What is the correct hydrostatic test pressure for a stored pressure dry chemical fire extinguisher?

For a stored pressure dry chemical fire extinguisher, the correct hydrostatic test pressure is typically defined as either 1.5 times the service pressure or a specific pressure level set by standards. In the case of common practice, many extinguishers are subjected to a hydrostatic test pressure of 300 psi, which is adequate for assessing the integrity and functionality of the extinguisher under high-pressure conditions. This test ensures that the cylinder can withstand pressure beyond normal operating conditions without failure.

The other choices may not align with standard procedures for testing dry chemical extinguishers. While some testing methods use factors related to operating pressure, the specific standard practice for dry chemical extinguishers involves the definitive 300 psi pressure requirement for hydrostatic testing.