Safety Alerts 5

Storage Tanks

• Static Electricity: Spark between a steel weight used with a top filling hose and Ethyl Acetate tank. Tank was grounded but flow thru non-conductive hose generated static and top filling caused vapor generation in top. Ground and bond all equipment + avoid top or free fall filling (Inert gas padding avoids air) + Use conductive materials

• Static Electricity: Spark around an internal floating roof of a gasoline tank

• Static Electricity: Reformate transfer to a gasoline tank for blending. Static discharge due to high pumping rate and temperature changes caused inbreathing/ flammable atmosphere. Mild internal explosion that distorted tank roof. BP

• Static Electricity: Switch loading. Diesel routed to floating roof tank that had contained Gasoline earlier. Gasoline: air accumulation above diesel. High velocity diesel transfer resulted in static charge and explosion. Keep low velocities, inert or gas free, vapor test and extra care on switch-loaded tanks. Similar explosion while diesel filling a semitrailer that had contained gasoline. BP

• Static Electricity: MTBE tank was cleaned and a high pressure rotating water nozzle was introduced thru tank top manhole for jetting out. Static discharge from high speed fine water mist. Internal explosion. Manhole blown off. BP

• Static Electricity: Seal Oil Tank with HC and seal oil mist. Splash filling. Exploded. Avoid splash filling. BP

• Static Electricity: Aerosol mix of Benzene and air. Explosion. Splash filling. Limit velocity and inert. BP

• Static Electricity: CO2 jet from extinguishers contain small solid CO2 particles. A charge may accumulate. CO2 was used to inert a naphtha tank and it exploded. Similar, CO2 used in a jet fuel tank. Similar, high pressure water jets used to clean supertankers. WWW

• Static Electricity: Floating roof sank. Foam application on exposed naphtha ignited a fire it was supposed to prevent. 3 naphtha tanks destroyed. BP

• Static Electricity: After loading a tanker with naphtha from a shore tank, the loading line was backflushed with water. An explosion occurred in the tank probably caused by static electricity generated by the mixed flow of water and naphtha. BP

• Static Electricity: Emulsion layer in a heater treater was removed to a vacuum truck via a 3" hose. After spotting the oil layer, heater treater valve was closed and the hose disconnected. Oil-Water flowed out from the truck and was ignited by hot heater treater casing or static. Heater treater burner was online and the hose components were non-conductive + truck was not electrically bonded or grounded. Heater treater should have been isolated and depressurized. CSB

• Pyrophoric: Exercise caution with pyrophoric materials - coke, adsorbents, Butadiene compounds, - with Iron Sulfide (H2S presence). Pyrophoric materials slowly self-heat and eventually catch fire

• Pyrophoric: Minor internal explosion. Pyrophoric fire. Vacuum bottoms tank roof joint failed, spilling oil into dike/bund. BP

• Pyrophoric: Oil tank was emptied and filled with water, to eliminate any oil. Water was then drained allowing air via roof manhole. It mixed with pockets of oil and exploded, triggered by FeS. BP

• Pyrophoric: Air into an empty slop oil tank via PVRV. Ignited pyrophoric scale. Fire and explosion. BP

• Pyrophoric: Naphtha floating roof tank was emptied for maintenance but left unattended for weeks. Pyrophoric scale ignited residual Naphtha. Fire. BP

• Pyrophoric: Slop Oil Tank open top floating roof deck sunk after heavy rain due to a blocked internal drain. After the oil was pumped out and tank cleaning commenced, a fire occurred in the rim seal area. Pyrophoric FeS. Fire. BP

• Pyrophoric: Partially submerged steam suction heater vaporized lighter fractions in a Short Residue tank. Ignited by dried up Sulfide deposits. BP

• Flare: FCC Unit liquid sent to flare ignited a water treatment tank without roof 140m away. Tank water had crude from the Desalter. BP

• Floating Roof: Collapse or sinking. Pontoon buckling. Sank on excessive rainwater accumulation. Pushed oil to roof via vacuum breaker/ vent. Avoid closed roof drain valve, frozen drain, debris/fouling the drain. Ensure draining capacity matches rain fall

• Floating Roof: Excessive rain water on the roof of a double deck external floating roof tank caused the roof to sink, exposing a crude naphtha mixture. Flooded dykes limited access to roof drain. BP

• Floating Roof: Wax from waxy crude, melted in the sun, ran on the roof and plugged the internal drain. BP

• Floating Roof: Primary and secondary seals were separated from a tank wall, to avoid heat damage while the wall was cut to add an access door. Oil that had accumulated in the seal spaces drained out. No internal inspection was done before starting the welding. Fire. In addition to gas testing, visual inspection to check for oil, sludge or wax is a must. BP

• Floating Roof: Single seal was replaced by a double seal. The tank was emptied, cleaned, inspected, gas tested and refilled with water to raise the floating roof to the level required for execution of the repair. Gas tests were performed inside the tank, on top of the roof, and around the circumference; but the space in between the seals and underneath the seals was not tested. During hot work - cutting, grinding and welding, explosion. Damage to tank roof and seals. BP

• Floating Roof: Single deck floating roof. Emergency drain was replaced by a longer pipe. Emergency drain was to route rain water into the tank if the normal roof drain is closed or clogged, to prevent overloading the roof. After a heavy rain, excess rain water on the roof and its weight forced Jet A1 to flow up through the emergency drain and flood the roof. Avoid emergency drains on single deck floating roofs. Go for good sized rainwater drains with outlet valves kept open. BP

• Floating Roof: Rim seal fire escalated quickly to a full surface fire when vapors in the leaking pontoons exploded. Regularly gas test pontoons to eliminate vapor build-up in the pontoons. BP

• Gasoline tank roof seal changed from liquid filled type to gastight spring loaded type. Bumpers under the roof (that hit the tank shell when the seal is fully compressed) were also modified. New bumpers were closer to the tank shell and made contact more often, deforming the pontoon welds over the years. The roof finally sank and three pontoons were flooded. Regularly gas test the pontoons. BP

• Earthquake: Liquid sloshing resulted in rim-seals damage and crude oil overflow. Metal-metal contact between floating roof and side wall resulted in sparks that ignited the overflow

• Earthquake: Damaged the roof of a naphtha tank. Foam applied as a preventive measure. Continuous dripping of water and foam onto the naphtha surface - static discharge and fire. BP

• Internal roof collapse: Tank was emptied, cleaned and inspected. When firefighters tested its foam systems, the internal roof, not designed to withstand the weight of water collapsed. BP

• Crude Oil Tank: While removing sludge, workers started smoking. HC trapped in the sludge ignited. Fire and fatality. BP

• Isolation: While swinging spec/ hammer blind, valve passing led to gasoline leak/ flashing and accumulation in a tank pit. Operator overcame by fumes. VCE. Similar incident in an LPG plant. All valves leak. Use buddy system

• Styrene polymerized, an exothermic reaction, due to - higher temperature in top layers, CS rust particles in an unlined tank, lack of inhibitor inside stalactites on tank roof, improper O2 level to help inhibitor, lack of refrigeration and poor liquid mixing/ stagnation without mixers - and pressurized tank. Under sized vents and atmospheric venting instead of flaring led to toxic cloud release. Must measure temperature along the liquid height and in vapor space

• Waste Water Tank: Propylene Oxide Styrene Monomer (POSM) plant. Light HC vapor was compressed and sent to recovery. Tank had N2 padding. O2 was liberated in the tank from light peroxide decomposition. N2 sweep maintained to keep O2 within limits. When the compressor failed, N2 sweep was shutdown. O2 accumulation was not detected by O2 analyzer. Compressor start-up created enough energy to ignite the tank vapor space. Explosion. BP