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Peer Review Article | Open Access | Published 18th December 2025
Performance of Cleanroom Garment Fabrics When Processed in an Industrial Laundry: Cleanroom Undergarments and Non-Sterile Outer Garments
Dr Davey Stoker*, Jamie Kelly, Andrew Edwards - Micronclean Ltd | EJPPS | 304 (2025) | https://doi.org/10.37521/ejpps30403
Key Words: Cleanroom fabric, cleanroom undergarments, non-sterile cleanroom garments, lifetime, performance.
Summary
Cleanroom apparel forms a primary barrier between personnel and the manufacturing environment. Despite the widespread use of reusable garments, there are limited peer‑reviewed studies describing their performance through repeated industrial laundering and wear cycles. EU GMP Annex 1 requires reusable garments to be replaced based on qualification studies, rather than visual inspection alone.
This study characterises the through‑life performance of a non‑sterile outer garment constructed from WF5505JG non-sterile cleanroom fabric and three cleanroom undergarment fabrics (Buxton, Carsington, Sandwash), in order to derive evidence‑based replacement intervals.
Garments from multiple users, across multiple use cases, were processed using validated laundry workflows and tested across defined process counts. Performance attributes included durability (tensile strength), particulate shedding (Helmke drum), and colour stability by colorimetry (ΔE). For undergarments a repair frequency analysis was also conducted. WF5505JG non-sterile outer cleanroom garments were assessed between 0 and 150 processes; and the three cleanroom undergarments were assessed at 0–80 (Buxton); 0–150 (Carsington); 0–200 (Sandwash) processes.
The WF5505JG non-sterile outer garments maintained a high performance to approximately 110 processes, beyond which tensile strength and particle release trended adversely. For undergarments, the recommended replacement intervals were Buxton=60 processes, Carsington=120 processes, and Sandwash=150 processes. These lifetime processing thresholds balance the containment performance and the durability of the garment systems.
The lifecycle qualification in this study supports objective, fabric‑specific replacement policies for reusable cleanroom apparel, consistent with EU GMP Annex 1. The data provide practical limits that can be embedded in cleanroom facility quality systems to mitigate contamination risks and control costs.
Introduction
People are the dominant source of contamination in cleanrooms¹. Modern cleanroom garment systems are therefore designed to limit the release and transfer of viable and non‑viable particles from these people to the cleanroom environment, whilst also providing durability and wearer comfort². Cleanroom standards and guidance, such as ISO 14644‑5 ‘Cleanroom Operations’ ³, IEST RP CC 003 ‘Garment System Considerations’⁴, and USP <797> ‘Garbing Requirements for Sterile Cleanrooms’⁵, set expectations for garment use and testing, while EU GMP Annex 1⁶, sets explicit requirements for reusable garments to be replaced at defined lifetime limits, following qualification studies that define these lifetimes. In practice, many cleanroom facilities still rely primarily on visual inspection of the garment prior to donning, or generic supplier claims for garment life, which may not reflect the actual performance under specific laundry regimes, sterilisation/decontamination exposures, and wearer conditions.
Lifecycle testing provides an objective basis to determine when reusable garments should be withdrawn from service. Many industrial laundries operate a managed rental model, overseeing materials selection, garment construction, and validated laundry processes. This end‑to‑end control allows for a systematic through‑life evaluation of the garment system, that encompasses both the barrier fabrics and the fully assembled garments. Previously Micronclean reported the lifecycle studies of sterile cleanroom outer garments, demonstrating the importance of fabric selection and the differences between gamma sterilisation and steam sterilisation, on cleanroom garment lifecycles⁷. This paper integrates two further complementary studies: a WF5505JG (WF55) outer cleanroom garment life study and an undergarment fabric study (comparing three cleanroom undergarment fabrics, referred to here as Buxton, Carsington, Sandwash). Non-sterile outer cleanroom garments are mostly used in GMP Grade C/D (ISO 6-8) cleanrooms, where no open sterile product is present, or in cleanrooms where particulate control but not microbial control is required (electronics, optics, aerospace, precision engineering cleanrooms, for example). Cleanroom undergarments (sometimes also called inner garments or cleanroom pyjamas) are mostly required in GMP Grade A/B (ISO 3-5), where microbial control is critical and outer coveralls alone cannot sufficiently control particle shed from normal clothing.
The objective of this study was to characterise performance trends over repeated processes and to ascertain defensible replacement intervals/lifetime limits, that maintain contamination control. This paper reports the results for durability, particulate shedding and aesthetic performance for all fabrics, and additionally analyse maintenance signals (repairs) for the undergarments. The findings are discussed in the context of regulatory expectations and the practical adoption by cleanroom operators.
Materials and Testing Methodology
Study design: Garments in active circulation, across multiple customers and use cases, were sampled at random, at predetermined process counts, and laundered using validated Micronclean processes before testing. Three garments were analysed at each process count. Process count windows were set to capture low, medium and high process count behaviour for each fabric and garment type.
Garment types and process ranges: Non-sterile WF5505JG (WF55) outer cleanroom garments were evaluated between 0 and 150 processes (±3), with sampling at, or near to, 0, 25, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 and 150 processes. Undergarment fabrics were evaluated as follows: Buxton (0–80 processes), Carsington (0–150), and Sandwash (0–200) (the different study lengths being reflective of their qualitative lifetimes and how many garments survive to be measured to these process counts). Outer garments were laundered and packed in an ISO Class 4 cleanroom, undergarments in an ISO Class 6 cleanroom, before testing. Table 1 shows a basic comparison between the fabrics used in this study.
Table 1 - Comparison of the fabric’s specified physical properties
Fabric | Type of Cleanroom Garment | Weight of Fabric (g/m²) | Constructionᵃ (ends x picks) | Weaveᵇ | Fibre Type |
WF5505JG | Outer | 105 | 176x94 | Plain | Polyester |
Buxton | Inner | 135 | 61x34 | Plain | Polyester |
Carsington | Inner | 200 | 25x23 | Plain | Polyester |
Sandwash | Inner | 93 | 121x91 | Plain | Polyester |
[a – Construction = The numerical description of a woven fabric’s yarn density, typically given as the number of warp yarns (ends) by weft yarns (picks) per inch (e.g. 132 × 110), indicating how tightly the fabric is woven; b – Weave = The specific pattern in which warp and weft yarns are interlaced to create the fabric’s surface and texture (e.g. plain, twill, or satin)]
Durability (tensile strength): The tensile strength of a fabric is a useful indicator of a fabric’s capability to withstand the rigours of repeated donning, wearing and laundering. Garments with a lower tensile strength are more likely to develop holes during use. Fabric tensile strength (the force required to break a fabric) was measured using a universal tensiometer in a "grab" configuration, aligned with ISO 13934‑2⁸. Rectangular samples were cut in warp and weft orientations, measuring 50mm x 200mm, and the force was reported in Newtons as the peak tension force of the fabric recorded prior to rupture). Three warp and three weft samples were analysed per garment and the average force per process was reported, the trends by orientation being evaluated.
Particulate shedding (Helmke drum): The particulate shedding level of a fabric is a useful indicator of a fabric’s own ability to not shed particulate itself, over its lifetime after repeated use. Particle release was quantified by tumbling garments in a rotating Helmke drum and sampling the internal air using a discrete particle counter for 10 minutes, according to IEST-RP-CC003⁴. Particle counts at ≥0.5 µm and ≥5.0 µm were recorded. Results were normalised to a medium garment size to allow direct comparison across sizes.
Colour stability (colorimetry): Colour stability is an indication of chemical and physical damage to the fabric over time, and whilst changes in colour do not necessarily correlate directly with fabric chemical or physical damage, the two often do tally. Colour change relative to baseline (zero process garments) was calculated as Delta E (ΔE) using a spectro‑colorimeter (illumination D65, 2° observer, M2). Five readings were taken per garment at standardised positions and averaged.
Visual condition / maintenance signal: All garments were visually inspected at each process sampling point, for obvious damage. For the undergarments, the corresponding repairs data was also analysed (garments with visually obvious damage) from a wider pool of garments (thousands instead of hundreds), to infer latent physical degradation that might not be apparent at single‑time inspection, but which becomes evident as repair frequency increases. This repairs data was analysed as a ‘real world’ data set whereby the integrity of the garment system has been, or is about to be, compromised. This data was composed from 36,573 ‘real world’ cleanroom garments.
Particle Filtration efficiency (PFE) testing was not included within this study. For woven non-sterile cleanroom garments, filtration performance is primarily a function of fabric construction and integrity, both of which were assessed through the tensile strength and particle shedding testing. Studies ², including our own previous study on sterile outer cleanroom garments⁷, have shown that PFE in reusable woven fabrics remains effectively unchanged, until significant mechanical or surface degradation occurs, at which point increased shedding and tensile strength loss are already evident. Consequently, the parameters selected in this short study were considered more representative and practically relevant indicators of garment end-of-life performance, than PFE measurements.
Non-Sterile Cleanroom Outer Garment Results and Evaluation:
When the tensile strength of non-sterile cleanroom outer garments was analysed, between 0 and 150 processes, the tensile strength was found to decline approximately linearly with process count (see Figure 1). In the warp direction, the average breaking strength decreased from ~ 1140N at baseline to ~960N at 150 processes. In the weft direction, the strength decreased from ~630N at baseline to ~530N at 150 processes (~15% reduction from baseline in both the warp and weft). This progressive loss of strength indicates an increased susceptibility to breach under real world in‑use stresses, later in the garment’s lifecycle.
When the particle shedding aspect of non-sterile cleanroom outer garments was analysed, the Helmke drum testing showed baseline garments shedding ~1500 particles of size ≥0.5 µm (consistent with Class II garment⁸), in the 10 minutes, which increased through the life of the garment (garment shedding eventually exceeding 10,000 particles after 130 processes, at which point it becomes a Class III garment; see Figure 2). For ≥5.0 µm particles, non-sterile garment shedding increased from ~25 particles at baseline to ~125 particles around 150 processes. These thresholds are consistent with a late‑life onset of elevated shedding risk.
Note that the tensile strength of woven cleanroom fabrics is typically higher in the warp direction. This is because the warp yarns are engineered to endure greater mechanical stress during weaving, are maintained under a higher tension (reducing crimp), and are present at a higher density. As a result, they form a straighter, more load-bearing network of yarns, compared to the more crimped, lower-density weft yarns.
The colour change of the non-sterile outer garments was most rapid over the first ~60 processes and then started to plateau, indicating that appearance standards can be maintained through mid‑life but will diverge rapidly from the baseline early (see Figure 3).
Cleanroom Undergarment Results and Evaluation:
When the tensile strength of the undergarments was analysed, it was found that all three fabrics declined approximately linearly with process count, consistent with an accelerating material fatigue later in life (see Figure 4). For the Carsington fabric a steeper decline in fabric tensile strength was seen after 120 processes (after a slight initial increase at 25 processes versus 0 processes) and for Sandwash, after 150 processes.
Unprocessed undergarments (process count=0) exhibited relatively high initial particulate release. This emphasises the importance of pre‑issue washing, before use in a cleanroom. Beyond the initial processing, particulate release (both ≥0.5 µm and ≥5.0 µm) rose with process count. For Buxton the particulate shedding at ≥0.5 µm had exceeded the unprocessed condition by ~75 processes and the rate of particulate release rose sharply over this lifetime (see Figure 5). Particulate release for the Carsington fabric for ≥0.5 µm and ≥5.0 µm particles remained relatively low through mid‑life but approached unprocessed levels near 100 processes for ≥5.0 µm. Particulate shedding from the Sandwash fabric, at both ≥0.5 µm and ≥5.0 µm, after the initial processing, was consistent from ~20 to 200 processes. A transient spike in the data at ~120 processes prompted additional testing which confirmed shedding stability only up to 150 processes.
The colour of the Buxton fabric changed rapidly in the first ~60 processes and then more gradually, starting to plateau by ~75 processes (see figure 6). For the Carsington fabric, colour fastness deteriorated slowly to ~70 processes, after which ΔE increased more significantly. Colour change in the Sandwash garments increased progressively to ~200 processes, indicating a steady wearing down over time with no major spikes or sudden declines.
The repair data for the Buxton fabric showed an increasing frequency of garment failure with process count, with a marked rise in garments requiring 2 or more repairs after 70 processes (see Figure 7). Repair data for the Carsington garments was relatively stable to 120 processes with a gradual increase in garment failures seen, followed by a notable increase at 150 processes. Repair frequency for the Sandwash increased steadily with process count, with garments requiring ≥2 repairs increasing notably at 200 processes.
Discussion and Conclusions
This combined analysis demonstrates that through‑life performance of a cleanroom garment is likely fabric‑ and garment‑specific (we cannot say for definite, as the garments were sampled randomly from multiple customer and use cases and thus we cannot completely rule out different variations in ‘wear and tear’ across customers). The non-sterile outer cleanroom garments (WF5505JG) exhibited robust mid‑life performance but entered a region of increasing risk above ~110 processes, observed as elevated particle shedding and progressive fabric strength loss, after this point. The cleanroom undergarments each exhibited distinct lifetimes: Buxton (shorter), Carsington (intermediate), Sandwash (longer). These differences likely reflect variations in fibre composition, weave, surface finish and the garments interaction with laundry chemistry and mechanical action. For example, the moderate Buxton construction of 61x34, would likely result in a mechanically stronger fabric, versus a very loose cloth, but the larger pores and coarser surface can result in a fabric which sheds more and abrades faster, driving repairs, versus a fabric with a tight construction, such as Sandwash (121x91).
From a contamination control perspective, particle shedding trends provide the most direct indicator of environmental challenge, but decisions on garment lifecycle cannot rely on a single attribute alone. Durability and maintenance signals (repairs) indicate latent integrity risks, whilst colour change, although cosmetic, can be a practical surrogate/indicator for cumulative processing damage. Accordingly, replacement intervals should be set where multiple attributes converge on increased risk, and should not be based on a single variable, or the first sign of change.
When analysing garment lifecycle data, it is important to be cognisant of regulatory alignment. EU GMP Annex 1⁶ requires that reusable garments be replaced if damaged, or at a defined frequency, established during qualification studies. The intervals set below constitute such qualification outputs and can be embedded in site cleanroom procedures, to ensure compliance with EU GMP.
Managed rental models enable consistent materials, controlled processing, and responsiveness to change (e.g., material or chemistry modifications) through ongoing monitoring. By contrast, purchased garments, or on‑premise laundering models, face challenges reproducing validated processing and conducting lifecycle studies across change events. Adopting fabric‑specific replacement intervals reduces unplanned repairs and late‑life failures, supports audit readiness, and stabilises costs. Cleanroom facilities should embed these intervals in SOPs and quality agreements, with their garment suppliers, to demonstrate Annex 1 compliance.
From these studies, and from analysing all of the garment system attributes, we can conclude that the following lifecycle limits should be put in place for these garment systems:
For non-sterile WF5505JG garments, a process limit of 110 processes should be put in place.
For Buxton undergarments, a process limit of 60 processes should be put in place.
For Carsington undergarments, a process limit of 120 processes should be put in place.
For Sandwash undergarments, a process limit of 150 processes should be put in place.
These limits reflect the trends of all the available attributes and are a holistic amalgamation of where each attribute starts to indicate fabric deterioration or damage, but where it has likely not yet occurred. In addition to these conclusions, this study also reinforces the need to pre‑condition new garments (initial wash) before service, to minimise early particulate release. It is also clear from these studies that garment suppliers should track repair frequency as an early‑warning signal of latent degradation. These technically justified process limits can also be lowered for commercial reasons, or to make contract lengths, or technical agreements, more practical and user friendly.
It should also be noted that the previous study⁷ which looked at the sterile WF5505JG outer cleanroom garments, set a process limit of 50 processes for gamma sterilised garments and 70 processes for steam sterilised garments. Both are considerably lower than the corresponding non-sterile limit of 110 processes, indicating the relative additional damage caused to the fabric by the additional sterilisation process.
Overall, this study demonstrates that garment lifecycle qualification can support contamination control objectives, when managed with fabric‑specific replacement intervals. Cleanroom facilities should integrate such intervals into their quality systems, thereby maintaining control of operator‑generated contamination risk and optimising the total cost of ownership, across the entire lifecycle of the whole cleanroom garment system.
Acknowledgements
The authors would like to acknowledge Marta Underwood and Claire Myszczyszyn for their oversight contributions and their support to the authors of this study.
References
1. B Reinmüller, B Ljungqvist. Modern cleanroom clothing systems: People as a contamination source. PDA Journal of pharmaceutical science and technology. 57(2):114-25. 2003.
2. T Eaton, W Whyte. Effective Re-usable Cleanroom Garments and Evaluation of Garment Life. EJPPS. 254 (2020)
3. ISO 14644‑5: Cleanrooms and associated controlled environments — Part 5: Operations. International Organisation for Standardisation.
4. IEST RP‑CC003.5: Garment System Considerations for Cleanrooms and Other Controlled Environments. Institute of Environmental Sciences and Technology (IEST).
5. USP <797>: Pharmaceutical Compounding — Sterile Preparations. United States Pharmacopeia.
6. European Commission. EU GMP Annex 1: Manufacture of Sterile Medicinal Products. 2023
7. K Broadbridge, D Stoker, G Cochran, M Kuzma. Performance of Cleanroom Garment Fabrics When Processed in an Industrial Laundry, Comparing Irradiation and Autoclave Sterilisation. 264 (2021).
8. ISO 13934-2: Textiles — Tensile properties of fabrics Part 2: Determination of maximum force using the grab method. International Organisation for Standardisation.
Authors
Dr Davey Stoker
Micronclean Ltd
* Corresponding author:
Dr Davey Stoker davey.stoker@micronclean.co.uk