Which test is required to measure the ability of an extinguisher cylinder to withstand steady internal pressure?

The hydrostatic test is employed to assess the ability of an extinguisher cylinder to withstand steady internal pressure. This test involves filling the cylinder with water, pressurizing it beyond its normal operating pressure, and then observing for any leaks, bulges, or permanent deformations. By subjecting the cylinder to this increased pressure in a controlled environment, it helps ensure that the cylinder can safely contain the pressurized extinguishing agent under normal usage conditions, which is crucial for the safety and effectiveness of fire extinguishers.

Other tests, such as the static test, pneumatic test, and fatigue test, measure different aspects of the cylinder's integrity or performance but do not specifically focus on its ability to handle internal pressure like the hydrostatic test does. For instance, the pneumatic test assesses the cylinder’s integrity under air pressure, but hydrostatic testing is the standard for checking how well the cylinder can manage the pressures it will face when filled with the extinguishing agent.