Acoustic - Sound Insulation Facades - Ift

7/27/2019 Acoustic - Sound Insulation Facades - Ift

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International Rosenheimer Window & Facade Conference2006Dr. Joachim HessingerSound Insulation of Facades

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Dr. Joachim Hessingerift Rosenheim

Sound Insulation of FacadesDoes each facade need an individual test? Simple extrapolation rules for sound insulation, interconnections and flanking sound transmission

1 IntroductionSound insulation of facades plays an increasinglyimportant role, not least due to the increaseinexterior noise exposure and the higher noiseaw areness of occupants and building users. How-ever, a certain degree of uncertainty with regardto sound insulation in the design and constructionof curtain w alls can be observed in the industry concerned. This article discusses the most important aspects of sound insulation of curtain walling. When considering the sound insulation of curtainwalls, tw o important aspects and their associatedcharacteristics should be considered (see Fig. 1):1. The airborne sound insulation against exterior

noise describes the ability of the curtain w all toreducethe sound emitted from exteriorsources.

2. The identification of the characteristics of theflanking sound insulation describes to w hatextent a facade in its role as a flanking buildingcomponent is able to influence the soundinsulation in the building interior.

The characteristics and the teststandards forboth parameters are summarized in table 1.

2 Rules and regulations relevant tocharacteristics and marking

2.1 Product standardCE marking of curtain walls according to theproduct standardEN 13830 : 2003 covers onlyairborne sound insulation. Evidence of perfor-

Figure 1Basic sketches:left: Sound protection against

exterior nois eright: Vertical linear sound

transmission across curtain

ift Rosenh eim International Rosenheimer Window & Facade Conference 2006 Page 1 of 6


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International Rosenheimer Window & Facade Conference2006Dr. Joachim Hessinger

Sound Insulation of Facades ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

mance is provided by laboratory testing of arepresentative test specimen. EN 13830 does notprovide any details for the selection of the testspecimen. The specified test value is Rw(C;Ctr).The product standard neither refers t o anyforecasting methods for calculat ion nor contains any tabulated values. The product standarddoesnot provide for classification of flanking soundinsulation, although the practice in Europeregarding invitations to tenders sh ows that it mustbe taken into account.

As a rule, the required flanking sound insulationof curtain walls is usually planned and specifiedby specialised design offices in the preparatoy phase of invitations to tenders. Characteristic quantities are the weighted normalised flankinglevel difference Dn,f,w(laboratory value) or thecalculated value of the linear w eighted soundreduction index RL,w,R = Dn,f,w 2 dB.

3 Airborne sound insulation ofcurtain walls

2.2 Application in Germany As regards sound insulation of buildings in Ger-many, the German standard DIN 4109 : 1989-11 specifies performance characteristics and values for sound insulation against both exterior and interior noise. For sound insulation against exte-rior noise, the calculated value of the w eightedsound reduction index Rw,R (deduction of atolerance of 2 dB) is used. As an alternativemeans of verification the completed project canbe inspected.DIN 4109 does not contain any specific requirements for the flanking sound insulation ofcurtain w alls, but flanking sound insulation is included in the design and verification of soundinsulation of adjacent separating walls and floors.

Verification of sound insulation of facades as perEN 13830 must be based on laboratory measurements according to EN ISO 140-3. Proceduresusing tabulated values,calculations or measure-ments in completed buildings are not suitable forproviding evidence of performance. Due to the fact that advance laboratory testing of facades is not always possible, the sound insulation ofcurtain walls must be forecast. This kind ofplanning, however, is uncertain due to lack of know-ledge or insufficient knowledge of many influ-encing factors.

In order to help the industry deal with thisproblem, the ift Centre for Acoustics prepared aconcept that contains specifications for the system testing of the sound insulation of curtain

Table1 Characteristic quantities and test standards of airborne sound insulation and flanking sound insulationCharacteristic

Laboratorytesting eighted sound reductionindex Rw (C;Ctr)

eighted structure- relatedsound reduction indexR45;W (C;Ct r)

eighted normalisedflanking sound pressure level differenceDn,f,w (C;Ct r)

Test standard EN ISO 140-3,EN ISO 717-1EN ISO 140-5,EN ISO 717-1EN ISO 10848-1and -2,EN ISO 717-1

Relevant omarking as per

product standard EN 13830

yesno

ApplicationDIN 4109

Calculated valueRw,R = Rw -2 dBRequirementR45,w = erf . Rw,resCalculated valueRL,w,R = Dn,f,w -2 dB

Airbornesound

Testing ininsulation completed

buildingFlanking

Laboratorysound

testinginsulation

no

Page 2 of 6 ift Rosenheim International Rosenheimer Window & Facade Confe rence 2006


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? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

walling which makes it possible to evaluate the sound insulation of thesetypes of facade. Theconcept is based on a combination of measurements made of selected facade elements,extrapolation rules, and calculations for theintegration of variations. The selection of the testspecimens and the extrapolation for different

facade variants are based on the parameters relevant to the sound insulation, which areschematically represented in Figure 2.As an example, the effects of glazing and the dependency on si zewill be discussed here:The dimensions of the individual panels or fields are likely to havean influence on the soundinsulation of the facade, e.g. as s hown in Figure 3.In order to estimate this effect, the extrapolationrules for windows set out in the product standardEN 14351-1, Annex B can be used for the time

being.Infills, i.e. the glazed or panel sections, areessential when it comes to assessing th e soundinsulation of a facade (see Figure 4). The values can be extrapolated for different infills based onthe sound insulat ion properties of the glass orpanel. These can be verified separately by testing or by using the tabulated values.

Figure 2 Schematic of a facade construction and hetechnical details relevant to sound transmis sion:a) Type of facade construction, e.g. unitised or

stick constructionb) Facade profil e sections, i.e. geom etry of

profiles, material, construction depths, face widths.

c) Dimensions of facade, i. e. field width andheightsd) Facade infills, i.e. IGU, panel fiel de) Inse rt units, e.g. windows, doors , ventilation

devices4 Flanking sound insulation ofcurtain wallsFlanking sound insulation is laboratory test ing according toand -2 (formerly D IN 52210-7).only be made by comparing

determined by EN ISO 10848-1A prediction canthe parameters

Figure 3Importance of size and dimensions ofinsulating glass units of similar configuration(from: archive if t Centre for Acoustics)



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International Rosenheimer Window & Facade Conference 2006Dr. Joachim Hessinger


relevant to sound insulation with the valuesprovided by literature [1]. Theseare:a) Direction of transmission horizontal/vertical,b) Characteristics of the profiles (material wood/

aluminium/steel, geometry, construction depth, construction type (divided/undivided),

c) Glazing system, in particular the inner pane,d) Connection to partitioning w all/ceiling/floor, tight-

ness of wall connection,e) Profiles positioned vertically to wall connec-

tions and hollow chambers,f) Connection to profiles or sheet panels in the

case of horizontal sound transmission.

In the special case of horizontal flanking soundinsulation of stick constructions, the flankingsound insulation is influenced to a great extent by the sound transmission through the facademullions. Here, a calculation formula can be usedthat combines by calculation the sound transmission through the mullions (the weighted

normalised sound level difference Dn,e,w) with thesound transmission across the remaining facade(influence of glazing, transoms, ...), see e.g. [1]and Figures 5 and 6. In this way, the sound insulation of different mullion/glazing combina- tions can be assessed in advance.

Dn, f, without mullions, w

Dn, e, Pf, wRw, wall

Figure5 Sound transmission paths of stickconstruction

55Soundreductioncurtain wallRw in dB

50

45

40

35

3030

Figure 435 40 45 50 55

Sound reduction glazing Rw,P,Glass in dB Sound insulation of curtai n walls featuring fixed ligh ts for sound reduction Rw,P,Glass of he glazing (from: Archive ift Centre for Acoustics)



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Due to the fact that the sound transmission pathscannot be clearly separated, there is no equi-valent calculation method for vertical flankingsound insulation.

Literature[1] Final report research project berprfung des

Einflusses von Stostellen bei Fassaden ift Rosenheim, 2000

Normalisedflankingsound leveldifferenceDn,f in dB

Flanking sound insulation of facademeasured Dn,f,w = 50 db

Frequence f in Hz Flanking sound insulation of facadecalculated D n,f,w = 50 dBFigure6 Comparison of measured and calculated flanking sound insulation for aluminium stick construction (from:

Archive ift Cen tre for Acoustics)



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International Rosenheimer Window & Facade Conference2006Dr. Joachim Hessinger


Useful information in brie hich basic rule should be observed for verification of he sound

insulation of curtain walls?1 For CE marking, the product standard EN 13830 applies;

he airborne sound insulation of curtain wallsis determined by labora-tory testing of a representative test specimen.

2 In Germany, he requirements for sound insulation and heir verifica-ion are laid down in DIN 4109. In addition o airborne sound insula-

tion, the flanking sound insulation of the curtain walling should also betaken into account. For verification purposes, the valuesof the soundreduction index and of the linear sound reduction index (tolerance of2 dB) are determined by calculation.

3 There are no procedures for determining he sound insulat ion in ad-vance. In order o evaluate he sound insulation of curtain walling sy -tems, a series of measurementsare carried out on curtain wallingelements of the original size. These measurements can be applied tothe requested system variants i f properly designed and planned.

4A forecast for linear sound insulation may be based on previouslyested constructions. Horizontal flanking sound insulation of stickconstructions of simple design can be determined up to an averagesound reduction level by separating the sound transmission pathsviamullionsand the remaining curtain walling.

Dr. Dipl.-Phys.Joachim Hessinger

Born on November14, 1964 in Mainz, Germany1983 19921993 1995since 1996

Physics studies at he Johannes Gutenberg University atMainz, Degree: diploma in physics/Dr. rer. nat.Post doctorate at he Cornell University, Ithaca, Ne Yorkmember of staff in he field of building acoustic of helaboratory for sound measurement technique LSW, since2004 LSW GmbH/ ift Centre for Accoustics at Stephanskirchen/RosenheimHead of Testing Department of he ift Centre forAccousticssince 2005


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Acoustic - Sound Insulation Facades - Ift