Study on the Bathroom Space and the Application of Same-Floor Drainage in Congregate Housing

Round 1

Reviewer 1 Report

The article is not very innovative, but the approach is unpublished, so it can be considered for publication. However, it should be mentioned as a less positive aspect the fact that it focuses on Taiwan's constructive practice and economic reality, which makes it difficult to generalize the conclusions.

The discount rates adopted must be justified, all the more so as it is unusual to consider negative rates for very long periods.

Construction costs vary with location, economic context, materials applied, etc., etc. Therefore, the values indicated in the Tables seem to be too detailed, justifying their rounding.

Figures 2, 3 and 4 must be referred to in the text before their inclusion.

Author Response

Thank you for your comments. Modifications to the manuscript are labeled in red.

1. The discount rates adopted must be justified, all the more so as it is unusual to consider negative rates for very long periods.

Thank you for your comments. In this study, the discount rates of -0.01% and 0.29% were used to calculate the life cycle cost. The discount rate values were determined based on the average interest rate of the five major banks in Taiwan defined by the Central Bank of the Republic of China as well as the annual growth rate of the Consumer Price Index (CPI) for balancing the inflation. The 20-year interest rate and inflation rate were also used as a reference. The final cluster was obtained through cluster analysis to improve the accuracy of future estimates.

2. Construction costs vary with location, economic context, materials applied, etc., etc. Therefore, the values indicated in the Tables seem to be too detailed, justifying their rounding.

Thank you for your comments. The values for the cost analysis have been rounded off to the nearest hundred.

3. Figures 2, 3 and 4 must be referred to in the text before their inclusion.

Thank you for your comment. The description of Figure 2 to Figure 4 has been revised.

Author Response File: Author Response.docx

Reviewer 2 Report

This study uses life cycle cost analysis for investigating the construction piping of traditional piping system method as well as the construction piping of Same-Floor Drainage. The results show that even though the adopting Same-Floor Drainage increases the cost by about 0.3%-2.7%, the benefits of maintenance and construction time are significant. Therefore, this paper should have academic and practical reference value. To make the paper more in line with the accepted publication level, the following suggestions are provided to the authors as a reference when revising the article.

1. Please explain why two discount rates of -0.01% and 0.29% (or 2.9%) were used to calculate life cycle cost in this study?
2. In recent years, many journal articles on similar topics have used the term "Same-Floor Drainage" instead of "same-floor draining".
3. Figure 3 and Figure 4 may have errors, usually toilet drainage and floor drainage do not use the same vertical drainage pipe.
4. Please supplement the data source in Table 1, Table 2 and Table 3 (for example: market price survey or literature)
5. The full English name of NTD should be New Taiwan Dollar.
6. This paper should explain why "same-layer drainage" can reduce maintenance and repair costs compared to traditional drainage methods to demonstrate the core value of this research. In addition, the author should also avoid overly optimistic reduction in maintenance costs for "same-layer drainage".
7. It is recommended to adjust the maximum and minimum vertical coordinates of some analysis diagrams (Figure 6 to Figure 10) so that readers can read the information in the analysis diagram more clearly.
8. Reference format is incorrect and should be corrected.
9. It is recommended to increase the number of citations of journal articles in recent years as a comparison between the research methods of this research and the analysis of research results.
10. It is recommended to use templates for article writing.

Author Response

Thank you for your comments. Modifications to the manuscript are labeled in red.

1. Please explain why two discount rates of -0.01% and 0.29% (or 2.9%) were used to calculate life cycle cost in this study?

Thank you for your comments. In this study, the discount rates of -0.01% and 0.29% were used to calculate the life cycle cost. The discount rate values were determined based on the average interest rate of the five major banks in Taiwan defined by the Central Bank of the Republic of China as well as the annual growth rate of the Consumer Price Index (CPI) for balancing the inflation. The 20-year interest rate and inflation rate were also used as a reference. The final cluster was obtained through cluster analysis to improve the accuracy of future estimates.

2.In recent years, many journal articles on similar topics have used the term "Same-Floor Drainage" instead of "same-floor draining".

Thank you for your comments. Correction to “Same-Floor Drainage” has been made.

3. Figure 3 and Figure 4 may have errors, usually toilet drainage and floor drainage do not use the same vertical drainage pipe.

Thank you for your comments. Figures 2 - 4 have been revised.

4. Please supplement the data source in Table 1, Table 2 and Table 3 (for example: market price survey or literature)

Thank you for your comments. The data is based on the market survey price. Further explanation has been added to the manuscript.

5. The full English name of NTD should be New Taiwan Dollar.

Thank you for your comments. Correction to “New Taiwan Dollar” has been made.

6. This paper should explain why "same-layer drainage" can reduce maintenance and repair costs compared to traditional drainage methods to demonstrate the core value of this research. In addition, the author should also avoid overly optimistic reduction in maintenance costs for "same-layer drainage".

Thank you for your comments. Currently, the same-layer drainage technique is not common in Taiwan. Therefore, for cost analysis, market surveys of actual construction projects in northern, central and southern Taiwan, as well as in-depth interviews with industry experts from general contractors and construction companies were conducted in this study. Based on the techniques, construction methods, and materials used for the same-layer drainage, initial costs for building the sanitary system were obtained, thus improving the accuracy of the result.

7.It is recommended to adjust the maximum and minimum vertical coordinates of some analysis diagrams (Figure 6 to Figure 10) so that readers can read the information in the analysis diagram more clearly.

Thank you for your comments, the maximum and minimum values of the vertical axis been revised.

8.Reference format is incorrect and should be corrected

Thank you for your comments. The format of the references has been revised.

9.It is recommended to increase the number of citations of journal articles in recent years as a comparison between the research methods of this research and the analysis of research results.

Thank you for your comments. The journal articles has been added.

10. It is recommended to use templates for article writing.

 Thank you for your comments.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors have rewritten and improved the article based on all the review comments. Therefore, this article should meet the publication standard. English language and style are need slight spell check.

Author Response

Thank you for your comments. English has been re-edited.

Author Response File: Author Response.docx