Maintainability Analysis of Remotely Operated LNG Marine Loading Arms Based on UNE 151001 Standard
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper can be accepted after a minor revision.
1. The resolution of Figure 2 and Figure 3 should be improved.
2. Line 418 mentioned surveillance. Does this one refer to ‘monitoring’ in line 339? Need to be consistent.
3. In Line 438 ‘six maintainability indicators’, why and which six are not clear.
Author Response
We would like to thank the referee 1 for all the valuable comments and suggestions for improving the manuscript. Below are detailed responses to each of them.
The paper can be accepted after a minor revision.
1. The resolution of Figure 2 and Figure 3 should be improved.
The figures were improved in terms of resolution.
- Line 418 mentioned surveillance. Does this one refer to ‘monitoring’ in line 339? Need to be consistent.
We kept the term surveyance. Done.
- In Line 438 ‘six maintainability indicators’, why and which six are not clear.
The expression was replaced by the following text: “The evaluation of six maintainability indicators is required: a general maintainability indicator that is obtained from the evaluation of the general attributes of the equipment plus five specific maintainability indicators, one for each level of maintenance (see Table 1).”
Reviewer 2 Report
Comments and Suggestions for AuthorsThis study pays attention to the maintenance demands of LNG marine loading arms. This topic is interesting and the paper is well-organized. I have the following concerns.
1. I am curious about the distinctive features of LNG marine loading arms. And I think these distinctive features can help develop the research motivation.
2. The theoretical and practical contributions of this study should be summarized.
3. LIne 453-471, the symbols in the formula need to be italicized.
4. How to determine the weight in each table?
5. Why choose UNE 151001 standard?
Comments on the Quality of English Language
The writing is easy to understand.
Author Response
Reviewer 2
We appreciate the valuable comments and suggestions provided by Referee 2 to enhance the manuscript. Detailed responses to each comment are provided below.
This study pays attention to the maintenance demands of LNG marine loading arms. This topic is interesting and the paper is well-organized. I have the following concerns.
- I am curious about the distinctive features of LNG marine loading arms. And I think these distinctive features can help develop the research motivation.
We believe that the distinctive characteristics of LNG marine loading arms and the importance of ensuring their operational continuity are detailed in the first paragraphs of the introduction.2. The theoretical and practical contributions of this study should be summarized.
- LIne 453-471, the symbols in the formula need to be italicized.
Done.
- How to determine the weight in each table?
The procedure has been extended and refined. It is detailed in the latest version of the manuscript (see section…).
In this section, we discuss the application of a Fuzzy AHP to determine the weight of each index for calculating the Global Maintainability Index. Regarding the weights in each table, as the standard points, the specialist or group of specialists must assign values based on the predefined values and scales established by UNE151001.
- Why choose UNE 151001 standard?
Because there are no specific maintainability analysis standards explicitly dedicated to industrial equipment, there is a Chinese standard and a military standard that are more focused on the product. These standards do not cover as many maintainability attributes and do not distinguish between levels for maintenance interventions.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe scientific article should primarily contribute scientific value, and in my opinion, this aspect is greatly blurred in the reviewed text. The authors do not emphasize the scientific aspect at all. I believe that the entire methodological part is rather poorly prepared. The authors have not demonstrated what new discoveries or insights they bring to science. In a scientific article, new discoveries, research, or insights should be presented, which contribute something new to the given field of science. Obviously, it can be, as in this case, the adaptation of a known norm to specific conditions, however, this requires justification as well as indicating the replicability and utility of the method itself. However, the formulated research objective does not indicate this at all:
“The main objective of this document has been to adapt and apply a method for evaluating Maintainability, based on the UNE 151001 standard, grounded on a set of indicators that allow quantifying the maintainability of liquefied natural gas (LNG) discharge arms.”
I also do not believe that the structure of the article is correct. There are too detailed information and definitions in the introduction, which I personally would include in the "materials and methods" section. In my opinion, in the introductory part of the article (introduction and literature review), the authors should demonstrate, against the background of current literature, the research gap and the innovation of their own research. The article should contribute to the existing scientific discussion precisely through a critical analysis of existing theories, previous research, and results. It was necessary to indicate the SCIENTIFIC research objective, identify the research hypothesis, and research problem. Only then present the solution to the problem, justifying why precisely a method such as "case study" was justified for use. It is important to demonstrate that the article is original, that it contains unique ideas that have not been previously published. However, the literature review presented does not prove this; it contains many general, widely known statements.
Additionally, a few minor comments:
Lack of references in the text to all tables
Inconsistent marking of indicators (in subscript or without subscript)
I believe that large tables, occupying several pages, should be included in the appendix.
Author Response
We deeply appreciate your comments and suggestions for improving our manuscript. We have taken the time to review each of your points and have made the necessary modifications to address your suggestions. Below, we present our detailed responses to each of them.
Comment 1: The scientific article should primarily contribute scientific value, and in my opinion, this aspect is greatly blurred in the reviewed text. The authors do not emphasize the scientific aspect at all.
Response: Thank you for your observation. We have revised the methodological section to clearly emphasize the scientific aspects of our research. We have added a more detailed discussion on the preliminary steps to the application of the procedure dictated by the UNE 151001 standard, that is, how the analysis begins with the application of RCM and the determination of criticalities. Subsequently, and as detailed in the methodology section, we have proposed a phase that we have called MCA, to complement the RCM-based analysis with a procedure for analyzing the maintenance levels to be considered in the maintainability analysis according to the UNE 151001 standard. Additionally, we detail the incorporation of the AHP analysis for obtaining the weights at each level and in obtaining the Aggregated Maintainability Index
Comment 2: I believe that the entire methodological part is rather poorly prepared. The authors have not demonstrated what new discoveries or insights they bring to science. In a scientific article, new discoveries, research, or insights should be presented, which contribute something new to the given field of science.
Response: As we mentioned in the previous response, we have reorganized the methodological section to clarify and delve into the new findings of our research. This includes a decision diagram for determining the maintenance levels to be considered in the maintainability analysis, a Decision Sheet that has been attached to the proposed RCM, and the use of AHP for obtaining the weights in the overall and level-specific maintainability analysis, to which we have added concrete examples and empirical data that support this procedure. Additionally, we propose the creation of an Aggregated Maintainability Index to demonstrate, in a single index, the maintainability characteristics of a given physical asset.
Comment 3: Obviously, it can be, as in this case, the adaptation of a known norm to specific conditions, however, this requires justification as well as indicating the replicability and utility of the method itself. However, the formulated research objective does not indicate this at all.
Response: We have revised the research objective to include a more explicit justification for adapting the UNE 151001 standard. We have also added more detail aiming at the replicability and utility of the method for various operational scenarios and different physical assets.
Comment 4: I also do not believe that the structure of the article is correct. There are too detailed information and definitions in the introduction, which I personally would include in the "materials and methods" section.
Response: We have moved the detailed information and definitions from sections to sections to improve the manuscript's structure and enhance reader comprehension.
Comment 5: In my opinion, in the introductory part of the article (introduction and literature review), the authors should demonstrate, against the background of current literature, the research gap and the innovation of their own research. The article should contribute to the existing scientific discussion precisely through a critical analysis of existing theories, previous research, and results.
Response: We have modified the introduction to include a more detailed discussion of the research gap and the innovation of our work. We have added a critical analysis of existing theories, previous research, and relevant results.
Comment 6: It was necessary to indicate the SCIENTIFIC research objective, identify the research hypothesis, and research problem. Only then present the solution to the problem, justifying why precisely a method such as "case study" was justified for use. It is important to demonstrate that the article is original, that it contains unique ideas that have not been previously published.
Response: We have added the following text with objective of clarifying the research challenge and objective: In this paper, we propose a method to integrate this standard within an RCM context to improve the traceability of the assessments carried out during its application. Similarly, we incorporate the AHP technique for defining the weights during the level-specific maintainability analysis. Finally, in order to address the lack of a single maintainability indicator, we propose an aggregated indicator, which is constructed from the aforementioned AHP-based procedure.
Comment 7: However, the literature review presented does not prove this; it contains many general, widely known statements.
Response: We have revised and updated the literature review and we have added more specific and relevant references that pursuit to demonstrate the novelty and scientific value of our work.
Additionally, a few minor comments:
Lack of references in the text to all tables.
This situation was corrected.
Inconsistent marking of indicators (in subscript or without subscript)
This issue was corrected.
I believe that large tables, occupying several pages, should be included in the appendix.
Some of the tables were relocates in an appendix.
We once again appreciate your valuable suggestions and are confident that these improvements will enhance the quality and impact of our manuscript.
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors took my comments into account, in my opinion the article can be published.
