What is the smallest percentage of gas (vapor) that will make an ignitable mixture called?

What is the smallest percentage of gas (vapor) that will make an ignitable mixture called?

• A. Flammable limit
• B. Low explosive limit (LEL)
• C. Upper explosive limit (UEL)
• D. Ignition threshold

Answer: (B)

The smallest percentage of gas (or vapor) in the air that will support combustion is known as the Low Explosive Limit (LEL). This term is used in the context of flammable substances, where concentrations below this threshold are too lean to ignite, while concentrations above it may pose a risk of explosion if an ignition source is present. Understanding the LEL is crucial for ensuring safety in environments where flammable gases are present, as it helps in assessing the risks associated with different concentrations of gas. By identifying the minimum concentration required for ignition, personnel can implement appropriate safety measures. The other terms, while related to flammability, do not represent the same concept. The flammable limit refers more generally to both the LEL and the Upper Explosive Limit (UEL). The UEL indicates the maximum concentration of gas that can ignite, beyond which there’s too much fuel and not enough air for combustion. The ignition threshold is a broader term that may encompass various conditions required for ignition, but it does not specifically denote the smallest percentage of gas necessary for an ignitable mixture.

The smallest percentage of gas (or vapor) in the air that will support combustion is known as the Low Explosive Limit (LEL). This term is used in the context of flammable substances, where concentrations below this threshold are too lean to ignite, while concentrations above it may pose a risk of explosion if an ignition source is present.

Understanding the LEL is crucial for ensuring safety in environments where flammable gases are present, as it helps in assessing the risks associated with different concentrations of gas. By identifying the minimum concentration required for ignition, personnel can implement appropriate safety measures.

The other terms, while related to flammability, do not represent the same concept. The flammable limit refers more generally to both the LEL and the Upper Explosive Limit (UEL). The UEL indicates the maximum concentration of gas that can ignite, beyond which there’s too much fuel and not enough air for combustion. The ignition threshold is a broader term that may encompass various conditions required for ignition, but it does not specifically denote the smallest percentage of gas necessary for an ignitable mixture.