Traditionally, different formulae have been used to size the explosion vents for strong (P-red > 0.1 bar-g or 1.5 psig) and weak (P-red < 0.1 bar-g or psig) enclosures. Recently, the National Fire Protection Association (NFPA) 68 Committee has developed a simplified equation for strong ann weak structures that may be subjected to full volume or partial volume internal explosions. This paper presents a simplified analysis which was used to develop the unified formula. The analysis provides insight into the form of the correlating parameters, as well as into the validity of the key, hypotheses risen in vented dust explosion data analysis.