When carrying out a DSEAR risk assessment, a common question is: what is your basis of safety going to be?
The concept can be difficult to define, but it is central to demonstrating that risks to personnel are controlled and reduced to As Low As Reasonably Practicable (ALARP). In simple terms, it describes how a fire or explosion risk will either be prevented or its consequences mitigated.
Understanding the Basis of Safety in DSEAR
In the context of a DSEAR assessment, the safety approach explains how people are kept safe from hazardous events. This requires clearly demonstrating the measures in place to either prevent a flammable atmosphere or ignition, or to reduce the impact should an event occur.
From our experience across multiple industries, there are typically two types of approach.
Preventative Safety Approach
A preventative basis of safety focuses on stopping a hazardous event from occurring in the first place. This aligns with the hierarchy of inherent safety and is always the preferred approach where practicable.
Examples include:
- Avoiding the formation of a flammable atmosphere through inerting, ventilation or material substitution
- Eliminating ignition sources where possible
- Controlling ignition sources using appropriately rated equipment
While effective, fully eliminating ignition sources can be challenging in complex operating environments.
Mitigative Safety Approach
Where prevention is not fully achievable, a mitigative basis of safety is used to reduce the consequences of an event.
Typical examples include:
- Explosion venting to a safe location or through flameless venting systems
- Explosion suppression systems
- Restricting or excluding personnel from hazardous areas
Mitigation measures are often more complex and may require additional justification to demonstrate they achieve an ALARP level of risk.
Demonstrating an Effective Basis of Safety
Once a basis of safety has been selected, it is essential to ensure that all required safeguards are in place and functioning effectively.
This is where risk assessment findings and recommendations become critical. If there are gaps in protection layers, these must be addressed to ensure the intended safety strategy is achieved.
For example, where explosion venting is the chosen approach, considerations may include:
- Ensuring explosion panels are correctly specified and maintained
- Confirming venting does not discharge into occupied areas
In many cases, equipment may already provide the foundation for the chosen approach, but improvements are required to ensure it is robust, reliable and meets ALARP expectations.
Choosing the Right Basis of Safety
Selecting the appropriate safety strategy comes down to a simple principle: should the hazard be prevented, or should its impact be mitigated?
Preventative measures are always preferred, but not always achievable. A well defined approach, supported by appropriate safeguards, ensures risks are managed effectively and in line with regulatory expectations.
If you would like to discuss how your organisation defines and demonstrates its basis of safety, our team can provide practical support aligned with DSEAR requirements.