Identifying and Analyzing Hazards
Safety Planning starts with a review of the project objectives, scope, and preliminary design. Working together, the person leading the work, Subject Matter Experts (SMEs), facility and line management, and workers should use the techniques discussed in Hazard Analysis and Risk Assessment to identify specific hazards, risks associated with those hazards, and possible controls to mitigate the risks.
Hydrogen hazard assessment should address the specific hazards associated with hydrogen use in a particular application. In priority order, these are:
- Combustion
- Pressure
- Low temperature (either from cryogenic liquid hydrogen or from expansion of hydrogen gas)
- Hydrogen embrittlement
- Exposure of equipment and personnel
For example, in an assessment of a combustion hazard, the following elements should be considered: mixture formation, flammability, ignition sensitivity, possible ignition sources, propagation of deflagration, transition to detonation, detonation, and temperature and overpressure effects.
The effect of hydrogen quantity, separation distances, barriers, and mitigations by equipment and procedures should also be addressed.
Hazard identification answers the question:
- "What could go wrong (what parts or systems could fail, what human errors could occur)?"
Hazard analysis begins with an analysis of the severity of an event, by asking:
- "What are the potential impacts if it did go wrong (to personnel, property, the environment, etc.)?"
And continues with an analysis of the likelihood of such an occurrence:
- "How likely is this event to happen (daily, monthly, almost never)?
Tools such as a Hazop analysis offer well-defined metrics for quantifying Hazard, Risk, and Likelihood and indicating where an unacceptable risk may exist. Other methods are listed in Ranking-Risks.