What makes a cryogenic valve different from a standard valve, and what stem extension length do I need for my LNG or liquid nitrogen service?

Cryogenic valves feature an extended bonnet (stem extension) that keeps the packing and stem seal away from the cold process fluid, preventing the packing from freezing and becoming brittle — which would cause leakage or valve failure. The required extension length depends on the pipe insulation thickness and operating temperature; for liquid nitrogen (−196°C) or LNG service, extensions typically range from 6 to 24 inches. Bonney Forge cryogenic valves are also tested at cryogenic temperatures per BS 6364 to verify seat and stem seal integrity before shipment. Always confirm the required extension length with your insulation spec.