Avoidance of error by control interface redesign

Task

As part of the output from a chemical process plant, condensate, water or a water/methanol mixture is loaded into trucks from different storage tanks, and then delivered to its destination.

The existing control interface was not user-friendly (as shown in Figure 5) and truck-drivers occasionally made the wrong selection on the control panel and loaded the wrong liquids into the truck. As a result, drivers were hauling unknown liquids to the wrong destination, a situation which arose on average three times per year. To prevent these errors, the truck-driver was supervised by an operator.

Finding solutions

The solution was to adapt the design of the control panel so that it was compatible with the task in hand, and so that the thought process involved was simplified. The new design consists of a sequential panel which takes the user through the procedure step by step, eliminating the chance of error. The newly designed panel is shown in Figure 6. The new design was piloted in an existing plant. The drivers found the new design much easier to use than the old panel. The company intends to implement it in all future facilities.

Results

The risks of the driver carrying and delivering unknown liquids and the need for operator intervention have both been eliminated, reducing costs and inconvenience to staff.