In the world of textiles, the success of a brand is measured not only by the elegance of its designs but also by the resistance of those designs against time. A sweatshirt or T-shirt bought with great excitement that shrinks two sizes after the first wash is both a huge disappointment for the end consumer and a serious loss of prestige for the manufacturer. At this point, one of the most critical stages of textile engineering and quality control comes into play: The Fabric Shrinkage Test. At Baykar Kumaş, we have been aiming for the highest quality standards in knitted fabric production for over 40 years.
What is a Fabric Shrinkage Test?
A Fabric Shrinkage Test is a technical analysis that measures the change in dimensions (width and length) of a fabric after it has been exposed to processes such as washing, drying, ironing, or steaming. In textile terms, this is called “dimensional change.”
If a fabric shortens after these processes, it is called “shrinkage”; if it expands, it is called “growth” or “sagging.” Shrinkage testing allows us to foresee how a fabric will behave before mass production, enabling sewing patterns to be adjusted according to this data.
Why Do Fabrics Shrink?
Understanding why fabric shrinks is vital for managing risks in the production process. The main reasons for shrinkage can be listed as follows:
- Fiber Structure: Natural fibers like cotton, wool, and linen swell when they absorb water. During the drying stage, the fibers tend to shorten as they return to their original state.
- Production Tension: During production on knitting machines, yarns are under high tension. When the fabric is washed, this tension on the fibers is released, and the fabric “relaxes” back to its natural form. This is known as “relaxation shrinkage.”
- Heat and Moisture: High heat and the mechanical effect of water cause fibers to bond more tightly together (felting or contraction).
How is the Shrinkage Test Performed on Knitted Fabrics?
Knitted fabrics are more flexible than woven fabrics due to their loop structure, but this flexibility makes them more prone to shrinking. This is why it is critical to test every batch (lot) in wholesale fabric orders. Here is the step-by-step process:
- Sample Preparation and Marking: A square, usually 50cm x 50cm or 35cm x 35cm, is drawn on the fabric. The distances in both the width (course) and length (wale) directions are precisely measured and marked.
- Washing and Drying: The sample is washed according to standards determined by the type of fabric (usually ISO or AATCC standards). For example, while a single jersey fabric might be washed at 30°C or 40°C, a brushed three-thread fabric may be tested on a different program. Drying is done by hanging, flat drying, or tumble drying.
- Conditioning and Final Measurement: The washed fabric is left in standard atmospheric conditions for a period (conditioning) to reach moisture equilibrium. Then, the distance between the originally marked points is measured again.
Expected Shrinkage Rates by Knit Fabric Type
Every type of knit fabric reacts differently based on its knit structure and yarn content. Some generally accepted tolerances are:
- Single Jersey (Süprem): A shrinkage allowance of 5% to 7% is generally expected. While elastane content in Lycra jerseys increases stability slightly, testing is still mandatory.
- Interlock and Rib: Since these are double-knit structures, their widthwise elasticity is high. They must be monitored closely for lengthwise shrinkage risks.
- Two-Thread and Three-Thread: Especially in brushed (fleece) models, dimensional change can be more pronounced because the brushing process relaxes the fabric.
- Piqué (Lacoste): Due to its honeycomb texture, it may show a tendency to shrink lengthwise after washing.
The Importance of Shrinkage Testing for B2B Brands
If you are a clothing brand or operate a garment workshop, starting production without knowing the fabric shrinkage values is a big gamble.
- Pattern Optimization: If you know the fabric will shrink 5% lengthwise, you prepare the cutting patterns 5% longer to ensure the product reaches the perfect fit after washing.
- Cost Management: Cutting done without accounting for shrinkage leads to products being considered defective and results in significant financial losses.
- Reducing Return Rates: A decrease in products returned with the complaint “it shrank after washing” increases brand loyalty and profitability.
- Sanforization Decision: If test results are too high, it is decided to apply a “sanforizing” (dimensional stabilization) process to the fabric during the production stage.
Quality Assurance with Baykar Kumaş
At Baykar Kumaş, we consider the dimensional stability of every roll of fabric we produce as our top priority. We perform the necessary technical analyses for every sample and batch we offer during our wholesale fabric supply process.
In our laboratories equipped with modern technology, we meticulously apply shrinkage tests at every stage, from knitting to dyeing and finishing. With our 40 years of expertise in sustainable and high-quality knitted fabric production, we ensure your collections maintain their form just like the first day.
If you want to avoid risks in your collections and make quality a standard, you can contact us for professional fabric solutions. Carry your brand into the future with the right test, the right pattern, and the right fabric.
