Safety Alerts 14

Fire Fighting

• Gas Detection: May fail to work, due to internal deposits caused due to UV-A induced decomposition reactions of materials inside the source unit assembly, especially in SS housings

• Small leaks: Do NOT ignore. Indicates thinning of pipe or vessel wall. Usually leads to catastrophic failure

• Inergen: System relied on F&G system triggering N2 release from a cylinder. N2 pressure fired off first Inergen cylinder + held open a spring-loaded valve to divert released Inergen to turbine enclosures. Released Inergen from the first cylinder to operate the release mechanisms on the remaining bottles. Falling N2 pressure led its spring-loaded valve to close, as the valve had no latch to keep it open. Routine inspection only checked N2 triggering and not a full system test

• Dry Chemical Extinguisher: On activation of a gas cartridge type dry chemical powder filled extinguisher, its bottom failed. Corrosion? Extinguisher propelled up. Fatality. Check your units 

• Halon Cylinder: Dropped while handling. Sheared top threaded connection, resulted in cylinder flying off 400m like a projectile over a tank farm

• CO2: Release failed to operate. Mismatched shipyard schematics Vs vendor manual on valve locations, control panel etc. Inoperable valve actuators and leaks inline. Check your system

• Firewater Pumps: Was on manual start as divers were in the sea. Condensate fire prevented access to FW Pump switches; no alternative way to switch on pumps. Check for common cause failures

• Diesel FW Pumps: 2 fuel injectors malfunctioned, allowing diesel into exhaust. Ignition in exhaust pipe resulted in excessive heat that ignited its insulation blanket

• Compressor Fire: Water mist system didn’t work as N2 regulator was incorrectly set. Its outlet valve might have been closed. Water deluge didn’t work as CSO valve might have been closed. Several deluge system nozzles were blocked with rust and scale. GRE pipe failed as fire duration exceeded its rating. Foam system didn’t work as valves were wrongly installed

Hydraulic Oil

• Hydraulic Oil Accumulator. Flammable atmosphere developed inside as hydraulic lubrication oil was being drained. Ignited by an electric heater within the accumulator

Air/ Oxygen/ Nitrogen

• Air: Receivers without PSV or PSV isolated have ruptured in service

• Compressed Air: Failures of tanks, vessels or piping are known during pneumatic testing. 36” - 600m piping burst while at 12.3 MPa (target 15.6 MPa)

• Compressed Air: Used to blow an inlet line blew off a tank whose vent was choked. Air used to blowoff dirt and mill scale from work areas or clothing has resulted in eye and skin injuries. WWW 

• Compressed Air: Above 140°C, lube oil vaporized and deposited in the discharge line of a compressor. Caught fire. In a plant bitumen lined discharge vessel produced flammable vapor and exploded. Mol Sieve preferentially absorbed Nitrogen and increased Oxygen concentration, widening flammability. Explosion. WWW 

• Oxygen: Autoignition temperature (AIT) and minimum ignition energy (MIE) are lower with higher oxygen content. Where O2 was used instead of air or N2 for purging due to mix-up unexpected ignition occurred

• Air Separation Unit in GTL plant: Combustible airborne particulates (soot) from forest fires accumulated on distillation column aluminium vaporisers - in liquid oxygen service. Hydrocarbon combustion led to aluminium combustion that vaporised the cryogenic liquids. Resultant pressure ruptured the distillation column. Note: 0.2-mm-thick Aluminium fins. Combustible contaminants from forest fires and pollution deposits on turbine blades cleaned by water washing

• N2 Surge Vessel: Liquid N2 was evaporated and sent to vessel for blanketing etc. Evaporator malfunctioned sending liquid N2 into vessel. ~ -196°C. Embrittlement and vessel rupture

• N2 Truck: Heat source lost. Brittle fracture in 16” HC pipe

• Liquid N2: Used to flash freeze in a food facility leaked and flashed. Asphyxiation. 6 fatalities

• N2 pressure testing. PRV lifted and vent line rotated through 90°. Fatal injury

• N2 Asphyxiation: Inadvertent use of N2 instead of air for breathing due to hose mix-ups/interchangeable coupling or stepping into N2 purged vessels cause death only after 1 or 2 breaths. Exposed person has no warning and cannot sense that O2 level is too low. At < 16% O2 level, brain signals the victim to breathe faster and deeper. In 4 - 6% O2, the victim falls into a coma in less than 40 seconds. Use unique hose connectors. Monitor O2 level in confined spaces. Use body harness to pull out the victim without buddy becoming a victim, as happens in many cases

• N2 Asphyxiation: Coil Tubing water displaced with N2 into return tank. While trying to check water level, 3 fatalities. N2 asphyxiation

• Same tank cars may be used to supply Nitrogen and Oxygen. Good to analyse supplied ‘nitrogen’ for O2. WWW