In situations where raw materials or tools have to enter a high-care environment, a disinfection step is desired and sometimes required.
This for example be done with a liquid disinfectant, manually or automatically. Another option is disinfection with UVC light via a UVC tunnel (including a transport system) or a transit sluice with UVC light (also pass through box, pass box or hygiene sluice for materials).
Read how a pass-through box with UVC light works what common options and configurations are.
The basics of a pass-through box
A pass through box is an enclosed space with doors or hatches on each side, often only one can be open at a time (interlock). A pass-through box equipped with UVC light ensures that micro-organisms on the outside of the item in the box are deactivated before it is removed on the high-care side.
Operators manually place items such as raw materials or tools in the lock, after disinfection the items can be removed from the cleanroom side. Depending on the desired security level, software can ensure that the door on the clean side can only be opened after a disinfection cycle has been successfully completed.
Advantages of UVC light in a pass box:
- Dry disinfection without residue
- Easy process for operators
- Regular validation possible
Cleanability of the system, robustness and the ability to easily perform preventive maintenance influence the design of the system. For maximum cleanability, it is possible to opt for quartz glass, which ensures an almost completely smooth interior and no hidden spaces. This is the most hygienic option.
A version in quartz glass does mean that robustness is compromised. Glass can break with point load or careless use. For tools or use of the pass box by external parties, we do not recommend the use of quartz glass, or only in combination with (removable) grids for protection.
The desired functionality and user scenarios are key when designing a pass through box. For example:
- It is possible to work with simple start / stop buttons or a touch-screen with different scenarios.
- If the cleanroom is not visible from the unclassified side by operators, acoustic or visual signals can be used to ensure that the status of the pass box is clear. Optionally, an HMI (display) can also be provided on both sides.
- Interlock functionality is often present so that only one door or hatch of the pass through box can be open. This guarantees the safety of the cleanroom and the overpressure situation.
- Regular validation and preventive maintenance can be programmed in the control. If lamps are individually monitored for operation, the system can release if it is determined that all UVC lamps have functioned.
- If desired, a pass box can also be used to return materials from the cleanroom, with or without disinfection.
The degree of disinfection of a pass through box depends on the intensity of the light (power) and the treatment time. An average pass through box has a cycle of about 2 minutes. Validation can be done during FAT (Factory Acceptance Test) using biological indicators in a worst-case scenario.
During SAT (Site Acceptance Test) and once installed in the factory we recommend validating with UVC measurements with a calibrated hand-held measuring instrument. The lifetime of UVC lamps is limited and the intensity decreases during the lifetime.
We design and produce custom pass boxes for the food industry, laboratories and pharmaceutical industry.
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