Experimental Heat Transfer, Sound Insulation and Interior Comfort Parameters Assessment on a Box Double-Skin Façade

Round 1

Reviewer 1 Report

The authors need to clarify the merit of this work. It is important to show the main advantages of their proposed approach in comparison with other available methods. The results should be adjusted in such a way that can convince the readers about the reliability of your work.

Please mention the previous work about structural acoustic design optimization of rectangular frames as the following:

Ranjbar, St. Marburg, H-J Hardtke, “Structural-Acoustic Optimization of a Rectangular Plate: A Tabu Search Approach”, Journal of Finite Elements in Analysis and Design 50, pp. 142-146 (2012)

Author Response

Thank you for your comments.

We have explained the main advantage of our study from line 127 to 135.

We have included the recommended the previous work indicated.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors, the paper is interesting but some major revisions are needed.

1) please fix the reference order in the text! this must be 1, 2 , 3 etc and not as it is

2)  The treated topics lacks of a focus in the introduction. You state just that "they are important". Ok but WHY? please add some more papers and briefily discuss them. some hints:

doi.org/10.1016/j.apacoust.2020.107484

etc.

for comparison of the (at least) European facade sound insulation requirments, why did not you compare facade sound insulation index instead of indoor sound pressure?

doi.org/10.1016/j.apacoust.2009.08.011

etc.

Lines 66-69. I do not understand this statement. ISO 16283 series are meant for the index calculation. In this case, D2mnt or D2mntw. So I do not get why you are referring to sound pressure level and its reliability as a method...

Line 82: you keep repeating that thermal comfort is guaranteed by building elements. However, thermal comfort is not guaranteed by them by the edifice as a whole, thus comprising surfaces, service equipment AND building elements as well as clothing and done activities... This has to be clearly specified since you are mostly referring to indoor air temperature rather than thermal comfort!

Lines 132-135: why did you chose this precise assembling? is representing some typical Romanian construction?

line 143: CO2 meter? why? you do not have any source of CO2 inside...

lines 158 161: again WHY sound pressure levels? and not sound insulation index? sound pressure level directly depend on a) external sound source level and characteristics and b) the measurement point!

line 171-173: why did you use this generation? is this representative of something? no standard or literature which I know... so why?

Figure 4: it is clear that the sound source provide a serious flaw at about 800 Hz... why?

Figure 5: now the flaw is at 1000 Hz... does this sound strange only to my eyes?

Line 235: "office space" so this paper is focused on office spaces? please state it in the introduction!

lines 241-245 I disagree. The traffic provide a quite flat frequency trend more like a pink noise (which by the way suggested by the cited standard...) While your noise is not flat in frequency...

Figure 7: the box orientation is missing so these values could not be interpreted.

338-341 2013? why did it take so long to analyze these results? Is 2013 representing also 2022? or future? is this a typical year at least in Romania? please explain

The same two comments above can be applied to winter season paragraph

line 411 It is clear that humidity is very low, since you do not have any source of humidity inside!!

paragraph 3.3.2

I really do not get these results use... what you state is already acknowledged in literature and standards... and the facade has NO influence on it... so... WHY?

Author Response

Thank you for your comments.

Dear authors, the paper is interesting but some major revisions are needed.

1) please fix the reference order in the text! this must be 1, 2 , 3 etc and not as it is

Fixed.

2)  The treated topics lacks of a focus in the introduction. You state just that "they are important". Ok but WHY? please add some more papers and briefily discuss them. some hints:

doi.org/10.1016/j.apacoust.2020.107484

Added

etc.

for comparison of the (at least) European facade sound insulation requirements, why did not you compare facade sound insulation index instead of indoor sound pressure?

doi.org/10.1016/j.apacoust.2009.08.011

Added

etc.

Lines 66-69. I do not understand this statement. ISO 16283 series are meant for the index calculation. In this case, D2mnt or D2mntw. So I do not get why you are referring to sound pressure level and its reliability as a method...

We deleted the paragraph to remove the confusion

Line 82: you keep repeating that thermal comfort is guaranteed by building elements. However, thermal comfort is not guaranteed by them by the edifice as a whole, thus comprising surfaces, service equipment AND building elements as well as clothing and done activities... This has to be clearly specified since you are mostly referring to indoor air temperature rather than thermal comfort!

We have replaced thermal comfort with thermal insulation

Lines 132-135: why did you chose this precise assembling? is representing some typical Romanian construction?

Because it’s an experimental model, made on an existing building. It was part of a PhD.

line 143: CO2 meter? why? you do not have any source of CO2 inside...

The experimental room was designed as an office room, for one person. DSF can have natural, mechanical, hybrid or no ventilation and thus can influence the CO2 concentration inside the room.

lines 158 161: again WHY sound pressure levels? and not sound insulation index? sound pressure level directly depend on a) external sound source level and characteristics and b) the measurement point!

This part of our research was intended just to show that the presence of a third layer of glass on a curtain wall lowers the sound pressure levels inside the rooms.

Sound pressure levels can be easily measured while the sound insulation index is a laboratory-only measurement. 

line 171-173: why did you use this generation? is this representative of something? no standard or literature which I know... so why?

Traffic noise is between 400 and 1100 Hz. We extended the measurement interval to 3000 Hz just as a curiosity, to observe the differences.

Figure 4: it is clear that the sound source provide a serious flaw at about 800 Hz... why?

We did measurements once again and the mean value for that frequency was 98.2 Hz.

Figure 5: now the flaw is at 1000 Hz... does this sound strange only to my eyes?

Wrong graph. We have included now the good one.

Line 235: "office space" so this paper is focused on office spaces? please state it in the introduction!

Specified

lines 241-245 I disagree. The traffic provide a quite flat frequency trend more like a pink noise (which by the way suggested by the cited standard...) While your noise is not flat in frequency...

We have removed the traffic word

Figure 7: the box orientation is missing so these values could not be interpreted.

The box orientation is indicated “In situ measurements were carried out in the city of Brasov, Romania on an experimental model that was built on the ground floor of the Civil Engineering Faculty, on the south façade of the building.”

338-341 2013? why did it take so long to analyze these results? Is 2013 representing also 2022? or future? is this a typical year at least in Romania? please explain

The same two comments above can be applied to winter season paragraph

The results are partially from a PhD research finished in 2014.

line 411 It is clear that humidity is very low, since you do not have any source of humidity inside!!

The experimental room was occupied by one person, only from time to time, for various daily experiments, not the entire measurement campaign, that’s why the average values are low. 

paragraph 3.3.2

I really do not get these results use... what you state is already acknowledged in literature and standards... and the facade has NO influence on it... so... WHY?

In this case it can have an influence, since the façade can be naturally, mechanically or hybrid ventilated. Now, with a person inside the experimental room, depending on the ventilation strategy, inside the cavity, the CO2 concentration can be different inside the room, considering that we had ventilation grilles on the lower and upper part of the interior double-pane window (the boundary between the cavity and the experimental room).

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors present an holistic study of the thermal and sound insulation performance of a box-like double skin facade. I congratulate the authors for this excelent work and thank them for sharing their research. The assessment methodology and analysis was very judicious. I recommend for publication in Buildings journal. Likewise, I would like to encourage the authors to include physical modelling in their future studies which may help to further understand and optimize the performance of building systems.

Author Response

We thank you very much for the time and effort put into considering and reviewing our paper.

We will make another study in the future, that will include a physical modelling which may help to further understand and optimize the performance of building systems.

Kind regards,

Reviewer 4 Report

I can detect no problems with undue self-citation from the authors. The following recommendations are a MUST:
1. Results about noise should be presented in a way that acousticians can recognize. The outdoor signal should be presented using a wideband noise source with a usable frequency range of 50 Hz to 5000 Hz. Results should be shown as sound insulation according to ISO 16283-3 or 16283-1, both of which require a presentation in standard 1/3-octave bands. More than one position of the noise source is highly recommended.

And then some suggested by the reviewer (obviously not mandatory):

A method to determine indoor level using the outdoor spectrum and the level difference measured with a loudspeaker because the level difference in dBA may be different with a different noise source, even with a different type of traffic noise:
Olafsen, S: Sound insulation against traffic noise in wooden houses, proceedings Baltic-Nordic Acoustical Meeting, Lyngby 2002

The effect of poor craftmanship may destroy the whole sound insulation:
Olafsen, S & Strand, M.K.:Field versus laboratory sound insulation of windows, proceedings Internoise 2009, Ottawa

For practical field work, here's another recommendation on how to control sound insulation of a facade:

Olafsen,S;   Bard, D; Strand, M.K.; Espejo, T.F:  Methods of field measurements of facade sound insulation  Noise Control Engineering Journal, Volume 63, Number 5, 1 September 2015, pp. 467-477(11)

Sorry, I had to mention these things, as it would be important to be able to implement the research work in practical building design

Author Response

We totally agree with your observations, but noise is most commonly described in terms of a sound pressure level, and as this paper is focused on experimental, practical measurements, instead of a scientific approach.

We have included all the indicated citations.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Authors, most comments have been addressed.