What is an area source and give an example in process safety?

• A. A point release from a valve.
• B. A jet release from a nozzle.
• C. An area source releases across a surface, such as a surface leak along a tank wall or a diffuse leak along a pipe trench.
• D. A release confined to a closed vessel.

Answer: (C)

An area source is a release that occurs over a surface or along a region, not from a single pinpoint. In process safety this means vapors or liquids escape across a surface or along a length, so the release is distributed rather than concentrated at one point. An example is a surface leak along a tank wall, where leakage occurs along the length of the wall and vapor escapes over that area. Another example is a diffuse leak along a pipe trench, where gas escapes along the trench rather than from a single hole. This contrasts with a release from a valve (a point source), a jet release from a nozzle (a concentrated jet), or a release confined to a closed vessel (no release to the surrounding environment).