8481.40.00.00 - Safety or relief valves

HTS Code 8481.40.00.00 specifically encompasses safety or relief valves. These valves are designed to automatically protect systems, such as boilers, tanks, or piping, from overpressure. They function by opening at a predetermined pressure, releasing excess fluid (liquid or gas) to prevent damage or hazardous conditions. The primary purpose is to act as a fail-safe mechanism, ensuring operational safety.

This category is distinguished from its sibling categories by its specific function. Unlike pressure-reducing valves (8481.10.00), which maintain a constant downstream pressure, or check valves (8481.30), which prevent backflow, safety or relief valves are solely concerned with overpressure protection. Valves for oleohydraulic or pneumatic transmissions (8481.20.00) are designed for controlling fluid power systems, and "other appliances" (8481.80) and "parts" (8481.90) cover a broader range of valve types and components not specifically designated as safety or relief valves.

As a leaf node, 8481.40.00.00 does not have further subdivisions. Classification within this category hinges on the valve's design and primary function as an overpressure protection device. Examples include spring-loaded safety valves, pilot-operated relief valves, and rupture disc assemblies specifically designed to burst at a set pressure. The materials of construction and the specific overpressure setting are secondary to the fundamental purpose of safeguarding against exceeding maximum allowable working pressure.