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ISO 25841:2014 – Feminine Hygiene Products — Requirements and Test Methods
Requirements and standardized test methods for sanitary napkins, panty liners and tampons
1. Scope and Product Classification
ISO 25841:2014 specifies requirements and test methods for feminine hygiene products, including sanitary napkins (pads), panty liners, and tampons. The standard addresses dimensional specifications, absorption performance, liquid distribution, leakage prevention, and material safety requirements. It provides manufacturers with a consistent quality framework and enables consumers to make informed product comparisons.
The global feminine hygiene market exceeds USD 35 billion annually, with product innovation driven by comfort, discretion, absorbency, and increasingly, environmental sustainability concerns.
Product classification under ISO 25841 is based on absorption capacity ranges, with each class having defined minimum performance requirements. Sanitary napkins are classified as regular, super, super plus, or night use. Panty liners are classified by thickness (ultra-thin, thin, regular) and absorbency. Tampons have additional safety requirements related to vaginal health, including strict limits on cytotoxicity and material extractables.
| Product Type | Absorption Range (g) | Min. Length (mm) | Leakage Test Pass |
|---|---|---|---|
| Panty liner | 1 – 5 | 150 | N/A |
| Regular pad | 5 – 10 | 230 | 95% pass |
| Super pad | 10 – 15 | 260 | 98% pass |
| Night pad | 15 – 25 | 300 | 99% pass |
| Tampon (regular) | 6 – 9 | N/A | 95% pass |
| Tampon (super) | 9 – 12 | N/A | 98% pass |
2. Performance Testing and Quality Metrics
The standard defines standardized test methods for absorption capacity using synthetic menstrual fluid, with specified viscosity, surface tension, and temperature (37 ± 1 °C). Liquid strike-through time measures how quickly fluid penetrates the cover sheet, while liquid distribution analysis evaluates how effectively the core distributes fluid along its length. Rewet testing quantifies moisture returning to the surface under controlled pressure conditions.
Advances in acquisition distribution layer (ADL) technology have reduced strike-through time from 3-5 seconds to under 1 second, while keeping the topsheet 95% dry during use — a dramatic improvement in user comfort since the early 2000s.
Material safety testing includes pH measurement (target range 5.5-7.5 to maintain vaginal health), cytotoxicity testing per ISO 10993-5, dermal irritation assessment, and extractable metals analysis. The standard also requires testing for pesticide residues on raw cotton materials, dioxin content in bleaching process byproducts, and fragrance sensitization potential.
3. Engineering Design Insights
Product engineering for feminine hygiene products involves sophisticated material science. The typical multi-layer construction includes: a hydrophilic or perforated film topsheet for fluid acquisition, an acquisition distribution layer (ADL) for rapid lateral wicking, an absorbent core (fluff pulp + SAP – superabsorbent polymer) for fluid retention, and a liquid-impervious backsheet. Each layer’s material selection, basis weight, and processing conditions must be optimized for the product’s intended absorbency class.
Superabsorbent polymer (SAP) quality is critical — particle size distribution must be controlled to within 150-850 μm with fines content below 1%. Oversized particles cause gel blocking (preventing fluid penetration), while undersized particles increase dusting and reduce core integrity. Centrifuge retention capacity should exceed 30 g/g for standard SAP grades.
Environmental considerations increasingly influence product design. Biodegradable materials, reduced plastic content, and compostable packaging are growing trends. The standard does not currently mandate biodegradability but provides testing references for manufacturers pursuing eco-design. Odor control technologies incorporating activated carbon, cyclodextrin, or pH buffering systems are optional performance enhancements not covered by the standard’s mandatory requirements.
4. Frequently Asked Questions
Q: How does ISO 25841 differ from national standards?
A: ISO 25841 provides a globally harmonized framework. National standards (e.g., China GB/T 8939, EU EN 16421) may have additional regional requirements.
A: ISO 25841 provides a globally harmonized framework. National standards (e.g., China GB/T 8939, EU EN 16421) may have additional regional requirements.
Q: Are reusable products covered?
A: No — ISO 25841 covers disposable products only. Reusable menstrual products fall under different standards.
A: No — ISO 25841 covers disposable products only. Reusable menstrual products fall under different standards.
Q: What testing is required for organic cotton products?
A: In addition to standard performance tests, organic certification verification and pesticide residue analysis per the standard’s annex are required.
A: In addition to standard performance tests, organic certification verification and pesticide residue analysis per the standard’s annex are required.
Q: How is product shelf life determined?
A: Accelerated aging tests at 40 °C / 75% RH for 6 months (equivalent to 2 years ambient storage) evaluating absorption performance and material integrity.
A: Accelerated aging tests at 40 °C / 75% RH for 6 months (equivalent to 2 years ambient storage) evaluating absorption performance and material integrity.
