Every 40 hours the Cream Plant carries out a Clean in Place (CIP) process. This requires operators to remove the face plates from the Butter Blender lobe pumps to place the rotors into the CIP basket/enclosures.
Fonterra policy requirements are such that the full permit to work and isolation protocol must be adhered to when accessing these.
To decrease production down time it was decided to install safety monitoring/isolation on each pump as per Fonterra Engineering Standard “FES 51”. This states that access to hazardous parts at a frequency of more than once per month will require a safety function.
The outcome of the Machine Risk Assessment allowed us to use a simple solution.
The use of trapped key isolation switches with the isolating key also required to open a lockable enclosure around the pump.
This limits wiring to just the areas immediately adjacent to the motors, and allowed cost savings due to not requiring electrical monitoring of the faceplate position, which seems to be the accepted “industry norm”.
Project Requirements as per Machine Risk Assessment (MRA)
- Performance Level “c” – (PL)c
- Category 1 architecture