What Is Fiber Composition?
Fiber composition analysis is the determination of which fibers and in what proportions a textile product consists. In blended fibers, one of the components is selectively dissolved with a suitable solvent, the remaining fiber is weighed and the ratio is calculated by mass. Visually indistinguishable fibers (such as cotton–viscose, wool–cashmere) are also identified by microscopic examination.
Purpose of Fiber Composition
The aim is to verify whether the fiber content declared on the label reflects reality. Fiber nomenclature and labeling is mandated in the European Union (EU) by Regulation 1007/2011; Misrepresentation is a direct cause of non-compliance in market surveillance.
Which Products Is Fiber Composition Applied To?
- Woven and knitted fabrics
- Ready-to-wear garments
- Ev tekstili (nevresim, havlu, perde)
- Yarn and fiber
- Technical textiles
In Which Sectors Is Fiber Composition Used?
Standards Related to Fiber Composition
- TS EN ISO 1833-1 (genel ilkeler)
- TS EN ISO 1833-2 … -27 (binary and ternary mixtures)
- TS EN ISO 17751-1/-2 (cashmere, yak, camel hair — microscopy)
- TS EN ISO 5088 (ternary mixtures)
- AATCC 20 / 20A
Fiber Composition Conditions
- Pre-treatment
- Non-fiber substances such as oil, finishing and size are removed from the sample.
- Conditioning
- In standard atmosphere (20 °C ± 2, 65 ± 4% relative humidity) according to ISO 139
- Account basis
- The result is given as a percentage by mass, applying the agreed moisture content
Equipment for Fiber Composition
- Analytical balance (0.0001 g)
- Oven and desiccator
- Glass crucible and vacuum filtration device
- Water bath and shaker
- Light microscope; scanning electron microscope if necessary
Sample Requirements for Fiber Composition
- Separate samples for each color and each fabric structure
- Approximately 1 g of clean fiber is required for chemical separation
- Lining, sewing thread and trimming are evaluated separately
- Printed areas and the ground should be sampled separately.
Duration of Fiber Composition
The time depends on how many components the mixture has: binary mixtures result in a single separation step, ternary and quaternary mixtures require sequential separations. Evaluation takes longer for animal fiber blends that require microscopic identification.
Fiber Composition Procedure
- 1The sample is identified and non-fiber materials are removed.
- 2It is conditioned in a standard atmosphere and its dry mass is determined.
- 3One of the components in the mixture is selectively dissolved with the appropriate solvent.
- 4The residue is washed, dried and weighed.
- 5The mass loss of insoluble fiber is calculated by applying the correction coefficient.
- 6In ternary mixtures, the second separation step is applied.
- 7The result is reported as a percentage by mass, with the agreed moisture content.
Fiber Composition Acceptance Criteria
The acceptance criterion is the difference between the label declaration and the measured ratio. (EU) 1007/2011 allows a small tolerance in certain circumstances; There are also separate provisions for foreign fibers not exceeding 5% by mass of the product. Whether the tolerance applies to your product depends on the declaration form.
Evaluation of Results
The result is compared with the label declaration. When a deviation is found, it is first questioned whether the sampling is representative of the product: lining, sewing thread and trim are declared separately from the main fabric, and when mixed, the wrong result is produced.
Fiber Composition Report
- Sample description, color and fabric structure
- Applied ISO 1833 part and solver system
- Result in percent by mass for each component
- Applied moisture content and correction coefficients
- Comparison with label declaration
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Regulation (EU) 1007/2011 on Textile Fiber Names and Labeling
Tekstil Testleri — What Does This Testing Field Cover?
The section below describes the field that the Fiber Composition test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Textile testing answers two questions separately: does the fabric hold up physically over its service life, and does it carry any substance restricted for human health? These two axes require different laboratory infrastructure and different decision mechanisms.
On the physical side, breaking and tear strength, abrasion resistance, pilling, dimensional change, colour fastness and water and oil repellency are measured. Most of these tests depend on the USE SCENARIO: Martindale abrasion cycles are decisive for an upholstery fabric, while dimensional change in washing and colour fastness come to the fore for a shirting fabric. The same fabric goes through a different test set for a different use.
Colour fastness is a body of work of its own in this field and is not a single test. The fastness of the same fabric to light, washing, rubbing, perspiration, saliva, chlorinated water and ironing is measured separately; each represents a different moment of use. Results are rated from 1 to 5 on the grey scale and the specification gives a separate minimum rating for each agent.
On the chemical side, aromatic amines released from azo dyes, formaldehyde, heavy metals, phthalates, short-chain chlorinated paraffins, alkylphenols and PFAS compounds are screened. These items come from REACH restrictions, brand restricted substance lists (RSL) and voluntary schemes such as OEKO-TEX. Brand lists are often stricter than legislation; the target customer is decisive.
There is NO CE marking on consumer textiles. The obligation has three legs: fibre composition and care labelling, compliance with chemical restrictions, and general product safety. Textiles claiming a protective function (workwear, flame-resistant clothing, high-visibility clothing) fall under personal protective equipment legislation, where CE is mandatory — this distinction is commercially critical.
Verifying the label declaration is the most routine work in the field. Quantitative fibre analysis confirms the blend ratio stated on the label; tolerance ranges are defined in legislation. An incorrect fibre declaration both misleads the consumer and affects customs classification.
Sustainability claims have added a new body of work to the field in recent years: verification of recycled content (GRS, RCS), organic content (GOTS), restriction of harmful chemicals and water/energy footprint declarations. These claims now require auditable evidence.
Method groups in this field
Strength and durability
Strip and grab breaking strength, tearing by the Elmendorf and tongue methods, seam strength, bursting strength.
Abrasion and surface
Martindale and rotary platform abrasion, pilling and fuzzing, fabric mass and thread density measurements.
Dimensional stability
Dimensional change in washing and drying, wrinkling behaviour, appearance after ironing.
Colour fastness
Fastness to light (xenon), washing, rubbing, perspiration, saliva, water and chlorinated water; rating on the grey scale.
Functional properties
Water repellency (spray test), oil repellency, waterproofness, air permeability, effectiveness of antibacterial finishes, UV protection factor.
Chemical analyses
Aromatic amines from azo dyes, formaldehyde, pH, heavy metals, phthalates, chlorinated phenols, PFAS and alkylphenols.
Commonly confused in this field
- A brand restricted substance list (RSL) may be stricter than legislation; REACH compliance does not mean compliance with the customer specification.
- Textiles claiming a protective function fall under PPE legislation and require CE; an ordinary textile test report does not satisfy that file.
- Colour fastness is not a single number; a rating cannot be interpreted without stating which agent it relates to.
- A result obtained for a fabric does not cover the whole garment made from it; lining, sewing thread, print and trims are assessed separately.
- Performance claims after washing are valid together with the stated number of wash cycles; the word "permanent" on its own is not verifiable.
Which decisions these results support
- Compliance with the brand restricted substance list (RSL)
- Verification of label declarations: fibre composition and care instructions
- Determining the performance class of upholstery and technical textiles
- Pre-import shipment inspection and lot acceptance
- Supporting sustainability and recycled content claims
Related Tests
Frequently Asked Questions About Fiber Composition
Are lining and sewing thread included in the declaration?
No. (EU) 1007/2011 declares the lining separately; Accessories such as sewing thread, labels and buttons are not included in the fiber declaration. Analyzing them together with the main fabric will give incorrect results.
How to differentiate cotton from viscose?
Both are cellulose-based and cannot be separated by simple solvent separation; selective systems such as formic acid/zinc chloride or microscopic cross-sectional examination are used. That's why cotton–viscose blends last longer than other blends.
Can you verify the cashmere declaration?
The distinction between cashmere, yak and wool is a microscopic definition, not a chemical one (ISO 17751). Quantitative ratio can be given, but distinguishing between fine wool and cashmere requires an experienced operator and its uncertainty is higher than other methods.








