🔍 Key Concepts

• Fixed CO₂ system operating sequence (what happens after you open the control valve to the protected space) • Safety features of machinery space CO₂ systems, including automatic discharge controls • Why entering or opening a space during CO₂ discharge is extremely dangerous

💭 Think About

• After you open the control valve to the protected space, what must actually cause the CO₂ bottles to discharge—does that happen automatically, or is there another control? • Which choices would require you to be near or inside the machinery space during or after discharge, and why is that unsafe? • In normal design, is the amount of CO₂ ‘modulated’ manually, or is the system sized to flood the entire space at once?

✅ Before You Answer

• Eliminate any option that would cause you to open the protected space or look inside during discharge • Ask yourself which option matches a two‑step operating procedure: first select the space, then release the CO₂ • Confirm that machinery space fixed CO₂ systems are designed to fully flood the space, not to be ‘throttled’ bottle by bottle