GCAP Book Complete Practice Test 2025

When ammonia in a vessel is heated without room for expansion, the most concerning outcome is a rupture due to hydrostatic pressure. As the temperature of the ammonia increases, it tends to expand. In a confined space where there is no possibility for that expansion to occur, the pressure inside the vessel rises significantly as the liquid and vapor phases cannot increase their volume. If the pressure exceeds the design limits of the vessel, it may lead to a catastrophic failure, resulting in a rupture.

This phenomenon is rooted in the principles of gas laws, where gas pressure increases with temperature under constant volume conditions. The heated ammonia will strive to maintain equilibrium, but in the absence of expansion space, it leads to dangerous conditions that can cause a physical failure of the container. This scenario emphasizes the importance of safety measures, such as pressure relief valves, in systems that handle pressurized gases and liquids. Understanding this concept can significantly enhance the approach to safely handling and storing volatile substances like ammonia.