Flammable Gas Detector's Zone

Flammable Gas Detector's Location을 정하는 기준

HC leak scenario에 근거한 consequence analysis -fire size, gas cloud size를 기준으로 extent를 정함.

HAC (for flammable gas) + toxic gas -> gas detector 

• Consequence analysis (fire size, gas cloud size) for FGD zone: TOTAL. SHELL
• HAC for FGD zone: ADNOC 

HAC와 FGS와 일치하지 않는 부분은 무엇인가? 

CA로 FGS를 정했을 때 보완이 필요한 부분은 무엇인가? 

 

Company A - HAC & F&G zone을 동일하게 판단함. EI 15 code 에 따라 HAC를 구하고 이를 FGS와 동일하게 적용함. 

 

Company T- Consequence analysis -> FGS 

The basis of the location of detectors 

Study about typical leakage calculations, taking into account the layout of the installation, the heat and the material balance of the process, the environmental condition (prevailing wind speed and direction, local atmospheric conditions), and the structural arrangements (walls, partitions, etc.) which could allow gas to accumulate. The possible ignition source shall be considered. 

 

The worst scenario shall be determined by estimating the size of the flammable gas cloud that
could exist in the sensitive area without being detected. => Layered gas detection system 로 해결 

 

Company S - Consequence analysis (fire size, gas cloud sizes -> FGS 

The typical sequence of design activities relevant to a Fire, Gas and Smoke Detection System is:

• Identify hazards related to fire, gas and smoke events;
  • zone definition (containment, fire, hazard)
  • detection requirements per zone
  • FGS hardware robustness requirement 
  • FGS system C&E matrix 
• Define site hazardous zones, fire zones; Extent & zone boundaries 
• Classify the level of criticality of the identified hazards: Voting for  FGS LOPA 시행함.
• Generate fire & gas design requirements and philosophy;
• Detailed Design of FGS, including configuration and layout;
  • for early detection and from gas accumulation 
  • Layered FGS: detection or boundary/perimeter detection
  • Optimized mapping. 
• Construct and commission;
• Operate and maintain.

It may be necessary to reiterate some steps to achieve the optimum result. The above steps also apply to modifications to Fire, Gas and Smoke Detection systems.