The Importance of Wash Testing
A fundamental question that needs to be answered before textiles are officially introduced to the public: how will these products perform once they have been washed by customers? Consumers have expectations of what they will look like after washing. It is intolerable for garments to experience significant variability, which will result in products being returned to retailers, poor reviews, loss of revenue and brand/reputation damage.
What appears to be a relatively simple test for labs and retailers is actually quite a complex and multifaceted challenge that needs to be fully evaluated. First of all, every customer washes their clothes in a different way. Factors may include: frequency, temperature, color separation, load size, type of washer, type of detergent, drying method, and more. This provides retailers with an evolving target that allows them to better understand how their products perform in home washing. If we consider what retailers are actually assessing during the product washing evaluation process, we can illustrate how the standard was developed to minimize variation and provide retailers with the best opportunity to understand the performance of their products.
To help determine the best approach to standardized testing, garment care instructions need to be considered. Most retailers will specify that home wash testing be done at the care label temperature, and if tumble drying is available, this will be chosen as the method of drying as it is the most 'rigorous' test allowed by the care instructions. Some retailers will go the extra step and test at 10°C above the care label to allow for the possibility that customers may choose to wash in water at a higher temperature than recommended. There are now a lot of 30°C care instructions because the trend in home laundry is to wash at lower temperatures, but a significant number of customers still choose 40°C water because they think it will clean their clothes more thoroughly.
Different types of wash tests
Size Stability Test
This is often referred to as a shrinkage test, but this is a misconception. Size stability refers to any change in the size of the product during the washing/washing process, so we must also consider whether the product is shrinking and getting bigger at the same time - this is common in knitwear and real knitwear. In addition, we can observe other phenomena such as bowing and skewing - straight yarns running perpendicular to the width through the fabric can become twisted, resulting in the yarn tilting from one side to the other (skewing) or a pronounced curve in the yarn between two edges (bowing). Additionally, a visible spiral can also occur in knit garments where the side seams seem to start twisting at the bottom of the garment. This is usually caused by an imbalance in the yarns used in single-sided knitwear.
Promotional Claim Validation
Not only is this important for retailers to assess whether their claims are true, it is also required for the legitimacy of the claims. Consumer law does not allow retailers to make false performance claims. Examples of such claims include: improved color retention, permanent creasing, improved stain removal, long-lasting water-resistant finishes, Hi-Viz durability, and more.
All such claims need to be tested and benchmarked against products claiming to be 'better'. These results will be retained in the event of a customer complaint to Trading Standards or similar bodies.
Appearance after washing
As well as size changes in garments or fabrics, retailers are also concerned about the appearance of garments after multiple washes. Typically, they will assess this after 1, 5, 10 or a similar increase in the number of washes. They want to see how the fabric surface behaves over time. They may look for color loss, pilling/pilling, cross-dyeing, creasing, and the performance or attachment of trims or decorations to the fabric. A full set of evaluations will be performed with each wash. This may overlap with the validation of promotional claims as described above.
Preparatory washes for subsequent testing
Not all washes are intended to reach the end point of the test. Some washes are performed as preparatory steps for different tests. Examples include flammability testing and various pilling method tests.
