Process safety calculators, methods and equations

Each module below documents the calculation it performs, the governing equations, the nomenclature and the assumptions behind the result, so the output can be checked and defended in a safety study. The calculations themselves run in the browser-based toolkit.

• Gas Discharge

  Calculate the mass release rate of a compressed gas through a hole or leak path, including choked and subsonic flow, real-gas compressibility and discharge coefficient effects.

• Two-Phase Blowdown

  Blowdown calculation for saturated vessels: two-phase depressurisation with wet and dry wall heat transfer, orifice sizing and minimum wall temperature prediction.

• Indoor Release

  Calculate indoor gas concentration build-up from a leak in a ventilated enclosure, including steady-state concentration, time to reach a concentration of interest and delayed ventilation start.

• Gas Dispersion

  Atmospheric dispersion calculator for neutrally buoyant and dense gas releases: downwind concentration, cloud footprint and receptor-point results by stability class.

• Flare Radiation

  Flare radiation calculator: flame length, tilt and thermal radiation flux at grade, with exclusion distances for personnel and equipment radiation criteria.

• Gas Detection Mapping

  Gas detector coverage mapping: design-basis gas cloud sizing, geographic and scenario coverage scoring, and detector placement assessment on a plot-plan.

• Noise Mapping

  Industrial noise mapping calculator: combine multiple equipment sound sources into free-field sound pressure level contours across a plot-plan.

• Chemical Properties

  Look up thermophysical and flammability properties for process safety calculations: molar mass, critical constants, vapour pressure, flammability limits and heating value.

• Pool Fire

  Pool fire calculation steps: liquid burning rate, pool diameter, flame height, surface emissive power and thermal radiation distance to 4, 12.5 and 37.5 kW/m2.

• Fireball / BLEVE

  Fireball and BLEVE calculation steps: fireball diameter, duration, lift-off height and thermal radiation dose versus distance for a pressurised liquefied gas vessel failure.

• Jet Fire

  Jet fire calculation steps: flame length from release rate, flame tilt, surface emissive power and thermal radiation distance to escalation and personnel criteria.

• Flash Fire

  Flash fire calculation steps: flammable cloud extent to LFL and half-LFL, cloud mass in the flammable range and the burnt-area footprint used for occupied-area risk.

• Vapour Cloud Explosion

  Vapour cloud explosion calculation steps: flammable mass, TNT equivalence and multi-energy blast curves, and distance to 70, 140 and 200 mbar overpressure damage levels.