Safety, compliance and convenience
First of all, the number one priority of any industrial facility must always be the safety of its staff and of the public. Also, the designers of plant compliance safety systems and operating procedures must consider the needs of the personnel. All the while, those staff will be working hard to meet challenging targets for yield, quality and productivity.
Most of all, if a safety system places an extra burden on operators, there is consequently a greater risk that important steps will be missed. Worse yet, staff may try to work around the system. Therefore, safety procedures need to fit 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. That dust was accumulating on surrounding equipment, which was especially relevant for safety concerns. Due to this, there was a higher risk of secondary explosions.
As a result, the client asked us to reduce the chance of dust from the vents after an off-loading operation. Hence, our solution had to be fully-automated and integrated into the existing procedures to minimise the risk of the hazard. Also, we had to ensure that it did not create an additional burden for operators.
First, 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 also a provision for a PROFIBUS connection to the site Management Information System.
Finally, 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, followed by formal commissioning and handover. We also gave all the documents to ensure full compliance with all relevant standards. As a result, the company now has a simpler and more controlled off-loading process that also provides improved safety and compliance.