Garment Testing - Home Laundering Methods

Garment Testing - Home Laundering Methods


1. Introduction to garment testing 

A garment undergoes various tests as per the requirements and set guidelines by the buyer in the garment package test (GPT). Wash and shrinkage test is one of the tests in GPT. The garment subjected to washing is assessed for its overall appearance, dimensional stability and shrinkage, spirality, and bow and skew.

Process flow for carrying out any test in the wash and shrinkage lab is:
Conditioning of original sample (4 hours at standard conditions) --> initial measurements --> wash and wet lab --> Conditioning washed sample (4 hours at standard conditions) --> Final measurement --> Appearance assessment

2. Tests and Purpose of garment testing

a. Overall Appearance
Overall garment appearance is checked after laundering and compared to that of the original garment. This includes the smoothness of the fabric, colour change, and the appearance of the trims used in the garment. These parameters are assessed in order to understand the visual condition of the garment after the home laundering process by the consumer.

b. Dimensional Stability and Shrinkage
Dimensional stability is a common concern in apparel performance characterization. The dimensional stability of fabric refers to the change of fabric size when it is used or reprocessed due to the properties of a material. Shrinkage of a garment is the changes in its dimensions after it is subjected to washing/ laundering. Shrinkage is of two types- minus and plus. 

Dimensional stability and shrinkage problems usually arise in cellulosic fibres (cotton, viscose rayon, linen) fabric. Continued dimensional change over several launderings can be interpreted as a lack of durability by the consumer. 

c. Torque or Spirality

Spirality refers to the twisting of fabric in a garment after laundering. It is also called torque or skewness. Spirality is checked only in warp wise (fabric) or length-wise direction (garment). 

d. Bow and Skew

The skewness in fabric of garment specimens resulting from home laundering practices is measured using benchmarks applied to the specimens before laundering. The bow is the condition wherein the warp or weft yarns do not lie straight but follow a curved course. When two sets of yarns are not at right angles, the cloth is said to be skewed. The fabric of the garment is assessed for bowing and skewing after laundering.

3. Test Methods

AATCC WASHING
  • Machine: Top loading washing m/c
  • Ballast: 920 mm x 920 mm hemmed pieces of bleached cotton (type 1) or 50/50 polyester/cotton bleached and mercerized poplin (type 2) or 50/50 polyester/cotton plain weave (type 3)
  • Total load in washing: Preferably specimen + ballast should weigh 1.8 ± 0.1 kg.
  • Detergent: 1993 AATCC Standard Reference Detergent in amount 66 ± 1 g for m/c wash.

ISO WASHING
  • Machine: Preferably front loading m/c.
  • Ballast: 100% knitted polyester texturized filament fabric having a mass per unit area of 310±20 g/m2. Four pieces of size 20 x 20 cm, overlocked together on all four sides or 100 % bleached cotton fabric or 50/50 polyester/cotton plain-woven fabric of mass per unit area 155±5 g/m2 and of size 92 x 92 cm.
  • Total load in washing: specimen + ballast should weigh 2± 0.1 kg.
  • Detergent: ECE or IEC ref detergent + Sodium perborate tetrahydrate + bleach activator TAED in 77:20:3 ratio.

Sufficient detergent should be added to provide suds having a height of not more than 3±0.5 cm at the end of the washing cycle.

A. Overall Appearance

The smoothness of the garment or fabric after washing is assessed by AATCC 124 method. There are 3D replicas available. The specimen is compared to these and a rating of 1/ 2/ 3/ 4/ 5 is given, 1 being poor and 5 being best. The assessment is done under standard light in a dark room with grey painted walls, from a distance of 4 feet.

Image 1: Smoothness and appearance

Various other parameters that are assessed and reported are colour change, self-staining, yellowing, pilling, seam puckers, seam opening, fraying of embroidery, fraying/ ravelling of buttonhole, button detachment, button break, lustre loss of shank buttons, functioning of zipper, removal/ cracking of print, loss of print, peeling of print, pilling. The observations are noted in a sheet with a specific format containing the parameters.

Colour change and self-staining are assessed with the use of greyscale.

Image 2: Self-staining garment



B. Dimensional Stability and Shrinkage


Procedure
Step 1: Mark the dimension on the piece of fabric or garment before washing with a textile marker. The markings on a piece of fabric are done with a standard template. For garments, the following locations are marked: Top- neck width/ collar, shoulder, chest, armhole, centre back length, sleeve length, side seam, lining length, and width. Bottoms- waist, inseam, side seam, front rise, back rise, hip, leg opening, thigh, lining

Step 2: After the wash, measure the reduction in that dimension with a scale

Step 3: The change in dimensions or shrinkage is reported in percentage.

Specifications are as follows:

Particulars
AATCC
ISO
Test No./ Code
AATCC135 & 150
ISO 6330
No. of washes
Evaluated after the 3rd wash
Evaluated after the 3rd wash
Evaluation unit
Inch
Centimetre
Specimen size
61cm X61cm
50cm X 50cm
Dimensions for evaluation
46cm X 46cm
35cm X 35cm
Drying Temperature
<26°C
<26°C

Formula
Shrinkage %= (Dimensions before wash – Dimensions after wash)/ (Dimensions before wash)
Figure 3: Shrinkage measurement

C. Torque or Spirality

Procedure

  • Step 1: Mark the side seam before sending the garment for washing
  • Step 2: After the wash, measure the shift in the side seam.
Formula

Spirality % = [(shift in side seam)/ (side seam length)]* 100

Image 4: Spirality measurement


D. Bow and Skew


AATCC test method 179
Procedure

  • Step 1: Full width fabric is taken i.e. in weft direction. 
  • Step 2: For bow- Place the ruler along the weft direction and measure the maximum displacement of the bowed yarn.
  • Step 3: For skew- Set square is placed along the selvedge and the displacement of yarn is measured.

Formula:

Skew or Bow% = [(Displacement/ Fabric Width)] x100

4. Test Result

The desired test result or requirements for the tests mainly depends upon the buyer and the fabric. Mostly the following are the acceptable values:
  1. Smoothness appearance - Class SA4
  2. Dimensional stability and shrinkage - The dimensional stability of a garment should be 3-5% at the most after 3 home laundering. Shrinkage with respect to dimensions of the garment should be within tolerance as mentioned by the buyer depending upon the fabric and weave. The differential shrinkage between shell and lining should be no more than 2%.
  3. Torque or spirality- Torque of seams should be less than 5% of side seam length.
  4. Bow and skew- Bowing can be maximum 1” , while skewing can be maximum 3% of Fabric Width or 1.5”

References

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