Hazards
Unplugging might require opening of installations that can unexpectedly result in a release of hazardous substances.
When Important
When process equipment is blocked, e.g. by fouling, polymer, corrosion, objects after maintenance etc.
Challenges in the Field
- Unexpected severe flow restrictions.
- No unplugging procedure or good options.
- Not wanting to stop production.
Options to Get it Right
- Consider to stop production before unplugging.
- Do not start unplugging without an approved plan that includes a hazard analysis.
- Understand the source and reason of plugging.
- Understand the hazards while unplugged and have a mitigation plan for unexpected releases.
- Understand that instrumentation might give misreading or that safety valves do not operate properly.
- Understand that opened equipment can still have pressurized hazardous material inside behind the plug.
- Apply isolation and First Line Break principles in the unplugging procedure.
- Do not use hazardous gas to blow out pipelines / equipment.
This page only summarises the guidance – refer to the EPSC website for further information.
For more information on our Process Safety Fundamentals (or other) playing cards please contact us.