Cleanroom Wipesare used in all cleanrooms as one of the main cleaning methods.

They are chiefly used to remove the invisible contamination of particles and fibres 50µm and smaller. Uses include the wiping of surfaces such as bench tops, the cleaning of small pieces of equipment such as bottles or trays, wipe down (or preparation) of items or their outer packaging before being taken into the cleanroom or isolator and glove wiping for cleanroom staff. Wipes may also be needed to absorb and pick up spillages which occur during the production process.

Wipes may be used dry but are much more efficient in removing contamination when dampened with cleaning or sanitising solutions.

In all instances wipes for cleanroom use must not introduce significant particulate or fibre contamination into the controlled areas.
In a few operations, notably surface finishing, re-usable wipes may be employed which can be re-processed by a cleanroom cleaning and decontamination plant, however the majority of cleanroom wipes are discarded after a single use.
Wipes are available in a very wide range of materials, presentations and price and so it is important to select the product which will satisfy cleaning requirements in the most efficient and cost effective manner.
The main factors to consider when comparingcleanroom wipesare;
• Physical properties
• Wiper materials
• Wiper edge finish
• Wiper size, fold and packaging
• Wiper cleanliness and sterility
• Dry or pre-wetted wipes
• Supporting documentation
• Cost

Physical properties
Wipes are made from materials which must have good surface contact so that particles can be pushed free from the surface being wiped. Wipes must not be abrasive or cause damage to the wiped surface. Wiper materials must be able to withstand the cleaning operation without tearing or suffering surface breakdown resulting in the loss of particles and fibres from the wipe.
The wiper materials must be compatible with any chemicals with which they come into contact and not be dissolved or otherwise broken down by cleaning agents or production chemicals. In many applications the wipe should not contain materials which can be released in solution during use such as ionic chemicals or endotoxins.

Where the wipe will come into contact with hot surfaces it should have sufficient heat resistance to withstand this without damage. If control of electro-static dissipation (ESD) is a requirement the wipes must have good ESD properties.
Cleanroom wipes should have good sorption. This indicates the volume of liquid the wipe will absorb in relation to its weight and the time taken to do this. Good sorption properties will allow a wipe to quickly take up a spillage and will also enable an impregnated wipe to cover a large area without drying out.

Wiper materials
Cleanroom wipes are usually manufactured from knitted or non-woven fabrics however woven fabrics and foam material wipes are also available.
Wipes specified for use in high grade cleanroom areas are usually produced from knitted filament yarns, usually polyester or nylon, and these include those made from microfibre yarns which give increased surface contact area.
Filament polyester is low shedding and can be effectively cleaned and decontaminated before use. It will withstand sterilisation by gamma irradiation or autoclaving without damage.
Knitted fabrics are very pliable and this allows the wipe to maintain a high contact area and to be easily folded for use. Knitted fabrics generally have high sorption properties which increase with fabric weight and this will further increase when the wipe is produced as a double layer (2-ply).

Non-woven materials are usually a combination of polyester and cellulose or polypropylene and are normally specified for use in lower grade cleanrooms, less critical wiping operations or spill control. The materials can be sterilised for aseptic area use and have good sorption.

As wipes are usually a disposable product it is preferable to use materials which can be re-cycled.

Wipe edge finish
Wiper fabric is produced in large rolls and must be cut down to produce individual wipes. The cut edges of the wipe can produce particles or fibres and to reduce this source of contamination the wiper edges can be sealed using various methods including sealing with heat or laser and heat rolled edges.

Wipe size, fold and packaging
Cleanroom wipes are available in an extensive range of sizes and presentations. They may be presented flat in a layer with each wipe being removed by the user. Cleanroom wipes may also be folded so that they are interleaved and removing a wipe pulls the start of the next wipe from the pack. Wipes can be sourced on rolls, in tubs, or in individual packs and most packaging will incorporate a re-sealing system, especially if the wipes are pre-wetted with a volatile chemical such as an alcohol or solvent. Several layers of packaging may also be utilised to facilitate transfer into a high grade area. Whatever packaging is employed clear and adequate labelling must be used which is not damaged by wiping with alcohol or other solvents and the packaging
material must not produce significant fibre or particulate contamination during opening. Whenever possible packaging and containers for wipes
should be made from materials which can be re-cycled.