1、BRITISH STANDARD Thermal performance of buildings - Determination of thermal resistance by hot box method using heat flow meter - Masonry BS EN 1934:1998 The European Standard EN 1934.1998 has the status of a British Standard ICS91.120.10 STD-ES1 ES EN L934-ENGL 1998 m 3624bb9 0732970 609 m Amd. No.
2、 BS EN 19341998 Date Text affected This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 July 1998 O BSI 1998 National foreword This British Standard is the English languag
3、e version of EN 1934A998. The UK participation in its preparation was enhsted by Technid Committee RHE/s, Thermal insulahg materials, to Subcommittee RHE/9/2, Thermal properties of insulating materials, which has the responsibility to: - aid enquirers to understand the te* - present to the responsib
4、le European committee any enquiries on the - monitor related international and European developments and promulgate interpretation, or proposals for change, and keep the UK interests informed; them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its
5、secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Stan
6、dards Electronic Catalogue. A British standard does not purport to include all the necessary provisions of a contract. Users of British standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legai obligations. Summary of pa
7、ges This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 17 and a back cover. ISBN O 680 29671 7 STD-BSI BS EN 1934-ENGL 1998 1624669 0712971 545 EUROPEAN f3lxNDrn NORMI3 EUROPENNE EUROPATSCHE NORM EN 1934 March 1998 ICs 91.060.10; 91.080.30; 91.120.10 Descript
8、ors: Buildings, walls, laboratory tests, measurements, thermal properties, thermal resistance, heat transfer, fidelity calibration English version Thermal perfomance of buildmgs - Detem-rhation of fhed resistance by hot box method using heat flow meter - Ms0ru-y Performance thermique des btiments -
9、Dk-on de la rsistance thermique selon la mthode de la bote chaude avec fluxmtre - wnnerie Wrmestrommesser - Mauerwerk Wrmetechnisches Verhalten von Gebuden - Messung des Wrrnedurchlai3widerstandes Heizkasnverfahren mit dem This European Standard was approved by CEN on 24 January 1998. CEN members ar
10、e bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to t
11、he Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same sta
12、tus as the oficial versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, German% Greece, Iceland, Ireland, Italx Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. European Committee for Standardi
13、zation Comi6 Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart, 36 B-1050 Brussels O 1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 1931:1998 E STD-BSI BS EN 1934-ENGL 1998 1624bb9 0
14、712972 481 Page 2 EN 193k1998 Foreword “his European Standard has been prepared by Technical Committee CENnC 89, Thermal performance of buildings and budding components, the Secretariat of which is held by SIS. This European Standard is one of a package on measurements with hot box apparatus. The ba
15、sic principles of the method and the guarded and caiibrakd implementations are described in EN IS0 8990. In this European Standard the basic principles of the method and the implementation of a heat flow meter in a hot box for measurements on masonry is described, keeping the style and structure as
16、similar as possible to EN IS0 8990:1996. The numbering of clauses in this European Standard follows the clause numbering in EN IS0 8990:1!396. In the same package of European standards the procedure to test window panes, window frames, complete windows and doors in a hot box are described. This Euro
17、pean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 1998, and conflicting national standards shall be withdrawn at the latest by September 1998. According to the CEN/CENELEC Intimai Regulations, the
18、national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Noway, Portugal, Spain, Sweden, Switzerland and the United Kingdom
19、. Contents Foreword introduction 1 2 3 4 5 6 7 8 9 10 Scope Normative references Definitions, symbols and units Principle of the method Limitations and sources of errors Apparatus design Performance evaluation and calibration Test procedure Accuracy and reproducibility Test report Annex A (nonnative
20、) Calibration of heat flow meters Annex B (informative) Bibliography page 2 3 3 3 4 4 6 7 12 13 14 15 16 17 O BSI 1998 STD-BSI BS EN 1934-ENGL 1998 1624bb9 0732973 3L * * m Introduction Many masonry elements are such that in practice the heat tramfer through them is a complex combination of conducti
21、on, convection, radiation and mass transfer. The method described in this standard determines the total mount of heat transferred from one side of the specimen to the other for a given temperature Merence in defined testing conditions. However, the heat transfer properties often depend on the specim
22、en itself and on the boundary conditions, specimen dimensions, direction of heat transfer, temperatures, temperahire differences, air velocities and relative humidity In consequence the test conditions either replicate those of the intended application or are convertible to them. For ease of interco
23、mparison of resuits, conventional testing conditions are adopted during the tests. nsted values are the base used in conversion procedures to get the appropriate design values. The results obtained from a single specimen are not necessarily representative or applicable to all samples of a masonry wa
24、ll and product standards should be consulted for appropriate sampling. The design and operation of the heat flow meter hot box is a very complex subject. It is essential that the designer and user of such apparatus has a thorough background knowledge of heat tramfer, and has experience of precision
25、measurement techniques. For a particulas specimen it should be decided whether the method is applicable or whether other measurement methods or calculations are more suitable. For homogeneous specimens the guarded hot plate apparatus (see IS0 8302) or the heat flow meter apparatus (see IS0 8301) sho
26、uld be preferred. For specimens not meeting the homogeneity criteria of 6.2.1 of this standard, or with a possibility of convection within internal cavities, the metering section of a heat flow meter might not cover a representative portion of the specimen: for such specimens the use of a guarded or
27、 calibrated hot apparatus of suitable size should be considered (see EN IS0 8990). box 1 Scope This standard establishes the principles and criteria to be complied with for the determination of the laboratory steady-state heat transfer properties of masonry walls in a hot box by means of a heat flow
28、 meter mounted on one face of the masonry wall to be tested (i.e. the test specimen). It describes the apparatus, measurement technique and necessary data reporting. It does not, however, specify a particular apparatus design since requirements vary particularly in terms of size, and also to a lesse
29、r extent, in terms of operating conditions. Page 3 EN 19M.1998 The property that is measured is the surfacetosurface thermal resistance of the specimen, provided that the metering section of the heat flow meter covers a representative portion of the specimen, and the homogeneity criteria of 6.2.1 ar
30、e met. From these measurements the thermal resistance for application in buildings is derived. The thermal transmittance of a masonry wd can en be calculated from this value with standardized surface coefficients. This standard is applicable to measurements on both dry and moist specimens, provided
31、that the conditions indicated in 5.3.3 are met. The influence of moisture content on the thermal properties of masonry can be taken into account by measurements at different moisture contents of the specimen in the range of the practical moisture content including the dry state, which corresponds to
32、 the most frequent testing condition. The method is also suitable for horizontal elements such as ceilings and floors. 2 Normative references This standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places i
33、n the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred applies.
34、EN IS0 6946, Building components and building elements- Themull resistance and thermal transmittance - Calculation method (IS0 69461996). EN IS0 7345, insulation - Physical qu,antit.ieS and definitwns (IS0 73451987). EN IS0 8990 1996, ?“hmnal insulation - Determination of steady-state themtal transm
35、ission properties - Calibrated and guarded hot box (IS0 8990 1994). IS0 8301:1991, l7wrmd insulation - Determination of steadystate themzal resistance and related properties - Heat $ow meter apparatus. IS0 8302: 1991, l7wrwud insulation - Determination of steay-state thermal resistance and related p
36、roperties - harded hot plate apparatus. O ES1 1998 STDOBSI BS EN 3934-ENGL 1998 D 3624669 0732974 254 D Page 4 EN 19341998 3 Definitions, symbols and units 3.1 Definitions For the purposes of this standard, the definitions in EN IS0 7345 and EN IS0 8W.1996 and the following defnitions apply 3.1.1 me
37、an radiant temperature1) appropriate weighting of the temperatures of surfaces “seen” by the specimen for the purpose of determining the radiant heat flow rate to or from the surface of the specimen 3.1.2 environmental temperature) appropriate weighing of air and radiant temperatures, for the purpos
38、e of determining the heat flow rate to the surface of the specimen 3.1.3 moderately inhomogeneous specimen specimen which, when tested, meets temperature uniformity criteria as stated in 6.3.2 3.2 Symbols and units Quantity area perpendicular to the density of heat flow rate surace thermal resistanc
39、e specimen thermal resistance (surface-to-surface) totai thermal resistance (environment to environment) air temperature environmental temperature mean radiant temperature surface temperature thermal transnu ttance (VRT) specimen thickness caibration factor of the heat flow meter guard width surface
40、 coefficient of heat transfer (l/ that corresponds to the metering section of the specimen and is smaller than the total heat flow meter section. 4.3 Determination of the surface-to-surface thermal resistance of the specimen Steady-state measurements are made of surface temperatures and of the densi
41、ty of heat flow rate through the specimen. From these measurements the surface-to-surface thermal resistance of the specimen is calculated. 4.4 Guarding and guard section The surface of the specimen surrounding the metering section is called hereafter “guard section“. To ensure a uniform density of
42、heat flow rate in the metering section, the guard section shall be held as close as possible to the same temperature as the metering section, so that the lateral heat flow rate 2 from the metering section to the guard section through the specimen is nearly zero, see Fgure 1. The guard section shall
43、be iarge enough to ensure that the edge heat loss error 5 is low. The use of insulation on the edge of the specimen helps in reducing edge heat loss errors, hence it may be used to increase the maximum allowed specimen thichess for the apparatus. NOTE Heat flows at a rate through the metering areail
44、 = (2Q2; in the metering area the density of heat flow rate, g, is expected to be uniform; Q2 is an imbalance heat flow rate parallel to the specimen: Q6 is the transverse heat flow rate at the edge of the specimen; g is the guard width. Figure 1 - Principle of a heat flow meter hot box apparatus O
45、BSI 1998 STD.BSI BS EN 3934-ENGL 1998 M 1624bb 0732976 027 M Metering section width 500 500 500 500 500 Page 6 EN 19341998 Guard width 150 250 375 500 750 6 Limitations and sources of errors 6.1 General The operation of the apparatus, to a certain desired accuracy, is limited by a number of factors
46、related to equipment design, calibration and operation and specimen properties, e.g. thickness, thermal resistance and homogeneiw. 6.2 Limitations and errors due to apparatus 6.2.1 Limitations due to lateral heatflow rate lb keep the lateral heat flow rate 2, equal to zero, even when testing homogen
47、eous specimens, the hot and cold surfaces of the specimen should be kept at uniform temperatures; this in turn requires that environmental temperatures and local surface heat transfer coefficients be uniform both on the hot and on the cold side of the specimen. These requjrements are always met with
48、 a certain approximation even with an adequate air flow on both surfaces of the specimen and correct choice of apparatus size and design. Consequently there is usually a temperature difference between the average temperatures of the metering and guard portion of the hot side surface of the specimen.
49、 Additionally, this temperature difference, due to the mentioned non-uniformities, is known with a level of uncertainly, so that, in practice, it is almost impossible to reduce to zero the latera heat flow rate z. Furthermore, specimens tested in a heat flow meter hot box are not homogeneous (otherwise they could be tested with better accuracy in a guarded hot plate apparatus). To keep imbalance errors within acceptable iimits when tesjng a wall made of elements (bricks, blocks), the heat flow meter should cover an integral number of
