Exam Question
(a) State why double walled fuel pipes are employed for high pressure fuel lines. (6)
(b) Sketch and describe such a double walled pipe arrangement and show how high pressure pipe failure is indicated. (10)
Class 4 (4th Engineer)
MEKM
📅 Mar 2026
Reference Answer
### (a) Rationale for Double Walled High Pressure Fuel Pipes (6 Marks)
Double-walled high-pressure fuel pipes are employed on marine diesel engines primarily as a critical safety measure to prevent engine room fires, in compliance with international regulations.
1. **Prevention of Fire Hazard (Primary Reason):**
* **High Pressure Atomization:** The fuel in the high-pressure lines between the fuel pump and the injector is at an extremely high pressure (typically 1000-2000 bar). A fracture or leak in a single-walled pipe would release this fuel as a highly atomized, flammable mist.
Double-walled high-pressure fuel pipes are employed on marine diesel engines primarily as a critical safety measure to prevent engine room fires, in compliance with international regulations.
1. **Prevention of Fire Hazard (Primary Reason):**
* **High Pressure Atomization:** The fuel in the high-pressure lines between the fuel pump and the injector is at an extremely high pressure (typically 1000-2000 bar). A fracture or leak in a single-walled pipe would release this fuel as a highly atomized, flammable mist.
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