🔍 Key Concepts

• SCBA (Self-Contained Breathing Apparatus) low-air alarm purpose • Typical percentage of cylinder pressure at which the low-air warning activates • Safe time margin needed to return to a safe area before the air is fully depleted

💭 Think About

• Think about why the low-air alarm sounds before the air is gone — how much time does a firefighter or crew member reasonably need to exit safely? • Consider standard training: when the alarm goes off, are you expected to keep working, or to begin leaving the hazardous area immediately? How long should that evacuation window be? • Compare the answer choices: which one best represents a safety buffer rather than a near-empty or overly generous remaining time?

✅ Before You Answer

• Verify what your STCW/basic firefighting or vessel safety training said about low-pressure alarm activation on SCBA sets. • Remember that the alarm usually activates at about 20–25% of cylinder pressure — which of the choices most closely matches how long that remaining air typically lasts under moderate exertion? • Eliminate any options that would either give too little time to escape safely or seem excessively long for a low-air warning condition.