An overpressuring of a vessel resulting in an explosion is an example of which release type?

• A. Narrow breach
• B. Wide aperture
• C. Local rupture
• D. Leakage

Answer: (B)

The key idea is that release types are defined by how large the opening is when the vessel fails. An overpressured vessel that explodes creates a large opening, through which a large amount of contents rushes out rapidly. That rapid, voluminous escape is described as a wide aperture. This classification emphasizes the scale of the vented material and the speed of release, which are what drive the explosive potential.

A leakage implies a slow, small escape through tiny gaps, not an explosive event. A narrow breach describes a small, restricted opening that can produce a fast jet but not the large, rapid release associated with an explosion. A local rupture refers to a rupture in a localized area, which may release contents but doesn’t necessarily imply the large opening characteristic of an explosion.