If appliances are designed for operating pressures less than the test pressure, how should they be treated?

When appliances are designed for operating pressures that are less than the test pressure, they must be isolated by capping the outlet(s). This approach is vital to prevent damage to the appliance during the testing process. The test pressure is typically higher than the maximum operating pressure for these appliances, which can lead to potential leaks, failures, or unsafe situations if they are subjected to pressure beyond their design specifications.

By capping the outlets, the system ensures that no gas flows through those appliances, effectively safeguarding them from the potentially damaging effects of high pressure. This method allows for the integrity of the test to be maintained while ensuring the appliances remain intact and safe for future use.

The other methods mentioned—testing separately, adjusting to accommodate the test pressure, or recalibrating—do not adequately protect the appliances from the risks associated with high-pressure testing and would compromise their operational safety and longevity.