What special considerations apply to cryogenic control valves?

Cryogenic valve considerations (LNG, liquid nitrogen, etc.): materials rated for low temperature (impact tested per ASME, typically 304SS or 316SS), extended bonnet design (keeps packing at ambient temperature), special packing (PTFE or graphite, spring-energized), avoid moisture traps (can freeze and block flow), and proper insulation. Actuator: position away from cold section, consider thermal contraction effects on stem. Selection: globe valves common, cryogenic ball valves available. Testing: cryogenic seat test per BS 6364 or MSS SP-134. Installation: vertical with actuator above for proper drainage. Consider ice formation on external surfaces.