Special Features & Benefits Fugitive Emissions - Complies to ISO 15848-1: 2006 Class AH leakage SIL3 Safety Integrity Level for Automated Valves The bellows lifecycle is designed as per MSS SP-117 Metal bellows seal the moving stem and increase durability of packed stem seal valves Bellow provide a barrier between the stem at its point of entry through the pressure boundary and the process fluid within the valve, to eliminate stem leakage An anti-rotation device is provided in the bonnet to ensure bellow does not get twisted during assembly and disassembly or by vibration Bellow-sealed valves are usually leak tested using a mass spectrometer to detect leakage rates below 1x10E-06 std.cc/sec. Bellow-sealed bonnets are backed up with a standard stem packing set and a leakage monitoring port between the bellows and the packing in order to prevent catastrophic release of hazardous fluid in the event of a bellows leak.