What is a major advantage of the demand type self-contained breathing apparatus?

The major advantage of the demand type self-contained breathing apparatus (SCBA) being operational in around 45 seconds is significant for several reasons. This prompt activation is crucial in emergency situations where every second counts, particularly in hazardous environments where immediate access to breathable air is necessary for the safety of the user.

Demand-type SCBAs are designed to deliver air only when the user inhales, which allows for quick preparation versus other types that may require more complex startup procedures. The rapid deployment time ensures that individuals can respond to emergency scenarios more effectively and maintain a continuous supply of breathable air while managing their actions and tasks.

This unique feature supports the overarching requirement of SCBAs to protect users from harmful atmospheres effectively. Being able to put the unit into operation quickly can be life-saving in various situations, such as firefighting or rescue operations in toxic environments.

Other options, while they might have merits in different contexts, do not provide the immediate critical advantage of rapid deployment that is essential in emergencies.