Glossary

Cleanroom

An environment with limited airborne particle concentration, classified to ISO 14644. For lifting equipment it means low-particle materials, enclosed guides, extracted drives and no open lubrication points. Because every movement generates particles, the design aims at as few friction points as possible – a requirement that belongs in the design early.

Also: Cleanroom class · ISO 14644 · Reinraum

Also known as

Cleanroom class
ISO 14644
Reinraum

What makes a cleanroom

A cleanroom is a room in which the concentration of airborne particles is controlled and limited. This is achieved by filtered supply air, a defined airflow, positive pressure relative to the surroundings and rules for personnel, material and equipment.

ISO 14644-1 classifies cleanrooms from ISO 1 to ISO 9. The smaller the number, the cleaner the air; from class to class the permitted particle concentration changes by a factor of ten. The class is always stated together with the occupancy state: as built, at rest or in operation.

ISO classes and GMP grades

Pharmaceutical production is additionally subject to cleanliness grades A to D of the EU GMP Guide, Annex 1. They limit microbial contamination as well as particles. In terms of particles, grade A corresponds roughly to ISO 5; grade B to ISO 5 at rest and ISO 7 in operation; grade C to ISO 7 at rest and ISO 8 in operation; grade D to ISO 8 at rest.

The older designation under the withdrawn US standard FED-STD-209E – class 100, 10,000, 100,000 – is still common in everyday usage.

Every movement generates particles

In a cleanroom a hoist is above all a particle source. Particles arise wherever surfaces move against each other: chain in the chain wheel, rope on the drum, trolley wheels on the rail, bearings, brakes, cable carriers. Added to this are lubricants that outgas or are thrown off, and the exhaust air of pneumatic drives.

Whether equipment is suitable for a given class is demonstrated by measuring its particle emission; ISO 14644-14 describes the procedure.

Design answers

Cleanroom-compatible handling equipment follows a few principles.

Avoid or enclose friction points; extract air from drives and guides.
Belts or sheathed load-bearing elements instead of lubricated chains.
Low-abrasion material pairings, stainless steel or anodised aluminium, smooth wipeable surfaces.
Cleanroom-grade lubricants, used sparingly and enclosed.
Duct the exhaust air of pneumatic drives out of the cleanroom.
No horizontal surfaces or cavities where particles collect.

Do not disturb the airflow

In cleanrooms with unidirectional airflow, air flows from the ceiling downwards and carries particles out of the work zone. Anything hanging above the product stands in that flow: it casts a flow shadow, and particles generated there fall straight onto the product.

Ceiling-mounted systems are therefore placed beside the critical zone where possible and built to disturb the flow as little as possible. This requirement belongs in layout planning, not in retrofitting.

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Overview

Cleanroom classes under ISO 14644-1

ISO class	Maximum particles ≥ 0.5 µm per m³	Former designation (FED-STD-209E)
ISO 5	3,520	Class 100
ISO 6	35,200	Class 1,000
ISO 7	352,000	Class 10,000
ISO 8	3,520,000	Class 100,000

Frequently asked questions

Frequently asked questions about Cleanroom

What does ISO 7 mean for a cleanroom?

That each cubic metre of air contains no more than 352,000 particles of 0.5 µm and larger. The occupancy state is part of the statement, because the values are harder to maintain in operation, with personnel and running machines, than at rest.

Can a standard hoist be used in a cleanroom?

In the less stringent classes possibly, if it works away from the product. In stricter classes and above open product it needs a version with enclosed drives, low-abrasion load-bearing elements and evidence of its particle emission.

Is a pneumatic device suitable for a cleanroom?

In principle yes, if the exhaust air does not escape into the room but is ducted away, and if the compressed air itself is filtered and oil-free. Open vents and silencers in the room are particle sources.

Who defines the cleanroom class required?

The operator, derived from product and process and – in pharmaceutical production – from the GMP requirements. The supplier of equipment demonstrates the class for which it is suitable.

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