UPF
UPF is an ultraviolet protection factor that indicates how much UV light clothing and textiles block, based on the effect on the skin when exposed to ultraviolet light.
Contents6 sections
Definition and Overview
UPF is an indicator of the performance that suppresses ultraviolet rays passing through clothing and textile. A higher value indicates higher ultraviolet protection performance, but the stated value is an evaluation under specified test conditions and does not uniformly guarantee the protective effect when worn.
UPF is not the material name, weave or knit structure, or processing name of the textile, but an evaluation of performance related to ultraviolet rays. Even with the same material, UPF changes depending on color, density, thickness, yarn type, and post-processing.
Factors That Affect Performance
In general, dark-colored, high-density, and less sheer textiles tend to block ultraviolet rays more effectively. On the other hand, light-colored, thin, coarse mesh, and highly sheer textiles may have lower UPF. Do not judge performance by appearance, color, or thickness alone; check the test value.
Some treatments use ultraviolet absorbers or ultraviolet scattering agents to improve ultraviolet protection performance, and some use special raw materials or yarns. However, these formulations may affect hand feel, water absorbency, breathability, and color, so confirmation according to the application is necessary.
- UPF is an index of ultraviolet protection performance.
- Ultraviolet shielding rate is an indicator of the proportion of ultraviolet rays blocked.
- UV-cut treatment is one method used to add or improve ultraviolet protection performance.
Main Applications
Textiles with UPF labeling are used for spring and summer shirts, blouses, dresses, pants, outerwear, and other items that are exposed to sunlight. Materials that combine light weight and breathability are also suitable for sports, outdoor wear, uniforms, and kids' clothing.
Swimwear and rash guards, and other items worn near water, also require ultraviolet protection performance. Because wetness, stretching, and close contact with the body change the state of the textile, it is important to confirm whether the testing and labeling are intended for that application.
Selection and Handling Precautions
When planning, select not only the target UPF value, but also the test values for light and dark colors, sheer level, breathability, quick-drying absorbency, and heat shielding comprehensively. If the product is labeled, also clarify whether the value is for the textile alone or for the finished product after sewing.
Washing, friction, long-term exposure to sunlight, and water containing chlorine can change the color and condition of the treatment, which may affect performance. Check the results of wash durability tests and care labeling, and evaluate whether the required performance is maintained after the expected number of washes.
Cutting and sewing themselves do not increase the UPF value. Seams, darts, pocket openings, and similar areas have overlapping fabric, but some areas may also open more easily due to stretching or pulling, so sample checks should be carried out with consideration for stretch during wear and the specifications.
Differences from Similar Terms
UV-cut treatment refers to processing that adds the function of suppressing ultraviolet rays, while UPF is the index that evaluates the result. A high-density textile without such treatment may still achieve UPF, so UV-cut treatment and UPF do not mean the same thing.
Ultraviolet shielding rate is a numerical value that shows the proportion of ultraviolet rays blocked by the textile under specific conditions. Because the evaluation concept differs from UPF, the two cannot be simply converted even if the shielding rates are similar. In specifications, state the test method and the basis for the labeling together.
Frequently Asked Questions
What is the difference between UPF50 and UPF50+?
The plus sign appended to UPF is sometimes used to collectively indicate a certain high evaluation range. However, handling differs depending on the standard and labeling criteria adopted, so do not compare only the numbers; check the test method, testing organization, and conditions before and after washing.
Can white or light-colored textiles also be made with a high UPF?
Yes. Methods include weaving or knitting at high density, suppressing sheerness, and using raw materials or treatments that provide ultraviolet protection functions. However, because these may affect hand feel, breathability, water absorbency, and appearance, test the actual light color and judge according to the intended use.
Does UPF decrease after washing?
It depends on the structure and treatment method of the textile. Washing may increase density if the textile shrinks, but performance may also change due to the loss of treatment agents, stretching, pilling, or fading. It is necessary to confirm wash durability and handle the product according to its care label.
