What is the maximum operating temperature for fusible vents on portable flammable liquid tanks?

The maximum operating temperature for fusible vents on portable flammable liquid tanks is 300 degrees Fahrenheit. Fusible vents are designed to help prevent the dangerous build-up of pressure within a tank during a fire by melting at a specific temperature and allowing the contents to vent to the atmosphere. This system is crucial in mitigating the risks of explosion or fire spread in emergency situations.

A fusible vent that operates at 300 degrees Fahrenheit ensures that it will react appropriately to elevated temperatures typically encountered in a fire scenario. Allowing for venting at this temperature helps to protect the integrity of the tank and minimizes hazards associated with flammable liquids.

In contrast, lower temperature thresholds, such as the options listed that are below 300 degrees, would not provide sufficient safety margin under hotter conditions that may arise during a fire. Thus, the selection of 300 degrees as the maximum operating temperature represents a critical balance between safety and operational effectiveness within regulatory frameworks governing flammable liquids.