Safety, compliance and convenience
To work well, safety systems need to consider the needs of operators.
The first priority of any industrial facility must always be the safety of its staff and of the general public. That’s obvious enough, but the designers of plant safety systems and operating procedures also need to consider the everyday needs of the personnel that will operate them. Those staff will be working hard to meet challenging, and sometimes conflicting, targets for yield, quality and productivity.
If a safety system places a significant additional burden on operators, there is a greater risk that important steps will be missed, or even that staff will attempt to override or work around the system. To stop that happening, safety procedures need to integrate as seamlessly as possible into the operator’s workflow.
During a Dangerous Substances and Explosive Atmospheres (DSEAR) Risk Assessment and Hazardous Area Classification exercise at a large food manufacturer, we identified the need for improvements in the control of road tanker off-loading operations.
The issue arose from dust ejected by the vent system at the end of the operation. That dust was accumulating on surrounding equipment, creating an elevated risk of secondary explosions.
The client asked us to find a way to minimise the chance of dust being ejected from the vent system following an off-loading operation. Our solution had to be fully automated and integrated into the existing procedures to minimise the risk of the hazard, while also ensuring that it did not create an additional burden for operators.
To meet those objectives, we designed and implemented a system incorporating tanker off-loading interlocks, silo overpressure protection, and Castell Key-based personnel access interlocking to the silos. The project also included the specification, procurement and management of new instrumentation and Remotely Operated Solenoid Operated Valve (ROSOV) installations for the silos, links to existing silo instrumentation, and provision for a PROFIBUS connection to the site Management Information System.
To maximise ease-of-use, our engineers designed a panel to with an integrated PLC configured to provide the interlocking functions and monitor the instrumentation, all controlled from a single touch-screen HMI in the off-load area.
We completed the full installation, which was followed by formal commissioning and handover to the client. We also prepared all the documentation required to ensure full compliance with all relevant standards. The company now has a simpler, more straightforward and more well-controlled off-loading process that also provides improved safety and compliance.