Last updated on June 14th, 2023 at 05:31 pm
This procedure describes the process for determination of dimensional changes of fabrics when subjected to home laundering process.
Dimensional Change: Percentage change in length and width of fabric specimen when subjected to specified conditions.
Growth: Dimensional change result in increase in length and width of specimen.
Shrinkage: Dimensional change result in decrease length and width of specimen
Laundering: A process intended to remove soils and/or stains by washing with detergents or soap solutions and normally includes rinsing, extraction and drying.
Apparatus and Equipment
- Automatic Washing Machines and Tumble Dryer
- Ballast of 920mm x 920mm (36” x 36”)
- Type 1 – hemmed pieces of bleached cotton sheeting, or
- Type 3 – 50/ 50 polyester/ cotton bleached plain weave
- Measuring Devices
- Steel ruler marked in millimeters, tenth of an inch, or
- Digital Imaging System
- Scale with weighing capacity of 5kg (10lbs)
- Iron, with maximum temperature at least 200°C (390°F)
- Overlock machine
Reagents and Consumables
- 1993 AATCC Standard Reference Detergent (Powder) or New Ultra Tide Powder Detergent with Original Scent or Original Tide with Acti-Lift Crystals.
- Indelible ink marking pen or other marking devices (i.e. Tex marker)
- Sewing thread
Sampling and Preparation
- One representative specimen of each sample to be tested is required.
- Fabrics that are distorted in their unlaundered state due to faulty finishing may give deceptive dimensional change results when laundered by any procedure should be taken out.
- Avoid use of the sample area within ten percent of the sample width. Identify the length direction of the specimens before cutting out the sample.
The specimens are conditioned at standard atmosphere of 21 ± 1 °C (70 ± 2 °F), 65 ± 2% RH for at least 4 hours prior to testing.
- The washing cycle, water level and water temperature on the washing machine are set according to specifications in Tables I below or as per the care instruction.
- The temperature of water must comply with that required by specifications listed in Table I. Use a thermometer to measure the water temperature. Whenever needed, add hot or cold water to the water bath to adjust to the appropriate temperature.
- The washing machine is switched on.
- The washing machine is filled to the 18 ± 0.5 gal water level and adds 66 ± 1.0 g of 1993 AATCC Standard Reference Detergent or 52.8 ± 1.0 g of New Ultra Tide Powder Detergent /Original Tide with Acti-Lift Crystals.
- Agitate the water briefly to dissolve detergent.
- Add the specimens and ballast into the washing machine. Set the washer for the selected washing cycle and time.
- The door of the washing machine is needed to be closed.
- The specimens and ballast are removed from the washing machine at the completion of washing cycle.
Specimens with the wet ballast are removed from the washing machine and are dried as follows:
NOTE-01: The drying machine is operated for 45 minutes or until dry.
NOTE-02: The specimens and ballast are removed immediately after drying.
Conditioning and Restoration
After the completed washing, drying and ironing interval, the specimens are conditioned at standard atmosphere of 21 ± 1°C (70 ± 2°F), 65 ± 2% RH for at least 4 hours prior to measurement by laying fabric flat in perforated trays.
Measurement and Calculation
n After conditioning, each test specimen is laid without tension on a flat smooth, horizontal surface. Calculate length and width averages separately to the nearest 0.1% for each direction.
A = Original dimension
B = Dimension after laundering
DC = Dimensional change
A final measurement smaller than the original measurement results in a negative dimensional change which is shrinkage. A final measurement larger than the original measurement results in a positive dimensional change which is growth.