DIN EN 1946-2-1999 en 4990 Thermal performance of building products and components - Specific criteria for the assessment of laboratories measuring heat transfer properties - Part .pdf

1、DEUTSCHE NORM April 199 Thermal performance of building products and components DIN Specific criteria.for the assessment of laboratories measuring heat transfer properties EN 1946-2 Part 2: Measurements by guarded hot plate method English version of DIN EN 1946-2 ICs 91.100.01; 91.120.10 Wrmetechnis

2、ches Verhalten von Bauprodukten und Bauteilen - Technische Kriterien zur Begutachtung von Laboratorien bei der Durchfhrung der Messungen von Wrmebertragungseigenschaften - Teil 2: Messung nach Verfahren mit dem Plattengert European Standard EN 1946-2 : 1999 has the status of a DIN Standard. A comma

3、is used as the decimal marker. National foreword This standard has been prepared by CEN/TC 89. The responsible German body involved in its preparation was the Normenausschu Bauwesen (Building and Civil Engineering Standards Committee), Technical Committee W2rmeschufz. EN comprises 27 pages. No pari

4、of this standard may be reproduced without the prior permission of Ref. No. DIN EN 1946-2 : 1999-0 N Deutsches Institut fr Normung e. V., Berlin. wth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group 11 Sales No. 11 11 10.99 EU ROPEAN

5、 STAN DAR D NORME EUROPENNE EUROPISCHE NORM EN 1946-2 January 1999 ICs 91.100.01; 91.120.10 English version Thermal performance of building products and components Specific criteria for the assessment of laboratories measuring heat transfer properties Part 2: Measurements by guarded hot plate method

6、 Performance thermique des produits et composants pour le btiment - Critres particuliers pour lvaluation des laboratoires mesurant les proprits de transmission thermique - Partie 2: Mesurages selon la mthode de la plaque chaude garde Wrmetechnisches Verhalten von Bauprodukten und Bauteilen - Technis

7、che Kriterien zur Begut- achtung von Laboratorien bei der Durchfhrung der Messungen von Wrmebertragungseigenschaften - Teil 2: Messung nach Verfahren mit dem Plattengert This European Standard was approved by CEN on 1998-1 2-1 3. CEN members are bound to comply with the CENKENELEC Internal Regulatio

8、ns 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 stand- ards may be obtained on application to the Central Secretariat or to any CEN member. The Europ

9、ean Standards exist 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 status as the official versions. CEN members are the natio

10、nal standards bodies of Austria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, and the United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisati

11、on Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1999. CEN - All rights of exploitation in any form and by any means reserved worldwide for CEN national members. Ref. No. EN 1946-2 : 1999 E Page 2 EN 1946-2 : 1999 Contents Foreword 1 Scope 2 Normative refe

12、rences 3 Definitions 4 Equipment manual 5 Calibration and maintenance files 6 Measurement procedure document 7 Assessment Annex A (normative) Determination of apparatus emissivity Annex B (normative) Edge heat losses and maximum specimen thickness Annex C (informative) Calculations of some guarded h

13、ot plate errors Page 3 4 4 4 5 13 14 15 16 19 22 Page 3 EN 1946-2 : 1999 Foreword This European Standard has been prepared by Technical Committee CENEC 89 “Thermal performance of buildings and building components“, the secretariat of which is held by SIS. This European Standard shall be given the st

14、atus of a national standard, either by publication of an identical text or by endorsement, at the latest by July 1999, and conflicting national standards shall be withdrawn at the latest by July 1999 This European Standard is divided into parts. The first part covers common criteria applicable to al

15、l heat transfer property measurements; each subsequent part covers the specific technical criteria applicable to each heat transfer property measurement method described in appropriate standards. The following parts have been developed: Part 1: Common criteria Part 2: Part 3: Part 4: Part 5: Measure

16、ments by guarded hot plate method Measurements by heat flow meter method Measurements by hot box methods Measurements by pipe test methods According to the CENKENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard:

17、Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands. Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. Page 4 EN 1946-2 : 1999 1 Scope This part 2 of this standard provides specific technical criteria for th

18、e assessment of laboratories to undertake steady-state heat transfer property measurements by the guarded hot plate method according to prEN 12667 and prEN 12664. It complements the common criteria in part I. Guidance is given on the organization and contents of the equipment manual, the calibration

19、 and maintenance files and the measurement procedure document. It provides information on mandatory equipment performance specifications, equipment description and on calculations for the equipment design and error analysis. It provides information on experimental procedures suitable for the assessm

20、ent of equipment accuracy. 2 Normative references This standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amend

21、ments 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 to applies. EN 1946-1:1999 prEN 12664: 1996 prEN 12667: 1996 prEN 12939 IS0 8302:1991 Thermal perform

22、ance of building products and components - Specific criteria for the assessment of laboratories measuring heat transfer properties - Part 1 : Common criteria Building materials - Determination of thermal resistance by means of guarded hot plate and heat flow meter methods - Dry and moist products of

23、 medium and low thermal resistance Building materials - Determination of thermal resistance by means of guarded hot plate and heat flow meter methods - Products of high and medium thermal resistance Building materials - Determination of thermal resistance by means of guarded hot plate and heat flow

24、meter methods - Thick products of high and medium thermal resistance Thermal insulation - Determination of steady-state thermal resistance and related properties - Guarded hot plate apparatus 3 Definitions The definitions in EN 1946-1 and in IS0 8302: 1991 also apply to this part of the standard. Pa

25、ge 5 EN 1946-2 : 1999 4 Equipment manual 4.1 General The equipment manual shall provide the information specified in 5.2.2 to 5.2.5 of EN 1946- 1 : 1999 and the information specified in this clause. NOTE: Information common to more than one piece of equipment need not be duplicated, e.g. the princip

26、le, details of the design and operation of two pieces of equipment built to a common design. Annex B of prEN 12664: 1996 or prEN 12667: 1996, which indicates all limiting values for apparatus performance and testing conditions, shall be used as a check-list during the assessment process by the parti

27、es concerned to ensure compliance with all the requirements of those standards. 4.2 Equipment performance specifications According to 2.3.1 of IS0 8302:1991, the upper and lower limits for the following relevant tested properties and testing conditions, including possible interactions among them, sh

28、all be specified: - specimen thickness; - thermal resistance; - - - temperature difference across the specimen; heating and cooling unit temperature; surrounding environment (temperature, relative humidity) at the edge of the specimen during the test. 4.3 Equipment description The following informat

29、ion shall be documented and shall be available for examination during the assessment: - - - principle of operation (see 1.6.1 of IS0 8302: 1991); type of apparatus (see 1.6.2.1, 1.6.2.2 and 1.6.4 of IS0 8302:1991); principal dimensions of apparatus, in particular heating unit width, guard width and

30、gap width; simple diagrams illustrating the design of the equipment with special attention to the gap design (see 2.1.1.5 of IS0 8302:1991), the cooling unit piping (see 2.1.2 of IS0 8302:1991) and edge insulation (see 2.1.3 of IS0 8302:1991); position, connections and numbering of temperature senso

31、rs (see 2.1.4.1 of IS0 8302:1991); electrical components/instruments, apparatus enclosure and main ancillary equipment; details of data acquisition system and related computer programs for data analysis. - - - - To avoid duplication, reference can be made to manuals supplied by the instrument manufa

32、cturers or to relevant clauses of IS0 8302: 1991. Page 6 EN 1946-2 : 1999 Maximum thickness (edge Iimit for e = 0,25) 4.4 Equipment design and error analysis Flatness tolerance (0,025%) 4.4.1 General Max. gap With reference to the performance specification given in 4.2, details shall be given of the

33、 design guidelines followed, and the error analysis based on 2.2 of IS0 8302:1991, as summarized in 4.4.2 to 4.4.11. Minimum thicness “ (gap limit) Some guidelines on error analysis are given in this subclause; more specific information on some errors is supplied in annex B, while error calculations

34、 are supplied in annex C for some typical cases. Examples of equipment conforming to annex C are supplied in D.2 of prEN 12664: 1996 and in D.2 of prEN 12667:1996. For equipment having characteristics exactly as indicated in this subclause or design details as indicated in annex C of this part and i

35、n D.2 of prEN 12664: 1996 or in D.2 of prEN 12667: 1996, no further calculations are needed. In other circumstances similar calculations can be performed by analogy. 4.4.2 According to 3.2. I of IS0 8302: 199 1, the sum of the imbalance error and edge heat loss error shall be kept within 0,5 %. In a

36、 good equipment design, the two errors will be of the same order of magnitude, hence a 0,25 % limit can be suggested for both. Table 1 shows for some apparatus dimensions the maximum allowed specimen thickness according to 2.2.1 of IS0 8302: 199 1, when there is no edge insulation and when the edge

37、temperature ratio, e, is 0,25; e is defined as (Te - T2) / (Ti - T2), where Ti and T2 are respectively the temperatures of the hot and cold surfaces of the specimen, and Te is the temperature at the edge of the specimen, assumed to be uniform. Edge heat losses and maximum specimen thickness 30 35 45

38、 60 80 65 75 85 90 100 120 150 Table 1: Minimum and maximum aiiowed specimen thickness 0,05 0,08 0,08 0,lO 0,lO 0.13 0,13 0,13 0,15 0,20 0.20 0,25 Dimensions in millimetres 1,25 2,50 1,88 2.50 1,25 3,75 3,13 2.50 3,75 6,25 5.00 6,25 Overall size 12,s 25,O 18,s 25,O 123 373 31,3 25,O 37,s 62,5 50,o 6

39、2,5 Metering section Guard width 200 300 300 400 400 500 500 500 600 800 800 lo00 100 200 150 200 100 300 250 200 300 500 400 500 50 50 75 100 150 100 125 150 150 150 200 250 I I 1) Thicknesses applicable for gap w Minimum thickness (flat. tol.) 10,o 15,o 150 20,o 20,o 25,O 25,O 25,O 30,O 40,O 40.0

40、50,o imn of table 1 Page 7 EN 1946-2 : 1999 EXAMPLE: e = 0,25 corresponds to a temperature of the edge of the specimen 5 K below the mean test temperature, when the temperature difference between the hot and cold side of the specimen is 20 K. NOTE: The edge heat loss error is zero for homogeneous is

41、otropic specimens when e is close to 0,5; the absolute value of the edge heat loss error increases almost symmetrically when e deviates on either side from 0,5. In the range 0,25 I e I0,75, this error is maximum for e = 0,25. Larger specimen thicknesses can be used for some specimens if edge insulat

42、ion or edge temperature control is used, if auxiliary or gradient guards are installed, or medium and high conductivity specimens are tested. See annex B for additional information. When the maximum specimen thickness to be specified according to 4.2 exceeds the appropriate value given in table 1, l

43、ateral losses shall be calculated. If, according to these calculations they exceed those permitted by IS0 8302: 1991, the performance check data shall be examined and, if no experimental evidence exists to justify the claimed maximum specimen thickness, the maximum specimen thickness to be specified

44、 according to 4.2 shall be reduced. 4.4.3 According to 2.1.1.3 of IS0 83021991 the gap width, g, shall be such that the gap area is less than 5 % of the metering area, i.e. the gap width, g, shall not be greater than 1,25 % of the metering area side, L. The maximum gap width resulting from this requ

45、irement is given in the seventh column of table 1. The minimum specimen thickness, dm, is related to the gap width. d, shall be at least ten times the gap width, see 1.7.6 of IS0 8302:1991. Thus, when the gap width reaches its maximum allowed value according to the above criteria, the minimum specim

46、en thickness shall not be less than 12,5 % of the side L of the metering section. The minimum specimen thickness resulting from these requirements is given in the eighth column of table 1. When the minimum specimen thickness to be specified according to 4.2 is less than those of the eighth column of

47、 table 1, the actual gap width, g, shall be used to compute dm = 10 g, see also 4.4.6. If this requirement is not met, then the minimum specified specimen thickness shall be increased to meet this requirement. Maximum gap width and minimum specimen thickness Minimum specimen thickness shall also be

48、checked against maximum allowed flatness tolerances, see 4.4.9,4.4.10 and 4.4.1 1. 4.4.4 Imbalance error According to 2.2.1 of IS0 8302:1991, an error heat flow rate cDg can be expressed as follows: jg = (Do -+ A. .)AT, (1) where AT is the actual gap temperature imbalance through the apparatus and G

49、o, representing the heat jr by radiation through the gap; O, through the mechanical connections through the gap; Oc through copper wires; Ow through metal wires (excluding copper). Page 8 EN 1946-2 : 1999 To calculate these terms, the elementary equations of heat transfer through a plane layer can be used. A c is the heat flow rate through both specimens due to a 1 K gap imbalance with c expressed by the following equation: c = (1 6 Un) ln4/( 1 - exp(-ng/d) (2) In this equation 21 = L is the side of the metering area (centre gap to centre gap), g is the gap w