Let’s break down what the "crack" actually means and why it changes how we think about risk. In the context of DNV PHAST, “crack” refers to a pressurized leak from a small, slit-like opening —such as a fatigue crack in a pipe weld, a partially open valve, or a corroded seam.
If you’ve spent any time in process safety or quantitative risk assessment (QRA), you’ve likely heard the term . It’s the gold standard for modeling the consequences of hazardous releases—fires, explosions, and toxic dispersions. dnv phast crack
Most legacy studies use round holes because they are conservative for release rate but not always for consequence . For toxic gases (like H2S or chlorine), a crack's directional jet can send a plume directly toward an air intake that a round hole might miss. Let’s break down what the "crack" actually means