Choosing cleanroom paper - what really matters?

What makes paper cleanroom-compatible?

Ordinary wood-pulp paper constantly sheds fibres and particles when you write on it or turn a page, which rules it out of any cleanroom. Cleanroom paper therefore uses a low-particle base coated on both sides with LDPE (low density polyethylene) or is built entirely from synthetic material. This traps the cellulose fibres so the surface releases only minimal particles.

The coating also makes the paper tear- and wipe-resistant and resistant to the wipe and spray disinfectants common in cleanrooms, such as isopropanol. It can be written on with conductive or purpose-made cleanroom writing tools without bleeding through or generating dust.

• LDPE-coated wood-pulp paper: economical, easy to write on, sufficient for many ISO classes.
• Fully synthetic paper (e.g. polyethylene): highest particle cleanliness, for strict classes and autoclavable use.
• Always fold or roll it crease-free so no fibres are released at broken edges.

Which paper suits which ISO class?

Cleanroom air cleanliness is classified under ISO 14644‑1 from ISO 1 (cleanest) to ISO 9, based on the permitted number of particles per cubic metre at defined sizes from 0.1 µm upward. The lower the class, the stricter the requirement on any consumable brought in.

For strict classes (ISO 3 to 5), use fully synthetic, double-bagged paper that is unpacked with low particle release inside the cleanroom. In classes ISO 6 to 8, LDPE-coated paper on both sides with a documented particle test is usually enough. What matters is that the material is tested and declared for the target class.

Folded or roll - which is better?

Cleanroom paper comes as pre-folded single sheets in a dispenser and as a continuous roll. The choice depends on consumption, the zone and how you want to dispense it.

• Folded paper: single-sheet dispensing, no contamination of the remaining sheets, ideal for documentation and frequent handling.
• Roll stock: economical at high consumption, flexible length, good for shelf liners and surfaces.
• Dispensers in stainless steel or conductive plastic keep the paper dust-protected and controlled.
• Sheet formats such as A4 and A5 make orderly filing of batch and inspection records easy.

For pure documentation, folded A4 or A5 paper is usually the best choice because each sheet is drawn individually with minimal contact. Rolls come into their own where large areas are covered or long sections are needed. In both cases the paper should be conductive or ESD-safe when electronic assemblies are handled in the cleanroom.

Frequently asked questions