ANALYSING RELATIONSHIPS BETWEEN BUILDING CHARACTERISTICS AND AIRTIGHTNESS OF DUTCH DWELLINGS CHELY N. BRAMIANA (S )


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1 MASTER THESIS ANALYSING RELATIONSHIPS BETWEEN BUILDING CHARACTERISTICS AND AIRTIGHTNESS OF DUTCH DWELLINGS Paper a Documeation CHELY N. BRAMIANA (S76322) Analysi rationships between buili characteristics a airtightness of Dutch wlis 1
2 CHELY N. BRAMIANA (S76322) CONSTRUCTION MANAGEMENT AND ENGINEERING GRADUATION COMMITTEE PROF. DR. IR. J.I.M. HALMAN DR. IR. A.G. ENTROP AUGUST 26, Analysi rationships between buili characteristics a airtightness of Dutch wlis
3 Table of Coen Preface 4 Paper Abstract 6 I. Irouction 7 II. Literature Review 9 III. Research Metho 12 IV. Resul V. Discussion 22 VI. Conclusion a recommeations 24 Acnowlegemen 2 References 2 Research proposal 28 Abstract Irouction Research Design 3 3. Research Metho Literature Review 40 References 46 Appeix 0 Documeation of the research 1 I. Digital available ocumeation 2 II. Descriptive Statistics 2 III. Corrations Analysis 4 IV. Regression Analysis 7 V. Oneway ANOVA 62 VI. Twoway ANOVA 78 VII. Summary of Exploratory Analysis 86 VIII. Multi linear regression 87 IX. Original ata on sprea sheet 89 X. Moifie ata on sprea sheet 106 Analysi rationships between buili characteristics a airtightness of Dutch wlis 3
4 PREFACE This research is the final proof of competence for obtaini Master of Science (MSc) egree in Construction Manageme a Eineeri (CME), from the University of Twee. This research has been assigne iernally a execute in Departme of Construction Manageme a Eineeri, University of Twee uer supervision of Prof. Dr. Ir. J.I.M. Halman a Dr. Ir. A.G. Erop. The execute research focuses on rationship between buili characteristics a buili airtightness of wlis. Ierest in this wo was informe by the lacuna fou in both policy on a practice of energyefficie builis. This is irectly influence by the quality of buili envope to preve air leaages. The cere of this stuy are Dutch wlis to further expa nowlege on airtightness a air leaages of builis in The Netherlas. This is hope that fiis coul also coribute to the pool of literature on airtightness all over the worl. Enschee, 26 th August 201 Chy N. Bramiana 4 Analysi rationships between buili characteristics a airtightness of Dutch wlis
5 PAPER ANALYSING RELATIONSHIPS BETWEEN BUILDING CHARACTERISTICS AND AIRTIGHTNESS OF DUTCH DWELLINGS STATISTICAL ANALYSIS OF BUILDING AIRTIGHTNESS MEASUREMENTS Analysi rationships between buili characteristics a airtightness of Dutch wlis
6 Analysi rationships between buili characteristics a airtightness of Dutch wlis ABSTRACT Several stuies have shown that buili airtightness is an importa parameter to improve energy efficiency of builis. Towars this e, many couries also emphasize the importance of aressi air leaage in their regulatory policies. Many scholars a research organizations have attempte a/or evope mos to preict buili airtightness in orer to ensure that builis comply with the minimum requiremen permitte by law. However, none of these mos can substaially substitute the resul of blower oor tes. This warran the nee to explore factors that have both effec a ieraction with buili airtightness. This paper explores 320 Dutch wlis by stuyi the rationship between measure buili airtightness a buili characteristics abstracte from past stuies. Corrational analyses as wl as the ANOVA test were one to etermine rationships between buili characteristics a measure buili airtightness. Multiple linear regressions were also one to measure the effec of these factors on buili airtightness. Year of construction, total leaage, roof type, buili metho a buili typology were fou to have significa rationships with buili airtightness; but, only year of construction a total leaage were fou to have influence on buili airtightness, in terms of specific leaage rate. A significa ieraction was also fou between these two variables a specific leaage rate (m 3 /(h.m 2 )). This means that actors in the construction iustry must strive to minimize the chances of air leaage by improvi the quality of womanship at all phases of construction to reuce the chances of the leaage paths happeni in the buili at all ierfaces. This stuy recommes more exploration of other factors to test their rationship a effect on buili airtightness. Keywor: buili airtightness, specific leaage rate, air leaage, buili characteristics, Dutch wlis Nomenclature: Symbol Quaity Unit V m Measure air flow rate m 3 /h V env Air flow rate through the buili envope m 3 /h V L Air leaage rate m 3 /h V 0 Air leaage rate at 0 Pa m 3 /h C env Air flow coefficie m 3 /(.Pa n ) C L Air leaage coefficie m 3 /(.Pa n ) n Air flow expone  p Pressure Pa Δp Iuce pressure ifference Pa A E Envope area m 2 A F Floor area m 2 v Iernal buili volume m 3 N 0 Air chae rate at 0 Pa h 1 Q 0 Air permeability at 0 Pa m 3 /(h.m 2 ) w 0 Specific leaage at 0 Pa m 3 /(h.m 2 ) 6 Analysi rationships between buili characteristics a airtightness of Dutch wlis
7 I. INTRODUCTION A. Energyefficie builis a airtightness: an overview The buili sector is responsible for a significa portion of energy use in the worl. Differe staeholers across the worl such as governmen, scieis a environmealis are aware of the impact of builis on the environme. With the issue of sustainability getti more importa, several attemp are mae to reuce the energy use of builis by improvi buili energy efficiency. This calls for more evopme a wie aoption of sustainable builis. It motivates the actors in the construction iustry to promote innovations such as zeroenergy builis, energy neutral builis, highefficiency buili a smart builis. The focus is still the same: to reuce the energy nees of builis. Therefore, while innovation in the buili technology area is rapily evopi to reuce energy consumption, it is also irinsic that eineers a coractor ensure they construct new builis in compliance with the curre regulations. Apart from guiines in the policy, other organizations such as the Energy Savi Trust (EST) in the Unite Kiom (UK) [1] a SBRCURnet [2] in The Netherlas also foster compliance with the legal irectives. This is geare towars the ultimate goal of achievi energyefficie builis. However, to achieve this goal, iffere active or passive strategies are employe [3]. Measures such as improvi heati veilation a air coitioni (HVAC) systems a installi a solar pan are categorize as active strategies. On the other ha, improvi the quality of the buili envope through improveme of the wall, wiow a oor penetration, a roofs is categorize as a passive strategy. Moreover, passive houses, which require certain measures of buili envope (air chae rate N 0 of 0.6 ACH), are obvious examples of passive strategy implemeation. In aition, not every househol can affor to apply active energy efficie strategies. Therefore passive strategies such as improvi the thermal insulation a buili airtightness to reuce heat loss are recommee a regulate in the buili coe. As part of the passive strategy, airtightness is consiere importa for improvi the energy efficiency of builis. Buili airtightness has been inclue in the regulations in many couries to achieve energy efficie builis, which is in most cases usually measure in terms of air permeability lev. The term airtightness pertains to the iensity of the uncorolle flow of air through the buili envope as a result of pressure ifferences between ierior a exterior air [4]. Several stuies have aresse the importance of ensuri buili airtightness in orer to reuce air infiltration a thus reuci the cooli loa a heat loss of the buili [3]. These stuies iicate that tighteni the buili envope provies a large energy benefit[], [6]. Rece stuies suggest the importance of buili airtightness towars energy efficiency, thermal comfort a ioor air quality of wlis [7] [10]. Maiaini buili airtightness is also esseial for the effectiveness of heat recovery installe in the buili [11], [12]. Therefore, it is importa to maiain a certain lev of buili airtightness to optimize the energy efficiency of a buili. B. Issues arisi: the Dutch coext European legislation on the energy performance of builis (Energy Performance Buili Directive EPBD) states that member states must calculate the energy efficiency of a buili in their couries []. The ripple effect of this, for example, is evie in the Dutch Buili Coe [], which requires resieial builis to comply with a certain lev of energy performance (Article.2) a a given limit of total airflow (Article.4). However, there is a minor flaw in the Coe. It explicitly meions the minimum requireme of the energy performance coefficie () to comply with a maximum total airflow allowe. Neverthess, it oes not explain other minimum requiremen such as how the total airflow is broen own io veilation a infiltration; a egree of buili airtightness. This might initiate some confusion as it is fou in some cases that builis comply with the minimum require but they o not comply with the minimum value of buili airtightness or vice versa. Every Dutch house is require to have an energy performance certificate which coains the energy performance coefficie. A every new Dutch house to be constructe taes the value of q v10 io accou in the calculation of energy performance coefficie. Therefore, the eineers or architec must inclue in their esign a calculation the value of q v10 that will be assigne to the. However, it is still unclear how this value of q v10 is generate a justifie for certain since the Analysi rationships between buili characteristics a airtightness of Dutch wlis 7
8 new buili must inclue this minimum value in the. Moreover, they cannot be certain whether this value can be achieve. To ensure that this minimum value is fulfille, a blower oor test can be coucte, to measure the airflow rate of the assigne buili. However, another problem is that coractors only ry on the measuremen resul one after the completion of the buili. The require airtightness is then sometimes not complie with. Whereas, effor can be taen to ensure that a certain lev of buili airtightness is iegrate from the beginni of any new construction project. For the last couple of years, this blower oor test has been taen prior to completion or the mome of turney in orer to ensure that any minimum requireme set for the buili is fulfille. Therefore, coractors can still manage to improve the buili before it is occupie. In aition, plans for the retrofitti or rehabilitation of existi builis are require to get measure [], [6], [1], [16]. Neverthess, it is unfortunate that coractors cannot harness their resources to provie better overview of estimati buili airtightness. Even though they have the complete specification of the forthcomi buili, they might not be able to estimate the exact value of q v10 because they cannot estimate the buili airtightness from the rawis they provie themsves. Therefore, analysi estimate buili airtightness prior to coucti blower oor test, might be an importa ierveion. C. Research objectives a scope of stuy The objectives of this research are to etermine the buili characteristics abstracte from past stuies that have significa rationship with buili airtightness a those that have the most significa influence on measure buili airtightness of existi buili ex post. Therefore, this research aims at explori variables that substaially influences buili airtightness by assessi existi measuremen in orer to evop a preictive mo. There have been many stuies in the past to estimate airtightness without tai the blower oor test. Even though a preictive mo still cannot replace the resul of a blower oor test, it still can hp staeholers to improve buili airtightness. At least coractors a esigners can use it to maiain the target of minimum air permeability uri the early construction phase. Even though not every variable is expecte to be useful to evop a preictive mo, the fiis can coribute to future research in preicti buili airtightness of wlis more consistely. The scope of this research will cover only resieial builis in The Netherlas, base on ata from pressurization tes on wlis gathere by the University of Twee. The reason resieial builis are in this stuy s ierest is preicate on the followi fac. First, there are more resieial builis than service builis in the Netherlas. The 20 report from the Ceral Bureau of Statistics shows that there are more than 7.2 million wlis in The Netherlas. With a share of 87.3%, wlis constitute the bul of the total buili stoc compare to nonwlis, which only mae up approximaty one eighth of the total buili stoc in the Netherlas (nearly 1.1 million objec) [17]. Consequely, the resieial builis yi the highest energy cost. Seco, the inhabitancy of resieial builis a the usage of the structures iffer to service builis, because people generally live their lives a spe more time at home. Therefore, resieial builis are more iensy use than service builis, which have more structure a regular openi a closi hours. The remaini part of the paper procees as follows. Section 2 begins by layi out the theoretical imensions of the research by efini buili airtightness, followe by the previous research coucte in the fi of buili airtightness. The thir section is concerne with the methoology use for this stuy. The fourth section presen the fiis of the research, focusi on the corration between variables a target of measure buili airtightness. Section iscusses the fiis in more aborate manner. Finally section 6 conclues the research a presen the recommeation for further stuies. 8 Analysi rationships between buili characteristics a airtightness of Dutch wlis
9 II. LITERATURE REVIEW A. Air leaage measuremen In orer to etermine the airtightness of a buili, a test is usually carrie out to measure the amou of air leai within buili envope. The lev of buili airtightness is firstly measure in terms of the amou of air leaage between iffere ioor a outoor pressure usi staarize metho. The most common metho to measure air leaage in a buili is the pressurization test, which uses a blower oor. This metho is base on the mechanical pressurization or epressurization of a part of a buili, usi a blower oor moue in the fro oor with all veilation seale a all ajacency remain open. The airflow rate measure through the buili envope is cause by the ifferences in pressure between the air insie a ouie. The airtightness of buili componen a emen is measure accori to staar NENEN 829 [18]. Another thi to be notice is that even though the measureme metho is not complicate a can be carrie out with little amou of equipme a time, the ierpretation of the resul requires a certain exte of nowlege. When measuri the buili airtightness, the occurri air leaage is quaifie as the airflow getti through the buili envope, which is V as a function (m 3 /s), through ifferences in pressure, expresse in P (Pascal). The pressureflow rationship, which ac accori to the power law, is often expresse by the equation: Equation 1 The flow coefficie is a function of the size of buili openis, a the pressure expone is expresse 0. n 1.0. An expone of 0. enotes fully turbule a an expone of 1.0 represen laminar flow. Usually the flow expone is 0.6 [10]. The airflow is often enote with the reference pressure as a subscript (e.g. V 0 or V 2 ). The reference of 0 Pa in air pressure ifferences is most often use. Another common reference pressure use is 4 Pa, but 1 Pa, 10 Pa, 2 Pa, a 7 Pa are use as wl [10]. B. Defini airtightness The next step of measuri airtightness is to efine the buili airtightness term by normalizi the measure air leaage (V L ). There are three quaities commonly use to normalize the measure air leaage: buili volume, envope area a floor area [10], [19], [20]. These normalisations are use epei on the coext of the regulation either where or for what purpose. Consequely, there are three iffere terms use to aress buili airtightness, which this research borrowe the term from NENEN 829. Each has avaages a isavaages a each is useful for evaluati iffere issues: 1) Air chae rate When the buili volume is use to normalize such ata the result is normally expresse in air chaes per hour at the reference pressure a it is the seco most common air tightness metric reporte in the literature [7], [21], [22]. Many people fi this metric convenie since infiltration a veilation rates are often quote in air chaes per hour. The air chae rate at 0 Pa pressure ifference (N 0 ) is calculate by ivii the mean air leaage rate at 0 Pa by the iernal volume usi equation 2 with unit h 1 : 2) Air permeability Equation 2 Most stuies use the terms air permeability as the target of their research [4], [8], [16], [19], [23], [24]. Air permeability is the capability of a surface to let air pass through in this case, the capability of the buili envope if. Normalization usi envope area is particularly useful if one is looi to efine the quality of the envope as a uniform fabric [10]. In the case of Ref. [24], it inclues buili componen a veilation evices. Such a term can sometimes be har to use. However, it can be particularly useful in attache builis were some walls are expose to the outoors a some are not. The terms air permeability a airtightness are sometimes ierchaeably Analysi rationships between buili characteristics a airtightness of Dutch wlis 9
10 use, but they are actually opposi terms. The lower the air permeability is, the more airtight a buili is. The air permeability in 0 Pa pressure ifference is symbolise as Q 0 a the unit is m 3 /h.m 2. Air permeability is calculate by ivii the mean air leaage rate at 0 Pa by the envope area usi equation: 3) Specific Leaage Rate Equation 3 Normalization usi floor area, expresse as specific leaage rate at reference pressure ifference, is the easiest to etermine from a practical aspect compare to the other normalizations. Since usable livi space scales most closy rate to floor area, normalizi these scales is sometimes viewe as bei more equitable [10]. This normalisation is also use in the in the Dutch Buili Coe. Specific leaage rate at 0 Pa ifference, w 0, is calculate by ivii the mean air leaage rate at 0 Pa by the floor area usi equation 4 a the unit is m 3 /h.m 2 : Equation 4 Table 1 explains the ifference between iffere buili airtightness terms use in iffere coext. Table 1 Differences in buili airtightness terms Terms Normalisation Symbol Uni Air chae rate (infiltratie vou) Air leaage rate ivie by iernal buili volume N h 1 Air permeability Air leaage rate ivie by buili envope surface Q m 3 /h.m 2 Specific air leaage rate Air leaage rate ivie by usable floor area w m 3 /h.m 2 Even though, Q 0 a N 0 are the most commonly use in many couries, The Netherlas use the norms w 10 (equivale to q v10 in Dutch policy) which is the specific leaage rate at 10 Pa ifference. On the other ha, Dutch Buili Coe only meions that the permitte total air flow rate of resieial inclui toilet a bathroom must not be bigger than 0.2 m 3 /h. The esire specific leaage rate is state in, epei on the volume of the buili. For comparison, the ration between q v10 a N 0 is epei on the flow coefficie (n) a ivie by about The airflow (q v10 ) of about 1 m 3 /s, equals to an N 0 of about 3. to 4. [De Gis, 2010]. C. Airtightness preiction a importa variables Stuies carrie out with the purpose to evop a mo to preict buili airtightness can be ivie io two broa research categories: experimeal a corrational [8]. Experimeal research is carrie out uer corolle experimeal coitions with the purpose of measuri the causal effec of iepee variables on epee ones, while corrational research is carrie out uer statistical corol with the purpose of uerstai the corration between variables. Experimeal stuies can be carrie out by buili simulation a test specimen which can be fou in the stuies carrie out in Portugal [24], in Ira [16] a in Italy [2]. Corrational research mostly employ regression metho, which can be fou in some stuies carrie out in Finla [7], in the UK [8], in the US [19], in Catalonia [21], in Greece [22] a in Estonia [23]; a the most rece one use neural netwos coucte in Croatia by Krstic et al. [4]. These stuies, furthermore, were carrie out to evop a mo to preict or estimate value of buili airtightness prior to a blower oor test. Moreover, Raer, Holøs a Thue [26] categorize metho to estimate buili airtightness io three groups: (1) estimation base on multiple regressions, (2) estimation base on the rough characteristics of the buili a (3) estimation base on the compone leaage a geometry of the buili. There is a plethora of variables influenci airtightness which are suggeste in the literature. Chan, Joh & Sherman [19], Alev et al. [9], Mooya et al. [21], Sinott & Dryer [16] consiere year of construction as one of the preictors when estimati airtightness. Structural a nonstructural buili characteristics have also been note as variables to be consiere in estimati buili airtightness. Structural buili characteristics inclue variables such as wli type [8], 10 Analysi rationships between buili characteristics a airtightness of Dutch wlis
11 construction type [21], type of fouation [19] a buili metho [23]; while nonstructural buili characteristics inclues floor area [19], house height [19] a number of storeys [23], veilation system [19], [23], insulation type [21] a manageme coext [8]. Many literary stuies has shown that the quality of womanship plays a critical role in achievi buili airtightness [16], [23], [24], especially that it correspos irectly to possible leaage path. Parameters inclue in womanship are: installation methos, etail of join a amou of opaqueness a transparency of buili envope. The possible leaage paths on join were fou in the wiowwall ierface [27], as wl as the structural floor [28]; the join between the baseme wall a the wooen frame wall [29]; between the wall a the roof [30]; a in the roof join [31]; many of which were cause by the metho of seali join [27] [29]. Table 2 summarise the abstracte variables from past stuies. These abstracte variables will constitute the iepee variables to be teste for significance a inclue in the analysis. Table 2 Summary of preictors of buili airtightness from past stuies Coury Unite Kiom Unite States Finla Greece Average permeability Influenci variables Q 0 of.97 m 3 /(h m 2 ) Construction type Type of resieial buili Manageme coext N ACH N ACH Estonia Q m 3 /(h m 2 ) Spain a France Ira Q m 3 /(h m 2 ) Portugal Year of construction Climate zone Floor area House height Type of fouation Location of veilation system Energy class of family house Annual infiltration rate Total wiow frame leth number of storeys, womanship quality a supervision, buili technology (built in site or prefab), a The veilation systems. year of construction, Construction type Number of storeys Floor area Year of construction Design etail Retrofitti Quality of womanship Croatia Q ACH at 0 Pa opaque part of buili envope, i material a structure transpare part of buili envope, i material a structure Number of measuremen Metho 287 Multi linear regression [8] Source Multi linear regression [19] 1 Sensitivity analysis simulati buili mo [7] 20 Regression [22] 32 Experimeal analysis [23] 21 Multi linear regression [21] 28 Experimeal stuy [16] Experimeal stuy [24] 8 Neural netwo preiction [4] Analysi rationships between buili characteristics a airtightness of Dutch wlis 11
12 III. RESEARCH METHOD This research focuse on the resul measuremen of 320 Dutch resieial builis. A quaitative analysis was employe in this research to stuy the corration between variables since it can give more aborate analysis. This stuy falls io corrational research. A. Description of ata Measuremen are gathere from several organizations that run blower oor tes in many houses in The Netherlas. Because the blower oor tes were coucte by iffere organization, consequely, there are iffere forma of measuremen resul. Some repor reporte more ata than the others a few of them i not meion the location of the buili, only the resul of the blower oor test. 7.% of the measuremen were taen uri construction, 70% arou completion, 8.1% uri occupancy a.4% of them were unnown. Even so, all repor must iicate some esseial emen which are: the value of q v10, which further will be meione as w 10 in this paper, the airflow leaage from iffere pressure ifference, flow coefficie a pressure expone. Some repor separate the resul by pressurization a epressurization, while other only meion the general result. The buili ata, such as: rawi plan, veilation system a buili characteristics; leaage path a infrare image to ieify the leaage path were also provie in some repor. Neverthess, the regulation in The Netherlas meione the pressure reference is at 10 Pa ifference, the resul of 0 Pa ifference are also analyse. The pressure reference at 10 Pa ifference is use because it refers to the coition uer normal weather circumstances, while 0 Pa ifference is use to measure buili airtightness since it is low enough not to eteriorate the measuremen a high enough to be iepee from weather coition. Equation 1 a 4 is use to convert the specific leaage rate to 0 Pa by calculati the flow expone a leaage coefficie gathere from the measureme resul. The specific leaage rate at 0 Pa ifference (w 0 ) will be use in some analysis because regari the local coext of Dutch regulation, the buili airtightness is measure as specific leaage rate at 10 Pa ifference (w 10 ). Hence, the main target of this research will be the specific leaage rate at 10 Pa ifference. B. Variables accoue Literature on buili airtightness sugges a wie rae of influenci variables groupe uer year of construction, structural a nonstructural buili characteristics a quality of womanship. Besies those variables, some aitional parameter also inclue in the measureme resul will be taen io accou in the research. This section summarizes the variables from those two sources that will be analyse in this research. The variable year of construction (YEAR) is inclue in this research, because many stuies suggeste that there is a corration between year of construction a buili airtightness. Even though the target fou in the literature is mostly air permeability at 0 Pa ifference (Q 0 ) a air chae rate at 0 Pa ifference (N 0 ), this research will test the corration of year of construction a specific leaage rate at 10 Pa ifference (w 10 ). Variables that fall io structural buili characteristics are buili metho (BM) a buili typology (BT). Buili metho correspos on how the buili is constructe, either by onsite construction, prefabrication or combination of both. Buili typology correspo to the main material of the construction type such as: concrete, woo frame, masonry a ste construction. Variables nonstructural buili characteristics that will be inclue in this research are: wli type (DT), roof type (ROOF), esign target (Q), a floor area (FLOOR). Other variables such as veilation type a insulation type are not inclue because there is no complete information regari those provie in the measuremen resul, which yi in many missi ata a possibly affect the riability of the research. While other nonstructural variables have been stuie, the corration between variable roof types a buili airtightness has not been eeply researche. Differe types of roof such as: pitche roof, flat roof, she roof or combination of roofi are teste because iffere roof types have iffere construction etails. 12 Analysi rationships between buili characteristics a airtightness of Dutch wlis
13 The next variables measure are leaages occur in the measure buili. Some measuremen resul reporte the leaage path or air leaage penetration either with infrare image or usi smoe to ieify the location of leaage paths a etermine the amage cause by the leaages. There are four classifications of leaages provie in the measuremen resul. Lev 1 is for the least amagi leaage a lev 4 is the most critical one. To accumulate this iffere lev of leaages, we compute the total score of leaages a name it uer a new construct 'TotalLK'. Construct Total Leaage is efine by the cumulative amou of all leaage together by weighti the leaage lev 1 is 1 a so on. Therefore, the construct TotalLK = LK1*1 + LK2*2 + LK3*3 + LK4*4. This variable is teste to show the rationship between leaages that occur in the buili a buili airtightness. C. Analysis metho There are 320 measureme resul of iffere houses in The Netherlas provie. The first attitue towars the ata is to compile the ata in the Microsoft Exc to ease the categorization of the measureme resul. Afterwars, the sprea shee will be exporte io statistical software program for more complex analysis. This research use IBM SPSS 20 because this software provies more aborate analysis resul. Variables meione in the previous section will act as iepee variables with the target of specific leaage rate at 10 Pa ifference (w 10 ) a 0 Pa ifference (w 0 ), act as epee variables. The variables are treate ifferely accori to the type of ata. Variables YEAR, DT, BM, BT a ROOF are nominal ata where each number represen another value. To chec the corration between these variables a epee variables, we run the ANOVA test between variables by compari means the iepee a epee variables. The variables are teste to see which variables iffers significaly, thus are significa factors to preict buili airtightness. For the scale ata, which are FLOOR, Q a TotalLK, linear regression analysis is carrie out to see the rationship a how significa the corration is. For both i of ata type, corration analysis is carrie out for all epee variables a iepee variables. The ANOVA test is run to compare means a the resul shows whether there is a significa ifference betweengroup of means. The significance of each variable was assesse accori to the P value of the Ftest, a applyi confience ierval of 9%; that is, Pearson value (pvalue) higher than 0.0 is consiere not significa. Variable year of construction, for example, have Ftest with pvalue < 0.0 implies that there is significance ifference in means between groups, meani that this variables is a goo preictor to be inclue in the mo evopme. On the other ha, the test of homogeneity of variances is also carrie out to chec the equal variances of the ata (Levene.801, p < 0.0). The variance of the ata in variable year is not equal. Higher Ftest resul means the ata is sprea out arou the mean a to each other. Because F test only tls whether there is significa ifference between groups but o not inform where it lies, therefore, a posthoc Scheffe test was run to suggest significa ifference between the means of all the pairs. Furthermore, the ieraction between variables is stuie usi twoway ANOVA, because there are some variables that o not give significa effect iiviually but give significa effect with ieraction with other variables. IV. RESULTS The average specific leaage rate at 10 Pa of all wlis is 0. m 3 /s.m 2 (SD = 0.38). There are nine extreme cases with specific leaage rate higher than 2.0 m 3 /s.m 2 as seen in Figure 1. In most cases, the maximum specific air leaage at 10 Pa allowe in is 0.62 m 3 /s.m 2, which iicate by the re line in the Figure % of the wlis stuie lie before the line, which means they comply with the minimum requiremen. Analysi rationships between buili characteristics a airtightness of Dutch wlis
14 Figure 1 Specific air leaage of all wiis stuie; max =.04 m3/s.m2, min = 0.06 m3/s.m2 From 320 measuremen, only 310 meione the location of the buili in 11 provinces: Gronien, Friesla, s, Flevola, Utrecht, Holla, ZuiHolla, Gerla, Zea, Braba, a Limburg. Figure 2 illustrates the mean ispersion of buili airtightness in The Netherlas. From the represeation, houses measure in Province Utrecht have the lowest mean of specific leaage rate (0.32 m 3 /s.m 2 ) compare to other provinces, followe by Limburg (0.33 m 3 /s.m 2 ) a Gronien (0.38 m 3 /s.m 2 ). The highest mean of buili airtightness is reporte from houses in Province Zea (0.68 m 3 /s.m 2 ). Figure 2 Distribution a airtightness means of sample Dutch Builis by Province Analysi rationships between buili characteristics a airtightness of Dutch wlis
15 A. Corration between buili characteristics a specific leaage rate The first analysis carrie out is the corration analysis between epee variables w 10 a w 0, a iepee variables. Table 3 presen the resul of the corration analysis. Pearson value (Pvalue) sugges the type of corration a how stro the corration is. In this case the corration is significa at N shows how many vali ata is use to analyse the corration between variables a missi ata is not inclue in the analysis. Table 3 resul of corrational analysis between variables N w 10 w 0 Total Leaage * (.000).426* (.000) Design Target (.272).073 (.212) Floor Area (.083) (.192) Year of Construction * (.000) .31* (.000) Dwli Type (.12) (.288) Buili Metho * (.000) .204* (.000) Buili Typology * (.004) .119* (.033) Roof Type (.117) (.187) Note. * Significance at 0.0. w10 = specific leaage rate at 10 Pa ifference. w0 = specific leaage rate at 0 Pa ifference Table 3 sugges that variables year of construction, buili metho, buili typology a total leaage are significa a might be a goo preictor to specific leaage rate at 10 Pa. However, variable buili year a total leaage are the best preictors because they have higher P value ( a 0.437) compare to the rest. Compare to specific leaage rate at 10 Pa, variable year of construction, buili metho a total leaage are also significa for specific leaage rate at 0 Pa. However, the corration analysis only shows whether there is corration between variables but not the effect of one variable to another; a also i not give eeper insight of the ifferences between groups means. Therefore, an ANOVA test is carrie out to explore those variables that influence specific leaage rate. 1) Total Leaages Figure 3 Scatter Plo of Total Leaages Some of the ata show the number of leaage path fou in the buili measure a also the lev of leaages. 41% of leaage paths were fou occur in wiowwall ierface, 22% in joi between floor a wall, 3% in joi between ceili a wall, 7% were fou in roof joi, % in plumbi installation, % in ectrical socet a 8% in ve. This empirical stuy sought to see the corration between numbers of leaage path by accumulati it usi construct TotalLK. Analysi rationships between buili characteristics a airtightness of Dutch wlis 1
16 A positive corration was fou between measure specific leaage rate at 10 Pa ifference a total leaages in the buili with r = 0.437, (p < 0.0, 2taile) for 10 Pa ifference, as plotte in Figure 3. Further statistical tes reveale the corration for measure specific leaage rate at 0 Pa a total leaages (r = 0.426, p < 0.0, 2taile). However, only 19.1% of the variation in w 10 a only 18.2% of the variation in W 0 can be explaine by the variable total leaages. This result poin out that leaages in the buili coributes to the buili airtightness in consierable amou. 2) Design Target As meione in the irouction, most of the builis were assigne a q v10 to be inclue in the calculation. This assigne q v10 is treate as a variable esign target, which means that this value is the minimum value that must be comple. 91.6% of the measuremen meione the target q v10 of the. 8. % of the eire measureme resul has targete bow 0.1, 49.% bow 0.4 a 91.1% bow However, no significa corration is fou between the variable esign target a specific leaage rate at 10 Pa ifference (n = 293, r = 0.064, p = 0.272) as wl as at 0 Pa ifference (n = 293, r = 0.073, p = 0.212). The scatter plot of esign target a specific leaage rate at 10 Pa, as seen on Figure 4, shows that the assigne q v10 on oes not necessarily ensure the accomplishme of buili airtightness. Figure 4 Scatter Plot of Design Target 3) Floor area Analysis was also carrie out of the corration between measure specific leaage rate a floor area. The result sugges there is no significa corration between floor area with specific leaage rate at 10 Pa ifference (n = 320, r = , p = 0.083) a at 0 Pa ifference (n = 320, r = , p = 0.192). B. One way ANOVA An exploratory analysis usi the ANOVA test was coucte to ieify possible significa rationship between buili characteristics variables a buili airtightness in terms of specific leaage rate. The variables accoue in the ANOVA test has been meione in previous section. The way of ANOVA test wos is by compari means between iffere groups inclue in the variable. 16 Analysi rationships between buili characteristics a airtightness of Dutch wlis
17 1) Year of construction The variable year of construction is goi to be stuie i corration with buili airtightness. Because there are many builis with iffere year of construction, the first step is recoe year built io rae. The consieration is base on Dutch Buili Coe, which are 'Bouwbesluit 1992, 2003 a 2012'. Therefore, we categorize the year rae base on the year of the regulation apply. Figure 2 shows that oler builis (pre2003) have significaly higher specific leaage rate (3.09 m 3 /s.m 2 ) compare to newer builis (0.17 m 3 /s.m 2 a 0.2 m 3 /s.m 2 ). However, the measureme resul were ominate by buili from post2012 (92.2%). Consequely, there is more sprea in the buili from this group with more extreme cases occurri. Figure Specific leaage rate by year built To compare the means of buili airtightness amo iffere group of year of construction, a oneway ANOVA Ftest was use. F test of (p < 0.01), for target of specific leaage rate at 10 Pa ifference, sugges that the iffere between groups is significa. Liewise, the resul with specific leaage rate at 0 Pa ifference (F = p < 0.01) also sugges that conclusion. The test of homogeneity (Levene Statistic , p < 0.0) sugges that the variance between 4 groups is not statistically equal. It means there is at least one group that iffers significaly than the others. Therefore, a posthoc Scheffe test was run to reveal where the ifferences lie between groups. The same proceure applies for the target of specific leaage rate at 0 Pa (Levene Statistic 7.468, p < 0.0) because the homogeneity test sugges the same resul. There is a positive linear rationship, as shown on Figure, amost the groups from pre1992 uil the previous buili coe (Bouwbesluit 2003). This might be cause by the sprea occurs in the newer buili group (post2012). Therefore, the variable year of construction encompasses other buili typology variables, which will be explaine further in the iscussion. On the other ha, statistics suggest that there is significa ifference in means specific leaage rate at 10 Pa ifference (p < 0.0) between builis from pre1992 with each of other 3 groups a between builis from a builis from post However, the result on the mean specific leaage rate at 0 Pa ifferences sugges slightly iffere resul. The significa ifference only existe between builis from pre 1992 a the other three groups. The resul together iicate that newly built wlis is consierably more airtight than oler builis. Analysi rationships between buili characteristics a airtightness of Dutch wlis 17
18 2) Dwli type The resieial builis stuie were groupe io seven types of wli type: apartme, uplex house, eterrace house, miterrace house, semietache house, etache house a the remaini builis which type weren t nown is groupe as unnown. ANOVA tes were run to compare betweengroups means ivie by the withingroups one. Firstly, the test of homogeneity (Levene s test) carrie out to show that the variance between 7 iffere groups. The resul of the homogeneity test sugges that variance between groups on specific leaage rate at 10 Pa ifference as target is equal (F = p = 0.073); however, with specific leaage rate at 0 Pa iffere as target, it was fou that there is a ifference between the variances amo 7 groups (F = p < 0.0). However, the resul of the ANOVA test sugges otherwise. The F ratio of (p = 0.09) implies that the ifferences between means of specific leaage rate at 10 Pa ifference were not statistically significa. The same conclusion applies to the means of specific leaage rate at 0 Pa ifference (F = p = 0.07). In conclusion, variables wli type is not a suitable preictor for specific leaage rate, neither at 10 nor 0 Pa ifference, because statistics suggest means between groups are not significa. Figure 6 Specific leaage rate by wli type 3) Roof type The ifferences between roof types are also stuie in this research. The wlis stuie in this research were groupe accori to the roof types that are: she roof, flat roof, pitche roof, combination (of more than one roof type) a the unnown group, which the roof type is not recognize. The test of homogeneity (Levene Statistic 2.1, p < 0.0) sugges that the variance between groups is not statistically equal. It means there is at least one group that iffers significaly than the others. The same proceure applies for the target of specific leaage rate at 0 Pa (Levene Statistic.168, p < 0.0) because the homogeneity test sugges the same conclusion. ANOVA test resul suggest (F = 4.21, p < 0.01), for target of specific leaage rate at 10 Pa ifferences, that the ifference between groups is significa. Liewise, the resul with specific leaage rate at 0 Pa ifference (F = p < 0.01) also sugges the conclusion. A posthoc Scheffe test is run to reveal where the ifferences lie between groups. In case of roof type variables, the resul suggest that there is significance ifference in means specific leaage rate at 10 Pa ifference (p < 0.0) between builis with pitche roof a the unnown group. Similar fiis also occurs on the mean specific leaage rate at 0 Pa ifferences. The only 18 Analysi rationships between buili characteristics a airtightness of Dutch wlis
19 significa ifference was fou in unnown group a pitche group. The explanation of this result will be iscusse in section. Figure 7 Specific leaage rate by roof type 4) Buili metho The wlis stuie are constructe usi three iffere methos: onsite construction, prefabrication a combination of both. Other builis with unnown buil metho fall io the group unnown. F test of 8.0 (p < 0.01) sugges that there is significa ifference in mean specific leaage rate at 10 Pa ifference between groups. Liewise, the resul with specific leaage rate at 0 Pa ifference (F = p < 0.01) also sugges that conclusion. The test of homogeneity (Levene Statistic 7.204, p < 0.0) sugges that the variance between 4 groups is not statistically equal. It means there is at least one group that iffers significaly than the others. Therefore, a posthoc Scheffe test was run to reveal where the ifferences lie between the groups. The same proceure applies for the target of specific leaage rate at 0 Pa (Levene Statistic 9.323, p < 0.0) because the homogeneity test sugges the same conclusion. The resul of post hoc test suggest that there is significa ifference in means specific leaage rate at 10 Pa ifference (p < 0.0) between builis with prefabrication metho a unnown group. The resul on the mean specific leaage rate at 0 Pa ifferences suggest the same conclusion. The statistical resul iicate the mean specific leaage rate oes not iffer significaly, except for the unnown group. Analysi rationships between buili characteristics a airtightness of Dutch wlis 19
20 Figure 8 Specific leaage rate by buili metho ) Buili typology The buili typology is categorize accori to the material of the structure, which are: concrete, woo frame, masonry, ste construction a group unnown. F test of 4.98 (p < 0.01) sugges that there is significa ifference in mean specific leaage rate at 10 Pa ifference between groups. However, the other resul (F = 3.02 p = 0.018) suggest that there is no significa iffere in mean specific leaage rate at 0 Pa ifference between groups. The test of homogeneity (Levene Statistic 9.827, p < 0.0) sugges that the variance between the four groups is not statistically equal. There is at least one group that iffers significaly from the others. Therefore, a posthoc Scheffe test was run to reveal where the ifferences lie between groups. However, a posthoc test cannot be run because there is one group that has less than two cases a that is the ste construction group. Figure 9 Specific leaage rate by buili typology In general, these resul iicates that stroer corration occur between variables a measure specific leaage rate at 10 Pa ifference. The resul of the ANOVA test (Table 4) showe that the 20 Analysi rationships between buili characteristics a airtightness of Dutch wlis
21 followi variables have significa influence on specific leaage rate at 10 Pa ifference: year of construction, total leaage, wli type, roof type, buili metho a buili typology. C. Twoway ANOVA The analysis above sugges that all variables, except floor area, esign target a wli type are significa to preict specific leaage rate at 10 Pa ifference. Even though every variable is significa, or equivale as havi main effect on buili airtightness, the ieraction between variables might have effect on buili airtightness as wl. Therefore, twoway ANOVA tes were run to analyse the ieraction between variables. The ifference between oneway a twoway ANOVA is that oneway ANOVA only stuies main effect of variables to the target variables, while twoway ANOVA also stuies whether ieraction between variables givi effect on target variables. There are six variables inclue in the analysis, which resulte in seveeen pair of twoway ANOVA to run. Although previous analysis shows both measure specific leaage rate at 10 a 0 Pa ifference, the main target of this research is still the Dutch coext with 10 Pa ifference. However, not all variables showe ieraction effect a cannot be accoue as goo preictors. The resul of twoway ANOVA test suggest that ieraction effect occur between buili year built x total leaages (F = 6.6 p < 0.01) with ajuste Rsquare 0.703; total leaages x roof type (F = p < 0.01) with ajuste Rsquare 0.28; total leaages x buili metho (F = 3. p < 0.01) with ajuste Rsquare 0.609; total leaages x buili typology (F = p < 0.01) with ajuste Rsquare These resul prove that ieraction between total leaage a other variables give effect on buili airtightness. The resul of the eire exploratory analysis can be summarise as seen on Table 4. Table 4 Summary of Exploratory Analysis resul Variables Analysis Metho pvalue* Ftest Pearson s r R square Total leaages (TotalLK) Linear regression Design target (Q) Linear regression Floor area (FLOOR) Linear regression Year of construction (YEAR) Oneway ANOVA Dwli Type (DT) Oneway ANOVA Roof Type (ROOF) Oneway ANOVA Buili Metho (BM) Oneway ANOVA Buili Typology (BT) Oneway ANOVA Year x TotalLK Twoway ANOVA Year x DT Twoway ANOVA Year x ROOF Twoway ANOVA Year x BM Twoway ANOVA Year x BT Twoway ANOVA TotalLK x DT Twoway ANOVA TotalLK x ROOF Twoway ANOVA TotalLK x BM Twoway ANOVA TotalLK x BT Twoway ANOVA DT x ROOF Twoway ANOVA DT x BM Twoway ANOVA DT x BT Twoway ANOVA ROOF x BM Twoway ANOVA ROOF x BT Twoway ANOVA BM x BT Twoway ANOVA Note. *significa at 0.0. D. Regression Analysis The analysis above shows that variable buili year (YEAR), total leaages (TotalLK), roof type (ROOF), buili metho (BM) a buili typology (BT) are significa to preict buili airtightness in terms of specific leaage rate at 10 Pa. Then we run linear regression analysis (with confience lev 9% = 1.960). This research uses linear regression with eer metho. Some articles fou in the literature review usi either stepwise or forwar metho [21]. Both of them automatically show the iffere regression resul by accoui only the most significa variables, a irectly show comparison between more than one mo where each mo accoue iffere Analysi rationships between buili characteristics a airtightness of Dutch wlis 21
22 significa variables; while eer metho only show one mo which shows only secte variables. Either eer, stepwise or forwar metho has been teste in this research usi SPSS 20 a all yi on similar resul. The initial mo evope as followe: w 10 = α + β totallk. TotalLK + β YEAR. YEAR + β ROOF. ROOF + β BM. BM + β BT. BT Equation The parameter β YEAR represen the coefficie for year category when the buili was built. Parameter β TotalLK represen the coefficie of total leaage a variable TotalLK is the total value of leaage amage lev fou uri measuremen. The reason to inclue total leaage nown in the measuremen is to preict whether seali certain poi of leaage path can improve buili airtightness of the buili prior to next measuremen. The same applies to ROOF, BM a BT, where β represen the coefficie a the variables are the value that represen the wli type, roof type, buili metho a buili typology. Apparely, the regression analysis has shown that variables ROOF, BM a BT are not significa to be applie in the mo. Table provie aborate coefficie value for consta a preictor variables for the equation. Therefore, regression was run again by removi the not significa variables. w 10 = α + β totallk. TotalLK + β YEAR. YEAR Equation 6 As seen on Table, Eq. 6 has slightly lower Rsquare than Eq., meani that 42.1% of w 10 can be explaine by the mo regression. However, Eq. 6 only accoue significa variables compare to Eq. that still accoue variables ROOF, BM a BT, which have significa influence accori to ANOVA but not accori to multiple linear regression. The justification this mo will be iscusse in followi section. Table Coefficie a ajuste Rsquare value for both mos Coefficie Regression 1 (Eq. 4) t pvalue Regression 2 (Eq. ) t pvalue α ± ± β YEAR 0. ± ± β TotalLK 0.0 ± ± β ROOF 0.02 ± β BM ± β BT 0.01 ± Ajuste R square F V. DISCUSSION This stuy aime at etermini the significa rationship between buili characteristics a buili airtightness. Corrational analysis a ANOVA tes were carrie out to measure these rationships. Furthermore, by incorporati significa variables erive from the ANOVA test, a multi linear regression is run to etermine significance factors that influence buili airtightness. Many variables were consiere from literature a the year of buili construction, buili metho, buili typology, roof type a total leaages were fou to have significa rationships with specific leaage rate. However regression analysis shows that only buili year a total leaage influences specific leaage rate. The resul above showe that buili characteristics such as wli type a floor area cannot explain the buili airtightness because the ifference in means were not significa. Even though the ANOVA test a the corration test were run for both target of specific leaage rate at 10 Pa a 0 Pa ifference, the resul suggest slightly iffere numbers with similar outcomes. The ANOVA test sugges that oler builis te to be leaier than newer builis. The fiis from the regression analysis confirm that year of construction actually have influence over airtightness. This corroborate with Chan, Joh & Sherman [19], Mooya et al. [21], a Sinott & Dryer [16]. Although this is an ieresti iscovery, it has little impact on practice because legislation only applies to newer builis, particularly since the 1992 Buili Coe was enacte. Other factors such 22 Analysi rationships between buili characteristics a airtightness of Dutch wlis
23 as buili metho, material use a buili technology are inculcate in the year of construction which is irectly rate to materials a buili practices prevale at that time. These might not be influence in curre legislation, but might be improve, for example, by retrofitti the leay builis. The analysis shows that total leaage has a stro corration with specific leaage rate a regression resul prove that the amou of leaage happen in the house give influence to the specific leaage rate. This confirms that the more leaages occur in the buili, the less airtight the buili woul be. Empirical ata also sugges rae of leaage path fou in the builis: wiowwall ierface, joi between floor a wall, joi between ceili a wall, were fou in roof joi, in plumbi installation, in ectrical socet a in ve. This sugges that atteion to etails improves the quality of womanship. As the literature shows[16], [23], [24], womanship is critical to achieve buili airtightness. Statistics also showe the same resul that leaages occur in the buili give significa influence on specific leaage rate, which in this case happen at 10 Pa iffere. In new houses, leaages can be minimize by payi close atteion to etails a this is anchore more on the quality of womanship. Buili metho was fou not to have an impact on specific leaage rate. This is in corast to the fiis of Kalamees [23], who iscovere that prefabricate etache houses are less leaier than houses that were constructe on site a therefore more airtight. However, because some of the cases i not explicitly categorize the buili metho, which in this stuy was categorize as unnown, it is possible that this coul have influence the outcome. Moreover, the ANOVA test sugges that there is a significa ifference in specific leaage rate means between groups. However, the significa ifference lies between group unnown a prefabrication buili. Even though, the regression analysis sugges no effect whaoever. Although Mooya et al. [21] a Chan, Joh & Sherman [19] note buili typology to be a preictor of buili airtightness, in the case of Dutch resieial builis, this variable was not iscovere statistically significa as a preictor of specific leaage rate. Just as in the buili metho, the ANOVA test sugges there is a significa ifference in means of specific leaage rate between groups. However, where the mean ifference lies between groups cannot be etermine by posthoc Scheffe test in this stuy. This coul have influence the outcome that buili typology cannot be a preictor. As the ANOVA test presen, there is rationship between roof type a specific leaage rate; this ifference in means of specific leaage rate lies between group unnown a pitche roof. However, resul of regression shows no impac of roof type on specific leaage rate. Neverthess, just as in buili metho, because some of the cases i not explicitly categorize the roof type, which in this stuy was categorize as unnown, it is possible that this coul have influence the outcome. Even though year of construction a total leaage both ha main effect on specific leaage rate, their influences on specific leaage rate is not simultaneous but ieractive. This means that the effect of total leaage is epee on the age of buili a vice versa. Total leaage also has ieraction with other significa factors which are: roof type, buili metho a buili typology. However they were statistically insignifica as preictors, therefore, the ieraction effect has no consequences on specific leaage rate. A. Implications Base on the significance buili characteristics etermine from the ANOVA test, regression resul sugges that only variable year of construction a variable total leaage influence specific leaage rate at 10 Pa ifference. Although the year of construction has influence on specific leaage rate, this iscovery however, has little revance on builis post This means that, at the e of the ay, the regulation (Dutch Buili Coe) on buili airtightness is only reva on newly built houses. This stuy confirms that year of construction a total leaages actually have influence on buili airtightness as suggeste in the literature. Apparely the influence of these factors is subject to their ieraction with each other as confirme by the twoway ANOVA test. In aition, year of construction actually encompasses other factors such as buili typology, buili material, buili metho, HVAC system, insulation type, etc. This is because these factors cannot be issociate from the prevale practices of rative perios in time. On the other ha, leaages path fou in some part Analysi rationships between buili characteristics a airtightness of Dutch wlis 23
24 of the buili is still a reva fii because it still coul be consiere uri the construction of new houses. Since total leaage has significa effect on specific leaage rate, more atteion shoul be pai to minimizi air leaage at the early phases of construction a this is epee on the quality of womanship. Also other stuies have suggeste that supervisor a manageme play importa role in achievi high quality womanship a this coul have positive impact on attaini less leaages a subsequely more airtight buili. Therefore, a riable mo coul not be generate with the fiis of this stuy. One ieresti area of this research was to explore if roof type influences specific leaage rate, because previous stuies overlooe it. A remaable iscovery is that roof type is actually rate with specific leaage rate although it has no effect on it. Together with variable total leaage, roof type has an ieraction effect on specific leaage rate. This might support the fac that leaage path fou in the roof joi might coribute significaly to total air leaage a, consequely, affect buili airtightness. B. Limitations This research, however, has some limitations. Since this stuy analyse resul from many other scieific stuies, one of the shortcomis of it is the heterogeneity of the resul from the inclue stuies can be affecte. A this is because there are inhere ifferences in the iiviual stuies such as metho of obtaini ata, analysi them a ierpreti them. This research uses the term specific leaage rate to refer buili airtightness while other stuies use iffere terms to normalize buili airtightness a measureme of such concep coul yi iffere outcomes. Also since this research uses regression to attempt to evop a mo, such mo metho is only applicable if the new ata is in rae of a ataset from which the mo was erive from. This is also a notable limitation to this stuy. Another limitation of these stuies is that there were some missi ata in the cases which are importa for riable fiis. Stuies coul mae stroer attemp to obtain a presen upate a comprehensive ata which future research coul riably built on. VI. CONCLUSION AND RECOMMENDATIONS Many stuies have attempte to preict airtightness prior to a blower oor test. As Raer [26] conclue that no such mo can substaially replace the blower oor test. However, preicti airtightness is a fruitful effort to achieve a esire lev of buili airtightness, especially in the case of Dutch regulations, that require a certain value of q v10 or w 10 to calculate the energy performance coefficie. In this stuy, while total leaage, year of construction, roof type, buili metho a buili typology have a rationship with airtightness, only year of construction a total leaage influence the buili airtightness. This supposes that a riable mo cannot be evope from those variables since the overall effect was still rativy moerate. Other probably factors will explain the variance in airtightness. There might be nee to further explore this area of ierest to iscover the coge variables that coul have effect on buili airtightness. However, the fiis of this wo coul be a spriboar for future researches on airtightness. Particularly the fact that year of construction influences airtightness, which actually encompasses other buili typology such as buili material, buili technology a practise uri that time. This calls for testi other variables that are not inclue in this empirical stuy such as veilation system a insulation type. Such buili characteristics might influence buili airtightness because veilation system etermines the ioor air quality a insulation type etermines the quality of buili envope. Other stuies have shown that supervision of womanship a manageme coext have effect on buili airtightness. This coul be confirme within the stuy scope of The Netherlas, as the empirical ata showe where the leaage path is a thus, atteion to etail a enhanci the supervision in orer to improve the quality of womanship is esseial to maiain achieve more airtight builis. As this research particularly has stuie resieial builis, future stuies coul be carrie out usi the same variables of this wo to test for rationship with buili airtightness a perhaps evop a preictive mo for airtightness of service builis. Furthermore, experimeal research coul be carrie out to fi out if ierference on variables affec buili airtightness. For example retrofitti 24 Analysi rationships between buili characteristics a airtightness of Dutch wlis
25 can be applie on oler builis by usi iffere material that configure the buili envope to measure the egree of improveme on buili airtightness. These coul perhaps be the ierveion neee to ensure aequate buili airtightness in the future a ultimaty energy efficiency. ACKNOWLEDGEMENTS The author woul lie to than The Ionesia Eowme Fu for Eucation, Ministry of Finance of Republic of Ionesia for provii the Master scholarship a the opportunity to stuy at the University of Twee. The author woul also lie to particularly appreciate the effor of Joop Halman a Bram Erop, for their guiance a encourageme that refine this stuy. Lastly, the author is grateful to Acniah Damayai for the coribution on SPSS a statistical analysis, Aeapo Tunmise Alaegbaiye for givi some significa avice on the writi process a Martin Platenamp for supporti on Dutch text translations. REFERENCES [1] NHBC Fouation, A practical guie to buili airtight wlis. Amersham: IHS BRE Press, [2] P. Kuiersma a H. M. Nieman, Luchticht bouwen, theorieowerppratij, Rotteram, 20. [3] S. B. Saineni, S. Maala, a R. F. Boehm, Passive buili energy savis: A review of buili envope componen, in Renewable a Sustainable Energy Reviews, vol. 1, no. 8, Elsevier Lt, 2011, pp [4] H. Krstić, Ţ. Koši, I. I. Otović, a M. Španić, Application of neural netwos in preicti airtightness of resieial uni, in Energy a Builis, vol. 84, 20, pp [] J. M. Logue, M. H. Sherman, I. S. Waler, a B. C. Sier, Energy impac of envope tighteni a mechanical veilation for the U.S. resieial sector, in Energy a Builis, vol. 6, Elsevier B.V., 20, pp [6] S. Nabier a A. Persily, Impac of airtighteni retrofi on veilation rates a energy consumption in a manufacture home, in Energy a Builis, vol. 43, no. 11, Elsevier B.V., 2011, pp [7] J. Joisalo, J. Kurnii, M. Korpi, T. Kalamees, a J. Vinha, Buili leaage, infiltration, a energy performance analyses for Finnish etache houses, in Buili a Environme, vol. 44, no. 2, 2009, pp [8] W. Pan, Rationships between airtightness a i influenci factors of post2006 newbuil wlis in the UK, in Buili a Environme, vol. 4, no. 11, Elsevier Lt, 2010, pp [9] Ü. Alev, L. Esola, E. Arumägi, J. Joisalo, A. Donarli, K. Siren, T. Broström, a T. Kalamees, Renovation alternatives to improve energy performance of historic rural houses in the Baltic Sea region, in Energy a Builis, vol. 77, Elsevier B.V., 20, pp [10] M. H. Sherman a R. Chan, Buili Airtightness : Research a Practice, Analysi rationships between buili characteristics a airtightness of Dutch wlis 2
26 [11] H. R. R. Saos a V. M. S. Leal, Energy vs. veilation rate in builis: A comprehensive scenariobase assessme in the European coext, in Energy a Builis, vol. 4, Elsevier B.V., 2012, pp [12] D. Micaël, B. Bruno, C. Valérie, L. Murile, P. Cécile, R. Jacques, a K. Severine, Ioor air quality a comfort in seven newly built, energyefficie houses in France, in Buili a Environme, vol. 72, Elsevier Lt, 20, pp [] EU, Directive 2010/31/EU of the European Parliame a of the Council of 19 May 2010 on the energy performance of builis, Off. J. Eur. Union, pp. 3, [] BRIS Bouwbesluit Online, Bouwbesluit [Online]. Available: [Accesse: 2Feb201]. [1] V. Iorache a T. Catalina, Acoustic approach for buili air permeability estimation, in Buili a Environme, vol. 7, 2012, pp [16] D. Sinnott a M. Dyer, Airtightness fi ata for wlis in Ira, in Buili a Environme, vol. 1, 2012, pp [17] Ceraal Bureau voor e Statistie, Voorraa wonien en nietwonien; mutaties, gebruisfunctie, regio, 20. [Online]. Available: a&d3=0,10319&d4=33&hd= &hdr=g1,t&stb=g2,g3. [Accesse: 26 Aug201]. [18] CEN, EN Staar 829: Thermal performances of buili  etermination of air permeability of builis  fan pressurization metho. Brusss: European Committee for Staarization, [19] W. R. Chan, J. Joh, a M. H. Sherman, Analysis of air leaage measuremen of US houses, in Energy a Builis, vol. 66, Elsevier B.V., 20, pp [20] W. R. Chan, W. W. Nazaroff, P. N. Price, M. D. Sohn, a A. J. Gagil, Analyzi a atabase of resieial air leaage in the Unite States, Atmos. Environ., vol. 39, no. 19, pp , 200. [21] M. I. Mooya, E. Pastor, F. R. Carrié, G. Guyot, a E. Planas, Air leaage in Catalan wlis: Devopi an airtightness mo a leaage airflow preictions, in Buili a Environme, vol. 4, no. 6, 2010, pp [22] A. Sfaianai, K. Pavlou, M. Saamouris, I. Livaa, M. N. Assimaopoulos, P. Maas, a a. Christaopoulos, Air tightness measuremen of resieial houses in Athens, Greece, in Buili a Environme, vol. 43, no. 4, 2008, pp [23] T. Kalamees, Air tightness a air leaages of new lightweight silefamily etache houses in Estonia, in Buili a Environme, vol. 42, no. 6, 2007, pp [24] M. Pio, J. Viegas, a V. P. e Freitas, Air permeability measuremen of wlis a buili componen in Portugal, in Buili a Environme, vol. 46, no. 12, Elsevier Lt, 2011, pp Analysi rationships between buili characteristics a airtightness of Dutch wlis
27 [2] D. F. R. Alfano, M. Dl Isola, G. Ficco, a F. Tassini, Experimeal analysis of air tightness in Meiterranean builis usi the fan pressurization metho, in Buili a Environme, vol. 3, Elsevier Lt, 2012, pp [26] T. O. Raer, S. Holøs, a J. V. Thue, Airtightness estimation  A state of the art review a an en route upper limit evaluation principle to increase the chances that wooframe houses with a vapour a wibarrier comply with the airtightness requiremen, in Energy a Builis, vol. 4, Elsevier B.V., 2012, pp [27] N. Van Den Bossche, W. Huyghe, J. Moens, A. Janssens, a M. Depaepe, Airtightness of the wiowwall ierface in cavity bric walls, in Energy a Builis, vol. 4, Elsevier B.V., 2012, pp [28] T. O. Raer, G. Bauwens, S. Ros, J. V. Thue, a S. Uvslø, The influence of structural floors on the airtightness of wooframe houses, in Energy a Builis, vol. 43, no. 2 3, 2011, pp [29] T. O. Raer, B. Heis, a J. S. Tysseal, The influence of the joi between the baseme wall a the wooframe wall on the airtightness of wooframe houses, in Energy a Builis, vol. 43, no. 6, Elsevier B.V., 2011, pp. 04. [30] J. Lamans, R. Klein, M. De Paepe, a S. Ros, Poteial of wi barriers to assure airtightness of wooframe low energy constructions, in Energy a Builis, vol. 42, no. 12, Elsevier B.V., 2010, pp [31] T. O. Raer, T. Kvae, a J. V. Thue, The influence of lightweight aggregate concrete eme chimneys on the airtightness of wooframe houses, in Energy a Builis, vol. 42, no., Elsevier B.V., 2010, pp Analysi rationships between buili characteristics a airtightness of Dutch wlis 27
28 RESEARCH PROPOSAL DEVELOPING A MORE RELIABLE MODEL FOR PREDICTING BUILDING AIRTIGHTNESS ANALYSIS OF BUILDING AIRTIGHTNESS MEASUREMENTS IN DUTCH RESIDENTIAL BUILDINGS AUGUST 4, Research Proposal
29 Table of Coen Abstract Irouction Bacgrou Airtightness of Builis in the Netherlas Research Design 3 Scope of stuy 3 3. Research metho Phase 1: Literature Review Phase 2: Analysis Phase 3 Mo Testi Implications a Limitations Scheuli Literature Review Irouction Reva Terms in Buili Airtightness 40 Air infiltration 40 Air leaage rate 40 Air permeability Measuri buili airtightness Estimati Buili Airtightness 42 Airtightness Estimation Research 43 Variables Priminary Conclusion 46 References 46 Appeix 0 Nomenclature 0 Symbol a Uni 0 Terms a efinition 0 Research Proposal 29
30 30 Research Proposal
31 ABSTRACT There is an increasi awareness for buili airtightness. This is ue to the nee to save energy, as wl as follow ictates of buili regulations, which state that coractors a house owners must comply with certain minimum requiremen. To etermine whether a buili mee the minimum requiremen or not, they are teste for their air permeability lev with a blower oor after completion. The uncertaiy of meeti these requiremen of buili airtightness measuremen, encourage staeholers to attempt to preict resul as accuraty as possible prior to completion. There have been many researches in the past on measuri buili airtightness, but none of them seem to supersee the resul of blower oor measuremen. This research, therefore, aims at improvi the existi mo to preict buili airtightness. This is one by stuyi the variables of buili characteristics, which will be euce from past stuies, that influence the airtightness of buili envope. The plan is to incorporate resul in a stroer mo that will be erive from linear regression. 1. INTRODUCTION 1.1. Bacgrou The builis sector incurs a significa portion of energy use in the worl. With the issue of sustainability getti more importa, several attemp are bei mae to reuce the energy use of builis by improvi their energy efficiency. Differe staeholers across the worl such as governmen, scieis a environmealis recognise the impact of energy efficiency on buili. The evopme a risi ema on zeroenergy, energy neutral builis, highefficiency builis a smart builis have motivate the actors in the construction iustry to innovate. The focus is still the same: to reuce the energy nees of builis. Therefore, innovation in the buili technology area has rapily evope, not only to reuce the energy nees but also to comply with the curre regulation. An energyefficie buili can be achieve either through active or passive strategies. Measures such as improvi heati veilation a air coitioni (HVAC) system, installi a solar pan, etc. are categorize as active strategies, while improvi the quality of the buili envope is categorize as passive strategy [3]. Buili envope improveme inclues improveme of the wall, wiow a oor penetration, a roofs. An obvious example of passive strategy is the concept of passive house, which requires certain measures of improvi the heat resistance a airtightness of the buili envope (air permeability N 0 of 0.6 ACH). Moreover, not every househol can affor to apply active energy efficie strategies because improveme on buili envope eme such as by improvi the thermal insulation a buili airtightness to reuce heat loss is suggeste a regulate in the buili coe. Airtightness is consiere importa for improvi the energy efficiency of builis, especially if one is followi the passive energy efficie strategy. Buili airtightness has been inclue in the regulations in many couries to achieve energy efficie builis. It is in most cases usually measure in terms of air permeability lev. The term airtightness pertains to the iensity of the uncorolle flow of air through the buili envope as a result of pressure ifferences between ierior a exterior air[4]. Buili airtightness is closy rate to air infiltration or air leaages within the buili as the lev of airtightness achieve is often measure as air permeability (m 3 /h.m 2 ) at 0 Pa, that is, the quaity of air (in m 3 ) that leas io or out of the wli per hour, ivie by the iernal area (in m 2 ) of the buili fabric at 0 Pa [1]. Several stuies have shown the importance of ensuri buili airtightness in orer to reuce air infiltration a thus reuci the cooli loa a heat loss of the buili [3]. The stuies iicate that tighteni of the buili envope provies a large energy benefit[], [6]. By coucti several experimeal analyses, most stuies showe how buili airtightness influences the energy performance within a house. Rece stuies suggeste the importance of buili airtightness with respect to energy efficiency, thermal comfort a ioor air quality of wlis [7] [10]. Maiaini buili airtightness is also esseial for the effectiveness of heat recovery installe in the buili Research Proposal 31
32 [11], [12]. Therefore, it is importa to maiain a certain lev of buili airtightness to optimize the energy efficiency of builis. Recely, European legislation on the energy performance of builis has become more strict [21]. The ripple effect of this is evie in The Dutch Buili Coe [], which requires resieial builis in The Netherlas to comply with a certain lev of energy performance, in terms of energy performance coefficie (Article.2), a a given limit of airflow rate (Article.4). However, there is a minor flaw in the Coe. It explicitly meions total maximum of airflow rate allowe in the buili but it oes not explicitly meion any other minimum requiremen such as egree of buili airtightness. This might initiate some confusion as it is fou in some cases that builis comply with the certain lev of energy performance but they o not comply with the minimum value of buili airtightness or vice versa. Furthermore, to ensure that reasonable staars are achieve, blower oor tes are taen for newly built houses in orer to measure a confirm their airtightness on completion. However, another problem is that coractors only ry on the measuremen resul one after the completion of the buili. The require airtightness is then sometimes not followe. Effor must be taen to ensure that a certain lev of buili airtightness a the awareness to apply measures a techniques to achieve this are iegrate from the beginni of any new construction project. In aition, plans for the retrofitti or rehabilitation of existi builis are require to get measure as wl [], [6], [1], [16]. To ensure this, it is stroly avise to use preictive methos of buili airtightness to assist the coractor or any other staeholer involve in the construction project to comply with the minimum requiremen of buili airtightness, especially prior to carryi out blower oor test. However, what really matters to some actors, such as coractors, is not to estimate the buili airtightness, but to comply with the given requiremen. On the other ha, estimati buili airtightness prior to official measuremen can offer guiance on which part of builis to improve in orer to meet the minimum value require. If airtightness can be accuraty estimate a measure on an acceptable lev, coractors can save some cos on performi blower oor test. In the e, it coul be a solution to achieve less infiltration occurrence, a ultimaty more airtight a energy efficie builis Airtightness of Builis in the Netherlas The airtightness of builis in the Dutch buili regulations is expresse as a flow rate at 10 Pa pressure ifference (q v10 ) a the measureme is taen by a blower oor test. While in other couries buili airtightness is expresse as air permeability lev at 0 Pa ifference (Q 0 ) or air chae rate at 0 Pa ifference (N 0 ). For comparison, the ration between q v10 a N 0 is epee on the flow coefficie (n) a ivision by about The average flow rate (q v10 ) is about 1 m 3 /s, which equals N 0 of about 3. to 4. [32]. However this equality cannot be etermine efinity because the normalization use to ivie the airflow rate is iffere between those terms; every airflow rate in iffere builis will have iffere exponeial coefficie. Therefore, the conversion between terms, either the pressure ifference or the permeability, epes on the exponeial coefficie. Every Dutch house is require to have an energy performance certificate that expresses an energy lab. A every new Dutch house to be constructe must have energy performance coefficie that taes the value of q v10 io accou in the calculation. There are four limi of q v10 iicate: 0.1, 0.4, 0.62 a 1.0 (this value is rary use). One of these values must be taen to calculate the value of energy performance coefficie. However, it is still unclear how this value of q v10 is generate a justifie for certain. Since the value of q v10 is iicate in the, the new buili must obtain this minimum value of q v10 as iicate. To assure that this minimum value is fulfille, a blower oor test is coucte to measure the airflow rate of the assigne buili. For the last couple of years, this test has been taen prior to completion or the turney in orer to ensure that any minimum requireme set for the buili is fulfille. Therefore, coractor can still manage to improve the buili before it is occupie. This is where the problem lies. It is unfortunate that coractors cannot harness their resources to provie better overview of estimati buili airtightness. The must iicate the minimum value of q v10 ; thus, the 32 Research Proposal
33 eineers or architec must inclue in their esign a calculation the value of q v10 that will be assigne to the. However, they cannot be certain whether this value can be achieve. Even though they have the complete specification of the forthcomi buili, they might not be able to estimate the exact value of q v10 because they cannot estimate the buili airtightness from the rawis they provie themsves. Therefore, analysi estimate buili airtightness prior to coucti blower oor test is highly recommee. Inavertely, therefore, what matters to coractor is that their buili complies with the minimum requiremen rather than estimati the exact value of q v10. Figure 1 shows the overview of buili airtightness problem lieri in Dutch construction iustry. Figure 10 CauseEffect Diagram on Buili Airtightness Problems in the Construction Iustry There are a limite number of empirical stuies regari estimati airtightness of resieial buili in The Netherlas. Therefore, this stuy ies to fill part of this literature gap. The objectives of this paper are to set up a research esign to tacle the problems in the buili iustry regari buili airtightness a provie priminary answer from the literature by analysi previous stuies. This paper is outline as follows. Chapter 2 will explain the problem stateme for this research with the corroborative research questions to be answere in probi this area of ierest. Chapter 3 will rivet on the research strategy aopte to answer the research questions, inclui the implications a limitations of the research. Chapter 4 will prese the literature review of previous stuies in the fi of buili airtightness preiction, inclui the existi metho to preict airtightness a the variables utilize in several preictive mos. Research Proposal 33
34 34 Research Proposal
35 2. RESEARCH DESIGN As meione earlier, The Netherlas has set a specific energy performance coefficie, a a maximum limit of buili airtightness to be met. It is rativy critical that airtightness of builis meet the staar set by The Dutch Buili Coe. Consequely, coractors a eineers must consier airtightness at all phases from initial esign, through construction process to final completion to ensure that comple performance can be met. However, because it is rativy ifficult for coractor a eineers to preict the value of q v10, this problem coinues to lier. Therefore, this issue coul be collapse io the followi problem stateme: Actors involve in buili processes o not now how to rate the buili characteristics to the buili airtightness. The corration between the variables: airtightness a buili characteristics will provie better overview on the rationship between the two factors. Afterwars, the preictive power of buili characteristics over airtightness will be etermine followi a regression analysis. Therefore, the objective of this research is: To ieify a analyse the rationship between buili characteristics a buili airtightness in orer to evop a riable mo to preict buili airtightness of Dutch resieial builis. As state in the objective, the aim of the research is to evop a mo to preict airtightness by explori variables that influence buili airtightness. Many past stuies have attempte to estimate airtightness without tai the blower oor test, yet the preictive mos coul not replace the resul of blower oor test. However, they coul still hp staeholers to improve buili airtightness. At the least, coractors a esigners coul use a riable preictive mo to maiain the target of minimum air permeability at the early construction phase. Although not every variables can be useful to evop a preictive mo, the fiis coul coribute to future research in preicti buili airtightness of wlis more consistely. From the problem stateme a research objective above, the main question to be answere within this research is as follows: How oes the rationship between buili characteristics a buili airtightness yi a mo to preict buili airtightness of Dutch resieial builis? This research question is broen own io the followi subquestions: 1. What mos currely exist to preict ex ae airtightness of resieial builis? a. What are the variables inclue in the preiction mo? b. How are these variables assesse? c. What rations o occur between the variables involve? 2. How are Dutch resieial builis bei assesse ex post regari buili airtightness? a. What variables apply in the Dutch coext? b. How is airtightness rate to the variables measure? c. What mo can be evope to preict the airtightness of Dutch resieial builis? 3. How accurate is this preictive mo compare to the other preictive mos? a. Which mo is the most accurate to be use prior to buili completion? b. What is the best metho to preict buili airtightness prior to buili completion? A. Scope of stuy The scope of this research will cover only resieial builis in The Netherlas, base on ata from a pressurization test on wlis gathere by the University of Twee. The reason resieial buili is in this stuy s ierest is preicate on the followi fac. First, there are much more resieial builis than service builis in the Netherlas. The 2012 report from Ceral Bureau of Statistics [17] shows there are more than 7.2 million houses in The Netherlas. Consequely, resieial builis incur the highest energy cost. Seco, the inhabitancy of resieial builis a the usage of the structures are iffere to service builis, because most people generally live their lives a spe more time at home. Therefore, resieial Research Proposal 3
36 builis are more iensy use than service builis, which have more structure a regular openi a closi hours. Therefore, certain moification coul be one to resieial builis to suit the nee of the inhabitan, a sometimes this coul also affect the structure of the buili. Furthermore, the followi section escribes the research strategy aopte to answer the research questions. 36 Research Proposal
37 3. RESEARCH METHOD In line with the given set of subquestions, this research will be coucte in three phases. The first phase is literature review of scieific journals a articles on reva applicable regulations. Reviews of the literature stuy a curre practises in The Netherlas will reveal some of the methos currely use to preict buili airtightness prior to the construction phase. They iicate some influenci factors that are taen io accou as coefficien in the mo s formula. The seco phase will be the corrational analysis of the variables: buili characteristics a measure buili airtightness. Finally, phase 3 will examine whether the curre ataset is aequate to be use for evopi a preictive mo a whether the variables teste in this research are in line with the literature. Each eme of the research will now be explaine in more etail Phase 1: Literature Review The literature stuy will cover the efinition of buili airtightness, air permeability, a methos to measure a preict airtightness. Past research will be reviewe to etermine which importa variables have been inclue in coucti measuremen a existi preictive mos. Every preictive mo in previous stuies woul have inclue some variables in the formula or equation. These variables coul be type of buili with a coefficie of certain value. There have been a lot of researches on factors that influence buili airtightness from which preictive mos have been evope in iffere couries. However, these variables iffer because of various governmeal policies a geographical peculiarities. Therefore, this stuy will attempt to collect, collate a summarize those variables in the literature a sect reva variables to be utilize. Then the appropriate metho to test Dutch resieial builis base on the ataset collecte will be etermine Phase 2: Analysis This phase will analyse the corration between buili characteristics a buili airtightness by compari means within variables. The first step is to summarise the variables that influence buili airtightness which were use in many mos to preict buili airtightness without havi to carry out a blower oor test. To evop a set of variables for the corrational analysis, the variables meione in the literature are collecte a compare to the variables meione in the blower oor test resul, provie by the Departme of Construction Manageme a Eineeri of University of Twee. 320 measureme resul of iffere wlis in The Netherlas were provie. These resul will be compile on Microsoft Exc for easy categorization. Afterwars, the sprea shee will be exporte io statistical software program SPSS v22. Since there is quite an amou of measureme ata use in the research, it is necessary to valiate the resul of pressurization tes. A statistical homogeneity test between regression coefficie pressurization measuremen will be performe. Usi the air tightness or air permeability lev suggeste by Sfaianai, et al. [22], every measure lev will be teste to verify whether the ata are statistically even. Levene s test will be use to show whether the variance of the ata is equal or not[8]. The next step will be to stuy the corration between buili characteristics variables (erive from the step one) a buili airtightness. Aapti the metho from Pan[8] a Mooya, et al.[21], ANOVA test will be use to measure the corration between buili airtightness a some influenci variables. This will be coucte usi univariate a bivariate analyses. In orer to run analyses, the variance between variable has to be equal. However, because iffere statistical ata from iffere stuies will be inclue in this wo, it is importa to note that they were treate accori to the type of ata usi iffere metho of analyses. Therefore, riability might be affecte. Moreover, how ata are treate a analyse greatly affect the ierpretation a euction of the outcome. Usually, when examini the rationship between a quaitative outcome a a sile quaitative explanatory variable, simple linear regression is the most commonly consiere analysis metho [33]. However, the ANOVA test will be aopte in this research; therefore, an empirical preictive mo will be evope usi multiple linear regressions by incorporati only the significa variables from the phase 2. Research Proposal 37
38 3.3. Phase 3 Mo Testi Finally, to answer the thir set of subquestions, the thir phase of the research will attempt to test the mo evope from the analysis. The first step of this phase is to valiate the empirical preictive mo with a new set of builis. There are nine wlis with etaile buili ata inclui the rawi plan a the blower oor test resul which constitute the ata that will be the input in the mo to iicate the preicte buili airtightness. Neverthess, since the preictive mo cannot be 100% accurate, therefore, this mo will be compare with the actual resul of blower oor. Finally, the next step will be to compare all mos (empirical mo a reva preictive mo from literature) suggeste in this research a to etermine which mos best preict the buili airtightness. The mo with the highest accuracy in comparison to the actual measuremen resul will be regare. However, besies the lev of accuracy, many other factors might also be involve uri this justification. Figure 2 summarises the research metho to be coucte in this research. Literature Stuy Buili airtightness a air permeability Fuameal measuremen Preiction mos available Variables on preiction mo Metho to asses variables Analysis Sect variables ANOVA test to etermine corration amo factors Determine the significa factors Multiple linear regressions test Devop a mo Mo Testi Apply the mo to new builis Chec accuracy with the blower oor measuremen Compare the resul between empirical mo a reva preictive mo from literature Figure 11 Research Framewo 3.4. Implications a Limitations Buili airtightness is consiere one of the factors that influence the energy performance of resieial builis, ue to i capability to reuce thermal loss. There have been many stuies concerni buili airtightness, but limite research regari Dutch builis. This research will attempt to coribute to literature a theory on improvi buili airtightness. The fiis of this wo coul be a spriboar for future researches on airtightness. This stuy coul also be practically reva by etermini preictive mos for buili airtightness if before oi any retrofitti or improveme in builis in orer to comply with the strict regulation. In reality, even though constructors trie to maiain buili airtightness a municipalities trie to corol the maximum air permeability, the quality (or quaity) of buili airtightness is affecte by several other factors. These factors, treate as variables in this research, will be stuie to gain more insight on achievi esire lev of airtightness a to evop certain mos that can hp coractors reach their minimum requiremen of air permeability before the blower oor test is taen. 38 Research Proposal
39 However, some limitations are aicipate: To ensure the riability of the resul, especially regari the climate factor, the measureme of a house shoul be taen at iffere times, uer iffere weather coitions. This importa because environmeal factors such as, wi spee, pressure a humiity coul influence the resul of blower oor test. However, some measuremen in the currely available ataset were one only once. This coul have implication on riability. The measuremen in the ataset were carrie out by iffere organizations; thus, report forma were iffere as some were more etaile than others. Therefore, there were a few missi information in the ataset. The mo woul be evope usi certain buili characteristics from the curre ataset available. Therefore, while it has iernal valiity, it is only applicable to new ata in rae of the curre ata set. Hence, external valiity coul be affecte. The teste buili in this research might be quite small for a valiation of a mo. Further research with bigger samples might yi more riable resul. 3.. Scheuli Bow is the esigne scheule for the whole research Figure 12 Gat Chart Research Proposal 39
40 4. LITERATURE REVIEW 4.1. Irouction This paper s literature review begins with stuyi a collection of articles in scieific journals regari buili airtightness. The articles reviewe were extracte from ScienceDirect a Scopus atabases. The avaage of usi these atabases search eine is that they mae it possible to set parameters to sect articles without the resul becomi too broa. The parameters chosen to filter the resul were: eywors, the year rae, the type of publication, the fi of stuy, a the name of journals. Keywor input consis of: buili airtightness, air infiltration, air leaage, air permeability a buili infiltration. The year rae was set for the last ecae ( ). The reason for this was to gather more rece articles, without havi to review the outate ones. The focus on journals only hpe extract scieifically reva resources. Energy a builis, construction a eineeri, were secte as the fi of stuy, while name of journals were restricte to journals within those fis of stuy, to exclue articles from other specializations in the search resul. Abstract of articles were peruse to etermine the revance for this stuy to ensure the focus on resieial builis a no other builis, such as public service builis. Finally, 30 articles were secte. The outcomes of the scieific literature review are presee bow Reva Terms in Buili Airtightness Differe authors conceptualize buili airtightness in their research in iffere ways. Some inclue environmeal factors a while others normalize the value to generate imensionless terms in their stuies. This section focuses on explori iffere terms use when investigati buili airtightness. 1) Air infiltration The unwae moveme of air from insie a buili to ouie is calle infiltration, a while the unwae moveme of air from ouie to insie of buili is calle exfiltration. Air infiltration occurs because of pressure ifference between outoor a ioor cause by temperatures ifference. Air infiltration value is usually influence by environmeal factors, while buili airtightness value is iepee of the environmeal factors. Therefore, it is importa to inclue the environmeal factors in the measuremen to ensure the riability of the resul. A corration between buili airtightness, air infiltration a energy consumption was iscovere in a typical family house in Finla, as the corration between the increase in air infiltration a the energy consumption for heati a veilation progresses in a linear manner[7]. In some stuies, the air infiltration rate is also etermine as air chae rates per hour (ACH) note with unit h 1 or /h. In buili airtightness research, air chae rates at reference pressure referre to the air leaage rates per iernal volume of the buili at the test reference pressure iffereial across the buili envope. The iernal volume is efine as the veilate active space within builis, not inclui the attic, the baseme a attache structures [18]. 2) Air leaage rate Buili airtightness is often measure in terms of how leay the buili envope is. The value air leaage measure uri the pressurization test also iicate how much air chae per hour is passi through the buili envope. The higher the air leaage, the less airtight the buili is. In most cases, pressurization tes were carrie out to measure leaage in whole builis, but these tes can also be utilise to measure leaage in separate par of a buili. Pressurization test methos coul be use to measure the exterior envope leaage, the leaage between the livi space a the crawl space a the leaage through the air istribution system uctwo [6]. This is terme also as airflow rate through the buili envope symbolize by V L a the unit is m 3 /h. To efine the buili airtightness, this value is normalize usi iffere parameters epei on the coext a regulation. The explanation of the normalization is presee more aboraty in next section. In the case of US builis, the term normalise leaage is use to preict the infiltration airflow. Normalise leaage is a imensionless term use by Logue, et al. [] a Chan, et al. [19] to 40 Research Proposal
41 correspo air leaage rates with iernal volume of a buili by ivii it with floor area a buili height. It is use in some analyses ue to i convenience, since the area a height are nown parameters it ensure consistency in the research[19]. 3) Air permeability The term airtightness pertains to the iensity of the uncorolle flow of air through the buili envope, as a result of pressure ifferences between the ierior a exterior air [4]. The lev of buili airtightness is often expresse in levs or air permeability. Compare to the air leaage rate (how much unwae air passes io the iernal volume of a buili at reference pressure iffere; usually 0 Pa) [18], air permeability is the capability of a surface to let air pass through in this case, the capability of the buili envope if. Therefore, the unit of air permeability is m 3 /h.m 2. The lower the air permeability is, the more airtight a buili is. In research on buili airtightness, air permeability a air leaage are frequely use for coucti research, since both refer to the capability of the buili envope to not let unwae air pass through the buili. The air permeability in 0 Pa pressure ifference is symbolise as Q Measuri buili airtightness In orer to etermine the airtightness of a buili, a test is usually carrie out to measure the amou of air leai within buili envope. The lev of buili airtightness is firstly measure in terms of the amou of air leaage between iffere ioor a outoor pressure usi two most common staarize methos, which are the tracer gas metho a the pressurization test, which uses a blower oor. However, more emphasis will be place on the blower oor test because it is more reva to this stuy. Tracer gas is usually use to measure the infiltration rate uer natural coitions. There are three iffere measuremen of gas conceration: the conceration ecay; the consta injection; a the consta conceration[34]. Since the measureme is carrie out uer natural coitions, the environmeal factors, such as wi spee a humiity, naturally affect the resul. There is a high chance that if the measuremen are one at a iffere time, the outcomes of the measureme will be iffere. Generally, the tracer gas metho is more accurate than a blower oor test, but it is less repeatable[2]. Therefore, many analyses in buili airtightness usi the measureme resul from fan pressurization tes use the blower oor. The most common metho to measure air leaage within buili envope is the fan pressurization test, usi a blower oor. This metho is base on the mechanical pressurization or epressurization of a part of a buili, with all ajacency open, usi a blower oor. The air flow rate through the buili envope is cause by the ifferences in pressure between the air insie a ouie. The airtightness of buili componen a emen can be measure accori to staar NENEN 829 [18]. The further mathematical formulations use in the measuremen is explaine in the followi section. Even though the measureme metho is not complicate a can be carrie out with little amou of equipme a time, the ierpretation of the resul requires a certain exte of nowlege. From a measureme stapoi, airtightness means measuri the air flow through the buili envope as a function of the pressure across the buili envope [10]. When measuri the buili airtightness, the occurri air leaage is quaifie as the airflow getti through the buili envope, which is symbolise as V (m 3 /s), through ifferences in pressure, expresse in (Pascal). The pressureflow rationship, which ac accori to the power law, is expresse by the equation: (Equation 1) The flow coefficie is a function of the size of buili openis, a the pressure expone is expresse 0.<=n<=1.0. An expone of 0. enotes fully turbule a an expone of 1.0 represen laminar flow. Usually the flow expone is 0.6 [10]. The air flow is often enote with the reference pressure as a subscript (e.g. V 0 or V 2 ). The reference of 0 Pa in air pressure ifferences is most often use. Another common reference pressure use is 4 Pa, but 1 Pa, 10 Pa, 2 Pa, a 7 Pa are use as wl [10]. Research Proposal 41
42 To efine the buili airtightness, there are three quaities commonly use to normalize the air leaage: buili volume, envope area, a floor area [10], [18]. These normalisations are use epei on the coext of the regulation either where or for what purpose. Each has avaages a isavaages a each is useful for evaluati iffere issues. Buili volume is particularly useful when normalizi air flows. When buili volume is use to normalize the airflow rate the result is normally expresse in air chaes per hour at the reference pressure; N 0 is the most common airtightness metric reporte in the literature. Many people fi this metric convenie since infiltration a veilation rates are often quote in air chaes per hour. Therefore, the air chae rate at 0 Pa pressure ifference is calculate by ivii the mean air leaage rate at 0 Pa by the iernal volume usi equation (Equation 2) Envope area is particularly useful if one is looi to efine the quality of the envope as a uniform fabric. Kalamees [23] efine buili envope inclues buili componen a veilation evices. This normalization pertains to the terms air permeability. Although this normalization can sometimes be the harest to use, it can be particularly useful in attache builis were some walls are expose to the outoors a some are not. The air permeability at 0 Pa ifference, Q 0, is calculate by ivii the mean airflow rate at 0 Pa by the envope area usi equation: (Equation 3) Floor area can often be the easiest to etermine from a practical stapoi. Since usable livi space scales most closy rate to floor area; normalizi these scales is sometimes viewe as bei more equitable. Specific leaage rate at 0 Pa ifference, w 0, is calculate by ivii the mean air leaage rate at 0 Pa by the floor area usi equation: (Equation 4) Normalization usi floor area is use in the followi the NEN 829 staar (please refer to Appeix 1). Compare to other coury regulation that buili airtightness is measure at 0 Pa, in The Netherlas buili airtightness is measure at 10 Pa iffere. Table 1 explains the ifference between iffere buili airtightness terms use in iffere coex. However, Dutch Buili Coe only meions the permitte total air flow rate of resieial inclui toilet a bathroom must not be bigger than 0.2 m 3 /h. The esire specific leaage rate is state in, epei on the volume of the buili. For comparison the ration between q v10 a N 0 is epei on the flow coefficie (n) a ivision by about The airflow (q v10 ) of about 1 m 3 /s, equals to an N 0 of about 3. to 4. [32]. Table 6 Differe terms use to express buili airtightness accori to EN 829:2000 Terms Normalisation Symbol Uni Air chae rate (infiltratie vou) Air permeability Air leaage rate ivie by iernal buili volume Air leaage rate ivie by buili envope surface N h 1 Q m 3 /h.m 2 Specific air leaage rate Air leaage rate ivie by usable floor area w m 3 /h.m Estimati Buili Airtightness It is importa to uersta the factors that influence the lev of buili airtightness. These factors can be the cause of the air leaage a that coul influence the quality of buili airtightness. This section will explore the importa factors that influence the quality of buili airtightness a the methos that several authors use to evop preictive mos for those factors. 42 Research Proposal
43 4) Airtightness Estimation Research Some organizations have evope some preictive mos such as: Lawrence Beey Laboratory (LBL) [3] a Alberta Air Infiltration Mo (AIM) 2 [36] that are use to calculate air infiltration a energy loss; a Stichti Bouwresearch (SBR) [37] metho that uses buili characteristics to preict airtightness. the Netherlas uses a mo evope by SBRCurNet to calculate buili airtightness value base on compone leaages a the geometry of the buili [2]. Moreover, other stuies have also been carrie out with the purpose to evop a mo to estimate or preict buili airtightness. These stuies coul be ivie io two broa research categories: experimeal a corrational [8]. Experimeal research is carrie out uer corolle experimeal coitions with the purpose of measuri the causal effec of iepee variables on epee ones. Experimeal stuies to evop buili airtightness preictive mo use buili simulations or by test specimens on whole or par of builis. An example of this inclues the stuy of airtightness in Portugal [24] a in Italy [2]. The acoustic approach, which is also use in air permeability preiction, is also experimeal in esign [38][1]. The avaages of this metho are that the measuremen are not weather epee a not as expensive as usi a blower oor. The metho is mainly base on usi verifie physical a acoustical methos. Corrational research is carrie out uer statistical corol with the purpose of uerstai the corration between variables. Corrational research stuies are use to evop a preictive mo usi regression analysis. This metho, however, has limitations: the preictive mo is only applicable if the new ata is in rae of ataset from which the mo was erive from. Examples of corrational research inclue the stuy of airtightness in Croatia [4], in Finla [7], in the UK [8], in the US [10], [20], in Catalonia [21], in Greece [22] a in Estonia [23]. Parall with these empirical stuies, there have been several practical guiines in literature to achieve airtightness in iffere couries. For example, in the Unite Kiom there are the Energy Savi Trust a the Buili Research Establishme (BRE) guiines. In the Unite States, there are weatherization assistance programs (WAPs) a resieial energy efficiency programs. The most rece corrational research metho on preicti buili airtightness uses neural netwos. This metho, which is often calle artificial neural netwos, was inspire from analogy on the biological neuron system [4]. In this system, a neuron receives a signal se from another neuron or external source, a processes this information. The neuron then transfers it to the next neuron or external poi. The artificial neuron netwos have a complex ability to learn from a generalise ata base on experience, a process comparable to how the human brain wos. The metho has been valiate by 20 iepee measuremen, which are, however, assume to be rativy small a nee to be valiate further. The basic avaages state for this preictive mo for airtightness in resieial builis is the possibility of a fast assessme of the value of airtightness, without the nee to couct fi measuremen. There have been many literary stuies which researche the factors that influence buili airtightness, as wl as the house characteristics that have corrations with airtightness. In most cases, the literary stuies are use to estimate the buili airtightness a priori to the start of the construction phase of new builis. Raer, Holøs a Thue [26] categorize three iffere methos to estimate the buili airtightness: (1) estimation base on multiple regressions, (2) estimation base on the rough characteristics of the buili a (3) estimation base on the compone leaage a geometry of the buili. Table 7 Summary of previous stuies Coury Average permeability Influenci variables Unite Kiom Q 0 of.97 m 3 /(h Construction type m 2 ) Type of resieial buili Manageme coext Unite States Year of construction Climate zone Floor area Number of measuremen Metho use to evop mo 287 Multi linear regression [8] Source Multi linear regression [19] Research Proposal 43
44 House height Type of fouation Location of veilation system Energy class of family house Finla N ACH Annual infiltration rate 1 Sensitivity analysis simulati buili mo Greece N ACH Total wiow frame leth 20 Regression [22] Estonia Q m 3 /(h m 2 ) number of storeys, 32 Experimeal analysis [23] womanship quality a supervision, buili technology (built in site or prefab), a the veilation systems. Spain a France buili age, 21 Multi linear regression [21] Construction type Ira Q m 3 /(h m 2 ) Buili age 28 Fi stuy [16] Design etail Retrofitti Portugal Quality of womanship Fi stuy [24] Croatia Q ACH at 0 Pa opaque part of buili envope, i material a structure transpare part of buili envope, i material a structure [7] 8 Neural netwo preiction [4] ) Variables In estimati buili airtightness, it is importa to uersta the variables that act as preictors. These variables will then be reviewe a assigne with corrective factors in the preictive mo. These variables were erive either from experimeal stuies or corrational stuies as meione earlier. Table 1 summarises iffere methos of research a the variables that constitute the corrective factors in the preictive mo. These are summarise bow. Buili age There have been many researches that reveale the corration between the age of builis a buili airtightness. However, not all researches showe similar resul. Ref [9], [19], [21] showe that oler builis te to be leaier than newer builis. This might be cause by ifferences in the buili technology use a iffere regulations applie uri the time the builis were constructe. However, coraictory resul were fou in other stuies which iscovere that oler builis yie the lowest mean of air permeability [16]. It can be conclue that oler builis cannot simply be generalise as leaier, since other factors such as etail of womanship a geographical location have to be taen io accou as wl. Geographical Location Most researches on buili airtightness have been carrie out in iffere couries. This means there are several factors regari geographical location that obstruct the reproucibility of the research. Some researches prove that climate affec the buili air leaages. Many couries have iffere climates a larger couries even have iffere climate zones across the coury [19]. As climates influences iffere seasons, in terms of air leaage rate, iffere seasons cause iffere amoun or air leaage [8], which means the lev buili airtightness iffers. Rather than monitori the infiltration rate every season, it is wiser to use the average annual infiltration rate to compare airtightness. Research coucte by Joisalo, et al. [7] suggeste that there is a linear corration between annual air infiltration rates a the airtightness of buili envope, as wl as the annual energy consumption for heati a veilation. It was fou that the average annual infiltration rate a energy consumption increase in almost linear manner. Structural buili characteristics 44 Research Proposal
45 In most preictive mos, buili structure is use as a corrective factor for measuri buili airtightness. This paper separates buili structure factors io two iffere categories: structural a nonstructural ones buili characteristics. Structural buili characteristics are efine as buili par that give structure to the buili a bear the loa of the construction. Parameters inclue in buili structure are: the typology of builis; the use of masonry or a wooen frame structure (NEN ); whether the buili is consiere a light or a heavy structure[21]; the type of fouation [19]; a buili technology, tai in accou onsite construction, the use of prefabricate buili emen, a assembly at the buili site[23]. It was fou that masonry builis are more airtight than builis with a wooen frame. This can be ue to the amou of join in a wooen frame house. Consequely, there are more chances that there will be leaage in the woo ajacency. Generally, builis with a heavy structure are more airtight than builis with a light structure. Builis that were built on site were fou leaier [23]. Houses that were built uer professional supervision te to be more airtight. Houses with coitione basemen were fou to be leaier than houses with slab fouation[19]. Nonstructural buili characteristics The seco type of buili characteristics are the nonstructural characteristics. Variables here are buili characteristics that o not bear the loa a give construction to the buili, but they are nonethess esseial since they etermine leaages paths. Variables inclue in nonstructural buili characteristics are: floor area house height a number of storeys veilation type insulation type Together with buili age, stuy coucte in US by Chan, et al. [19] a McWilliams a Ju [39] fou that floor area a numbers of storeys are statistically significa in stuyi normalise leaage. Builis with one storey te to be more airtight than two storey builis [23]. This coul be cause by the greater amou of join in two storey builis, especially in the join between the wall a the floor. Consequely, there is higher chance of leaage path formation. Houses with natural veilation were fou to be leaier than houses with mechanical veilation [23] or houses with balance veilation usi heat recovery. The combination of airtight builis a effective heat recovery resulte in creati more energy efficie builis. Another factor regari veilation is the location of uc. Houses with uc locate insie coitione spaces, such active space areas, te to be more airtight than houses with uc locate in uncoitione spaces, such as attics a basemen [19]. Insulation types can be ivie in exterior insulation, ierior insulation a iegrate insulation. Houses with exterior insulation te to be leaier than others [21]. Womanship is also a factor to be inclue in nonstructural buili characteristics. However, since supervision a the quality of womanship are esseial etail factors to be note, womanship is separate from this section as a variable on i own. Womanship It has been proven in many literary stuies that the quality of womanship plays a critical role in achievi buili airtightness. Parameters inclue in womanship are: installation methos etail of join Opaqueness a transparency of buili envope. There is noticeable corration between airtightness a the structural etail of wooen frame houses. The possible leaage paths on join were fou in the wiowwall ierface [27], as wl as the structural floor [28]; the join between the baseme wall a the wooen frame wall [29]; between the wall a the roof [30]; a in the roof join [31]; many of which were cause by the metho of seali join [27] [29]. Typical leaage fou in stuie Estonian houses [23] occurre in: Research Proposal 4
46 join between the ceili a floor with the external wall join between the iernal wall a the external wall a roof penetration of ectrical installations a plumbi installations penetration of the chimney a veilation uc leaage surroui ectrical soce leaage arou wiows a oors Research coucte by Pio a Viegas [40] showe variation in air permeability values on similar fla with similar buili characteristics. This occurre ue to variations in the gaps that appear in the roller shutter boxes a the gaps in the lower openi joi of the external oors. Consiste planni a careful womanship were prove to be esseial in achievi esire buili airtightness levs [16], [41]. 4.. Priminary Conclusion The purpose of this literature stuy on preicti buili airtightness, particularly stuie the uerlyi variables that influence buili airtightness. It attempte to etermine the significa coribution of iffere buili characteristics variables towars buili airtightness. The stuy coul hp not only in evopi preictive mo but also to get better uerstai on which critical variables are neee in achievi better buili airtightness. With the uerstai that buili characteristics can influence buili airtightness to certain significance preictive mos coul be evope. This coul also coribute to nowlege in research in uerstai buili airtightness whether empirical a practical coext. In practical coext, for example, extra atteion shoul be given to womanship uri construction phase to ensure less leay buili. Even though estimati or preicti the airtightness cannot simply substitute the airtightness measuremen in orer to comply with the regulation, it seems to be a parameter to hp the coractor in reachi the minimum requiremen. A suggestion coul be to set upper limit rather than tryi to estimate the efinite amou of specific leaage rate. Even so, it is still useful to try to get an estimate buili airtightness by usi the ata of buili characteristics a nown leaage path prior to blower oor test. This can minimize the possibility of havi costly retrofitti for the buili a the nee to perform another blower oor test. In the e, what matters by increasi buili airtightness is to reuce the energy nee for space heati system a reuce energy cost, since people might not wa to spe most of their buget only on retrofitti without getti lo term benefit of it. REFERENCES [1] NHBC Fouation, A practical guie to buili airtight wlis. Amersham: IHS BRE Press, [2] P. Kuiersma a H. M. Nieman, Luchticht bouwen, theorieowerppratij, Rotteram, 20. [3] S. B. Saineni, S. Maala, a R. F. Boehm, Passive buili energy savis: A review of buili envope componen, in Renewable a Sustainable Energy Reviews, vol. 1, no. 8, Elsevier Lt, 2011, pp [4] H. Krstić, Ţ. Koši, I. I. Otović, a M. Španić, Application of neural netwos in preicti airtightness of resieial uni, in Energy a Builis, vol. 84, 20, pp [] J. M. Logue, M. H. Sherman, I. S. Waler, a B. C. Sier, Energy impac of envope tighteni a mechanical veilation for the U.S. resieial sector, in Energy a Builis, vol. 6, Elsevier B.V., 20, pp Research Proposal
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48 [19] W. R. Chan, J. Joh, a M. H. Sherman, Analysis of air leaage measuremen of US houses, in Energy a Builis, vol. 66, Elsevier B.V., 20, pp [20] W. R. Chan, W. W. Nazaroff, P. N. Price, M. D. Sohn, a A. J. Gagil, Analyzi a atabase of resieial air leaage in the Unite States, Atmos. Environ., vol. 39, no. 19, pp , 200. [21] M. I. Mooya, E. Pastor, F. R. Carrié, G. Guyot, a E. Planas, Air leaage in Catalan wlis: Devopi an airtightness mo a leaage airflow preictions, in Buili a Environme, vol. 4, no. 6, 2010, pp [22] a. Sfaianai, K. Pavlou, M. Saamouris, I. Livaa, M. N. Assimaopoulos, P. Maas, a a. Christaopoulos, Air tightness measuremen of resieial houses in Athens, Greece, in Buili a Environme, vol. 43, no. 4, 2008, pp [23] T. Kalamees, Air tightness a air leaages of new lightweight silefamily etache houses in Estonia, in Buili a Environme, vol. 42, no. 6, 2007, pp [24] M. Pio, J. Viegas, a V. P. e Freitas, Air permeability measuremen of wlis a buili componen in Portugal, in Buili a Environme, vol. 46, no. 12, Elsevier Lt, 2011, pp [2] D. F. R. Alfano, M. Dl Isola, G. Ficco, a F. Tassini, Experimeal analysis of air tightness in Meiterranean builis usi the fan pressurization metho, in Buili a Environme, vol. 3, Elsevier Lt, 2012, pp [26] T. O. Raer, S. Holøs, a J. V. Thue, Airtightness estimation  A state of the art review a an en route upper limit evaluation principle to increase the chances that wooframe houses with a vapour a wibarrier comply with the airtightness requiremen, in Energy a Builis, vol. 4, Elsevier B.V., 2012, pp [27] N. Van Den Bossche, W. Huyghe, J. Moens, A. Janssens, a M. Depaepe, Airtightness of the wiowwall ierface in cavity bric walls, in Energy a Builis, vol. 4, Elsevier B.V., 2012, pp [28] T. O. Raer, G. Bauwens, S. Ros, J. V. Thue, a S. Uvslø, The influence of structural floors on the airtightness of wooframe houses, in Energy a Builis, vol. 43, no. 2 3, 2011, pp [29] T. O. Raer, B. Heis, a J. S. Tysseal, The influence of the joi between the baseme wall a the wooframe wall on the airtightness of wooframe houses, in Energy a Builis, vol. 43, no. 6, Elsevier B.V., 2011, pp. 04. [30] J. Lamans, R. Klein, M. De Paepe, a S. Ros, Poteial of wi barriers to assure airtightness of wooframe low energy constructions, in Energy a Builis, vol. 42, no. 12, Elsevier B.V., 2010, pp [31] T. O. Raer, T. Kvae, a J. V. Thue, The influence of lightweight aggregate concrete eme chimneys on the airtightness of wooframe houses, in Energy a Builis, vol. 42, no., Elsevier B.V., 2010, pp Research Proposal
49 [32] W. De Gis, Veilation in Dutch Houses A Stuy in a Represeative Sample of The Dutch Housi Stoc, Dft, [33] H. J. Stman, Experimeal Design a Analysis [34] ISO, ISO Staar 1269: Thermal performance of buili  etermination of air chae in builis  trace gas ilution metho. Geneva: Iernational Organization for Staarization, [3] M. Orme, Applicable Mos for Air Infiltration a Veilation Calculations, Covery, [36] W. Wa, I. BeausoleilMorrison, a J. Rearon, Evaluation of the Alberta air infiltration mo usi measuremen a iermo comparisons, in Buili a Environme, vol. 44, no. 2, 2009, pp [37] W. F. De Gis, H. J. M. Cornissen, a P.. Jo, Infiltratieverliezen U Bouw, Dft, [38] O. Hassan, An alternative metho for evaluati the air tightness of buili componen, in Buili a Environme, vol. 67, Elsevier Lt, 20, pp [39] J. McWilliams a M. Ju, Devopme of a mathematical airleaage mo from measure ata. Lawrence Beey National Laboratory, [40] M. Pio a J. Viegas, The influence of veilation systems on omestic gas appliances: An experimeal stuy, in Buili a Environme, vol. 69, 20, pp. 1. [41] H. Tommerup, J. Rose, a S. Svesen, Energyefficie houses built accori to the energy performance requiremen irouce in Denma in 2006, in Energy a Builis, vol. 39, no. 10, 2007, pp Research Proposal 49
50 APPENDIX B. Nomenclature 1) Symbol a Uni Symbol Quaity Unit V m Measure air flow rate m 3 /h V env Air flow rate through the buili envope m 3 /h V L Air leaage rate m 3 /h V 0 Air leaage rate at 0 Pa m 3 /h C env Air flow coefficie m 3 /(.Pa n ) C L Air leaage coefficie m 3 /(.Pa n ) n Air flow expone  p Pressure Pa Δp Iuce pressure ifference Pa A E Envope area m 2 A F Floor area m 2 v Iernal buili volume m 3 N 0 Air chae rate at 0 Pa h 1 Q 0 Air permeability at 0 Pa m 3 /(h.m 2 ) W 0 Specific air leaage at 0 Pa m 3 /(h.m 2 ) 2) Terms a efinition Source: [18] Air leaage rate: air flow rate across the buili envope. Iernal volume: iberaty heate, coole or mechanically veilate space within a buili or part of a buili subject to the measureme, generally not inclui the attic space, baseme space a attache structures. Buili envope: bouary or barrier separati the iernal volume subject to the test from the ouie environme or another part of the buili. Air chae rate at reference pressure: air leaage rate per iernal volume at the test reference pressure iffereial across the buili envope. Air permeability: air leaage rate per envope area at the test reference pressure iffereial across the buili envope (usually at 0 Pa). Specific leaage rate: air leaage rate per net floor area at the test reference pressure iffereial across the buili envope. 0 Research Proposal
51 DOCUMENTATION OF THE RESEARCH ANALYSING RELATIONSHIP AND INFLUENCE OF BUILDING CHARACTERISTICS ON AIRTIGHTNESS OF DUTCH RESIDENTIAL BUILDINGS RESULTS OF STATISTICAL ANALYSIS OF BLOWER DOOR TEST RESULTS Documeation of the research 1
52 I. DIGITAL AVAILABLE DOCUMENTATION Attache together with this ocume are the igital versions of the followi: This ocume Original ata in Microsoft Exc sprea sheet Moifie ata in Microsoft Exc sprea sheet Moifie ata in SPSS The followi sections are the resul of Statistic Infereial of DataSet 1 Ajuste.sav from 2 May 20. Dataset 1 Ajuste.sav is the moifie ata in SPSS. II. DESCRIPTIVE STATISTICS A. Frequencies of Specific Leaage Rate Statistics Measure specific leaage rate at 10 Pa (m3/s.m2) N Vali 320 Missi 0 Descriptive Statistics N Minimum Maximum Mean St. Deviation Measure specific leaage rate at 10 Pa (m3/s.m2) Vali N (listwise) Documeation of the research
53 B. Dispersion by Province Documeation of the research 3
54 III. CORRELATIONS ANALYSIS Corrations Design Measure Dwli Buili Buili Roof Floor Measure Total Year of Target specific Type Metho Typology Type Area specific Leaages Construction (m3/s.m2) leaage leaage rate at 10 rate at 0 Pa Pa (m3/s.m2) (m3/s.m2) Design (m3/s.m2) Target Pearson Corration ** .13 ** ** ** Sig. (2taile) N Measure specific leaage rate at 10 Pa (m3/s.m2) Pearson Corration ** ** **.437 ** .4 ** Sig. (2taile) N Dwli Type Pearson Corration **.94 **.400 ** ** Sig. (2taile) Documeation of the research
55 N Buili Metho Pearson Corration ** ** **.29 ** ** ** .38 ** .0 Sig. (2taile) N Buili Typology Pearson Corration .13 ** **.168 **.71 ** ** * ** * Sig. (2taile) N Roof Type Pearson Corration **.29 **.271 ** * * Sig. (2taile) N Floor Area Pearson Corration.297 ** ** ** *.041 Sig. (2taile) Measure specific leaage rate at 0 Pa (m3/s.m2) N Pearson Corration ** ** * ** ** Sig. (2taile) N Documeation of the research
56 Total Leaages Pearson Corration ** ** ** .4 *.8 *.426 ** * Sig. (2taile) N Year of Construction Pearson Corration.234 ** .4 ** ** * * ** .9 * 1 Sig. (2taile) N **. Corration is significa at the 0.01 lev (2taile). *. Corration is significa at the 0.0 lev (2taile). 6 Documeation of the research
57 IV. REGRESSION ANALYSIS For variables total leaage, linear regression analysis is carrie out. A. Total Leaage X W10 Iepee Variable: Total Leaage (LK1*1+LK2*2+LK3*3+LK4*4) Target : W 10 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) b. Preictors: (Consta), Total Leaage Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), totalscorelk Statistic shows moerate positive rationships between variable TotalLK a W10 because P value at.437. (If b1>0 shows positive rationships, b1=0 shows no rationship, b1<0 shows negative rationships.). However, only 19.1% of the variation in W10 can be explaine by variable totallk
58 B. Total Leaage X W0 Iepee Variable: Total Leaage (LK1*1+LK2*2+LK3*3+LK4*4) Target : W0 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 0 Pa (m3/s.m2) b. Preictors: (Consta), totalscorelk Statistic shows that total leaage is a goo preictor for estimati specific leaage rate at 0 Pa because Pvalue is less than 0.0. There is a significa rationship between iepee variables a epee variables. Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), totalscorelk Statistic shows moerate positive rationships between variable TotalLK a W10 because P value at.426. (If b1>0 shows positive rationships, b1=0 shows no rationship, b1<0 shows negative rationships.). However, only 18.2% of the variation in W0 can be explaine by variable TotalLK C. Design Target X w10 Iepee Variable: Q Target : W10 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) b. Preictors: (Consta), Design Target (m3/s.m2) 8 Documeation of the research
59 Statistic shows that esign target is not a preictor for estimati specific leaage rate at 10 Pa because P value is less than 0.0. There is no significa rationship between iepee variables a epee variables. Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), Design Target (m3/s.m2) D. Design Target X w0 Iepee Variable: Q Target : W0 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 0 Pa (m3/s.m2) b. Preictors: (Consta), Design Target (m3/s.m2) Statistic shows that esign target is not a preictor for estimati specific leaage rate at 0 Pa because P value is less than 0.0. There is no significa rationship between iepee variables a epee variables. Documeation of the research 9
60 Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), Design Target (m3/s.m2) E. Floor area x w10 Iepee Variable: FLOOR Target : W10 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) b. Preictors: (Consta), Floor Area Statistic shows that floor area is not a preictor for estimati specific leaage rate at 10 Pa because P value is less than 0.0. There is no significa rationship between iepee variables a epee variables. Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), Floor Area F. Floor area x w0 Iepee Variable: FLOOR Target : W0 60 Documeation of the research
61 ANOVA a Mo Sum of Squares f Mean Square F Sig. Regression b 1 Resiual Total a. Depee Variable: Measure specific leaage rate at 0 Pa (m3/s.m2) b. Preictors: (Consta), Floor Area Statistic shows that floor area is not a preictor for estimati specific leaage rate at 0 Pa because P value is less than 0.0. There is no significa rationship between iepee variables a epee variables. Mo Summary Mo R R Square Ajuste R Square St. Error of the Estimate a a. Preictors: (Consta), Floor Area Documeation of the research 61
62 V. ONEWAY ANOVA A. Year of construction a Specific Leaage Rate For year variables, one way ANOVA test is carrie out to compare means. 1) YEAR X W10 Does the W10 significaly iffer between iffere years (YEAR_C)? Test of Homogeneity of Variances Measure specific leaage rate at 10 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.000) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 10 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W0. Then, to fi which group iffers significaly from each other, we performe Scheffe test. 62 Documeation of the research
63 Multiple Comparisons Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) Scheffe (I) Year Rae (J) Year Rae Mean Difference (IJ) St. Error Sig. 9% Confience Ierval Lower Bou Upper Bou * Pre * Post * Pre * Post Pre * Post * Pre * Post * *. The mean ifference is significa at the 0.0 lev. The resul suggest that statistically iffere in mean W10 (p<0.0) existe between group builis from pre 1992 a all other builis (p = 0.000), a buili from a post 2012 (p = 0.031). Documeation of the research 63
64 2) YEAR X W0 Does the W0 significaly iffer between iffere years (YEAR_C)? Test of Homogeneity of Variances Measure specific leaage rate at 0 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.000) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 0 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W0. Then, to fi which group iffers significaly from each other, we performe Scheffe test. 64 Documeation of the research
65 Multiple Comparisons Depee Variable: Measure specific leaage rate at 0 Pa (m3/s.m2) Scheffe (I) Year Rae (J) Year Rae Mean Difference (IJ) St. Error Sig. 9% Confience Ierval Lower Bou Upper Bou * Pre * Post * Pre * Post Pre * Post Pre * Post *. The mean ifference is significa at the 0.0 lev. The resul suggest that statistically iffere in mean W10 (p<0.0) existe between group builis from pre 1992 a all other builis (p = 0.000). Documeation of the research 6
66 B. Dwli Type a Specific Leaage Rate For wli type variables, one way ANOVA test is carrie out to compare means. 1) Dwli Type X W10 Does the W10 significaly iffer between iffere wli types (DT)? Test of Homogeneity of Variances Measure specific leaage rate at 10 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.073) is bigger than the significance lev α (0.0), we on t reject H 0 (equal variances are assume) in favor of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all 7 groups are equal. ANOVA Measure specific leaage rate at 10 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total Because pvalue (0.9) is bigger than the significance lev (0.0), then all groups are statistically equal. From the boxplot, we can see that there are many extreme cases in terms of wli type. 66 Documeation of the research
67 2) Dwli Type X W0 Does the W0 significaly iffer between iffere wli types (DT)? Test of Homogeneity of Variances Measure specific leaage rate at 0 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.008) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 0 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total Because pvalue (0.07) is slightly bigger than the significance lev (0.0), then all groups are statistically equal. Documeation of the research 67
68 From the boxplot we can see the extreme cases in terms of wli type C. Roof Type & Specific Leaage Rate For roof type variables, one way ANOVA test is carrie out to compare means. 1) Roof type X W10 Does the W10 significaly iffer between iffere roof types (ROOF)? Test of Homogeneity of Variances Measure specific leaage rate at 10 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = 2.1 Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.039) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 10 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W0. Then, to fi which group iffer significaly from each other, we performe Scheffe test. 68 Documeation of the research
69 Multiple Comparisons Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) Scheffe (I) Roof Type (J) Roof Type Mean Difference (IJ) St. Error Sig. 9% Confience Ierval Lower Bou Upper Bou Flat Roof She roof Pitche roof Combination Unnown She roof Flat Roof Pitche roof Combination Unnown She roof Pitche roof Flat Roof Combination Unnown.3640 * She roof Combination Flat Roof Pitche roof Unnown She roof Unnown Flat Roof Pitche roof * Combination *. The mean ifference is significa at the 0.0 lev. There is significa ifference between pitche roof a unnown group, because the alpha lev is bow 0.0. The resul suggest that statistically iffere in mean W10 (p<0.0) only existe between pitche roof a unnown group (p=0.017). Documeation of the research 69
70 2) Roof Type X W0 Does the W0 significaly iffer between iffere roof types (ROOF)? Test of Homogeneity of Variances Measure specific leaage rate at 0 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F =.168 Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.000) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 0 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W0. Then, to fi which group iffer significaly from each other, we performe Scheffe test 70 Documeation of the research
71 Multiple Comparisons Depee Variable: Measure specific leaage rate at 0 Pa (m3/s.m2) Scheffe (I) Roof Type (J) Roof Type Mean Difference (IJ) St. Error Sig. 9% Confience Ierval Lower Bou Upper Bou Flat Roof She roof Pitche roof Combination Unnown She roof Flat Roof Pitche roof Combination Unnown She roof Pitche roof Flat Roof Combination Unnown * She roof Combination Flat Roof Pitche roof Unnown She roof Unnown Flat Roof Pitche roof * Combination *. The mean ifference is significa at the 0.0 lev. There is significa ifference between pitche roof a unnown group, because the alpha lev is bow 0.0. The resul suggest that statistically iffere in mean W0 (p<0.0) only existe between pitche roof a unnown group (p=0.0). Documeation of the research 71
72 D. Buili Metho (Prefab or On Site) a Specific Leaage Rate For buili metho variables, one way ANOVA test is carrie out to compare means. 1) BM X W10 Does the W10 significaly iffer between iffere buili methos (BM)? Test of Homogeneity of Variances Measure specific leaage rate at 10 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.000) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 10 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W10. Then, to fi which group iffers significaly from each other, we performe Scheffe test 72 Documeation of the research
73 Multiple Comparisons Depee Variable: Measure specific leaage rate at 10 Pa (m3/s.m2) Scheffe (I) Buili Metho (J) Buili Metho Mean St. Error Sig. 9% Confience Ierval Difference J) (I Lower Bou Upper Bou Prefabrication On Site Construction Combination (0:0) Unnown On Site Construction Prefabrication Combination (0:0) Unnown * On Site Construction Combination (0:0) Prefabrication Unnown On Site Construction Unnown Prefabrication * Combination (0:0) *. The mean ifference is significa at the 0.0 lev. There is significa ifference between prefabrication a unnown group, because the alpha lev is bow 0.0. The resul suggest that statistically iffere in mean W0 (p<0.0) only existe between prefabrication a unnown group (p=0.000). Documeation of the research 73
74 2) BM X W0 Does the W0 significaly iffer between iffere buili methos (BM)? Test of Homogeneity of Variances Measure specific leaage rate at 0 Pa (m3/s.m2) Levene Statistic f1 f2 Sig Test Statistic (Levene s): F = Pvalue (Levene s): p = Statistical Conclusion (Levene s): Because the pvalue (0.000) is lower than the significance lev α (0.0), we reject H 0 (equal variances are assume) instea of the H a (equal variances is not assume). Conclusion (Levene s): The variance of all groups is not equal. ANOVA Measure specific leaage rate at 0 Pa (m3/s.m2) Sum of Squares f Mean Square F Sig. Between Groups Within Groups Total There is at least a group that iffers from the other in terms of W10. Then, to fi which group iffers significaly from each other, we performe Scheffe test 74 Documeation of the research