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What happened?
During pigging operations on a temporary water transfer line, a pig became stuck due to an ice blockage and pressure was trapped upstream of the pig.
When it was freed, the pig and trapped pressure behind it travelled down the line causing a loose clamp to unfasten.
The pressure release caused the disconnected hose to swing and strike a worker on the leg, causing serious injury.
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Why did it happen?
- Proper heating operations were not in place. This resulted in ice/slush build-up in the line, which caused the pig to become stuck.
- A loose connection downstream of the stuck pig failed when the pig was freed, and pressure travelled downstream.
- Connection points in the water transfer line were not additionally secured with restraint devices (whip checks) to prevent movement in the event of a connection failure.
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What did they learn?
- Use heaters for all water transfer operations when there is potential for freezing conditions.
- Install restraint devices on all water transfer line connection points.
- Ensure pigging procedures adequately address and control line of fire hazards and are reviewed and understood by the entire crew.
- Ensure a supervisor is present and observing safety-critical tasks.
- A letter publicly acknowledging the incident and the actions taken is enclosed.
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Ask yourself or your crew
- How can something like this happen here (e.g. on our site)?
- What safety measures (i.e. procedures, controls/barriers) do we have in place to mitigate the risk?
- How do we know the risk controls/barriers are working?
- What improvements or changes should we make to the procedures, controls/barriers or the way we work?
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What happened?
During pigging operations on a temporary water transfer line, a pig became stuck due to an ice blockage and pressure was trapped upstream of the pig.
When it was freed, the pig and trapped pressure behind it travelled down the line causing a loose clamp to unfasten.
The pressure release caused the disconnected hose to swing and strike a worker on the leg, causing serious injury.
Why did it happen?
- Proper heating operations were not in place. This resulted in ice/slush build-up in the line, which caused the pig to become stuck.
- A loose connection downstream of the stuck pig failed when the pig was freed, and pressure travelled downstream.
- Connection points in the water transfer line were not additionally secured with restraint devices (whip checks) to prevent movement in the event of a connection failure.
What did they learn?
- Use heaters for all water transfer operations when there is potential for freezing conditions.
- Install restraint devices on all water transfer line connection points.
- Ensure pigging procedures adequately address and control line of fire hazards and are reviewed and understood by the entire crew.
- Ensure a supervisor is present and observing safety-critical tasks.
- A letter publicly acknowledging the incident and the actions taken is enclosed.
Ask yourself or your crew
- How can something like this happen here (e.g. on our site)?
- What safety measures (i.e. procedures, controls/barriers) do we have in place to mitigate the risk?
- How do we know the risk controls/barriers are working?
- What improvements or changes should we make to the procedures, controls/barriers or the way we work?
Published on 01/05/23
1208 Views
During pigging operations on a temporary water transfer line, a pig became stuck due to an ice blockage and pressure was trapped upstream of the pig. When it was freed, the pig and trapped pressure behind it travelled down the line causing a loose clamp to unfasten. The pressure release caused the disconnected hose to swing and strike a worker on the leg, causing serious injury.
