What term defines the concentration in air required for a gas or vapor to explode?

What term defines the concentration in air required for a gas or vapor to explode?

• A. volatile range
• B. explosive limit
• C. ignition index
• D. burst point

Answer: (B)

The term describes the concentration in air at which a gas or vapor can ignite and propagate a flame, potentially causing an explosion. This is known as the explosive limit, which encompasses two values: the lower explosive limit (LEL) and the upper explosive limit (UEL). The LEL is the minimum concentration that allows combustion to occur, while the UEL is the maximum concentration above which combustion cannot be sustained. Mixtures outside this range are either too lean or too rich to ignite. Within the explosive limits, an ignition source can trigger rapid combustion and explosion, making this concept critical for assessing hazards, ventilation needs, and safe operating conditions. For example, methane has an LEL around 5% and a UEL around 15% in air. Other terms like volatile range, ignition index, or burst point aren’t standard descriptors for these flammability thresholds.

The term describes the concentration in air at which a gas or vapor can ignite and propagate a flame, potentially causing an explosion. This is known as the explosive limit, which encompasses two values: the lower explosive limit (LEL) and the upper explosive limit (UEL). The LEL is the minimum concentration that allows combustion to occur, while the UEL is the maximum concentration above which combustion cannot be sustained. Mixtures outside this range are either too lean or too rich to ignite. Within the explosive limits, an ignition source can trigger rapid combustion and explosion, making this concept critical for assessing hazards, ventilation needs, and safe operating conditions. For example, methane has an LEL around 5% and a UEL around 15% in air. Other terms like volatile range, ignition index, or burst point aren’t standard descriptors for these flammability thresholds.