Safety Alerts 13

Fuel Gas

• Corrosion under insulation (CUI): In fuel gas piping led to hydrocarbon release and fire near a heater. Inspect insulated piping in close proximity to structures. Have Inspection windows

• Hard piped (not flexi hose) compressor fuel gas piping came apart and was ignited by hot exhaust gas

• Poor quality 40” HP Fuel Gas test flange failed before reaching test pressure of 1,750 psig. Color code and identify test flanges used for hydrotest as to their rating

• Power plant fuel gas piping “gas blow” to remove debris was ignited and exploded. Use non-flammable purge gas

Heating Medium

• Carbon Steel tubes in Hot Oil Service are prone to corrosion leaks. Fire

• Check regularly hot oil samples for degradation that will indicate localized heating/ higher corrosion

• Flow Maldistribution in a multi-pass heater led to coking and tube burst - fire

• Water trapped after hydro-test/ flushing expanded enormously when hot heating medium entered Expansion Tank and ruptured it. “Steam explosion”. Consider oil as hydrotest medium to keep water out 

• Nitrate salt used as HM to remove heat from oxidation reactor leaked into a 36” pipe dead-leg with carbonaceous deposits. Exploded

Gas Turbine

• Hot air leaking from a bleed (air) line within enclosure ignited lube oil and diesel in the base of the skid

• Leaking lube oil within turbine enclosure formed an oil mist and caught fire on contact with hot exhaust manifold. Check regularly fuel and lube oil line within enclosure. Keep diesel fuel SDV at a safe distance from GT. Many cases

• 600 MW GT Generator. 2m long LP blade broke-off. Crashed thru the casing and roof 20m above. It took another 15 blades with it. Turbine-Generator shaft broke

• Water Mist System: Steam used to displace air. Poses scalding and asphyxiation risk if on automatic mode. Restrict entry

• GT Transport: Prior bridge strength and root survey not done. Bridge collapsed while truck was on it with GT

Electrical/UPS

• Short circuit between two or more battery banks of UPS. Likely caused by leaking electrolyte fluid contacting a conductive metal cabinet frame in UPS battery room

• Hydrogen generated while charging batteries accumulated and blew 400 sq.ft roof. H2 is light and rises rapidly and has a wide flammability limit 4-74% vol Vs 2-15% for HC. Good ventilation a must

• Check for common cause failures that may make back-up power not available when main power fails. Primary and backup components should not be in the same place

• Purged enclosures: Even air purged units may have N2 backup. Check O2 level before entering. Leaking purge may over pressurize an enclosure, leading to blow-off while opening lid/cover. Check PG for proper range

• Temporary LQ on top of MCC + generator allowed CO laden gas engine exhaust enter LQ via AC intake. CO poisoning

• Emergency DG was regularly tested. In an actual incident its relay connecting it to plant failed to operate as it was not part of regular test. WWW 

• Engine room fire. Radiant heat from an uninsulated and cracked exhaust bellows ignited insulation soiled with soot and hydrocarbons. Main FW pumps not available once generators were shut. Emergency FW pump couldn’t cut in as fire destroyed rig air line

• Old battery bank was replaced but its charger was not removed. It was kept charged unknown to operation team, shorted and started platform fire

• Battery powered tools in classified areas may provide the energy required to ignite flammable gases 

ESD System

• Reactor: High pressure drop across an inlet globe type ESD did not allow it to close on TAHH. Test such valves against highest pressure and select a flow to assist closing type. Ball type ESD? WWW

• HX Tube Rupture: RD operated when higher pressure water came in contact with heating oil on shell side. Inlet and outlet ESD valves on water and oil side were slow to close. Oil spray caught fire. WWW

• Failure/degradation dual redundant 5V DC power caused ESD and Blowdown System into fault mode. Continuous 100s alarms/minute. Source A at 5V but B was at 3V. Fault occurred when A failed, leaving system with B at 3V only

• ESD panels may bleed air via an orifice into ESD loop, to keep it topped up against small leaks and avoid spurious ESD. Some Hi-Pilots may have a small bleed port that can result in topping rate matching bleed-off. This may prevent ESD being activated. ESD loop may take a long time to bleed off. Review and add pneumatic quick opening to depressurize ESD loop