The dangers of internal combustion engines as ignition sources

Internal combustion engines can be hazardous if used in facilities that process flammable gases and liquids. An internal combustion engine could ignite flammable gases or vapors, and the consequences could be devastating.

The Occupational Safety & Health Administration (OSHA) states that internal combustion engines fueled by diesel, gasoline, natural gas, propane, or other fuels, can act as ignition sources. The following engine types could cause explosions and fires if not used correctly:

• Stationary engines such as gasoline powered compressors, generators, and pumps
• Mobile equipment or transports such as vans, trucks, forklifts, cranes, well servicing equipment, drilling rigs, excavators, portable generators, and welding trucks
• Contractor vehicles and motorized equipment
• Emergency response vehicles such as fire engines and ambulances
• Vehicle-mounted engines on vacuum trucks, tanker trucks, and waste haulers
• Small portable engines such as mowers, blowers, generators, compressors, welders, and pumps

Internal combustion engines must have a specific fuel-to-air ratio to work properly. Air enters the engine through the intake and travels to the cylinder combustion chambers. Flammable gases and vapors can enter the cylinders with the air. The flammable material in the cylinders provides an external fuel source and increases the engine's fuel-to-air ratio creating an ignition hazard. OSHA recommends a workplace evaluation and other preventative measures, including:

• Identifying areas where flammable liquids or gases are located and where internal combustion engines are used
• Determine flammable material areas and internal combustion engine use by contractors
• Store materials and equipment according to OSHA standards
• Evaluate, establish, and mark acceptable routes through hazardous locations
• Install preventative measures such as intake flame and exhaust spark arrestors, shutdown systems, use a safe work permit lockout tagout system, and post hazard and precaution signs
• Train workers and contractors on hazardous areas and safety precautions

Develop programs that promote workplace safety and teach workers how to safely perform tasks involving internal combustion engines, and provide the appropriate safety equipment to protect employees against various workplace hazards.

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