What do "explosive limits" refer to?

"Explosive limits" specifically refer to the concentration ranges of flammable gases or vapors that can lead to an explosion when mixed with air. This concept is crucial in safety management and risk assessment within industries that handle volatile substances.

When flammable materials are present, they need to exist within a certain concentration range to form an explosive mixture. Below this range, the mixture is too lean to ignite (known as the lower explosive limit, or LEL), and above this range, it becomes too rich to ignite (the upper explosive limit, or UEL). Understanding these limits helps workers and safety managers ensure they maintain flammable substances at safe levels, preventing explosive incidents.

The other options touch on important safety aspects, but they do not directly define explosive limits. Options concerning containment areas and pressure limits focus on physical safety measures rather than the chemical interaction of flammable substances. The limitation on personnel in hazardous areas pertains to general safety protocols, but again, it is not a definition of what explosive limits are.