Improving process safety during surface disinfection

Regular floor disinfection is a necessary part of cleanroom operation but such manual processes are difficult to validate. Margarete Witt-Mäckel and Dietmar Pfennig describe how suitably designed equipment can help

System trolley CR 9 GMP

Even though production facility ceilings, walls and floors are not in direct contact with products, the cleaning and disinfecting of these surfaces is an important measure to maintain or restore the desired purity in the production areas and thus to preserve product security.

Because cleaning and disinfection of large cleanroom areas is usually a manual task, simple and systematic workflows are needed to achieve the desired validity of the processes. As a rule of thumb, the less possibility there is for operator error, the more reproducible and safe the process will be. The following article describes the implementation of a simple, valid cleanroom-specific mop disinfection process for GMP areas.

Equipment requirement: It is common knowledge that cleaning and disinfecting equipment can be a source of particles and micro-organisms. GMP regulations also require certain conditions for design, processing and material choice. All components of the system trolley are autoclavable and therefore suitable for use in the sterile area.

The cleanroom suitability and GMP compliance should be verified by an independent institute, such as the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA) in Stuttgart, Germany, which issues a ‘Tested Device’ certificate of inspection.

User safety: The ready-to-use preparation of mop covers is designed as a closed system, providing greater process reliability than open systems. This is reflected by, among other things, reliable prevention of incorrect operations such as mop reuse. In contrast to systems with a wringer or a wetting device, whose operation can be very variable, this system applies the precise amount of liquid needed for the valid wetting of the surfaces for effective disinfection and the removal of debris.

Components of the MopJump system

Saturation of the mop covers in the EasyMop GMP system box takes place without operator intervention. The mops are soaked uniformly through the use of defined conditions, storage and removal times. The even distribution of the liquid across the entire width of the mop cover is assisted by a specially formed sheet of alloyed stainless steel which is perforated and of the same width as a mop cover. The shape of the MopJump system conforms to that of the open mop holder so that the withdrawal of the mop is easy.

The necessary storage and retrieval times as well as quantities of liquid required were determined through work in a Bachelor thesis that was carried out at the University of Technology and Economics Albstadt-Sigmaringen; this has subsequently been awarded ‘Best work of the year’ by the Verein für Reinigungs-technik (Assoc. for Cleaning Technology) at the CMS in Berlin. These requirements were incorporated into the operation instructions to ensure a uniform saturation level. These parameters provide a reproducible and validatable wipe disinfection process.

The system box: The EasyMop GMP system box is at the heart of the disinfecting process. In addition to its special structure, the ability to autoclave the system box and the use of cleanroom-certified materials – used, for example, on the triple seal for the permanent closure of the box – are significant. GMP conformity is confirmed through the ‘Tested Device’ quality seal from the Fraunhofer Institute for Manufacturing Engineering and Automation (IPA).

The EasyMop GMP system box can also be used as a stand-alone solution, so in small cleanrooms, for example, no trolley is required. All necessary process steps can be carried out with the system box alone, reducing the space required for the cleaning equipment to a minimum.

The MopDrop system

Requirement for mop covers: Microfibre mop fabrics with a defined liquid adsorption behaviour are suitable for this system. Cleanroom mop covers must also be suitable for their intended purpose in the cleanroom and checked for GMP compliance. As the mop cover serves as a carrier for the active ingredients, both the disinfectants and mop fabrics used must be compatible. This means that in addition to the material compatibility, the interaction between fabric and chemistry must be considered. Only the actual release of the active agents onto the surface and adequate wetting will lead to the desired disinfection result.

Contactless operation: MopDrop is a semi-automatic opening mechanism for the mop holder. It enables the mop holder to be opened without being touched by the user. The mechanism is attached directly over the waste bag, so that the used mop cover falls into the waste bag directly without contact and further transport takes place in the waste bag, thus excluding contamination through the used mop cover.

Specially designed autoclavable wheels suitable for cleanroom use

Introduction into sterile areas: To meet the requirement of Annex 1 of the EU GMP Guide, all items that are required in the cleanliness class A/B, have to be sterile when loaded into a cleanroom. Therefore, not only do the system trolley and system box have to be sterile, but also the mop covers for the cleaning process. This demonstrates another advantage of the EasyMop system box which can be used to load the mop covers into the cleanroom. The special locking mechanism allows autoclaving of mop covers while they are inside the box.

The trolley is manufactured to EHEDG recommendations

Secure working with the trolley: Work with the system trolley can be carried out ergonomically with a clear workflow. In front of the trolley is a series of system boxes filled with a calculated number of mop covers. The front system box is opened and the box top hung on the side. The mop frame opens automatically without contact via the MopDrop before extracting the first mop cover. After the cleaning process is completed, the mop frame is opened above the sterile waste bag by the MopDrop and the used and wet mop cover falls, by gravity, into the waste bag without being touched by the user. The already opened mop frame is ready to take the next mop cover.

In conclusion, manual processes are difficult to validate but with logically structured and easy to learn working processes, errors such as insufficient moistening of surfaces or redipping the wipe covers, can be confidently avoided. Equipment that is ergonomically designed and easy to operate increases motivation and thus the willingness of employees to carry out the work thoroughly and safely.

Equipment that has been well-thought through can thus minimise sources of human error and achieve effective cleaning and disinfecting of large surface areas in compliance with regulatory guidelines.

The authors

Margarete Witt-Mäckel, Dipl. Ing. (FH) Hygiene Technology, Witt-Hygiene Management, Consulting & Training, Stuttgart.

Dietmar Pfennig, Dipl. Kfm., Building Sanitation Master, MD, Pfennig Reinigungstechnik GmbH

EasyMop©GMP, MopDrop© and MopJump© are registered trademarks of Pfennig Reinigungstechnik GmbH