What color marks first aid and discharge valves on dry docks?

• A. Blue
• B. Red
• C. Yellow
• D. Green

Answer: (D)

Color coding of valves in dry docks is used to quickly identify what system a valve controls, helping you act fast in emergencies or during maintenance. Green marking for valves signifies they are related to first aid and discharge (drain) functions. So, when you see green, you know those valves deal with medical response access and drainage, which is why green is the correct color for these valves. In practice, other colors map to other systems (for example, red for fire protection, blue for water supplies, yellow for certain auxiliary services), so this scheme lets crews locate the right controls without second-guessing.