Exam Question
(a) What is the purpose of providing air pipes to tanks in the vessel? (6)
(b) Sketch an arrangement of air vent head situated on the weather deck. (5)
(c) What factors are considered in deciding the bore size of air pipe? (5)
Class 4 (4th Engineer)
SC&S
📅 Sep 2025
Reference Answer
### (a) Purpose of Air Pipes (6 Marks)
The primary purpose of providing air pipes to tanks is to maintain the pressure within the tank at or very near to the ambient atmospheric pressure under all operational conditions. This prevents structural damage to the tank.
Key functions include:
1. **Prevention of Over-Pressure:** During the filling of a tank (bunkering, ballasting, or transfer), the incoming liquid displaces the air and/or vapour inside. The air pipe provides a free path for this displaced air/vapour to escape to the atmosphere. Without an adequately sized air pipe, pressure would build up, potentially causing deformation or rupture of the tank's bulkheads and plating.
The primary purpose of providing air pipes to tanks is to maintain the pressure within the tank at or very near to the ambient atmospheric pressure under all operational conditions. This prevents structural damage to the tank.
Key functions include:
1. **Prevention of Over-Pressure:** During the filling of a tank (bunkering, ballasting, or transfer), the incoming liquid displaces the air and/or vapour inside. The air pipe provides a free path for this displaced air/vapour to escape to the atmosphere. Without an adequately sized air pipe, pressure would build up, potentially causing deformation or rupture of the tank's bulkheads and plating.
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