# A Sustainability Analysis Based on the LCA-Energy-Carbon Emission Approach in the Building System
## 4 Results and Discussion
### LCA-Carbon Emission Analysis
#### 4.2.2 The Carbon Emission of Building Construction Stage  
During the construction phase, the specific carbon emissions of six subsystems are shown in Table 7. Therein, water supply and sewage system treatment facilities emit the most carbon dioxide, at approximately 22,640 tCO\({}_{2}\), accounting for 38.55% of the total construction carbon emission, followed by the telecommunications system (18,370.3 tCO\({}_{2}\), roughly 31.28%); labor and service (6341 tCO\({}_{2}\), roughly 10.79%); heating and cooling systems (5125.2 tCO\({}_{2}\), roughly 8.73%); the elevator system (4102.8 tCO\({}_{2}\), roughly 6.98%) and electricity installations (2151.1 tCO\({}_{2}\), roughly 3.66%), etc. In Figure 12A, the trend of fluctuation can be clearly identified. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Item** & **Data** & **Unit** & \
\begin{tabular}{c} **Carbon Emission** \\ **Factors** \\ \end{tabular} &
\begin{tabular}{c} **Carbon** \\ **Emission** \\ \end{tabular} & **Unit** \\ \hline Steel & \(2.5\times 10^{7}\) & Kg & 2.67 tCO\({}_{2}\)/t & 66,750 & tCO\({}_{2}\) \\ \hline Cement & \(4.7\times 10^{6}\) & Kg & 0.07 tCO\({}_{2}\)/t & 329 & tCO\({}_{2}\) \\ \hline Gravel & \(1.9\times 10^{6}\) & Kg & 16 kgCO\({}_{2}\)/kg & 30,400 & tCO\({}_{2}\) \\ \hline Brick & \(3.8\times 10^{6}\) & Kg & 0.24 kgCO\({}_{2}\)/kg & 912 & tCO\({}_{2}\) \\ \hline Lime & \(3.1\times 10^{5}\) & Kg & 0.44 tCO\({}_{2}\)/t & 136.4 & tCO\({}_{2}\) \\ \hline Sand & \(2.9\times 10^{6}\) & Kg & 2.51 kgCO\({}_{2}\)/t & 7.279 & tCO\({}_{2}\) \\ \hline Water & \(5.9\times 10^{5}\) & M\({}^{3}\) & 0.82 kgCO\({}_{2}\)/m\({}^{3}\) & 483.8 & tCO\({}_{2}\) \\ \hline Iron & \(6.4\times 10^{5}\) & Kg & 2.05 tCO\({}_{2}\)/t & 1312 & tCO\({}_{2}\) \\ \hline Wood & \(1.7\times 10^{6}\) & Kg & 0.31 kgCO\({}_{2}\)/kg & 527 & tCO\({}_{2}\) \\ \hline Glass & \(3.5\times 10^{5}\) & Kg & 1.4 kgCO\({}_{2}\)/kg & 490 & tCO\({}_{2}\) \\ \hline Polyester & \(4.6\times 10^{3}\) & Kg & 72.65 tCO\({}_{2}\)/t & 334.19 & tCO\({}_{2}\) \\ \hline Adhesive & \(7.8\times 10^{3}\) & Kg & 1.1 kgCO\({}_{2}\)/kg & 8.58 & tCO\({}_{2}\) \\ \hline Bituminous & \(9.1\times 10^{3}\) & Kg & 0.04 kgCO\({}_{2}\)/kg & 0.364 & tCO\({}_{2}\) \\ \hline Aluminum & \(6.3\times 10^{3}\) & Kg & 15.8 tCO\({}_{2}\)/t & 99.54 & tCO\({}_{2}\) \\ \hline Ceramic tile & \(4.7\times 10^{4}\) & Kg & 0.74 tCO\({}_{2}\)/t & 34.78 & tCO\({}_{2}\) \\ \hline Polystyrene & \(5.1\times 10^{3}\) & Kg & 3.78 kgCO\({}_{2}\)/kg & 19.278 & tCO\({}_{2}\) \\ \hline Fly ash & \(5.9\times 10^{3}\) & Kg & 0.18 tCO\({}_{2}\)/t & 1.062 & tCO\({}_{2}\) \\ \hline PVC & \(7.4\times 10^{3}\) & Kg & 4.79 kgCO\({}_{2}\)/kg & 35.446 & tCO\({}_{2}\) \\ \hline Diesel fuel & 1244 & Kg & 3.797 tCO\({}_{2}\)/t & 4.723468 & tCO\({}_{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The carbon emission in the building material production stage. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Item** & **Data** & **Unit** & \
\begin{tabular}{c} **Carbon Emission** \\ **Factors** \\ \end{tabular} &
\begin{tabular}{c} **Carbon** \\ **Emission** \\ \end{tabular} & **Unit** \\ \hline \hline
**Labor and service** & & & & \\ \hline Diesel fuel & \(6.00\times 10^{2}\) & t & 3.797 tCO\({}_{2}\)/t & 2278.2 & tCO\({}_{2}\) \\ \hline Machinery diesel & \(9.00\times 10^{2}\) & t & 3.797 tCO\({}_{2}\)/t & 3417.3 & tCO\({}_{2}\) \\ \hline Transport diesel & \(1.70\times 10^{2}\) & t & 3.797 tCO\({}_{2}\)/t & 645.49 & tCO\({}_{2}\) \\ \hline \hline
**Water supply and sewage system treatment facilities** & & & \\ \hline Steel & \(5.21\times 10^{6}\) & Kg & 2.67 tCO\({}_{2}\)/t & 13,910.7 & tCO\({}_{2}\) \\ \hline PVC & \(8.41\times 10^{3}\) & Kg & 4.79 kgCO\({}_{2}\)/kg & 40.2839 & tCO\({}_{2}\) \\ \hline Polystyrene & \(2.67\times 10^{3}\) & Kg & 3.78 kgCO\({}_{2}\)/kg & 10.0926 & tCO\({}_{2}\) \\ \hline Brass & \(7.40\times 10^{3}\) & Kg & 3.73 tCO\({}_{2}\)/t & 27.602 & tCO\({}_{2}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 7: The carbon emission in the building construction stage.