During ESD (Emergency Shut Down) validation testing with platform topsides pressurised, the close limit switch associated with sealine ESD valve failed to meet its limit. The platform instrument technician then investigated. When removing the cover off the PFP (Passive Fire Protection) enclosure his personal gas detector went into alarm >20% LEL (Lower Explosive Limit).
This was immediately reported to the control room and investigated. Further gas testing indicated that the source of leakage was around the stem seal area where a 100% LEL was recorded.
Once removed the seal failure mechanism to be determined by specialist vendor.
Valves of similar type and age within the assets should be subject to an Engineering Review as to whether we should look to plan to change the stem seals on these valves in the future.
Workscope being developed to replace stem seal assembly during scheduled Field shutdown period.
Sealine ESD (Emergency Shut Down) Valve