Safety and power · safety

Upper explosive limit

Also known as UEL, upper flammable limit.

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

Safety notes

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

Sources

Recommended Practices for Safety and Health Programs · Occupational Safety and Health Administration
Safety Bulletins · Contract Services Administration Trust Fund

Educational reference only. Requirements vary by jurisdiction, employer, venue, and production context.