Blast-overpressure screening — API RP 752 Appendix C
The credible flammable mass within the cloud (from a release / dispersion analysis).
VCE yields are typically 0.02–0.10 (Crowl & Louvar). Higher is more conservative.
Sets the collapse / damage overpressure used to judge the location.
Enter to get the overpressure, damage level, and pass / study / relocate verdict at that location.
How API RP 752, TNT-equivalence, and the Appendix C vulnerability thresholds combine to site occupied buildings
API RP 752 does not give a fixed distance — it requires a consequence-based evaluation. This tool screens the distance by modelling the vapour-cloud-explosion overpressure versus distance (TNT-equivalence with the Kinney-Graham blast curve) and comparing it against API RP 752 Appendix C building-damage thresholds. The 1.0 psi contour is the common occupied-building screening distance.
Per API RP 752 Appendix C: onset of damage is about 0.2 psi, an unreinforced masonry building collapses near 1.5 psi, a metal pre-engineered building collapses above 5 psi, and a reinforced-concrete shear-wall building near 6 psi. Building collapse implies roughly a 0.6 probability of occupant fatality.
TNT equivalence converts the flammable mass in a cloud to an equivalent TNT charge: W_TNT = yield × mass × heat of combustion / 4686 kJ/kg. The overpressure at a distance is then read from the TNT blast curve. VCE yields are typically 2 to 10 percent; higher is more conservative.
No. This is the explosion-overpressure screening step only. A full API RP 752 siting study must also address fire radiation, toxic release, fragments and missiles, escalation, and occupancy/risk. The TNO Multi-Energy method is recommended for the detailed congested-VCE analysis.