Cause & Consequence
- Moving, flying or falling object
- Failure of vessels or pipework
Description of Process
Throughout the industry we ask personnel to report unsafe conditions and potential dropped objects (PDO) are a common theme.
A safety observation noted a section of cladding and supports that looked like a PDO. Because it was an exhaust stack, the assumption was that the pipework would be a sweeping bend.
Other higher priority integrity threats meant a full investigation was delayed.
Description of Incident
A number of months after the PDO was reported, a member of the crew noticed a lot of insulation and cladding debris on a walkway. Upon further inspection a flange was found on an adjacent access platform grating.
The flange weighed 73.2 kilograms and had dropped 20 metres, the potential consequence based on the DROPS calculator could have been a fatality.
Through the subsequent investigation, the damaged cladding had led to water ingress over time and resulted in severe corrosion under insulation (CUI) to the flange bolts. It was found that all four exhausts on this particular stack were originally designed and built using “T” pieced flanges. Had the arrangement drawings been checked, this PDO threat would have been fully understood and addressed sooner.
Good Practice Guidance
When a PDO is identified think of the “What If?” question. What if that falls, could it hit people or plant and what is the worst outcome?
The company pre-task DROPS checklist has been updated to include this question.