The new Annex 1 adopts the Quality Risk Management method to guarantee prevention from the microbic, particulate and biological contamination. This model calls for the adoption of a Contamination Control Strategy, which takes into consideration from a systemic perspective all the critical components of the production cycle. In particular, Section 4.16 mentions the concepts of Design Control Strategy linked to the control of overpressures according to justified and validated strategies.
The theme of recovery times
In this regard, the possibility of managing and validating the “recovery times” of the airlocks and pass through boxes is particularly relevant. The setting and validation of recovery times very often takes place in the course of the Cleanrooms validation phases, setting the appropriate values on the control units or PLCs that control the airlocks or pass through boxes. Once the recovery times have been validated, they often remain set to the initial values even if the environmental conditions vary; a possible update of the recovery times, in fact, requires a in-field burdensome activity (possible in some cases only during downtime periods) and a new validation.
Dos&Donts has decades of experience in the design and production of control systems for airlocks; as a part of its articulate Pharma 4.0 development programme, it proposes a solution to make simple and immediately validable the update of recovery times, without intervention of specialised personnel and without need to stop the production cycles. The system consists of a Gateway and decremental counters with display, which can be positioned at the airlock or material pass through.
Use of gateway with Dos&Donts’ control units
Recovery times are set directly on the BMS, that transfer them through the Gateway to the Airlock control units.
Dos&Donts’ ILOCK Modular control units update the timer associated with the airlock and visualize the set time on the display. When the condition is met to start the recovery time, namely after opening and re-closing of the external door, the timer starts to decrement while showing the residual time on the display; after the set time has expired, the airlock is back again operational. At all times, the BMS can check the actual compliance to the set recovery time.
Use of the gateaway with different controllers
The Gateway and the count-down timers can also be advantageously used on existing plants and with any PLC model. The only requirement is that the PLC governing the airlock has a digital output to notify the opening and closing of a door, and a digital input to allow for the activation and deactivation of the recovery time. Recovery times are set on the BMS and transmitted to the count-down timers. When the PLC notifies its count-down timer to activate the recovery time, the timer starts and decrements. When the set time runs out, it notifies the PLC the time has expired, thus allowing to return to normal operating conditions.
The advantages of this solution are:
- Recovery times can be modified at all times by in-house staff without need of specialists, both during validation and periodic verification.
- The recovery times data are automatically validated at the BMS level, allowing for the easy conduct of the Audit Trail and a sharp reduction of the time required.
- Count-down timers allow operators to visualize the passing of time during waiting phases.
Dos&Donts’ solution for the management of recovery times for airlocks and pass thru
Each individual unit of a 4.0 architecture can be IP addressed, and it can exchange information with the other units in order to effectively operate complex functions.