Upper explosive limit

Hazards

• The concentration above which a fuel-air mixture is too rich to propagate flame under stated conditions.

Controls

• Never treat an above-range atmosphere as safe because dilution or air entry can move it through the explosive range.

Personal protective equipment

• Select task-specific PPE only after hazards and higher-order controls have been evaluated.

Regional considerations

• Applicable law, permits, collective agreements, venue rules, and qualified-person decisions take precedence.

In practice

Never treat an above-range atmosphere as safe because dilution or air entry can move it through the explosive range.

Explore related entries

• Lower explosive limit
• Permissible exposure limit