FAQ Skin Sensory

Summarized for you: all frequently asked questions on the subject of skin sensory.
Yet don’t hesitate to contact us in case you have additional questions. We’ll be happy to help!

General questions

1. In what way are skin sensory functions different from the "feel"?
Can you judge a textile's skin sensory functions from the way it feels to the touch?

One the one hand, the feel of a textile refers to how it feels when you touch it with your hands. Skin sensory functions, on the other hand, indicate how a textile feels on the skin of your body. There are big differences between how a textile feels to the touch and your skin sensory perception, so the latter cannot be judged simply by touching the textile.

2. Aren't people's perceptions very varied and subjective?

Far less so than you would think. Standardised measurements cover the way about 80% of adults perceive skin sensory comfort.

3. Do the measurements only apply to sensitive skin?

No, the measurements generally apply to "normal" skin. Sensitive or diseased skin can vary greatly and require different properties in textiles. The Hohenstein Institute's skin sensory measurements do not cover this.

4. How much do skin sensory functions contribute to wearing comfort?

Skin sensory functions account for about a third of the wearing comfort. Two-thirds of the wearing comfort is due to the heat and moisture management of a textile, i.e. its thermophysiological wearing comfort.

5. What affects a textile's skin sensory properties?

Textiles made, for example, of filament yarns are often too smooth, which means they perform poorly on the wet cling index, the surface index and the number of contact points between textile and skin. Slightly roughening the inside surface may lead to better results.

6. What kind of textiles can be tested?

All textiles can be tested which are in direct contact with human skin, i.e. underwear, nightwear, T-shirts, pullovers, shirts, bed-linen, towels, bathrobes, wellness textiles etc.

7. Do you perform tests only for every-day garments or for workwear also?

The skin sensory tests are applicable to both sectors, provided that the garment is completely or in parts in direct contact with the skin. Only under this condition a judgment can be made how the textile feels on the skin.

8. Is the procedure applicable for the ready-made garment only or also for single components, such as sewing thread?

The tests of the skin sensory properties always relate to the material area of a product or a textile. Sewing threads alone cannot be tested.

9. Do the skin sensory tests meet ISO or other standards?

The Hohenstein Institute measures thermal and water vapour resistance according to ISO 11092. The skin sensory tests are performed according to in-house standard operation procedures with standardised and accredited test methods. The test procedures and –methods have been developed by the Hohenstein Institute based on numerous wearer trials with test persons and decades of experience with testing skin sensory properties of textiles

10. How long do the skin sensory tests take?

The average duration for the skin sensory tests is about 10 working days

11. Meanwhile more and more textiles consist of different patterns. How do you judge their skin sensory comfort?

To give a statement about the skin sensory comfort of textiles consisting of different patterns we test different parts of the textile. From these values the average wearing comfort, with regard to the percentage of the single parts in the complete garment, is calculated.

12. Can textiles for children also be evaluated?

No. Children's skin is different from adults' skin. The Hohenstein Institute's evaluation system is not designed for children's skin.

13. Why do the textiles have to be washed before the tests?

After production, brightening and finishing agents often remain in the textile that were needed during its manufacture. These can have a considerable effect on its skin sensory properties. Since textiles that are in direct contact with the skin are generally only worn when they have been washed, or at most once in their brand-new state, washing them before the tests is more realistic.

14. Do detergents, fabric softeners and finishers have any effect on skin sensory properties?

The effect of these products on skin sensory properties can be significant. Softeners or impregnating agents in the final rinse can have a lasting detrimental effect on moisture transport and other skin sensory properties such as the wet cling index, stiffness and sorption index.

15. Can individual measurements also be carried out to resolve a specific problem?

Certainly. For example, the surface index can be used to compare the smoothness or hairiness of a textile in its new state and after use. The surface structure of a textile can be studied using the number of contact points. The textiles do not necessarily have to be intended for use in clothing.

16. How can data concerning skin sensorial properties be used for the perception of size and fit?

The skin sensory perception is caused by the construction of the textile, i.e. of fiber material, yarn, knit or weave and finishing. The perception of size and fit, however, is caused by the construction of the garment. Clothing physiology starts with the textile as material area, whereas clothing technology and, thus, tests of size and fit proceed from the ready-made garment or the garment in construction. Therefore the data cannot be used for the perception of size and fit.

17. Why can't compression textiles or shapewear be assessed?

These textiles exert pressure on the skin that can vary greatly. The sensations are therefore different from with textiles which only rest or lie loosely on the skin. The sensation of pressure is normally too strong for any other skin sensory perceptions to be noticed at all.

18. Which tests can be used for e-textiles (textiles with sensors and electronic components)? Do the normal tests apply?

There are no special skin sensory tests for textiles with sensors; the sensory perception of humans is independent from the kind of the textile – the textile feels comfortable on the skin or not.

19. Which marketing tools can be obtained?

If the skin sensorial comfort vote is good or very good, the tested products can be marketed with the Hohenstein quality label "Skin sensorial comfort vote".

20. What benefits does this product endorsement bring me as a producer?

The label uses a system of marks to provide information about the skin sensory comfort of the product. For consumers, the label offers a reliable and easily understood assessment of how comfortable the article will be to wear. This means you create confidence among consumers and make your products easily recognisable, with the chance of gaining new customers and reducing the number of returns.

21. How do I receive the label?

Use of the label is covered by a contract. Once we receive the signed contract, the label is prepared and sent to the customer by email.

Test methods

22. How does the test with the Skin Model run, and which properties does it have?

The Skin Model, developed by the Hohenstein Institute, has a measuring plate of 20 cm by 20 cm. The principle is that water vapour rises through a porous metal plate and simulates the thermoregulation of the skin by keeping the plate to 35 °C. By the evaporation process the plate cools, and an energy input is necessary to keep the temperature of the plate. Based on the values of energy input and further constants the water vapour resistance and the thermal resistance are measured.

23. Why does measuring the water vapour resistance, and therefore calculating the "breathability", form part of the skin sensorial comfort vote?

If the "breathability" of a textile is poor, the microclimate between the textile and the skin becomes damp. This dampness affects both the textile and the skin. Moist, sweaty skin is more sensitive and therefore more likely to be irritated by the textile. That is why good breathability is also an important part of skin sensory comfort.

24. Can you measure the contact points of socks in a shoe?

We have already tested the contact points of socks; however, technically a test within a shoe is not possible. Our test equipment is not constructed for such a test. Skin sensory tests of socks within a shoe can only be performed with wearer trials.

25. Is the wet cling index of a woven fabric tested only horizontally?

Yes, the measurement is done horizontally, in correlation, however, to the vertical perception of the wearer. This has been validated with numerous wearer trials.

26. Does wet cling of cotton get offset by absorption?

Cotton is very absorbent, but it does not transport the sweat from the skin into the ambience– thus, a cotton textile clings to sweat wetted skin.

27. What difference in water vapour resistance value does a person feel?

The perception of difference in water vapour resistance is dependent on the one hand on the end-use and on the other on the value of water vapour resistance itself. If e.g. a shirt, made of a thin woven fabric, has a water vapour resistance of, let us say, 5 m²Pa/W, the difference to a shirt of for example 2,5 m²Pa/W is perceived by the wearer. However, the difference of two sweaters with a water vapour resistance of e.g. 25 or 30 m²Pa/W, respectively, usually is not perceived.

28. Isn’t the skin tolerance of natural fibres (such as cotton with particular finishes) better for different working environments than the tolerance of artificial fibres?

Cotton would not be the first choice for functional garments worn directly on the skin, e.g. by fire fighters. When a person is sweating heavily, knitted fabrics made from cotton get wet and stay wet. Not only is the thermoregulation of the person impaired by the wet garment because it interferes with the evaporation, also the wetted skin becomes more sensible for irritation. If natural fibres for functional garments are demanded we would recommend very fine merino wool fabrics. Their wearing comfort can be very good