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Offsite Consequences of Accidental Releases - Analysis Parameters

A)  Endpoints

  • Toxics: Use the toxic endpoints given in Appendix A of the Risk Management Program regulation.
  • Flammables: Flammables: For the worst case, use an overpressure of 1 psi explosion. For the alternative, use a radiant heat/exposure time of 5kw/m2 for 40 seconds.

B)  Wind Speed/Atmospheric Stability

  • Worst Case: For the worst case, use a wind speed of 1.5 m/s and F atmospheric stability class (nighttime weather conditions).
  • Alternative Case: For the alternative, use the typical meteorological conditions at the source.

C)  Ambient Temperature/Humidity

  • Worst Case: Either the highest maximum daily temperature in the previous three years and average humidity for the site or 25 C and 50% humidity.
  • Alternative Case: Typical temperature and humidity for your site.

D)  Release Height

  • Worst Case: Assume a release height of 0 ft.
  • Alternative Case: Release height will be typical of your process you are modeling.

E)  Temperature of Released Substance

  • Worst Case: Either the highest maximum daily temperature in the previous three years or the process temperature, whichever is higher.
  • Alternative Case: Release is at a process or ambient temperature appropriate for the process.