Why Garments Need Laboratory Testing
Visual inspection tells you how a garment looks; laboratory testing tells you how it will behave. The two are complementary. An inspector can check measurements, stitching and appearance, as described in our AQL inspection guide, but only a test can show how much a fabric shrinks after washing, whether a colour will run or fade, or if a seam will split under strain. These problems are the source of many of the returns and bad reviews that hurt young brands, and they are almost always preventable if you test before bulk production.
Testing also supports your claims and labelling. If your label says “machine wash at 30°C” or your listing says “pre-shrunk”, you should have results that justify it. Our clothing labelling guide explains why accuracy matters.
When to Test
- At development: test the fabric you plan to use, before you finalise the pattern and size chart, because the results affect both.
- Before bulk: test a pre-production sample or fabric from the bulk lot, so you know the real performance of the material you are about to cut.
- During or after production: test random garments from the finished order, particularly for higher-risk products or new suppliers.
Testing early costs little and saves a great deal. Testing after production tells you what has gone wrong but leaves you with limited options.
Dimensional Change (Shrinkage)
Natural fibres, especially cotton, tend to shrink when washed, and knits can also twist or lose length. The dimensional change test measures how much a fabric or garment changes in length and width after washing and drying, following a standard procedure such as ISO 6330 for domestic washing and ISO 5077 for the measurement of dimensional change. Many brands accept a small percentage change, commonly in the region of 3% to 5% depending on the fabric and style, though tighter limits suit fitted garments and premium products. Check the figures your retailer or your own quality standard requires.
Shrinkage affects more than the customer's experience. It must be built into the pattern and the size chart, so that garments fit properly after the first wash, and it is one reason finished measurements should be checked after washing as well as before. Pre-shrunk (sanforised) fabric and garment washing reduce it, as discussed in our guides to hoodie fabric and T-shirt cotton.
Colour Fastness
Colour fastness tests measure whether dyes stay where they should. The most important ones for clothing are:
- Fastness to washing (for example ISO 105-C06): checks colour loss in the fabric and staining of other fabrics washed with it.
- Fastness to rubbing or crocking (for example ISO 105-X12): checks whether colour transfers when the garment is rubbed, wet or dry, which matters for dark denim and bright colours.
- Fastness to perspiration (ISO 105-E04): checks dye behaviour in contact with artificial sweat.
- Fastness to light (ISO 105-B02): checks fading in daylight, relevant for products worn outdoors or displayed in shop windows.
Results are normally graded on a scale of 1 to 5, where 5 is excellent and 1 is poor, with separate grades for colour change and for staining. Many brands set a minimum such as grade 4 for washing and for staining, though dark and deeply dyed shades can be harder to achieve, and some denim is deliberately allowed to crock more. Agree the standard with your factory in writing.
Pilling and Abrasion
Pilling is the formation of small balls of fibre on the surface of a fabric, which makes a garment look old and scruffy. It is a particular risk on fleece, jersey with short fibres and blends with synthetic fibres. The Martindale pilling test (ISO 12945-2) rubs fabric samples against a standard abrasive for a set number of cycles and grades the surface from 1 (severe pilling) to 5 (none). A grade of 3 to 4 or better is a common target for everyday garments, though expectations vary by price point. Abrasion resistance, which measures how many rubs a fabric withstands before it wears through, is similarly relevant for trousers, jackets and workwear.
Seam Strength, Tear and Tensile Tests
These mechanical tests check that a garment can handle real use. Seam strength and seam slippage tests (for example ISO 13935) show whether seams open under load, important for fitted trousers, children's clothing and any garment under strain. Tensile and tear strength tests show whether the fabric itself is strong enough, especially for woven fabrics and lightweight materials. Button, snap and zip pull-tests check that fasteners stay attached, which matters both for durability and, in children's products, for safety.
Fabric Weight and Composition
Two simple but critical checks are fabric weight (GSM) and fibre composition. Weight confirms that you received the fabric you specified, since a thinner fabric is a common, quiet cost saving; composition testing confirms the actual fibre content, which must match your label. Composition test results are the proper basis for your fibre label, because a supplier's description is not always accurate.
Chemical and Restricted Substance Testing
Chemical tests look for substances that should not be in clothing, such as certain azo dyes, formaldehyde above permitted levels, heavy metals and other restricted chemicals. In the UK and EU, the REACH regulations restrict the use of many substances in textile products, and many retailers apply their own, stricter restricted substance lists. Certifications such as OEKO-TEX Standard 100 test finished textiles for harmful substances and can give customers extra confidence, though a certificate covers only the specific items and fabrics tested. If you sell children's clothing, take particular care and research the applicable rules before development.
How to Read a Test Report
A good report names the sample tested, the standard and method used, the conditions, the results and a clear pass or fail against stated criteria. When you receive one, check that the sample description matches your fabric, that the method is the one you requested and that the numbers sit within your limits. A result that is marginally within tolerance deserves attention, because natural variation between fabric lots may push the next batch outside it. If a fabric fails, ask what can be done: a different finishing treatment, a revised dye recipe, a pre-shrinking step or a change of fabric. Fixing the problem at fabric stage is cheaper than at garment stage.
Also keep the reports. They document the care labelling instructions you chose, the composition you declare and the due diligence you carried out if a customer or a retailer ever raises a complaint.
Typical Failures and What Causes Them
- High shrinkage: fabric not pre-shrunk or compacted, or a relaxed knit that has not been stabilised before cutting.
- Bleeding colours: insufficient washing off of unfixed dye after dyeing, common on dark or saturated colours and some indigo or reactive-dyed cotton.
- Pilling on fleece: short, loosely spun fibres or insufficient anti-pilling finishing.
- Seam splitting: stitch density or thread strength too low for the fabric, or a fabric with a very low yarn count.
- Distortion and twisting: poor knit construction or a lack of fabric relaxation, visible after washing.
Choosing a Testing Laboratory
Use an accredited, independent laboratory. Major international testing companies operate in Bangladesh, the UK and across Asia, and many factories also run in-house labs for basic tests. In-house results are useful for quick checks, but an independent report is what carries weight with retailers and with your own records. Send the lab a representative sample of the actual bulk fabric or finished garment, not a favourable swatch, and state clearly which standard and which pass criteria you need. Ask for a written report with the test methods, results and grades, and keep it with your product records.
What Testing Costs and How to Keep It Sensible
Testing fees depend on the number and type of tests, and a full panel for one fabric costs more than a single shrinkage test. A sensible approach for a new brand is to test the key risks for each new fabric once, such as shrinkage, colour fastness and pilling, then repeat tests only when you change fabric, colour or supplier. Focus on the tests that match your product: dark denim needs rubbing and wash fastness, white cotton tees need shrinkage and composition, and fleece needs pilling. Include the cost in your landed-cost estimate, as shown in our manufacturing cost guide.
How to Specify Test Requirements
- List the tests, the standards and the minimum acceptable results in your tech pack or purchase order.
- State who pays for testing, and which party commissions it.
- Ask for test reports before bulk cutting for any critical fabric.
- Include shrinkage measurement and colour checks in the pre-production sample approval, as described in our sampling guide.
- Agree what happens if the fabric fails: a replacement, a different treatment or a change in specification.
Testing and Quality at Ruhrose
Ruhrose builds testing into development for the fabrics we use, with shrinkage and colour checks on samples, laboratory reports on request and inspection against your agreed standards, on low minimums from 500 pieces per style and colour. Start a product enquiry and tell us which tests your retailers or customers expect.