## 3 Results
### UV Protection  
When ultraviolet radiation strikes textile materials, different types of interactions occur depending on the substrate and its conditions. In other words, the UV protection of textile and clothing materials is a function of the chemical and physical-chemical characteristics of the fibers, the reinforcement of the fabric, the thickness, the porosity, the extension of the fabric, the moisture content of the fabrics, the color and the finish of the fabric itself. Consequently, deriving a reliable UV protection rate for fabric is not trivial, and traditional testing has not yet been established. Hence, the experiment was carried out according to recent literary works aimed at understanding the limits of the acceptability of the person to UV rays, especially in relation to skin color. As demonstrated in [20] the levels of acceptability (critical dose) range from a minimum of 15 mJ/cm\({}^{2}\) to a maximum of 100-200 mJ/cm\({}^{2}\) (see Table 6). Since the T4 Innovation prototype is designed for men's and women's clothing in the adult age of any nationality, the minimum value that is required must be lower than the minimum critical value shown in Table 6 (i.e., 10 mJ/cm\({}^{2}\)). A spectroradiometer is used to measure the real dose of UV radiation that passes through the newly designed fabrics. The part of the radiation that is transmitted through the fabric and reaches the skin is called the \"transmission component\". \begin{table}
\begin{tabular}{c c c c} \hline
**Skin Type** & **Critical Dose [mJ/cm\({}^{2}\)]** & **Self-Protection Time [min]** & **Risk Level** \\ \hline \hline White & 15–35 & 5–12 & \
\begin{tabular}{c} High risk of premature skin \\ aging, greatest risk of \\ developing skin cancer, burn \\ (and rarely tan) \\ \end{tabular} \\ Brownish & 30–50 & 10–15 & Tan and occasionally burn \\ Brown & 45–100 & 15–35 & Sufficient level of melanin: \\  & & & easily tan and rarely burn. \\ Dark brown -Black & 100–200 & 35–70 &
\begin{tabular}{c} Sufficient level of melanin: \\ easily tan and very \\ rarely burn. \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Critical UV dose depending to skin type. Figure 8: Waterproofing test on sample from fabric with code 286,290.  
component, UPF, increases with the density of the fabric and is inversely proportional to the porosity (i.e., UPF = 100/porosity). In detail, the UPF rate indicates how much of the sun's UV radiation is absorbed by the fabric. For example, a fabric with a UPF rating of 50 only allows 1/50 th of the sun's UV radiation to pass through it. To achieve a minimum UPF score of 15, which roughly corresponds to a transmission of 10 mJ/cm\({}^{2}\) at the daily average hourly irradiance standard value of 700 W/m\({}^{2}\), the fabric coverage factor must be greater than 93% and the fabric thickness greater than 1.5 mm. With regard to the type of fiber, from literature data [21] it can be deduced that the wool-synthetic fiber mix has average UPF values around 20-24 (if mixed in percentage 50%) while natural fibers such as linen or cotton allow higher values (e.g., UPF = 50). As far as color is concerned, as can be widely expected, the highest values of UPF are obtained for the white color. For the T4 Innovation prototypes developed in the paper, the coverage factor is 96.2%, thus guaranteeing a UPS value of at least 23-24. The thickness of the fabric, equal to 2.5 mm, offers additional protection from the fabric, which, therefore, in theory, has an overall value of UPF of at least 25-28. It is important to note that for Type 1 and Type 2 the percentage of wool fibers is, respectively, 60% and 67%. Since these fibers have a broad spectrum absorption range of 280-400 nm the main discriminating factor for the measuring of UV protection is related to the color used in dyeing (for the prototypes developed, goes from beige to red).