The First 3D-Printed Building in Spain: A Study on Its Acoustic, Thermal and Environmental Performance

Round 1

Reviewer 1 Report

The paper makes an interesting contribution to the topic of innovation in construction and sustainability considered under different aspects. The authors enumerate many of them: ease and safety in construction, energy and acoustic performance, environmental impact. Others could be mentioned in the paper in the introduction or in the section on research developments: e.g. the innovations that 3D printing technology can introduce in construction materials; the possible use of recycled materials; the absence of material waste during construction; the possibility of demolition, dismantling or recycling at the end of life. Important issues for sustainability in the life cycle. 

The authors then develop the thermal, acoustic and environmental performance in the life cycle with experimental tests and calculations. The development of the research is correct and the methods of calculation and on-site verification are well described. On the bibliography, I have a few suggestions to expand and update it, which I reproduce below.

In detail.

- Lines 58-66 

Citing a few examples of 3D printed houses, I recommend that the reference dates be stated for each one and that a clear distinction be made between cases where 3D printing of architectural components or of housing units is involved. Furthermore, something must be said about the material used in the cases cited. More frequently for building components, materials such as gypsum and cement with fine aggregates and also fine stone powder are used [H. Strauss, AM Envelope: The Potential of Additive Manufacturing for Façade Constructions, TU Delft, 2013. H. Strauss, U. Knaack, Additive manufacturing for future facades, J. Facade Des. Eng. 3 (2016) 225-235.], but

there are also examples of 3D-printed bioplastic for façade components (see the Mobile Europe Building, by Heijmans & DUS Architects).

- Lines 80-82

It should also be mentioned that LCA is referred to by construction standards as a method for assessing and declaring the environmental performance of components and buildings (UNI EN 15804, ''Sustainability of construction works. Environmental product declarations. Core rules for the product category of construction products" 2012-13).

- Line 116 and lines 124-125 

I suggest giving a precise description of the material and be consistent with the LCI in Fig. 9.

- Fig. 3

There is a mistake I think in the legend of the middle figure: precast concrete panel (?).

- Section 2.4

It is necessary to say whether a cradle-to-gate LCA has been done and UNI EN 15804 must be cited.

The reference (35) must be updated: COMMISSION RECOMMENDATION of 16.12.2021 

on the use of the Environmental Footprint methods to measure and communicate the life cycle environmental performance of products and organisations. 

I suggest saying something more about normalisation and weighting referred to in the results and Figs. 12 and 13, which are important to evaluate the results.

- Line 249 

It is suggested that the authors consider citing an Italian study that applied LCA assessement to a hypothesised façade component made with 3D Printing (FDM) technique:

Esposito Corcione C., Palumbo E., Masciullo A., F., Torricelli M.C., (2018). "Fused Deposition Modeling (FDM): An Innovative Technique Aimed at Reusing Lecce Stone Waste for Industrial Design and Building Applications", Construction & Building Materials, Volume 158, 15 January 2018, Pages 276-284.

- In Fig. 10, I believe there is an error: 0.0692 m3 (?)

- Lines 392-396

I suggest that more emphasis should be placed on the fact that the 3Dprinting wall has a much greater mass (kg/m2) than the others, this causes a greater environmental impact, so a future research development could be to figure out how to lighten the concrete used for the 3D printing wall. Even if this could worsen acoustic performance and thermal inertia.

Author Response

Reviewer 1

 

The paper makes an interesting contribution to the topic of innovation in construction and sustainability considered under different aspects. The authors enumerate many of them: ease and safety in construction, energy and acoustic performance, environmental impact. Others could be mentioned in the paper in the introduction or in the section on research developments: e.g. the innovations that 3D printing technology can introduce in construction materials; the possible use of recycled materials; the absence of material waste during construction; the possibility of demolition, dismantling or recycling at the end of life. Important issues for sustainability in the life cycle. 

The authors then develop the thermal, acoustic and environmental performance in the life cycle with experimental tests and calculations. The development of the research is correct and the methods of calculation and on-site verification are well described. On the bibliography, I have a few suggestions to expand and update it, which I reproduce below.

In detail.

- Lines 58-66 

Citing a few examples of 3D printed houses, I recommend that the reference dates be stated for each one and that a clear distinction be made between cases where 3D printing of architectural components or of housing units is involved. Furthermore, something must be said about the material used in the cases cited. More frequently for building components, materials such as gypsum and cement with fine aggregates and also fine stone powder are used [H. Strauss, AM Envelope: The Potential of Additive Manufacturing for Façade Constructions, TU Delft, 2013. H. Strauss, U. Knaack,

Additive manufacturing for future facades, J. Facade Des. Eng. 3 (2016) 225-235.], but

there are also examples of 3D-printed bioplastic for façade components (see the Mobile Europe Building, by Heijmans & DUS Architects).

 

We have added the year in which each one of the references was published. We have reorganized the text in the introduction to create a more clear timeline in our literature review. We also have explained the references mentioned more extensively and added information about the materials that were used in each case.

 

We have also added the suggested references:

6. Straus, H. AM Envelope: The Potential of Additive Manufacturing for facade constructions, TU Delft, 2013.
7. Strauss, H.; Knaack, U. Additive Manufacturing for Future Facades. J. Facade Des. Eng. 2016, 3, doi:https://doi.org/10.7480/jfde.2015.3-4.875.
8. Facade of Dutch EU building uses 3D-printed bioplastic Available online: https://www.dezeen.com/2016/01/12/european-union-3d-printed-facade-dus-architects-holland/

Changes are located from line 45 to line 78

 

- Lines 80-82

It should also be mentioned that LCA is referred to by construction standards as a method for assessing and declaring the environmental performance of components and buildings (UNI EN 15804, ''Sustainability of construction works. Environmental product declarations. Core rules for the product category of construction products" 2012-13).

 

We have added a reference to the EN 15804

 

- Line 116 and lines 124-125 

I suggest giving a precise description of the material and be consistent with the LCI in Fig. 9.

 

We have added Table 1 in section 2.1 specifying the dosage of the micro-concrete. We have also added some clarifications in lines 139 to 142.

 

- Fig. 3

There is a mistake I think in the legend of the middle figure: precast concrete panel (?).

 

Thank you so much for pointing out this mistake. We have corrected the legend. Now it says masonry blocks

 

- Section 2.4

It is necessary to say whether a cradle-to-gate LCA has been done and UNI EN 15804 must be cited.

The reference (35) must be updated: COMMISSION RECOMMENDATION of 16.12.2021 

on the use of the Environmental Footprint methods to measure and communicate the life cycle environmental performance of products and organisations. 

I suggest saying something more about normalisation and weighting referred to in the results and Figs. 12 and 13, which are important to evaluate the results.

 

We referenced the EN 15804 and added an explanation on the LCA stages that the study covers:

According to the EN 15804, The stages accounted for are A1 to A5.

 

We added the following paragraph in section to further explain the normalization and weighting processes:

The EF methodology calculates the results in 18 different impact categories. The results express impacts such as Climate Change Potential or Eutrophication and Acidification. As a way of comparing the different impact categories, the method provides a normalization method that consists in multiplying each value by a characterization factor. This normalization process has the objective of expressing the relative impact of each impact category in terms of its contributions to the total environmental impact. The final step is the weighting, in which the normalized results are multiplied by a set of weighting factors that represent the perceived relative importance of the impact categories under consideration. This process allows the results to be compared across categories and summed to obtain a single score.

 

- Line 249 

It is suggested that the authors consider citing an Italian study that applied LCA assessement to a hypothesised façade component made with 3D Printing (FDM) technique:

Esposito Corcione C., Palumbo E., Masciullo A., F., Torricelli M.C., (2018). "Fused Deposition Modeling (FDM): An Innovative Technique Aimed at Reusing Lecce Stone Waste for Industrial Design and Building Applications", Construction & Building Materials, Volume 158, 15 January 2018, Pages 276-284.

 

We have added a reference to the suggested study in lines 57 to 60.

 

- In Fig. 10, I believe there is an error: 0.0692 m3 (?)

 

The 0.0692 m³ that appear in what it is now Table 12 (formerly Table 10) are not an error. That quantity refers to the amount of concrete necessary to manufacture the concrete blocks contained in 1m² of that specific façade typology.

 

- Lines 392-396

I suggest that more emphasis should be placed on the fact that the 3Dprinting wall has a much greater mass (kg/m2) than the others, this causes a greater environmental impact, so a future research development could be to figure out how to lighten the concrete used for the 3D printing wall. Even if this could worsen acoustic performance and thermal inertia.

We have added the following text to lines 405 to 407:

It is important to note that, in the case of the 3D-printed façade, the higher concrete mass is the cause of the higher carbon emissions. Future research could explore the possibility of lightening the concrete.

We have also improved the statement in the conclusions section that makes reference to this:

After summing the normalized and weighted impacts, the single score result obtained shows that the overall environmental impact of the 3D-printed façade is similar to the concrete block façade. The difference is mainly due to the higher amount of concrete by square meter needed to build the printed one. This could be improved either by reducing the cement content in the concrete or by creating a concrete pattern that leave voids of holes. Those solutions would be consequences in the acoustic and thermal performance that need further analysis.

Reviewer 2 Report

The paper entitled “The first 3D printed building in Spain: a study on its acoustic, thermal and environmental performance” wants to investigate the thermophysical, acoustical, and environmental performance of 3D printed building located in Valencia. The paper is interesting and the paragraphs are very well structured. The devices of measurements are quite described but I suggest adding other information. Indeed, the authors didn’t report time, period of measurements, weather conditions, tools used for energy simulation and so on. The paper doesn’t explore enough the state of art in the paragraphs on measurements. I should suggest the following as examples.: https://doi.org/10.3390/en13123237 ;  https://doi.org/10.3390/en5020227. There are many typo errors. The authors need to explain better the novelty of their approach and the conclusions should be extended adding some meaningful results and further development of the research in the field.

Author Response

Reviewer 2

The paper entitled “The first 3D printed building in Spain: a study on its acoustic, thermal and environmental performance” wants to investigate the thermophysical, acoustical, and environmental performance of 3D printed building located in Valencia. The paper is interesting and the paragraphs are very well structured.

 

1. The devices of measurements are quite described but I suggest adding other information. Indeed, the authors didn’t report time, period of measurements, weather conditions, tools used for energy simulation and so on.

We have added the information on the date and weather of the tests in lines 231 to 232 and lines 272 to 273.

We have specified the tool used to calculate the dynamic behavior of the façade in lines 244 and 245.

2. The paper doesn’t explore enough the state of art in the paragraphs on measurements. I should suggest the following as examples.: https://doi.org/10.3390/en13123237 ;  https://doi.org/10.3390/en5020227.

The two suggested studies have been added to section 2.2

3. There are many typo errors.

We have made a thorough revision and corrected all the errors we have encountered.

4. The authors need to explain better the novelty of their approach and the conclusions should be extended adding some meaningful results and further development of the research in the field

We have improved and extended the conclusion section.

Reviewer 3 Report

The paper presents an interesting approach based on 3D printing for buildings. The innovation of the current research work should be further highlighted and emphasized. At the same time, the authors should consider the following comments to improve the quality of the paper significantly.

1.       In the abstract, add a final statement that highlights the importance of this research and its possible potential. Also, introduce the problem in the initial lines of the abstract.

2.       The introduction needs to be improved by relating to the mechanics of the studied materials and their mechanical characteristics. The references to be included are:

- Aksoylu, C., Mendi, Ş. E., & Arda, S. (2016). Ses yalıtımında ses azaltım indisi modellerinin karşılaştırmalı olarak incelenmesi. (https://dergipark.org.tr/tr/download/article-file/259822)

3.       Did the authors describe the 3D building preparation methods following a certain standard or do they follow previous procedures? Mention the various standards followed for the tests.

4.       Show the experimental test photos. Also, give equations for calculations.

5.       The conclusion needs to be modified to summarize the research outcomes in short statements with clear observations. You must compare the results with different regulations and make a general recommendation.

6.       Section 3.1 and Section 3.2need deep discussion.

7.      The work is a good report of experiments investigation, but which are the lessons learnt? The authors have to clarify.

 

 

Author Response

Reviewer 3

The paper presents an interesting approach based on 3D printing for buildings. The innovation of the current research work should be further highlighted and emphasized. At the same time, the authors should consider the following comments to improve the quality of the paper significantly.

1. In the abstract, add a final statement that highlights the importance of this research and its possible potential. Also, introduce the problem in the initial lines of the abstract.

We have improved the abstract following your recommendations.

2. The introduction needs to be improved by relating to the mechanics of the studied materials and their mechanical characteristics. The references to be included are:- Aksoylu, C., Mendi, Ş. E., & Arda, S. (2016). Ses yalıtımında ses azaltım indisi modellerinin karşılaştırmalı olarak incelenmesi. (https://dergipark.org.tr/tr/download/article-file/259822)

The mentioned study was referenced in line 309.

3. Did the authors describe the 3D building preparation methods following a certain standard or do they follow previous procedures? Mention the various standards followed for the tests.

The tests followed the international standards required for each one of the situations were mentioned in the text. These standards are the following:

Thermal transmittance (Section 2.2) was measured following the guidelines of the ISO 6946:2017 (Building components and building elements.Thermal resistance and thermal transmittance ) and the ISO ISO 7345. (Thermal performance of buildings and building components. Physical quantities and definitions) and the ISO 9869-1. Thermal Insulation. Building Elements. In-Situ Measurement of Thermal Resistance and Thermal Transmittance. Part 1: Heat Flow Meter Method.

The thermal lag was calculated using the ISO 13786:2017. Thermal performance of building components. Dynamic thermal characteristics. Calculation methods

The sound reduction index was measured following the guidelines of the ISO 16283-3:2016. Acoustics. Field measurement of sound insulation in buildings and of building elements. Part 3: Façade sound insulation

 

4. Show the experimental test photos. Also, give equations for calculations.

Photos of the experimental testing have been added in sections 2.2 and 2.3.

The equations used have been added to section 2.2 and section 2.3.

5. The conclusion needs to be modified to summarize the research outcomes in short statements with clear observations. You must compare the results with different regulations and make a general recommendation.

We have improved the conclusions section to follow your recommendations. Now, the bullet points contain shorter statements. We have added a brief comparison of the energy requirements of some European countries according to the thermal insulation requirements in lines 465 to 469. We have added a summary and recommendations.

6. Section 3.1 and Section 3.2need deep discussion.

We have added more information about the results, especially in the conclusion section.

     7.    The work is a good report of experiments investigation, but which are the lessons learnt? The authors have to clarify.

We have added the lessons learned to the summary and general recommendation part of the conclusions section (lines 506 to 516)

Round 2

Reviewer 2 Report

The paper was improved and deserves to be published

Reviewer 3 Report

The authors have satisfactorily responded to all the reviewers' comments. The revised manuscritp can be accepted in its present form