Cleanroom wipes and cleanroom swabs: properties and selection tips

Depending on the areas in which cleanroom wipes are used, a different type is used. As cleanrooms should be as particle-poor as possible , high demands are placed on the cleanroom wipes, so that they do not themselves contribute to contamination of the cleanroom – for example, through fibers coming loose or breaking. In some cases, not even ions may be emitted from these wipes.

Cleanroom wipes can be differentiated according to the following properties, among others:

• dry or pre-soaked/moistened
• sterile or non-sterile
• Disposable wipes or reusable wipes
• Cleanroom class suitability (GMP A/B, C, D; ISO 3-9)
• Antistatic or non-antistatic

Cleanroom wipes can also be differentiated according to the material from which they are made. For example, cotton, cellulose, polyester, polyester-cellulose, polyester-microfiber, polypropylene or nylon. Among other things, the material determines how many particles a cleanroom wipe emits. Cotton, for example, emits more particles than polyester.

There are different cleanroom classes depending on how many particles are permitted in a cleanroom. The cleanroom class is therefore one of the decisive selection criteria when purchasing cleanroom wipes. Class GMP A/B cleanrooms have the highest level of protection. Such cleanrooms are required, for example, in the production of pharmaceuticals, where sterile cleanroom wipes are used.

The possibility of contamination is further reduced by using “hands-free” wipes that are not directly produced by humans. Cleanroom wipes often state that they have been pre-washed in cleanrooms.

The question of whether you should opt for a pre-soaked (pre-moistened) cleanroom wipe also depends on what you want to use this wipe for. If surfaces or specific areas are to be disinfected, a cleaning cloth pre-soaked with a disinfectant has the advantage that there is no need to spray disinfectant, thus preventing room contamination from spray mist.

Both pre-soaked and dry cleanroom wipes should be characterized by a certain chemical resistance , which can be increased, for example, by avoiding the use of chemical binders during production. Instead, certain cleanroom wipes can be hydroentangled, for example. This means that a fiber mixture is bonded into a nonwoven fabric by water jets under high pressure. However, woven and knitted fabrics release fewer particles than nonwovens.

In addition to the absorbency of a cleanroom wipe with regard to liquids, the even release of liquids in which the cleanroom wipe has been soaked, such as disinfectants or cleaning agents, is often also desired.

Although cotton absorbs water well and may be heat-resistant and tear-resistant, it sometimes releases more particles than other materials. If you are looking for a material that releases fewer particles but is still absorbent, you should use microfiber cleaning cloths, some of which are made from polyester or a blend of polyester and nylon (polyamide).

There are also other combinations, such as the combination of polyester and cellulose, which is particularly suitable for wet cleaning due to its high absorbency. However, polyester cellulose releases more particles than pure polyester.

As a rule, a cleanroom wipe also has greater absorbency if it is not a single-layer but a double-layer cleanroom wipe.

The dimensions of the cleanroom wipe also play a role. There are small cleanroom wipes measuring 10 cm x 10 cm. But there are also sizes measuring 23 cm x 23 cm, 31 cm x 31 cm or even larger cleanroom wipes. Another selection criterion for a cleanroom wipe is the grammage, which is given in g/m². This information gives an approximate idea of the thickness of a wipe.

Cleanroom wipes also differ according to their surface. For example, there are smooth cloths or those with a structure.

For some applications, it is important that the cleaning cloths have a certain softness so as not to damage the objects to be cleaned. Cleanroom wipes that are too hard, for example, can scratch sealed surfaces. Microorganisms can colonize these scratches, making them difficult to remove.

Cleanroom wipes are also differentiated according to whether they are abrasion-resistant. There are also soft cleanroom wipes that are nevertheless abrasion-resistant. There are also wipes that are particularly suitable for rough surfaces.

Cleanroom wipes often also state how they were cut: cold-cut, heat-cut, laser-cut or ultrasonically sealed.

With cold-cut cleanroom wipes, the cut edge remains open. This allows particles to escape from the wipe.

To prevent this, at least in part, there are cleanroom wipes where the edges are sealed by a laser cut or a heat cut. Another sealing technique at the edges of the wipe is ultrasonic sealing, which can achieve the greatest reduction in particle emission at the edges.

As cleaning wipes cannot reach every spot in the cleanroom, such as small gaps, holes or corners, there are cleanroom swabs, which are also called cleanroom swabs, cleanroom cleaning sticks or cleanroom swabs. There is a choice of different head shapes for cleanroom swabs. The length of the swabs also varies. The designs of the swabs differ according to the cleanroom class for which the cleanroom swab is suitable, whether it is sterile or non-sterile and to what extent it is ESD-compliant, i.e. how great the risk is that an electrostatic discharge will occur when the swab is used.

The swabs are also differentiated according to the level of particle and ion release. As with the cleaning cloths, different materials are used for the swab heads. For example, there are heads made of cotton, polyester and microfiber. The material of the handle or shaft also varies. It can be made of wood or plastic. As a special feature, there are cleaning swabs with an integrated ampoule of isopropanol, which is used to moisten the swab head and are available as sterile cleaning swabs.