🔍 Key Concepts

• Starting air systems on diesel engines and how explosions can occur in air lines • Purpose of non-return (check) valves and isolation of systems on engines • Typical SOLAS/USCG requirements for protection of starting air mains against explosions

💭 Think About

• Which option actually prevents flame or pressure from traveling back through the starting air main to other machinery? • Look at which options describe a system design feature that is commonly required on each engine, not just one device in the line. • Ask yourself: If one engine’s starting valve fails and causes an explosion, which arrangement best limits the damage to that one engine only?

✅ Before You Answer

• Identify which choice describes preventing reverse flow from an engine back into the main air line. • Check which option is consistent with standard engine room safety design, where one failed component should not endanger the whole system. • Eliminate any answer that relies only on the strength of materials or on the assumption that valves "never fail".