Preventing the Next Diesel Runaway Explosion

High levels of uncertainty require larger margins of safety. The potential combination of fuel-hydrocarbons, oxygen-air, and energy ignition are highly comples making exact predictions of what is safe and unsafe difficult and impractical. The science needed to prove conclusively if combinations near explosive limits will be safe is not yet available.

The objective of the paper is to highlight the importance of ignition source elimination and the difference in approach mandated by law in different jurisdictions around the world. There are many potential ignition sources in the petrochemical, refining and oil and gas drilling industry; such as hot work, internal combustion engines, improperly classified or maintained electrical equipment, lighting, and adjacent fired equipment. These are typically controlled via measures such as hot work permits for:

- Welding/burning

- Hot work or vehicle entry permit requirements to operate engines inside posted areas

- Proper electrical classification along with programs to maintain it, and

- Programs/practices to prevent/detect releases of flammable materials.

A large number of diesel engines (in vehicles, lighting towers, power generators and other equipment) are used in the petrochemical and oil and gas industry for their day-to-day operation. Diesel engine runaway is a serious hazard in oil and gas drilling and production and similar industries where flammable hydrocarbon emissions or leaks may occur.  A runaway can be described as an engine running out of control on an external fuel source (i.e., the “fuel” in the air) where the operator cannot shut down the engine using conventional methods (i.e. turning off the engine ignition switch). 

In a total runaway engine situation, the result can range from minor engine damage to engine explosion, causing catastrophic damage to the equipment and surrounding facilities and/or death or injuries to personnel such as BP Texas City refinery and BP Deepwater Horizon explosions.

The industry has a history of diesel engine runaway related injuries and fatalities due fire and explosions when administrative controls have failed.. Fortunately, the engine manufacturers like Caterpillar and Cummins recognize this hazard and offer simple, inexpensive technology that can prevent a diesel engine runaway.

The paper is presented to increase awareness and lessons learned from many accidents involving runaway diesel engines.

The author will present what companies are doing around the world to prevent diesel engine runaway as an ignition source and analyze risk, probability and consequence of not addressing this serious safety hazard in the hydrocarbon industry.