# The Ability to Control VOC Emissions from Multilayer Building Materials
## 4 Conclusions  
The authors of the article present a method of assessing VOC emission from electrically heated floors using the modified chamber method. A provided method has new methodological and research elements. The article presents the practical application of the electrically powered radiant floor heating system in the laboratory conditions designed and used for VOC emissions tests (in a chamber). The system has to simulate the real conditions of electrically heated floors in dry and wet conditions. The authors studied the influence of various environmental conditions on the VOC emission from several tested floor systems (and construction products). Test were performed under working conditions of floors heated in dry-type rooms (t = 29 \({}^{\circ}\)C and RH = 50%) and wet-type rooms (t = 33 \({}^{\circ}\)C and RH = 80%) under standardised conditions for testing the emissions of building materials (23 \({}^{\circ}\)C and, respectively, RH = 50% or 80%). Considering the proposed method and obtained results, the authors provide the following conclusions:  
1. Test methods according to standards such as EN 16516 + A1 [5] providing test conditions at 23 \({}^{\circ}\)C (at \(n\) = 1 h\({}^{-1}\)) are not representative of the working conditions of the radiation floor, where the surface in the wet conditions is 33 \({}^{\circ}\)C and in dry conditions, 29 \({}^{\circ}\)C. Therefore, the authors propose their own experimental test method and C(\(t\)) model (17) allowing the determination of a profile of VOC concentration over time based on the obtained experimental results. For each tested sample, the model parameters (including \(k_{1}\) and \(k_{2}\)) were numerically determined. 2. The VOC concentrations in the experimental tests are delayed in relation to those resulting from the single-layer model (14) and the maximum peak appears much later. It results directly from the multilayer floor system's higher diffusion resistance. As the authors found out, on the basis of laboratory analyses, the proposed model (17) composed of elements presented in the literature (ASTM standard [36], see introduction), but with the addition of a logarithmic delay factor X, better reflects the nature of emissions from multilayer floor products, and in our case, due to several layers of multilayer floor products and the upper layer (ceramic tiles, wooden \"parquet\" panel), it gives good traceability with the obtained VOC results with determination R\({}^{2}\) in a range from 0.7 to 0.95. In Equation (18), the coefficient \(a\) from the proposed delay term X= \(a\cdot\log(t)\) chyba X = \(a\) log(\(t\)) + \(b\) takes in practice the value from 0.45 to 0.55 in the model fittings. The delay component reaches the value close to one in the time for \(C_{max}\). 3. The authors showed a significant effect of floor temperature on the level of VOC concentration in the chamber over time. Under conditions RH = 80% and 33 \({}^{\circ}\)C, the maximum concentration values in time \(C_{max}\) were higher by 124% (then for standard 23 \({}^{\circ}\)C) and under RH = 50% and 29 \({}^{\circ}\)C, conditions were 183% in relation to the \(C_{max}\) value at 23 \({}^{\circ}\)C (see Table 5). The percentage effect of increasing \(C_{max}\) with increasing a floor temperature T1 (RH = 80%) from 23 \({}^{\circ}\)C to 33 \({}^{\circ}\)C is twice as large as the effect of reducing ACH by half. 4. The greatest impact on the emission of volatile organic compounds for samples with a floor temperature of 29 \({}^{\circ}\)C and 33 \({}^{\circ}\)C is observed in the first 10 days from the test's start. In several tests in the first days, authors recorded very high TVOC concentrations (several thousand \(\mu\)g m\({}^{-3}\)), which can be considered, according to the literature [49; 50; 51], to have a serious impact on the health of the building users. This clearly shows that after the floor in the room has been made, the rooms should be ventilated without people inside for at least a dozen or so days. 5.