🔍 Key Concepts

• Enclosed survival craft air systems – how they keep breathable air inside when hatches are shut • Pressure balance between the inside of the craft and the outside atmosphere • Effect of a mechanical air supply (blower/compressor) on internal pressure

💭 Think About

• Think about what happens if you keep pumping air into a mostly closed space: what would the pressure inside try to do compared to the outside? • For crew comfort and door/ hatch operation, would designers want the inside pressure to be much lower, much higher, or about the same as outside? • If inside pressure were very different from outside, what effect would that have when opening a hatch or if the hull is slightly leaking?

✅ Before You Answer

• Consider whether the system is designed to slightly over-pressurize or to exactly match outside air, and why that might matter for fume/smoke exclusion. • Ask yourself if a survival craft air system would ever be intended to run at less than outside air pressure in an emergency environment. • Visualize how continuous air flow into a sealed or semi‑sealed space affects the internal air pressure relative to outside.