🔍 Key Concepts

• Compare symbol (51) with the other valve symbols on the same sheet (e.g., symbols (17), (29), and (41)) and notice which ones have letters on them and which do not. • Think about which fire‑fighting system actually runs throughout the entire ship and would need many isolation valves shown on the fire control plan. • Recall that on IMO fire control plans, the piping line for a system is drawn separately, and these double‑cone symbols are placed on that line to show the locations of its control valves.

💭 Think About

• When a valve symbol has a letter like F, S, or D, what does that usually tell you about the type of system it serves? How is symbol (51) different? • Of the answer choices (fire main, sprinkler, foam, bilge), which system’s piping would you expect to see on almost every deck and in most spaces of the ship? • Look at the nearby symbols around (51) (such as (50) and (52)). Do they suggest a special local system, or a general ship‑wide system? How does that help you narrow the choices?

✅ Before You Answer

• Verify which other symbol on the sheet clearly shows sprinkler valves (hint: it has an S on the double‑cone valve) and eliminate that answer choice for (51). • Verify which symbol clearly shows foam cylinders/tanks and see whether their valve symbol carries a distinguishing letter; compare that carefully with (51). • Before choosing, be sure you can explain to yourself which system would logically have many valves all along its main line throughout the ship, and match that to the symbol’s use on a fire control plan.