Test procedures for cleanroom products

Festo products for cleanrooms

FAQ and practical tips

In the past, very few industries used cleanrooms for their production. Today, however, cleanroom production has extended beyond electronics and photovoltaic manufacturing, medical technology and the semiconductor industry. Numerous other industrial sectors also need components that are suitable for use in cleanrooms. The most important information on this topic can be found here.

What products does Festo offer for use in cleanrooms?

You can use all cylinders, valves, grippers and drives, all handling, vacuum and compressed air systems, sensors, filters, regulators and fittings from more than 80 product ranges in ISO class 7 cleanroom environments. Most are suitable for use in classes 6 and 5, while many can even be used in class 4 environments. We can also provide customised special solutions.

All our cleanroom products are classified into cleanroom classes in accordance with ISO 14664. Since particle emissions depend on the specific application; it is best to discuss your exact requirements with our specialists. That is the fastest way to find a workable solution.

We have compiled all our cleanroom products in a single catalogue. Here is an overview of Festo’s cleanroom product ranges:

Overview of products for the cleanroom (PDF)

Useful information about cleanrooms

Does Festo only have standard cleanroom products?


Not at all. There are always applications where standard solutions are no longer sufficient. For example, when the cleanliness requirements are so strict that only a special solution can be used. We can help here, too. A simple modification is often all it takes. It is best if you contact our experts directly in cases like this.

Customised special solutions

We have more than 20 years of cleanroom experience, and our engineers continuously adapt series components to make them suitable for use in class 4 or stricter environments in accordance with ISO 14664.

We use a tried-and-tested two-stage consultation concept in which we listen to you and address the problem together. It is often possible to isolate highly sensitive zones so that outside of them only one ISO class 5 or 6 component is required. In all other cases, we pass everything on to our engineers who will then propose a solution along with a quote.

How does Festo qualify cleanroom products?

With the direct measuring method in accordance with VDI 2083-9.1, a test probe is first used to find out where the test object’s critical areas are located. In the case of pneumatic cylinders, for example, this is the area in direct proximity to the piston rod seal, because particles are released into the environment there as the result of reciprocating motion. Average particle concentration is then measured for a period of 100 minutes. The cylinder is operated at 80% of its maximum permissible load during this procedure. All of this takes place in a controlled, miniature test environment in accordance with ISO 14644-1 class 3.

At its location in Singapore, Festo cooperates with Nanyang Technological University where it has set up its own Competence Center for Cleanroom Technology which has been tested by the Fraunhofer Institute for Manufacturing Engineering and Automation IPA. Festo products are measured there and qualified in accordance with VDI 2083-9.1.

Cleanroom: tests for cleanroom products

Our products are tested and qualified by certified institutes in accordance with ISO 14644. You can read about how the measurements are carried out in the test reports. Here you can find out, for instance, what the operating conditions during the test were and which test equipment was used.

How is the test carried out?

We clean the products with isopropanol and pure air, carry out visual checks and then have them tested. Our test samples come directly from Festo stock, so we don't preselect them as is the case with other suppliers.

How are cleanroom products classified?



You can rest assured that cleanroom solutions from Festo are tested and classified in accordance with ISO 14644-1. ISO 14644 divides cleanrooms into nine classes according to the number and size of airborne particles.

Please note: our classification only provides an indication of how you can use our products in cleanrooms. If there is any doubt, we recommend performing the tests under real conditions.

How do I find suitable cleanroom products?


To ensure that you quickly arrive at a functioning cleanroom application, we have compiled all tested components from more than 80 of Festo’s product lines in our cleanroom catalogue. These include all types of pneumatic drives, valves and valve terminals, compressed air preparation and accessories, as well as electric drive technology. This is usually sufficient.

Cleanroom catalogue plus X

If you're interested in a product that we have not yet tested for cleanroom suitability, we will be happy to test it for you upon request. Our specialists are always happy to answer any other questions you might have and can also quite easily adapt particular products to be suitable for ISO class 4.

What should be taken into account when using cleanroom products?


The most important criterion is that the products comply with the specified cleanroom class during operation. That is what really counts. All cleanroom products from Festo are certified in accordance with the VDI standard and classified in accordance with ISO 14644-14. However, the cleanroom class depends on where in the application the product is used. This might sound complicated, but is actually good news.

Cleanroom class according to location of use

The fact that the cleanroom compatibility of a piece of equipment always depends on where it's used means that you don't have to ensure stricter cleanliness everywhere. Cleanrooms are not homogenous zones. Maybe you need ISO-14644-14 class 5 directly above the workpiece, while class 7 is enough for the rest of the workflow. In other words, the standard products from Festo fulfil the requirements in most cases.
The same positive answer also applies to cleanroom compatibility for packaging. Professional cleanroom packaging is possible with Festo, but it’s seldom really necessary and represents a cost factor that you can often do away with. Our experience shows that most components can be assembled and prepared for shipping in a normal environment. Final cleaning then takes place directly on-site.
Don’t hesitate to get in touch with us if you have any doubts. For example, if the component needs to fulfil a safety function or if your ambient conditions differ from the values listed in the data sheet.

Tips for cleanroom design

End-position switches

When wiring the end-position switches of double-acting cylinders, you need to make sure that the cables can’t be moved and that they don’t rub against each other or any other equipment.

Double-acting cylinders with cables for proximity sensors

When wiring the end-position switches of double-acting cylinders, you need to make sure that you cannot move the cables and that they don't rub against each other or any other equipment.

Cylinder cushioning

Avoid impacts with high force in the end position – cylinder cushioning is available for this purpose. Adjustable and self-adjusting PPV and PPS variants significantly reduce particle emission.

PPV and PPS cushioning in the compact cylinder

You should avoid high-force impacts in the end position; that's what cylinder cushioning is for. Adjustable and self-adjusting cushioning variants PPV and PPS significantly reduce particle emissions.

Single-acting cylinders

It’s better not to use any single-acting cylinders because particles are discharged into the atmosphere via the exhaust. The piston rod seal is also considerably thicker in double-acting cylinders.


Double-acting cylinders compared with single-acting cylinders

It's better not to use single-acting cylinders because particles are discharged into the atmosphere via the exhaust. The piston rod seal is also considerably thicker in double-acting cylinders.

Bellows actuators

When correctly assembled, cylinder fittings are leak-free [1]. In contrast, however, the piston rod seal is a source of particle contamination due to its design – a bellows or vacuum exhaust can be helpful in this respect [2].

 Electromechanical bellows actuator

The cylinder fittings are leak-free when correctly assembled [1]. The piston rod seal, on the other hand, is a source of particle contamination due to its design. A protective bellows or vacuum exhaust can therefore be helpful [2].

Mechanical abrasion

You should avoid the use of rod eyes [1], rod clevises, flexible couplings and swivel flanges [2] due to the abraded particles they cause. Make sure that tubing doesn’t move or rub against anything.


Double-acting cylinders

You should avoid using rod eyes [1], rod clevises, flexible couplings and swivel flanges [2] because they generate abraded particles. Make sure that tubing doesn't move or rub against anything.

Vacuum applications

In the case of vacuum applications it’s advisable to make use of our rotary actuators. This is due to the fact that rotary motion is easier to seal than linear motion, and is thus more suitable.

Rotary drive

For vacuum applications, it is best to select from our range of rotary drives. This is because rotary motion is easier to seal than linear motion and is therefore more suitable.

Compressed air preparation

Fine particulates and contamination should be filtered out in several stages during compressed air treatment. We recommend the use of a filter cascade with 40 [1], 5 [2] and 1 µm [3] stages in cleanrooms.

Compressed air preparation with filters

Fine particulates and contamination should be filtered out in several stages during compressed air preparation. We recommend using a filter cascade with 40 [1], 5 [2] and 1 µm [3] stages in cleanrooms.

Exhaust air

Pneumatic valve pilot air is rarely of significance [1]. In contrast, exhaust air must always be ducted and may not be discharged into the cleanroom via pneumatic mufflers [3]. Fittings are leak-free when correctly mounted [2].

Valve terminal

The pilot air for valves is hardly ever of any importance [1]. Exhaust air, on the other hand, must always be ducted should not be discharged into the cleanroom via silencers [3]. When correctly mounted, fittings are leak-free [2].

Spindle axes

Spindle axes are better suited for cleanrooms than toothed belt axes: they result in less abrasion and discharge fewer particles. Furthermore, the spindles are greased and bind abraded particles as a result.

Spindle axis for cleanrooms

Spindle axes are better suited for cleanrooms than toothed belt axes, as they cause less abrasion and discharge fewer particles. Furthermore, the spindles are greased and thus the abraded particles stick to them.

Cable chains

Standard energy chains are critical in cleanrooms. Although special cleanroom energy chains are available, it’s better to position the industrial robots underneath the workpiece already during the design engineering phase if at all possible.

Cable chains for cleanrooms

Standard cable chains are critical in cleanrooms. Although special energy chains for cleanrooms are available, it’s generally better to ensure during the design phase that the handling unit is placed, where possible, underneath the workpiece.

And last but not least,at Festo, cleanroom suitability always means that we assume that closed and monitored compressed air systems are being used, without leakages and without particles being discharged into the environment by the exhaust air.

It's important to note that our components are not suitable for conveying (with tubing and fittings) or switching (using valves) purified air! Our fine and micro filters are the only exception, since they generate highly purified air depending on the grade of filtration.

Is there anyone else who should know about this?

Cleanroom engineering is really quite an art. You should make sure that everyone involved has all the necessary information right from the planning phase. The quickest way is to use this link.