Fabric Shrinkage Test

In some cases, if we wash or launder a knitted, T-shirt, we may discover that the size of the T-shirt has decreased from its original size. In this case, shrinking is responsible for the problem. In this process, the fabric dimension becomes smaller than its original dimension. It happens either lengthwise or widthwise or both.

There are several factors that influence the price of fabrics, such as raw materials, fabric manufacturing procedures, and finishing. For example, fabrics made from natural fibers tend to shrink more than synthetic fibers.  This property affects the finished garments or product the most, as it can potentially distort the shape of the garment to different degrees. So it is better to test the degree or percentage of fabric shrinkage.

Fabric Shrinkage Test Procedure

A sample of the test specimen measuring 24 inches by 24 inches should be taken and marked with different colors of sewing thread. The specimen sample should be laid flat without tension on a smooth flat surface in the standard testing atmosphere (65% R.H. and 680 degrees F) at least for 18 hours. Reference measurements should be taken carefully and accurately.

Then test specimen should be put into the washing machine. The temperature should 380 C, Sodium carbonate and neutral wetting agent shall be added in quantities to give a solution containing 0.1% each. The weight of the specimen shall not exceed one-half pound per gallon of washing liquor.

The washing machine shall be set in motion and kept running without interruption until the washing and rinsing of the specimen are completed.

After running the machine for 15 minutes the washing liquor shall be drained off. After that, the specimen shall be washed for 5 minutes three times each at 38⁰C.

The specimen shall be taken out from the washing machine and folded to form a pad having 8 layers and laid against the side of the hydro-extractor machine. The hydro-extraction should be carried out for 10 minutes to remove excess water from the specimen.

Then the specimen should be taken out from the hydro-extractor and kept for a few minutes to equalize the distribution of remaining water inside the sample.

Then the specimen shall be laid flat without stretching on the pressing table and pressed with heated iron for 30-40 second and moving the iron without sliding to an adjacent position and repeating this process till the whole area of the specimen become dry. After pressing the sample should be reconditioned and measurements should be taken.

                           Original Length – Shrinked length

Fabric Shrinkage% = ………………………………………… X 100

          Original length

The shrinkage test result should be expressed in percentage for both the warp and weft way of the fabric.