🔍 Key Concepts

• Compare direction of air and smoke movement in each figure (mostly across the deck vs. mostly up and down). • Know basic definitions: horizontal ventilation moves smoke laterally through openings on the same level; vertical ventilation moves it up or down through decks or topside openings; combination ventilation uses both. • Look for any mechanical exhaust fan or trunk that might be pulling smoke vertically while air enters horizontally.

💭 Think About

• In Figure 1, trace the white and red arrows: Do they show smoke and air only moving along one deck, or do they also pass up or down through another level? • In Figure 2, ask yourself whether the smoke is mainly being drawn across the deck toward an opening on the same level, or if it is also using an opening above/below the fire compartment. • Which option best matches a setup where air is brought in one way and smoke is removed another way (two directions), versus a setup where smoke is mainly swept across on a single level?

✅ Before You Answer

• Identify whether Figure 1 uses both horizontal and vertical paths for smoke removal or just one direction. • Confirm that in Figure 2 the primary exhaust path for smoke is along the same deck level, not up through a higher deck opening. • Eliminate any option that labels a figure as vertical ventilation when the arrows do not clearly show smoke moving primarily through an opening above or below the compartment.