After completing installer-performed tests, which method shall be used to determine that no cross-connection exists?

After completing installer-performed tests, which method shall be used to determine that no cross-connection exists?

• A. Individual pressurization
• B. Pressure differential
• C. Both A and B
• D. Either A or B

Answer: (A)

To verify that no cross-connection exists, you need to prove that each gas service can be isolated and pressurized independently without affecting or communicating with the others. This is done by individual pressurization: apply a known test pressure to one system at a time while keeping the other systems isolated, and observe that the pressure in the tested line remains stable with no pressure appearing in the other lines. This direct, step-by-step demonstration of isolation shows that there isn’t any unintended path between systems for backflow or mixing. Relying solely on a pressure-differential approach can miss a cross-connection that doesn’t produce a clear differential, or can be confounded by other leaks, so the individual pressurization method provides the clearest evidence that cross-connections do not exist.

To verify that no cross-connection exists, you need to prove that each gas service can be isolated and pressurized independently without affecting or communicating with the others. This is done by individual pressurization: apply a known test pressure to one system at a time while keeping the other systems isolated, and observe that the pressure in the tested line remains stable with no pressure appearing in the other lines. This direct, step-by-step demonstration of isolation shows that there isn’t any unintended path between systems for backflow or mixing. Relying solely on a pressure-differential approach can miss a cross-connection that doesn’t produce a clear differential, or can be confounded by other leaks, so the individual pressurization method provides the clearest evidence that cross-connections do not exist.