Apparent separation of a stable or unstable flame above the flare burner, occurring if the fuel velocity exceeds the flame velocity.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards
Perpendicular distance between detector shoe and the surface – sometimes called “standoff”.
Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards