Reusable vs single-use cleanroom garments in traditional Grade B cleanrooms

Specially designed cleanroom garments have been used since the introduction of cleanrooms in the 1950's. Cleanroom garments are important to minimise the impact of particles and viable microorganisms generated by operators during work.

Recently, the safety aspects of reusable and washable garments, which are currently the most used garments, have been questioned. This situation is mainly due to what is outlined in the revised Annex 1, Volume 4, EudraLex, together with the overall increased interest in cleanroom garments, especially for traditional aseptic pharmaceutical manufacturing in Grade B cleanrooms.

The purpose of this article, which is a direct continuation of previous articles published in July’s Cleanroom Technology, is to summarise the current situation with regard to cleanroom garments, in relation to future demands and recent scientific findings.

Humans in cleanrooms

Cleanroom garments are important in the production and handling of sensitive products in controlled environments, i.e. a cleanroom. It has long been recognised that humans are the most critical source of contaminants. Due to natural reasons, we generate a significant number of particles per unit time, which carry viable microorganisms. The more physically active the operator, the more particles are generated and dispersed into the surrounding cleanroom air.

Two natural ways to minimise the number of particles generated are to:

• Minimise the total number of personnel in a cleanroom
• Minimise the movement pattern of the personnel present

Cleanroom garments

One other action to be added to this list, is to equip cleanroom operators with garments that:

• Are clean enough for the environment in which they are to be used
• Are made of materials that by themselves generates a minimum of particles
• Will act as a filter or a barrier for particles generated by the operators during work

In lower classified cleanrooms, i.e. Grade D, the operators are normally using garments that are less covering. In cleanrooms with higher cleanliness demands, i.e. Grade B, operators are more covered up, exposing no naked skin to the outer environment.

Operator comfort

As stated earlier, one of the most important features of a cleanroom garment is its ability to act as a filter or barrier, filtering out particles generated by the operators. The best filter in this respect is a material that will not allow any particles to pass, a situation equals something close to a plastic bag, i.e. nothing can pass.

However, there is another demand on cleanroom garments. It must be as comfortable as possible for the operator. Comfort, in this respect, can be divided into three parts:

• Temperature
• Tactility
• Movement

Thermal comfort means that the cleanroom garments should not be too cold nor too warm. This is a delicate equation to solve, since cleanroom garment should be permeable enough to be comfortable for the operator but still be able to filter out skin particles generated.

Gowning variations versus cleanroom cleanliness

The pharmaceutical industry can, according to Annex 1, produce sterile medicinal products in two distinct ways:

• Terminal sterilisation
• Aseptic production

Terminal sterilisation can be described as a “clean” process compared to aseptic production, which is a “sterile” process.

Aseptic production is the most critical production process used within the pharmaceutical industry, and it is also the production process that puts the patient at highest risk. This is traditionally the reason why clean zones and cleanrooms with the highest cleanliness demands are used for aseptic production.

The difference between terminal sterilisation and aseptic production is illustrated by the difference in gowning. Operators working with terminal sterilisation are normally less covered up as compared to those working with aseptic production. Furthermore, the cleanroom garment used in aseptic production performed in Grade B cleanrooms must be sterile and only used once.

Garment filtration efficiency

The efficiency of a filter largely depends on the