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According to Cherwell, the routine maintenance decontamination is best performed using a range of disinfectant products backed up by reserve measures that can be deployed if any resistance to normal cleaning products is encountered. Remedial decontamination can be done manually with

sterilising wipes and other cleaning products or semi- automatically using fogging systems when the cleanroom is empty and sealed.

DISINFECTANT CHOICE Choosing the right disinfectant to use can be complex and depends on many factors. The decontamination guide gives a comprehensive overview of the different types of disinfectant and the applications for which they’re best suited. For routine decontamination, the guide splits the types of disinfectants into oxidising, non-oxidising and hand sanitisers. Each type works in a different way and uses a different mode of attack on the contamination that needs to be removed so the choice of which to use must be based on full knowledge of what is most effective. Generally, the guide indicates that oxidising disinfectants for use in pharma environments have a broader range of activities than non-oxidising variants. Hand sanitisers are usually alcohol based and rely on correct method of usage for them to be effective.

SELECTION FACTORS For setting up a maintenance procedure for pharmaceutical cleanrooms using surface disinfectants, there are a number of other factors to consider than whether it should be oxidising or non-oxidising. Choices of product can come down to cost, health considerations, surface types to be cleaned and whether they are ready-to-use or require mixing before application, which takes additional time. Cleanroom operators and cleaning staff should have access to the full range of cleaning products that are required with clear procedures showing which product to use and how it should be applied for specific use cases. Procedural ambiguity very easily leads to mistakes being made and subsequent bioburden outbreaks that could easily be avoided and which result in expensive remedial decontamination. The guide gives expanded detail on all the factors that need to be considered in selecting disinfectant products. Some of these include: Contact time: should typically be low to enable the disinfectant to work rapidly to allow the cleanroom to continue operations.

Operator exposure: should be minimised or eliminated when using oxidising sporicidal disinfectants.

Compatibility: with other cleaning products that may have been used to remove dirt before disinfecting. Residues: can have an adverse effect on cleanliness and operations

Surface material: compatibility is important to avoid discolouration, corrosion, abrasion or tarnishing.

THE GUIDE Providing cleanroom personnel with an overview of decontamination technology, the Cherwell Laboratories guide aims to help operators to understand the complex protocols and heavily regulated procedures associated with pharmaceutical cleanrooms. According to Andrew Ramage, Cherwell Laboratories’ Microbiology Product Specialist, it provides the user with clear

6 /// Cleanrooms & Contamination Control 2017 AIRBORNE DECONTAMINATION

Sometimes, surface disinfecting isn’t enough or would take too long if a large decontamination exercise was needed. In these cases and when the cleanroom is opened after a shut- down or a bioburden outbreak, airborne decontamination is required.

A number of systems

are available for doing this including fumigation, gaseous methods, spraying and dry fogging. Cherwell recommends the use of dry fogging technology for its speed and lack of condensation related wetting. Ideal for decontaminating small and medium sized

cleanrooms with complex layouts, dry fogging systems use cold sterilant chemicals that are delivered into the air space using fogging nozzles at high level in the cleanroom. The vapour disperses rapidly and reaches all areas in even complex cleanrooms, as well as the High Efficiency Particulate Air (HEPA) filters. An enormous advantage of the fogging system is that it avoids wetting any of the surfaces thus avoiding any compatibility issues. It is also fast as a remedial disinfectant technology. The fogging delivery mechanism cannot penetrate

layers of dirt so a pre-clean is sometimes necessary if dirt is present on any of the cleanroom surfaces.

and concise information to better understand why and how best to decontaminate a cleanroom. “It will be especially useful for inexperienced and trainee

operators trying to get to grips with working in that type of environment, and also act as a handy reminder to the basics for more experienced operators,” he said. EE

❱ ❱ Fogging head nozzles disperse

disinfectant high into the air space for decontamination




A copy of the guide

can be acquired at the Cherwell site here

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