The Task
A major pharmaceutical company engaged IES to design, build and commission a chiller skid to provide coolant to a reactor.
The Challenge
As with many other IES projects, the work needed to be carried out with the minimum of disruption to the manufacturing process.
The Chiller Had To Have
- Two fully redundant streams.
- Enough onboard storage to ensure that a batch could be brought to a safe state even with the loss of both streams.
- It would also be required to provide a controls interface local to the reactor in a hazardous area, ATEX is compliant during wash cycles.
Access to the skid’s final home was restricted, and its design needed to be adapted accordingly.
The Strategy
The skid was designed to be easily broken down into two sections both electrically and mechanically; it could be fully tested off-site in all respects and then quickly reassembled in a location without the need to repeat a lot of the Factory Acceptance Testing (FAT).
Mechanically the system was constructed to allow the assembled skid to sit over two interconnected bunds to protect against any potential leaks of glycol coolant.
Because of its location in a hazardous area, ATEX automation was an essential element of the design of the chiller system.
The Design and Implementation Teams
IES provided supervision of mechanical and electrical contractors on-site during the installation phase and provided consultancy and design input with regard to ATEX compliance.
Their project management expertise ensured that ATEX compliance was built into every step of the process and that ATEX instrumentation and controls were integrated into the installation.
The skid itself was assessed by IES Certified Machine Safety Experts against ISO 13849 (safety-related parts of control systems) and found to have a Performance Level requirement of PL-a. (With Performance Level PL-a the control function’s contribution to risk reduction is regarded as ‘low’.)
The Design and Implementation Teams
Hardware and software designers and engineers collaborated at all stages of the upgrade and the development to ensure that the new system could be implemented as seamlessly as possible. The client’s requirement for the alarm structures to be fit for purpose for the foreseeable future, as well as being sufficiently flexible to operate in a range of control rooms, called for the best in qualified and experienced teams to handle a demanding challenge.
The Outcome
On completion of testing and qualification, the system was found to control the temperature to +/- 1°C, with full redundancy, and to be capable of maintaining that reactor temperature for 48 hours in the event of its Primary Chiller failure, ensuring that a safe state could be achieved in the event of the loss of both streams.
IES also produced a full Containment of Hazardous Energy (COHE) Plan for the completed plant.
Did You Know?
ATEX derives its name from the French title of the 94/9/EC directive: Appareils destinés à être utilisés en ATmosphères EXplosives.
Glycol coolant could be manufactured by trained caterpillars. The caterpillar of the greater wax moth, Galleria mellonella, has gut bacteria with the ability to degrade polyethylene (PE) into ethylene glycol.
The word ‘bund’ derives from an ancient Persian name for a causeway or embankment.