Scope of Application
Products and processes in cleanroom environments must be protected against contamination. ISO 14644 establishes numerous requirements for cleanrooms and provides guidelines for their classification. Appropriate protective clothing is essential to protect both the cleanroom environment and personnel working within it.
There are no specific official requirements, standards, or regulations for this type of protective clothing. However, numerous independent testing methods are available to assess its suitability for use in cleanroom environments.
Requirements for Cleanroom Protective Clothing
It is essential to protect both the cleanroom environment and the products being manufactured from contamination. Depending on the working environment and production process, personnel may also need protection against potential hazards. Suitable protective clothing must therefore serve a dual purpose: protecting both the cleanroom environment and the wearer.
We developed our DACH cleanroom hood in close collaboration with clinical partners to meet the demanding requirements of this specialized environment. Thanks to its precisely tailored design, this unique cleanroom hood protects both the cleanroom environment and the wearer. It maintains this level of protection even under demanding conditions, without compromising the wearer's freedom of movement or comfort.
The requirements for protecting the wearer are outlined in the regulations governing personal protective equipment (PPE). However, there are no officially established testing procedures for clothing designed to protect cleanroom environments. Instead, various testing methods are available, although they are not formally referenced in official regulations. One such method is the Helmke Drum Test.
The Helmke Drum Test Method
The Helmke Drum Test, conducted in accordance with IEST-RP-CC003.3, measures particle emissions from protective clothing under intense mechanical stress in dry conditions. This helps ensure that the protective clothing maintains low particle emissions even under demanding conditions, such as the wearer's continuous movement.
The garment is placed inside a rotating drum, where it is subjected to continuous mechanical stress. Particle emissions are measured every minute over a period of 10 minutes, with separate measurements for particles larger than 3 µm and 5 µm. The following table shows the classification recommended by the Institute of Environmental Sciences and Technology (IEST), based on the particle emission values obtained from the Helmke Drum Test.
Table 1: Classification According to IEST-RP-CC003.3 for Hoods and Head Covers
≤ 3 µm | ≤ 5 µm | |
Category I | <780 | <450 |
Category II | 780–7800 | 450–4500 |
Category III | 7800–78000 | 4500–45000 |
Interpretation of the Helmke Drum Test Results
There are no official guidelines specifying how the results of the Helmke Drum Test should be interpreted in terms of suitability for ISO-classified cleanrooms. According to laboratory assessments, products classified as Category I in the Helmke Drum Test may be suitable for ISO cleanroom classes 1–3, while products in Categories II–III may be suitable for ISO cleanroom classes 4–9. The DACH Schutzbekleidung cleanroom hood underwent this test and achieved a Category II classification. It is therefore suitable for use in ISO-classified cleanrooms and demonstrates very low particle emissions.