[Selective Reading] Strike the right balance between AFP and PFP.

Defining the AFP/PFP balance 

The objective of the fire safety design is

- to enable personnel to reach a safe location.

- to prevent escalation until the fire squad responds. 

- to limit damage to assets. 

 

The primary functions of fire safety systems are

- to protect escape routes,

- to mitigate the severity of the event, 

- to prevent escalation. 

 

FHA

Major credible scenarios at the facility

Choose which areas require AFP and PFP based on potential release locations, fire envelopes, and fire characteristics determined in the FHA. 

 

In the early design stage, to be based on prescriptive standards

 

Prescriptive guidelines specify how much and where PFP and AFP systems should be installed. 

=> Determining how much fire resistance is required. 

 

To assess the balance 

Decide on minimum AFP and PFP requirements. 

Regulatory requirements를 배치함. 그리고 나서 추가적으로 필요하다고 판단하는 것을 도출함. Min requirement. 

Different PFP ratings -> 이 것을 알아야 하네. 

APF and PFP complement each other. if APF is found to be lacking or insufficient, the PFP can be adjusted accordingly. 

 

Safety barrier to consider 

(1) FGD 

(2) CCTV

(3) Isolation and depressurization

(4) Layout

- proper fire-water coverage of equipment

- constraints on the escape route and access to it 

- constraints on the fire response team's access 

- adequate detection coverage

When reviewing layout issues that impact the balance of AFP and PFP requirements, consider these questions: 

- Are jet or pool hazards specific to certain parts of the unit? 

- Are any sections of the unit congested so that it would be difficult to apply firewater? 

- Will fire response teams have difficulty accessing any areas of the facility? 

(5) Deluge systems and FW monitors

- water deluge system: cool the surfaces 

- foam/water deluge system: extinguish 

- fixed water monitors: optimal location 

(6) Bunds

110% of the tank's maximum operational capacity. 

(7) Drainage 

The placement of drainage basins and gradient directions 

- Surface drainage capability, spread of flammable liquids, and fire water 

- Adequate collection, drainage, and oil/water separation facilities 

(8) Fire squad ER time 

PFP & APF to provide sufficient time for ER 

 

Additional Challenges

- OSBL pipe racks failure leading to escalation 

- Extreme worst-case scenarios: results are too severe to provide any meaningful insight. Cost-effective. 

- Spherical tanks