**2.2 The modeling of the woven fabric with conductive yarns**

The following relations of electric conductive grids from the EMC literature was applied to model the woven fabric with silver yarns by reducing the distance of the grid in order to increase EMSE [14]:

$$\text{LMSE} = 20 \log \left( \frac{\lambda / 2}{\mathcal{W} \sqrt{\pi}} \right) \tag{1}$$


**Table 2.** *The woven fabric properties.*

$$\mathbf{W} = \frac{\lambda}{2\sqrt{\pi}} \times \mathbf{10}^{-\frac{\text{EMSE}}{20}} \tag{2}$$

With *W* = distance between metallic yarns in a woven fabric structure.λ = wavelength of the incident EM field.

According to the model (**Figure 6**), the distance of the electric conductive grid has to shift from W = 5 mm to W = 3 mm, in order to increase the EMSE of the woven fabric by 8 dB at 100 MHz. Since the functional unit for the comparative LCA study was set to one sqm of shielding fabric with 50 dB at 100 MHz; it resulted in two variants of textile shields:


The next step was to collect the LC Inventory data for these two EM shields.

#### **2.3 The LC inventory data**

LCI includes all the inputs and outputs into the system, such as raw materials, electricity consumption, auxiliary materials, etc. **Table 3** presents the mass per sqm for the two textile shields: sample 1 is manufactured, and sample 2 is modeled. Sample 1 was subsequently coated by magnetron plasma.

The LCI of silver yarns was computed by considering the ratio of Silver and PA6.6 mass of the Statex Silver yarn [35] and mean data for the spinning process [27]. The LCI of copper coated fabrics was computed by considering the mass

**Figure 6.** *Modeled and experimental EMSE.*

### *Life Cycle Assessment of Flexible Electromagnetic Shields DOI: http://dx.doi.org/10.5772/intechopen.99772*


#### **Table 3.**

*Specific mass for the woven structure with silver yarns.*


#### **Table 4.**

*LC inventory – Sample 1 (plasma coated woven fabric).*


#### **Table 5.**

*LC inventory – Sample 2 (modeled woven fabric).*

of copper, the energy consumption of the magnetron sputtering equipment for laboratory scale deposition, and the release of Argon into the air (data provided by INFLPR). LCI data is included within **Tables 4** and **5**.

The main challenge of the comparative LCA study is the additional Silver coated yarn needed for the grid of W = 3 mm related to the plasma copper coating of 1200 nm on both sides of the fabric with the grid of W = 5 mm. The manufacturing process of the PA6.6 coated silver yarns was estimated with mean values according to the spinning processes of various raw materials based yarns [27]. Single main input/output factors into the system were considered within the indicative LCA study. Limitations applied for transport, heat, etc., of the industrial weaving process at SC Majutex SRL. INFLPR provided the magnetron sputtering inputs/ outputs into the system.

**Figure 7.**

#### **Figure 8.**

*Comparative single score diagram: Sample1 (left) and Sample2 (right).*

#### **2.4 Life Cycle Impact Assessment diagrams**

By introducing the LCI data into the SimaPro software, the following LCIA diagrams resulted:

**Figure 7** presents the comparative impact of the two textile shields on impact categories of the method EcoIndicator 99E. The main negative impact on the environment is given by the carcinogens followed by Respiratory inorganics, which could be explained by releasing Argon into the air within the plasma process. Another wide difference between the two shields is at the impact category Minerals, while Fossil fuels for electric energy are quite balanced.

The Single score diagram (**Figure 8**) presents the total comparative impact on the environment for the two textile shields by a single view. One of the processes is industry (weaving of metallic yarns – Sample 2), and the other process is of laboratory (coating with metallic layers – Sample 1), which is why manufacturing one sqm of shielding fabric has a significant impact on the environment in the laboratory process. The corresponding LCIA data of the two processes offers significant differences when related to the functional unit.

#### **2.5 Scale-up of plasma equipment**

One of the LCA study consequences is the need to scale up the plasma equipment for industrial use. A business plan considering the investment for the

equipment and the Return-On-Investment and Break-even point analysis has been done and will be published in the near future. The scale-up magnetron plasma equipment represents the key expertise of INFLPR. Textile shields properties are key expertise of INCDTP and the experimental set-up for EMSE measurement expertise of ICPE-CA.
