How long must a cylinder hold pressure during a hydrostatic test?

The correct duration for a cylinder to hold pressure during a hydrostatic test is typically 5 minutes. This time frame allows for ensuring the integrity and safety of the cylinder under the specified test pressures. Holding the pressure for this duration helps technicians observe any gradual leaks that may not be evident in shorter test periods. A longer test time also ensures that the materials of the cylinder can sustain the required pressure without fail, thus confirming that the cylinder is fit for service and complies with safety standards. Hydrostatic testing is a critical safety procedure for confirming the reliability of fire extinguishing equipment, making the duration crucial for effective assessment.