressurizes that downstream circuit. Hence, testing leaks upstream from the check valve, including vaporizers and flow controls, is correct.

The negative-pressure leak test checks the integrity of the gas-path components that lie upstream of the check valve. Since the check valve prevents backflow from the patient side into the fresh gas pathway, any leaks that could occur when the system is under negative pressure would be in the portion before that valve—things like vaporizers and flow-control valves. By applying negative pressure and observing whether the upstream portion holds pressure, you verify there are no leaks in those components. Leaks downstream from the check valve (toward the patient or scavenging system) are addressed by a different test that pressurizes that downstream circuit. Hence, testing leaks upstream from the check valve, including vaporizers and flow controls, is correct.