ISO Clean rooms
Appropriate clothing and protection for ISO cleanrooms

In clean rooms in particular, products and processes, and in some cases people too, have to be protected. ISO 14644 specifies requirements for clean rooms, but not for protective clothing in clean rooms. There are already many test methods that evaluate the cleanroom suitability of clothing. The DACH Cleanroom Hood was tested according to the Helmke Drum Test, but what is the Helmke Drum Test? We explain briefly and succinctly what is important during the Helmke Drum Test and clean room safety.

The Helmke-Drum-Test

Products and processes in clean room areas must be protected from contamination. For this purpose, ISO 14644 prescribes numerous requirements for clean rooms and a guideline for classification. Appropriate protective clothing to protect the clean room and employees is essential for work in clean rooms.

There are no official requirements, standards or regulations for such protective clothing, but there are numerous independent test methods that test the protective clothing for its suitability for use in cleanrooms.

Requirements for protective clothing in cleanrooms
It is necessary to protect the clean room and the production goods from soiling and contamination. Depending on the environment and production process, it is necessary to protect the user from environmental hazards. Suitable protective clothing must have a double function: Protection of the clean room and the user.

We developed our DACH Cleanroom Hood in close cooperation with clinical partners in order to meet the high requirements of this special environment. This unique clean room hood protects the clean room and the wearer with its specially adapted cut. It maintains this protection under heavy loads without affecting the freedom of movement or the comfort of the wearer.

Requirements to be met for the protection of the user can be found in the regulations for personal protective equipment. There are no official procedures for clothing to protect the cleanroom, but there are many test methods that cannot be found through official references. One such procedure is the Helmke-Drum-Test.

The Helmke Drum Test procedure
The Helmke Drum Test, according to IEST-RP-CC003.3, checks the particle emissions from protective clothing under very strong mechanical stress in dry areas. This ensures that the protective clothing has low particle emissions under heavy stress, such as the continuous movement of the wearer.

The garment is placed in a rotating drum. Under this constant stress factor, the particle emissions are measured for 10 minutes every minute. A distinction is made between particles that are larger than 3 μm and 5 μm. The following table shows the classification into classes recommended by the Institute for Environmental Sciences and Technology (IEST) based on the emission values generated by the Helmke test.

Categorization according to IEST-RP-CC003.3 for hoods / bonnets

≤ 3 μm≤ 5 μm
Category I< 780< 450
Category II780-7800450-4500
Category III7800-780004500-45000

Interpretation of the Helmke Drum Test results
There are no instructions that prescribe how the results of the Helmke Drum Test are to be interpreted for applicability in ISO cleanrooms. According to the assessment of the laboratories, products of category I of the Helmke Drum Test can be used in ISO clean room classes 1-3 and those of categories II-III in ISO clean rooms of classes 4-9.

The DACH Schutzbekleidung clean room hood was subjected to this test and was able to achieve a classification according to Category II. It is therefore a product that is suitable for use in ISO clean rooms and has the lowest possible particle emissions.  

Dust on a construction site
Most deaths from occupational diseases are related to respiratory diseases.