UK’s HSE guidance on failure modes in Refrigeration Processes

UK’s HSE provides some EXCELLENT guidance on how ammonia refrigeration process safety can be managed.  We have always taught our process safety courses with the underlying philosophy of process safety as PREVENT, PROTECT, MITIGATE, and in this HSE material they follow the same philosophy.  This information is particularly helpful as they have matched up the FAILURE MODES with the PREVENT, PROTECT, MITIGATE measures specific to an ammonia refrigeration process.  This tool could be helpful for facilities when they review their PHA’s every five (5) years; it could act as a “verification” of sorts that the PHA is utilizing the Hierarchy of Controls and Layers of Protection properly.  Here is their material:

PLEASE NOTE that the RAGAGEPs they reference may NOT be applicable outside the United Kingdom.

The failure modes associated with Refrigeration are: 

Air ingress measures

measures to prevent, control or mitigate major accidents involving air ingress effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Plant	Explosion Relief	Emergency Response
Operating Procedures	Leak Detection	Isolation
Reliability of Utilities	Training	Plant Layout (Escalation)
PPE
Secondary Containment
Spill Treatment

Corrosion measures

measures to prevent, control or mitigate major accidents involving corrosion effects of Refrigeration are:

Prevention	Control	Mitigation
Coatings	Corrosion Monitoring	Emergency Response
Selection of Materials	Inspection	Isolation
Leak Detection	Plant Layout (Escalation)
PPE
Secondary Containment
Spill Treatment

Design fault measures

measures to prevent, control or mitigate major accidents involving design fault effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Buildings	Inspection	Emergency Response
Design Codes – Plant	Leak Detection	Isolation
Relief Systems	Plant Layout (Escalation)
Vent Systems	PPE
Secondary Containment
Spill Treatment

External event measures

measures to prevent, control or mitigate major accidents involving external event effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Buildings	Flood Protection	Emergency Response
Design Codes – Plant	Lightning Protection	Isolation
Relief Systems	Plant Layout (Escalation)
Wind Loading Protection	PPE
Secondary Containment
Spill Treatment

Fire/explosion measures

measures to prevent, control or mitigate major accidents involving fire/explosion effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Plant	Active Fire Protection	Emergency Response
Hazardous Area Classification	Explosion Relief	Isolation
Operating Procedures	Passive Fire Protection	Plant Layout (Escalation)
Vent Systems	PPE
Secondary Containment
Spill Treatment

Human error measures

measures to prevent, control or mitigate major accidents involving human error effects of Refrigeration are:

Prevention	Control	Mitigation
Operating Procedures	Alarms	Emergency Response
Control Systems	Isolation
Training	Plant Layout (Escalation)
PPE
Secondary Containment
Spill Treatment

Impact measures

measures to prevent, control or mitigate major accidents involving impact effects of Refrigeration are:

Prevention	Control	Mitigation
Lifting Procedures	Leak Detection	Emergency Response
Maintenance Procedures	Training	Isolation
Operating Procedures	Plant Layout (Escalation)
Permit to Work	PPE
Secondary Containment
Spill Treatment

Impurities measures

measures to prevent, control or mitigate major accidents involving impurities effects of Refrigeration are:

Prevention	Control	Mitigation
Operating Procedures	Alarms/Trips	Emergency Response
Sampling	Isolation
Relief Systems	Plant Layout (Escalation)
Training	PPE
Secondary Containment
Spill Treatment

Maintenance faults measures

measures to prevent, control or mitigate major accidents involving maintenance faults effects of Refrigeration are:

Prevention	Control	Mitigation
Maintenance Procedures	Inspection	Emergency Response
Leak Detection	Isolation
Permit to Work	Plant Layout (Escalation)
Training	PPE
Secondary Containment
Spill Treatment

Overheating measures

measures to prevent, control or mitigate major accidents involving overheating effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Plant	Alarms	Emergency Response
Maintenance Procedures	Back-Up Cooling	Isolation
Operating Procedures	Expansion Systems	Plant Layout (Escalation)
Reliability of Utilities	Training	PPE
Vent Systems	Secondary Containment
Spill Treatment

Overpressurisation measures

measures to prevent, control or mitigate major accidents involving overpressurisation effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Plant	Alarms	Emergency Response
Maintenance Procedures	Relief Systems	Isolation
Operating Procedures	Training	Plant Layout (Escalation)
Trips	PPE
Vent Systems	Secondary Containment
Spill Treatment

Structural failure measures

measures to prevent, control or mitigate major accidents involving structural failure effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Buildings	Inspection	Emergency Response
Design Codes – Plant	Isolation
Plant Layout (Escalation)
PPE
Secondary Containment
Spill Treatment

Vibration measures

measures to prevent, control or mitigate major accidents involving vibration effects of Refrigeration are:

Prevention	Control	Mitigation
Design Codes – Plant	Inspection	Emergency Response
Leak Detection	Isolation
Maintenance Procedures	Plant Layout (Escalation)
Training	PPE
Secondary Containment
Spill Treatment

Wrong/defective equipment measures

measures to prevent, control or mitigate major accidents involving wrong/defective equipment effects of Refrigeration are:

Prevention	Control	Mitigation
Change Procedures	Alarms/Trips	Emergency Response
Design Codes – Plant	Leak Detection	Isolation
Relief Systems	Plant Layout (Escalation)
Training	PPE
Secondary Containment
Spill Treatment

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