Helmke Drum Test: Assessment of suitability for use of garments/clothing in Cleanrooms
One of the main difficulties faced by Cleanroom users, Auality Assurance and Validation teams when making new purchases and investments, as well as in the change management process, is whether or not a particular material or piece of equipment can be accepted in the cleanroom without risk to production. “ISO 14644 – Part 14, Assessment of the cleanroom suitability of equipment based on airborne particle concentration“, provides a methodology for assessing the suitability of equipment (e.g. tools, construction materials, etc.) for use in a given Cleanroom cleanliness class classified in accordance with ISO 14644-1 standard. In the case of material samples (e.g. for garment/clothing production, packaging films, etc.), VDI 2083 Part 9.1 is usually chosen as the test method, while in the case of complete cleanroom garments (e.g. overalls, lab coats, hoods, overshoes, etc.), cleanroom suitability tests are usually carried out according to IEST-RP-CC003.4 (Helmke drum test).
About our laboratory
BNT SIGMA is an independent testing laboratory for cleanroom materials and products. In our ISO Class 2 Particle Emission Laboratory, located near Poznan, Poland, we are able to perform tests according to ISO 14644-14, VDI 2083 Part 9.1 and IEST-RP-CC003.4 (Helmke drum test) for materials, products and equipment intended for use in ISO 3 – ISO 9 Class environments. We can assist your company both in the assessment of a particular end product offered by your company, as well as in carrying out some comparative analysis e.g. during the new product development process or when searching for some alternative suppliers of materials and products for your company.
Some examples of items that can be tested in our laboratory include:
IEST-RP-CC003.4 – Helmke drum test:
Cleanroom garments/clothing:
– coveralls,
– lab coats,
– hoods,
– overshoes,
– socks,
– gloves,
– trousers,
– T-shirts,
– blouses,
– jackets.
VDI 2083 Part 9.1:
Cleanroom consumables:
– packaging film,
– paper,
– sticky mats,
– wipes/cloths/mop wipes (in dry condition; reusable and single use).
ISO 14644-14:
Other items and equipment used in Cleanrooms
Test conditions: IEST-RP-CC003.4 - Helmke drum test
The garment is placed in a Helmke drum – a stainless steel drum similar to a tumble dryer. The drum is rotated to generate particles (rotation speed: 10 rpm).
Particles released from the test item are collected by the isokinetic probe of the laser particle counter.
The sampling time is 10 minutes.
The measured particle concentrations are compared with the respective classification limits given in IEST-RP-CC003.3.
IEST-RP-CC003.3 defines three categories of clothing: Category I (recommended for ISO 1-3 Class cleanrooms), Category II and III (recommended for ISO 4-9 Class cleanrooms). The IEST-RP-CC003.3 standard lists acceptable particle emission rates (particles/min) for each category depending on the size (average area for both sides) of the tested item.
This test method is used worldwide, mainly due to the fact that the whole garment can be tested in this way.
Typical products tested to IEST-RP-CC003.4 (Helmke drum test) are Cleanroom garments/clothing:
– coveralls,
– lab coats,
– hoods,
– overshoes,
– socks,
– gloves,
– trousers,
– t-shirts,
– blouses,
– jackets.
Why is it worth working with us?
We keep abreast of changes in Cleanroom standards
We are a member of Technical Committee No. 161 for Air Conditioning and Ventilation and Technical Committee No. 317 for Indoor Air Quality at the Polish Standards Institute. In this way, we are involved in the process of developing standards of the ISO 14644 series.
We know requirements and perspectives of Cleanroom users
Our team worked in Validation amd Quality Assurance Department for leading companis in Pharmaceutical inductry. Currently at BNT SIGMA we are involved in many cleanroom validation projects for our clients from Pharmaceutical/Medical/Laboratory sectors.
We are customer oriented company
You can easily contact us and speak directly to the person responsible for carrying out the test and preparing the test report.
We operate internationally
We prepare test reports in English. We are open to cooperation with clients from within and outside the European Union.
“Suitable for Cleanrooms. Particle Emission test”
- registered trademark
This mark (registered trademark) can work for your business. You will receive it for the tested item once the cleanroom suitability of the equipment has been confirmed. You can use it in commercial communications about the tested item (with no additional/periodic fees).
Pricing
The price of the test is calculated individually based on the type and number of items to be tested in one order. Contact us by email to receive a quote.
Testing process
Step 1. Contact us by email. Briefly describe your product, tell us where the product must be returned after testing.
Step 2. We will send you the quotation for testing.
Step 3. After accepting the quotation, you send the product to our laboratory (located in Poland).
Step 4. Once the test is completed and the report is ready (lead time: 7-14 days), we will send you the invoice for the test.
Step 5. Once we have received your payment, we will send you the test report and return the product to you.
Contact us
Contact person: Krzysztof Żarczyński, Senior Validation Engineer
Email: info@hygienicdesign.eu [English or your local language]
Phone: 00 48 530 30 90 30 [English]
Helmke Drum Test - Questions and Answers
The Helmke Drum Test is a standardized method to quantify particles released from garments by mechanically tumbling them under controlled dry conditions. It simulates particle shedding that might occur during actual garment usage.
In the Helmke Drum Test, garments are placed inside a rotating drum that mechanically agitates the material to release particles. An automatic particle counter measures particle concentration in the drum’s air for ten minutes to calculate the emission rate.
It allows assessment and classification of garment cleanliness, crucial for environments like cleanrooms, by determining particle shedding potential.
The test requires:
A rotating tumbling drum.
An air sampling tube positioned to sample air inside the drum.
A modified ball mill or similar device rotating the drum at precisely 10 rpm.
An automatic particle counter to measure airborne particles.
A stainless steel rod for positioning garments.
Timers and data recording sheets.
An automatic discrete-particle counter samples air at a controlled rate, typically 0.0283 m³/min (1 cfm), from the rotating drum. Measurements are recorded for particles sized 0.3 µm and larger.
Position the drum at a suitable working height in an ISO Class 5 or cleaner environment.
Verify drum rotation speed at precisely 10 rpm.
Position and secure the air sampling tube properly, checking for particle deposition.
Measure and record cleanroom background particle concentration and confirm the drum’s internal particle concentration closely matches it.
Excessive contamination is managed by:
Blowing the drum’s interior with filtered nitrogen or air.
Wiping the drum with cleanroom wipes moistened with DI water or a dilute IPA solution.
Cleaning or replacing contaminated sampling tubes as necessary.
The garment should be carefully removed from its protective envelope using cleanroom gloves, unfolded without touching other surfaces, and cuffs and legs should be opened to prevent resetting to original folded positions.
The garment is folded carefully to allow free tumbling and placed into the stationary drum, far from the opening, ensuring no direct contact with the sampling tube during operation.
Particle counting begins simultaneously as the drum rotation starts. Counts are continuously monitored and recorded for the initial ten minutes, with particles equal to or greater than specified sizes (usually 0.3 µm or 0.5 µm) tallied.
Cleanaliness classification is determined by comparing calculated particle emission rates to standard tables. Adjustments can be made based on garment size or specific user requirements. Particle emission rates for different particle diameters can be extrapolated using an empirically determined exponent.
An interlaboratory study validated reproducibility, with relative standard deviations at approximately 24.3% and 14.7% for particles ≥0.3 µm and ≥0.5 µm, respectively, consistent with ASTM E691 standards.