# Waste Reduction Methods Used in Construction Companies with Regards to Selected Building Products
## 4 Results
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Building Product** & \multicolumn{2}{c}{**Affirmative Responses from the Respondents (YES) Regarding the Use of Waste Reduction Methods**} \\ \cline{2-4}  & **Very Often** & **Often** & **Rarely** \\  & **(\(\geq\)100 Enterprises)** & **(60–99 Enterprises)** & **(0–59 Enterprises)** \\ \hline \hline \multirow{4}{*}{Steel} & (1) Adequate storage & \multirow{4}{*}{(4) Use of monitoring systems} \\  & (2) Ordering products as per size and in the right quantity & (6) Appropriate involvement of \\  & (3) Training of employees in & subcontractors & \\  & (3) Training of employees in & (9) Waste segregation on site & management plan \\  & waste management & (10) Designation of a place for waste & (8) Use of prefabricated \\  & (5) Proper transportation and unloading & segregation & elements \\  & (7) Site security & (11) Reuse of products within the & \\  & (12) Timely delivery & construction & \\ \hline \hline \multirow{4}{*}{Concrete} & (3) Training of employees in & \multirow{4}{*}{(1) Adequate storage} \\  & (3) Training of employees in & \multirow{4}{*}{(4) Use of monitoring systems} \\  & waste management & (6) Appropriate involvement of \\  & (5) Proper transportation and & subcontractors & the construction \\  & (7) Site security & (9) Waste segregation on site & (13) Having a waste \\  & (10) Designation of a place for & management plan \\  & & segregation & \\  & (12) Timely delivery of products & \\ \hline \hline \multirow{4}{*}{Masonry products} & & (1) Adequate storage & \multirow{4}{*}{(8) Use of prefabricated} \\  & & (2) Ordering products as per size and in \\  & (7) Site security & (3) Training of employees in waste & (10) Designation of a place for \\  & (5) Proper transportation and & management & waste segregation \\  & unloading of products & (4) Use of monitoring systems & (11) Reuse of products within \\  & & (6) Appropriate involvement of & the construction \\  & & subcontractors & (13) Having a waste \\  & & (12) Timely delivery of products & management plan \\ \hline \hline \multirow{4}{*}{Masonry products} & & (1) Adequate storage & \multirow{4}{*}{(8) Use of prefabricated} \\  & (7) Site security & (2) Ordering products as per size and in \\  & (5) Proper transportation and & \multirow{4}{*}{(3) Training of employees in waste} \\  & unloading of products & management & (9) Waste segregation on site \\  & & (4) Use of monitoring systems & (11) Reuse of products within \\  & & (6) Appropriate involvement of & the construction \\  & & subcontractors & (13) Having a waste \\  & & (12) Timely delivery of products & management plan \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Classification of waste reduction methods in terms of their frequency of use in construction companies. The chi-square test was performed for five groups of products and 13 methods of reducing construction waste. The calculated values of the \(\chi^{2}\) statistics (4) and the probability \(p\) are presented in Table 3. The results of the research allowed, with a high degree of probability, for the determination of whether the application of a given method of waste reduction in relation to particular building products depends on the size of the company. Based on the analysis of the results presented in Table 3, it can be concluded that in each group of products waste reduction methods are used, and their frequency of application in a company either depends on its size \((p\leq 0.05)\) or there is no such relationship \((p>0.05)\). For comparison purposes, the frequency charts of the \"Use of monitoring systems\" method and the \"Timely delivery\" method for the five analyzed products groups and five sizes of construction companies are shown in Figure 6.  
Figure 6a shows a graph illustrating the frequency of applying the \"Use of monitoring systems\" method in companies of various sizes. The height of the bars for all groups of products indicates increasing trend of used methods along with the size of companies.