Safety distance를 준수하지 못할 때 어떤 방식으로 justification을 할 수 있을까?

SHELL DEP 80.00.10.11 

General 

Reduced minimum separation distances or physical barriers shall only be used when sufficient  segregation is demonstrated to be ALARP by using appropriate consequence modelling or risk assessment. a. The methodology and criteria to be used for the modelling or assessment, and the  results, shall be subject to the approval of Principal’s designated Technical Authority

 

Flares and Vent Stacks

A consequence analysis to justify reduced separation shall take the following into account:

• Thermal radiation. See DEP 80.45.10.10-Gen. Section 4.7 for calculation of thermal radiation and the acceptance criteria for items such as process units, property boundary, areas where large numbers of people may be exposed and activities that cannot be stopped in a timely manner (e.g., turnaround activities);              
• The potential for liquid overfill out of the flare and associated consequence;
  • This shall be through a multi-discipline review, such as a HAZOP, considering  the scenarios of liquid to the flare knock-out (KO) facilities and associated barriers to reduce the probability of this event.
  • Refer to DEM 2 Process Safety Basic Requirements (PSBR) no 6: Avoid liquid release relief to atmosphere.
• Dispersion modelling for lower flammability limit (LFL) and toxics shall be carried out  to show that the LFL and toxic concentration contours do not overlap with ignition  sources or expected personnel locations, including grade level, elevated platforms and elevated areas.
  • This modelling shall consider the scenario of an unignited flare.

ANDOC AGES-GL-03-001