Warning About Programmable Logic Controllers

The International Marine Contractors Association (IMCA) has recently issued a safety warning following a tragic accident suffered by a member company, which resulted in four fatalities and three serious injuries. The association wants to warn a wider audience of its concerns over programmable logic controllers (PLCs) in marine operations in the strongest possible terms.

“The accident was so serious that our Marine Division’s Management Committee wants to bring the lessons learned to a far wider audience,” explains IMCA’s Chief Executive Hugh Williams. “As an industry we put great trust in PLCs and in the sub-contractors who install them, after all these devices control almost every piece of equipment on a modern vessel. But, as each vessel is bespoke it is difficult for one contractor to learn directly from another’s experiences.

“We want to urge members and non-members alike that where operations are undertaken by semi or fully automated machinery systems controlled by PLCs, that the behaviour of such machinery during restarting or resetting of their control systems must be fully understood; and then that the consequences of restarting or resetting such control systems during specific operations are fully risk assessed. This should apply to any PLC-based machinery system where (high-) potential risk of injury or damage exists.”