Introduction to on site risk assessment
The risk assessment is a tool to enable safe work. The main questions driving it are thus
- how can the worker be enabled to work safely
- what are the specific situations he goes into and their risks
- what skills, tools and information are necessary
A risk assessment consist basically of the following steps
- identification of possible risks
- evaluation of the risk in terms of severity and frequency of occurrence
- introduction of measures to reduce risk, when severity and occurrence are significant
- loop back to evaluation until risk is low
The risks have to be determined and evaluated for the specific work to be done. For details on risk evaluations please consult specific literature or attend seminars on this topic.
Examples of important risks during maintenance and repair on refrigeration systems with A2L refrigerants in a simplified presentation
Risk | Evaluation | Measure | New | Remark |
|---|---|---|---|---|
Work on system with flammable, pressurized and liquified gas | high | Worker has to be skilled and educated in handling the gas, also flammable | low | |
Unidentified risks from refrigeration system or other parts in the surrounding | high | Ask for system and system use risk assessment. If not available, make own assessment. If not possible, stop the work | low | Worker has to get introduced to existing risk evaluation of system and surrounding. Residual risks should be in system operating instructions and work procedure descriptions |
Ignition of refrigerant inside system | middle | Avoid having A2L refrigerant and air mixed in the system or its parts | Evacuation of air and flushing with nitrogen | |
Ignition of refrigerant coming out during connection of hoses | low | Careful work when connecting hoses | ||
Ignition of refrigerant coming out of system during work on open system | middle | Close valves to this part. Check for leak of the valves. Flush part with nitrogen | Use also mobile gas detector | |
Ignition of refrigerant coming out of larger leak | high | Identify leak location. Shut off electric power in this area. Shut off this part with valves. Ventilate until concentration is uncritical | Use also mobile gas detector | |
Ignition of refrigerant coming out of sudden larger leak | middle | Work with tools, that are not able to ignite A2L refrigerant | Have a fire extinguisher as backup | |
Ignition of refrigerant in areas, where refrigerant is released or ventilated to | high | Set up warning signs in these areas. Do not release to areas with ignition sources | low | |
Ignition of refrigerant when opening connections with a torch | high | Worker has to be skilled and educated. Pipes containing refrigerant, maybe in oil residues, shall only be opened with a tool without flame | low |