Development and use of prediction models in Building Acoustics as in EN Introduction. 2 EN 12354, part 1 & Lightweight single elements

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1 evelopment and ue of predcton model n Buldng Acoutc a n EN 1354 Eddy TNO Scence and Indutry, P.O. Box 155, N-600 A elft, The Netherland, eddy.gerreten@tno.nl Improvng the acoutc clmate n buldng an mportant ocal tem, both for new and renovated buldng, that nvolve many apect and many ound ource. To do o wth changng degn and contructon method make t neceary to ue approprate predcton model to lnk acoutc product performance wth buldng performance. The ere of tandard EN 1354 beng developed to meet th challenge. For arborne and mpact ound nulaton between room and ound reducton or radaton by facade the tandard are now avalable for ome tme. Experence n ung thee part have been ganed, rang queton at the ame tme about the applcaton n complex tuato the approprate nput data on product and the accuracy of predcton. The man tem for thee part reman the applcaton to lghtweght element and contructon method. For the reverberant ound n encloed pace the tandard became avalable only lat year. Though the man body cover well-known model, ome experence wth the ndcated approach for rregular pace more than welcome. The mot challengng tem left concern the ar-borne and tructure-borne ound from ervce equpment n buldng. A very frt draft beng crculated for comment recently. The general approach wll be preented, hghlghtng the man remanng problem to be olved uch a meaurement method for the producton of tructure-borne ound by equpment and ntallaton part. Thee tem wll be touched n th ntroducton and be addree by other paper n th tructured eon. 1 Introducton Intated by the requrement from the Contructon Product rectve n 1989, CEN tarted to draft tandard to relate the acoutc performance of buldng wth the acoutc performance of the product from whch thee buldng are contructed. Th reulted n x part of the tandard EN 1354 of whch the lat part ha jut been publhed n t frt draft veron. Experence wth the part already publhed [1] ha ndcated ome apect where mprovement and adjutment are derable and feable; th wll be addreed n the next ecton. Then attenton wll be gven to the approach and background for the ffth part on the ound level due to ervce equpment n buldng []. EN 1354, part 1 &.1 Arborne and mpact ound tranmon The predcton model for arborne and mpact ound tranmon n buldng a decrbed n EN 1354 part 1 and part are by now well etablhed [1]. Snce the publcaton n 000 the applcaton to homogeneou, relatvely heavy buldng element teted and backed by varou tude, f.. n a caul comparon wth an SEA-approach [3]. Practcal queton for uch applcaton are manly related to approprate nput data and the mot practcal way of applyng the tructural reverberaton tme n tandardzng the ound reducton ndex of buldng element [4]. The man dcuon n the applcaton of thee model relate to lght and/or hghly damped buldng element. Some apect wll be dcued here.. ghtweght ngle element The flankng arborne ound reducton ndex j for tranmon from element to element j gven by [1]. a a j j j = + + Kj (1) lj SS j Here, j are the n-tu value of the ound reducton ndce, S, S j are the area and a, a j the equvalent aborpton length of the element and j, l j the couplng length between thoe element, K j the vbraton reducton ndex for the juncton between thoe element and S the area of the eparatng element. Th relaton vald for the whole frequency range uually condered, but a tated n the tandard the ound reducton ndce hould than relate to reonant tranmon only. So n cae meaured value are ued an error ntroduced nce below the crtcal frequency alo forced tranmon can be mportant or even domnant. For heavy element uch an error uually mall and could be neglected, but that no longer the cae for lght element wth hgh crtcal frequence. The tandard addree th problem but wthout pecfyng a oluton. A oluton could be to correct the meaured ound reducton ndex mea S 1893

2 Forum Acutcum 005 Budapet below the crtcal frequency for forced tranmon τ forced, for ntance n the ame way a wa propoed n [4]. For f f 88000/ m' t follow: τ re forced c = 10lg 10 ρc = πfm' mea /10 [ τ ] σ f forced The only value needed for th correcton are the ma m of the element and the radaton effcency σ f for forced wave, for whch a fxed value wll normally be adequate [3]. The etmaton of the crtcal frequency not very crtcal nce the reult wll be domnated by reonant tranmon around that frequency anyway..3 ghtweght damped element In cae of hghly damped, homogeneou or double, element the tandard tate that the tructural reverberaton tme ether ndependent of the tuaton or rrelevant and relaton (1) reduce to: () j j = + + Kj (3) lj The appearance qute the ame but the ound reducton ndce now are no longer tuaton dependent, though tll erred to reonant tranmo and the meanng of K j omewhat dfferent. Th relaton doe not follow from ound power or SEA conderato but more drectly from average velocte of the buldng element, applyng recprocty and aumng dentcal radaton effcency at both de of an element. K j then defned on the ba of the average velocty level of a gven area of the element. ue to the element dampng th value wll be rather ndependent of the actual area of the element a long a the meaurement area (S and S j ) are not too mall: K j v, j + v, j S lj S S = (4) In th way th quantty nclude both the reducton effect at the actual juncton a well a level reducton over the damped element. In cae of double element there are dfferent poblte to apply th predcton cheme. It hould be realzed that the ound reducton ndex of the element ued to etmate the average velocty level of an element at the radatng de and the vbraton reducton ndex hould theore be related to the ame de of an element. So n cae of a double element ether only the nde condered, both for and K j, or the total element condered and K j baed on the velocty level of the not excted leaf of the double j element. In that cae the level dfference between both leaf of an element alo ncluded n the vbraton reducton ndex [5]. Th llutrated n fgure 1. I. II. Fgure 1: Illutraton of two poble approache for a juncton wth a double flankng element. Snce alo here only free vbraton have to be condered, approach I eem to be mot approprate for element wth rather uncoupled leaf, whle approach II. mot logcal for element wth coupled leaf. Snce the vbraton reducton ndex of juncton wth lght element could nclude varou dampng effect, t could be ueful to conder each of thee reducng effect more or le eparately n order to gather more generally applcable data. The varaton n juncton detal for a gven type of element could than be added n an approprate way to the dampng effect of the element telf. Thee and other apect are condered and worked out n more detal. Th relevant for the laboratory meaurement method a pecfed n EN [6] and for gudelne on the applcaton of the data n the predcton model. Varou of the tem connected wth the applcaton of thee part and epecally the applcaton to lghtweght tructure wll be addreed n everal contrbuton to th eon [19, 0, 1,, 3, 4, 5, 6, 7, 8, 9, 30]. 3 EN 1354, part 3 & 4 K j K j EN 1354 part 3 and 4 treat the ound tranmon through a buldng façade from the outde to the nde (part 3) or from the nde to the outde (part 4). The theoretcal bae for thee part rather well know though the formulaton partly new n order to cover varou tuaton adequately. Important tem n 1894

3 Forum Acutcum 005 Budapet relaton to thee part are manly the applcable nput data and the determnaton of ome new quantte lke the ound reducton ndex of ealng. However, n th paper thee part wll not be addreed further. 4 EN 1354, part 6 Part 6 on the ound aborpton or reverberant ound n encloed pace decrbe manly the well-known Sabne relaton. Snce t wa known that n varou tuaton wth devatng room hape or rregular dtrbuted aborpton that relaton not really adequate, nformaton alo gven on a poble dfferent approach n annex of that document. At the moment no new experence avalable on the accuracy of that approach, but ome work gong on n th feld. Such tude are more than welcome n order to ndcate the accuracy and feld of applcaton and to at future amendment to the tandard. Th part wll not be dcued further n th paper or th eon. o that the reultng ound preure level can be mply added. Bede the general decrpton of the calculaton model, the document gve gudelne for each type of ervce equpment on the applcaton of thee model and the bae for the approprate nput data. The current document a very frt draft for part 5, publhed at the begnnng of 005 to generate and collect comment and contrbuto alo from outde the reponble workng group. Varou apect tll to be olved are ndcated and wll be addreed alo n th paper and th eon. 5. Tranmon through duct The ound tranmon through ventlaton and heatng duct ha been treated already for a long tme n varou handbook, for ntance n [8], [9] and [10]. The bac approach to conder the ound power level W of varou ource, lke the ventlator or the ar flow, and to take nto account the power reducton W by each element n the ytem between the ource and the condered recevng room (ee fgure ). 5 EN 1354 for ervce equpment 5.1 Introducton W 1 element 3 element 4 room a A Servce equpment n buldng vare largely n type and dmenon. It concern water upply and wate water ytem, heatng, ventlaton and lft ntallato rubbh hut and varou type of houehold equpment. The ound level due to the equpment are caued by varou ound ource and varou tranmon mechanm, makng a predcton cheme rather complex. Even the am of the etmaton not very precely defned. The ound level n room due to ervce equpment have to be meaured n accordance wth EN ISO 1603 [7], but the meaurement quantte allowed n th tandard how a large varato both n frequency weghtng (A or C), tme weghtng (maxf, maxs or eq) a n normalaton (n or nt). Though th can be partly derved from the ame predcted ound pectrum, the relevant tme weghtng wll normally determne the approprate ource nput data. The man exctaton and tranmon mechanm dtnguhed are the arborne ound tranmon through duct, the arborne ound tranmon through the buldng contructon and the tructure-borne ound tranmon through the buldng contructon. For each of thee mechanm the ound tranmon for a ource decrbed eparately n general term of ound power tranmon. The contrbuton of each ource or partal ource condered to be ndependent Fgure : Sytem of a duct wth ource, tranmon element and recevng room (a and b). Th preented n equaton (5): = room b A 4 W, A d W (5) In the document the varou relevant element are condered and t ndcated how the avalable meaurement quantte for that element are related to the ound power reducton. For ome element a meaurement tandard avalable, for other uch tandard are tll mng and only global ndcaton can be gven. Snce the mentoned handbook are not alway n agreement wth each other, the mot content choce made for the defnton of the quantte takng nto account recprocty relaton where approprate. 1895

4 Forum Acutcum 005 Budapet 5.3 Ar-borne tranmon The ound power level W, a determned by varou extng tandard, pecfe the arborne ound radaton by ource. The properte of the ource room determne the reultng ound preure level n that room. The arborne ound tranmon through the buldng treated already n EN o that t can be appled alo here. Th llutrated n fgure 3. In thee tuaton t wll not be elf-evdent to er the flankng ound reducton ndex j to the area of a eparaton element, hence a erence area S = 10 m ued. ource W Fgure 3: Arborne ound tranmon from a ource through a buldng va tranmon path j. The relaton to be ued for a gven tranmon path j gven n equaton (6). ource room A ource ource near a, j buldng contructon between ource room element and recevng room element j recevng room S A = W +, j, 10lg (6) S 4 The term, pecfe the ound tranmon to element n the ource room. In cae of a dffue ound feld and a ource n the centre area of the room, th follow drectly from the ound aborpton n that room (=10lg S /A ). But uch condton wll often not occur n equpment room. Thu n etmatng th term, account wll have to be taken of non-dffue ound feld, drectvty of the ound radato drect and near feld of the ource. Thee apect wll tll have to be tuded further n order to be able to gve gudelne for the bet practcal approach. Another apect to conder concern the ound tranmon. EN conder the tranmon to adjacent room, but n cae of equpment the relevant recevng room may be potoned further away from the condered ource. Thu a relevant tranmon path may nvolve more than one juncton and the number of relevant path may quckly ncreae. Some ndcaton are gven how to deal wth th and for ome buldng type a complete SEA modellng mght be approprate. For that purpoe ome relaton between the typcal quantte n EN 1354 and for j A receve j,receve SEA modellng are already gve but t could be ueful to elaborate on th. 5.4 Structure-borne tranmon For mot equpment the ound level n room are manly due to tructure-borne ound tranmon. Th the mot complex apect and yet the bae for a practcal calculaton model rather weak. Not o much for the tranmo whch eentally dentcal to the tranmon of arborne ound, but due to lack of a practcal characterzaton of actual ource a a ource of tructure-borne ound. To olve th problem and to keep the predcton model n th repect open for future development, t wa decded to draft a model where the ource trength pecfed by a new and general quantty, the charactertc tructure-borne ound power level W,c a propoed by Moorhoue and Gbb [1] combned wth a couplng term C. Th a quantty that ha the potental to be general and practcal, though no meaurement method avalable at the moment but for the tme beng t can be related drectly wth extng quantte lke the ource force level. In ecton 5 th ource decrptor wll be dcued n more detal. Th ource ound power level and the couplng term together gve the ound power njected n the upportng buldng element. The tranmon of th njected power could be decrbed n varou way, for ntance relatng t to the mpact ound tranmon by the tappng machne a n EN However, t wa thought that n combnaton wth the ar-borne ound tranmon for equpment t would be more logcal to apply exactly the ame quantty to expre the tranmo.e. the flankng ound tranmon ndex j. Th predcton cheme llutrated n fgure 4. upportng element couplng term buldng contructon between ource upportng buldng element and recevng room element j recevng room A receve Fgure 4: Structure-borne ound tranmon from a ource through a buldng va tranmon path j. The relaton to be appled to each tranmon path pecfed by equaton (7). j j,recev 1896

5 Forum Acutcum 005 Budapet, j S A = + C, a, j, 10lg (7) S 4 Th equaton contan an addtonal adaptaton term a that expree the equvalence between the njected tructure-borne and the ncdent ar-borne ound power. Th quantty determned by the properte of the upportng buldng element only and follow for a homogeneou, heavy buldng element from the ma m and the crtcal frequency f c by: a 400 f 10lg mf c 17, lg m f = (8) 6 Structure-borne ound ource 6.1 Source trength characteraton A general characteraton of the ound producton by a tructure-borne ource ha to take nto account the ource moblty for all degree of freedom and for all the contact pont between ource and upportng element. From everal propoal the mot practcal eem to be the charactertc tructure-borne ound power W,c, whch the power, njected by the ource n t mrror mage [1]. In th way th quantty jut dependng on ource properte. The njected power n a pecfc tuato the ntalled ound power, wll tll depend on the moblty properte of the ource and of the upportng element though. So ource moblty wll have to be meaured, etmated and modelled n order to be able to perform predcton. For the general cae W,c follow from the complex free velocty v f and the ource moblty Y for each upport of a mult-degree of freedom ource by (8). * T * 1 f Y 10lg e{ v v }/ W = (8) In a mple one-dmenonal cae th reduce to: vf 1 = 10lg (9a) W e{ Y } or F = 10lg Y (9b) W Th ound power could be meaured and appled drectly and ueful already for comparon between comparable product. General meaurement method wll have to be developed and work gong on [16, 17, 18]. For ome mple tuaton the charactertc tructure-borne ound power level can be deduced from well-known quantte. Some example wll be gven n the next ecton. f 6 The ound power level Wnj njected nto the buldng tructure wth moblty Y follow n thoe mple cae from th ource power and the couplng term C a: Wnj c, = = + C, Y 10lg Y + Y e { Y } (10) Charactertc of the mountng lke relent element can be ncorporated n th couplng term. So to be able to predct the njected ound power n a practcal way, t wll be neceary to derve adequate model for the pecfcaton of the couplng term. 6. Example In cae a ource could be condered eentally a a one-dmenonal force ource the ource moblty n equaton (9b) very hgh; for the applcaton n buldng a value of Y = 10-3 /kg could be ued a erence value. Th would than lead to: W, c C, = F Y = = 10lg{ Y } + 30 F 30 (11) Agan the ntalled ound power follow from equaton (10), whch n th cae mplfe to a well-known reult: = + = e{ Y } (1) Wnj C, F Example of ource that could be condered a force ource are appendage n water upply ntallaton and watewater ntallaton. For thee ource meaurement tandard are avalable, the reult of whch could be expreed n a charactertc tructureborne ound power level. For element n water upply ntallaton the ound producton gven a the ound preure level ap n accordance wth ISO 38 [13]. Ung the properte of the faclty th reult can be tranlated nto the power level by: = ap ap e{ Y} σ 10lg ωηm lg(0,01f + 0,5 f ) (13) For watewater ntallaton the ound producton gven a the ound preure level p,c n accordance wth EN [14]. Th reult can be tranlated nto the power level by: = p, c p, c SS + 34,7 10lg f + 8lg f + 3,5 (14) For other ource for whch the force level or equvalent force level known or meaured the method can alo be appled, wth or wthout takng nto 1897

6 Forum Acutcum 005 Budapet account the effectve ource moblty. [15] llutrated th for a wahng machne and for the ISOtappng machne. For the lat cae the ource moblty and force level follow drectly from the pecfcaton of the machne, mply leadng to: = 5 10lg f F (15) 115 db re1pw per 1/3 oct Fnally, alo velocty ource can be relevant nce that would be the approprate way to charactere machne that uually wll be relently mounted. So aumng a low ource moblty a erence,.e. a hgh ource mpedance of Z = 10 6 kg/, the ound power would follow from velocty level by: v, eq + 10 lg Z W = v, eq = (16a) And the correpondng couplng term for a relently mounted machne wth the tffne of the mountng gven by k m would follow from: km C, = 10lg e{ Y } 60 ω v (16b) A an llutraton fgure 5 gve ome data on the charactertc tructure-borne ound power level of everal ource, baed on force and velocty meaurement, drectly or ndrectly, and tranferred by the approprate relaton jut gven. [db re 1 pw] frequency [Hz] drll; eq.. automat; dryng; eq.. dhw aher; eq.. boler; eq.. fllng bath; eq.. tappng machne; eq..3 lft machne, prng; eq..4 Fgure 5: Example of charactertc tructure-borne ound power level of ome ource; derved from meaurement of force or velocty. 7 Concluon urng the lat ffteen year predcton model have been pecfed for all relevant apect n buldng acoutc: arborne and mpact ound tranmon between room, ound reducton and ound radaton by facade, reverberant ound n encloed pace and ound level due to ervce equpment. The frt have been ued for everal year now and th experence ndcate apect that need further tudy and elaboraton. That for ntance the cae for lghtweght, damped buldng element. For the lat aepct a very frt veron of model wa drafted and comment and ongong reearch welcomed to mprove and extend that part n the near future. 8 Acknowledgement The author would lke to acknowledge the dcuon wthn the CEN workng group reponble for the EN 1354 tandard and the atance of dr. Henz-Martn Fher (FTH-Stuttgart) and of dr. Mchel Vllot (CSTB-Grenoble) n organzng the tructured eon on predcton model n Buldng Acoutc at Forum Acutcum 005. eference [1] EN 1354:000, Buldng Acoutc - Etmaton of acoutc performance of buldng from the performance of element- 1: Arborne ound nulaton between room; : Impact ound nulaton between room 3: Arborne ound nulaton agant outdoor noe 4: Tranmon of ndoor ound to the outde 6: Sound aborpton n encloed pace, 003. [] raft-pren , Buldng Acoutc - Etmaton of acoutc performance of buldng from the performance of element - Part 5: Sound level due to ervce equpment n buldng, 004. [3] Nghtngale, T.., I. Boma Expreon for 1 t order flankng path n homogeneou otropc and lghtly damped buldng, Acta Acutca /Acutca 89 (003) [4], E., Ung the tructural reverberaton tme n tandardzng laboratory meaurement of the ound reducton ndex, Forum Acutcum 00, Sevlla, [5], E., Calculaton of arborne and mpact ound nulaton between dwellng, Appled Acoutc 19 (1986),

7 Forum Acutcum 005 Budapet [6] EN ISO 10848, Acoutc aboratory meaurement of the flankng tranmon of arborne and mpact noe between adjonng room, Part 1 4, 005 [7] EN ISO 1603, Acoutc Meaurement of ound preure level from ervce equpment n buldng engneerng method, 003. [8] VI 081, Sound producton and reducton n ventlaton ytem, VI, 000. [9] ASHEA Handbook Heatng, ventlatng and ar-condtonng applcato chapter 47, Sound and vbraton control, ASHEA, 003 [10] AI-Standard 885, Procedure for etmatng occuped pace ound level n the applcaton of ar termnal and ar outlet, [11] Crak,.J., Sound tranmon through buldng ung SEA, Gower Publhng td, Hamphre, Vermont, [1] Moorhoue, A.T. & B.M. Gbb, elatonhp between the charactertc power of tructureborne ound ource and ther emon when ntalled, Proc. Euronoe 98, Munch; [13] ISO 38, Acoutc- aboratory tet on noe emon from applance and equpment ued n water upply ntallato Part 1 4, [14] EN 14366, Buldng Acoutc aboratory meaurement of noe from watewater ntallato 004. [15], E., Modellng tructure-borne ound from equpment n buldng current development n EN , ICA 004, Kyoto [16] Späh, M. e.a, New laboratory for the meaurement of tructure-borne ound power of antary ntallato Forum Acutcum Budapet, 005. [17] Vllot, M., aboratory characteraton and feld predcton of whrlpool bath noe, Forum Acutcum Budapet, 005. [18] Alber, T. e.a., Approach to decrbe valve a ound ource for flud- and tructure-borne ound, Forum Acutcum Budapet, 005. [19] Scheck, J. e.a., Approach for the characteraton of wooden tarcae a tructure-borne ound ource, Forum Acutcum Budapet, 005. [0] echler, A. e.a., Impact ound of lghtweght tar - actual reult of a reearch program, Forum Acutcum Budapet, 005. [1] Scholl, W., About a tet faclty for ntallaton noe n wooden houe, Forum Acutcum Budapet, 005. [] Nghtngale, T.. e.a., On the dtrbuton of tranvere vbraton n a perodc rb tffened plate, Forum Acutcum Budapet, 005. [3] Brunkog, J., Structural tranmon lo n jotrenforced plate tructure, Forum Acutcum Budapet, 005. [4] Schoenwald, S. e.a., Propagaton of tructureborne ound n lghtweght gypum board wall, Forum Acutcum Budapet, 005. [5] Nghtngale, T.. e.a., On the mportance of the drect feld n tructure-borne tranmon n framed contructo Forum Acutcum Budapet, 005. [6] Vllot, M. e.a., Predcton method adapted to lghtweght contructon and related laboratory characterzato Forum Acutcum Budapet, 005. [7] Crp C. e.a., The vbraton tranmon lo at juncton ncludng a colum Forum Acutcum Budapet, 005. [8] Schreuder, M. e.a., Flankng tranmon of maonry buldng element wth flexble nterlayer, Forum Acutcum Budapet, 005. [9] Gugou-Carter, C. e.a., Analytcal and expermental tudy of wood floorng, Forum Acutcum Budapet, 005. [30] Smmo C., Uncertanty of meaured and calculated ound nulaton n buldng - reult of a round rob Forum Acutcum Budapet,