Question 1388 Deck General

70% to pass

Petroleum cargo tanks should not be topped off at deck level when loading on a cold day because _______________.

A air pockets may cause the cargo to bubble out of the ullage hole
B the tank valve may be stiff and a spill will occur before the valve can be closed
C the increased viscosity of the product requires higher loading pressure which increases the chances of a spill
D a subsequent temperature rise will cause the cargo to overflow
AI Explanation

The correct answer is D) a subsequent temperature rise will cause the cargo to overflow. When loading petroleum cargo on a cold day, the tanks should not be topped off at deck level because the subsequent increase in temperature will cause the cargo to expand and overflow. As the temperature rises, the volume of the liquid cargo will increase, leading to an overflow if the tank is filled to the brim. This is a well-established safety practice to prevent spills and environmental contamination. The other options are incorrect because they do not directly address the issue of temperature-induced expansion leading to overflow. Air pockets, stiff valves, and high loading pressures may cause other problems, but they do not specifically explain why topping off on a cold day is hazardous.

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