1、BSI Standards PublicationBS EN 16322:2013Conservation of CulturalHeritage Test methods Determination of dryingpropertiesBS EN 16322:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16322:2013.The UK participation in its preparation was entrusted to Technical
2、Committee B/560, Conservation of tangible cultural heritage.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The B
3、ritish Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 76031 0ICS 97.195Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 October
4、 2013.Amendments issued since publicationDate Text affectedBS EN 16322:2013EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16322 October 2013 ICS 97.195 English Version Conservation of Cultural Heritage - Test methods - Determination of drying properties Conservation du patrimoine culturel - Mt
5、hodes dessai - Dtermination des proprits de schage Erhaltung des kulturellen Erbes - Prfverfahren - Trocknungsverhalten This European Standard was approved by CEN on 24 August 2013. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving th
6、is 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 the CEN-CENELEC Management Centre or to any CEN member. This European Standard exists in three official
7、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 CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Aust
8、ria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Swede
9、n, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN
10、 national Members. Ref. No. EN 16322:2013: EBS EN 16322:2013EN 16322:2013 (E) 2 Contents Page Foreword . 3 Introduction 4 1 Scope 5 2 Normative references . 5 3 Terms and definitions 5 4 Principle 6 5 Symbols and abbreviations . 6 6 Test equipment . 6 7 Preparation of the specimens 6 7.1 Number and
11、dimensions of the test specimens . 6 7.2 Pre-conditioning of the specimens . 7 8 Test procedure . 7 9 Expression of results . 9 9.1 Determination of the drying curve . 9 9.2 Calculation of the drying rate 9 9.2.1 Calculation of the drying rate corresponding to the first drying phase D19 9.2.2 Calcul
12、ation of the drying rate corresponding to the second drying phase D29 9.2.3 Determination of the knick-point . 9 9.3 Calculation of drying index 10 10 Test report 10 Annex A (normative) Numerical example . 11 Annex B (informative) Influence of ventilation on the drying curve . 14 BS EN 16322:2013EN
13、16322:2013 (E) 3 Foreword This document (EN 16322:2013) has been prepared by Technical Committee CEN/TC 346 “Conservation of Cultural Heritage”, the secretariat of which is held by UNI. This European Standard shall be given the status of a national standard, either by publication of an identical tex
14、t or by endorsement, at the latest by April 2014, and conflicting national standards shall be withdrawn at the latest by April 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible
15、for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, For
16、mer Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16322:2013EN 16322:2013 (E) 4 Intr
17、oduction This test method can be applied if it does not change the value of the cultural property according to the ethical code of conservation practice. The drying properties of materials can be calculated from a curve that indicates the weight loss of the mass of water inside the sample, as a func
18、tion of time, during a drying experiment. Usually the drying of specimens saturated with water consists of two phases. The first drying phase is characterised by transport of liquid water to the surface followed by evaporation. The surface remains wet allowing evaporation at a constant rate, as wate
19、r moves to the surface fast enough to compensate for the losses due to evaporation. The evaporation at the surface is determined to a large extent by the test boundary conditions. These are temperature, relative humidity and the flow velocity of the ambient air. The slope of the drying curve during
20、the first drying phase therefore reflects these conditions. The second drying phase starts when the amount of water brought to the surface becomes too small to keep the surface wetted and the rate of evaporation decreases. Transport of liquid water to the surface is no longer possible and only the l
21、ess efficient vapour diffusion mechanism remains available. Some materials, e.g. adobe or sandstones containing clay, do not dry in this typical two-phase drying curve. For example, in the case of material treated with water repellent, the first drying phase does not exist. BS EN 16322:2013EN 16322:
22、2013 (E) 5 1 Scope This European Standard specifies a method for the determination of the drying behaviour of porous inorganic materials used for and constituting cultural property. The method may be applied to porous inorganic materials either untreated or subjected to any treatment or ageing. 2 No
23、rmative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendment
24、s) applies. EN 15898, Conservation of cultural property - Main general terms and definitions 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 15898 and the following apply. 3.1 porous inorganic material material including natural stones as sandstone, l
25、imestone, marble, and others as well as artificial materials such as mortar, plaster, brick and others 3.2 drying rate mass of water transported through the specimen per area and time 3.3 drying curve graphical representation of water loss over time showing in most inorganic porous materials two dis
26、tinct drying phases 3.4 first drying phase characterised by transport of liquid water to the surface followed by evaporation 3.5 second drying phase characterised by a decrease in liquid water transport and an increase in water vapour diffusion limited by hygric material properties 3.6 knick-point o
27、f the drying curve time of transition between the first and the second drying phases shown on the drying curve 3.7 drying index area under the curve derived by graphical or mathematical methods BS EN 16322:2013EN 16322:2013 (E) 6 4 Principle Determination of the drying behaviour of porous inorganic
28、materials saturated with water and subjected to drying in a controlled environment. 5 Symbols and abbreviations mmaxmass of the saturated sealed specimen, in kg; mimass of the sealed specimen at time ti, in kg; mffinal mass of the sealed specimen at time tf, in kg; titime elapsed from the beginning
29、of the test, in h; tktime at which the knick-point is reached in h; tffinal time of the test, in h; A area of the drying face, in m2; D1drying rate corresponding to the first drying phase, in kg/m2h; D2drying rate corresponding to the second drying phase, in kg/m2h1/2;ID drying index; Miresidual amo
30、unt of water of the specimen at time tiper unit area, in kg/m2; vapour transfer coefficient. 6 Test equipment 6.1 A chronometer with an accuracy of at least 1 s. 6.2 A ventilated oven which can maintain a temperature of (60 2) C. 6.3 An analytical balance with an accuracy of at least 0,01 g. 6.4 A l
31、inear measuring device (calliper) with an accuracy of at least 0,1 mm. 6.5 Climatic chamber with temperature of (23 1) C and relative humidity (50 3) %. 6.6 Sand paper with grain size of 82 m (corresponding to grit number P180 according to the FEPA 1) classification). 6.7 Desiccator filled with desi
32、ccant such as self-indicating silica gel or other drying agent. 7 Preparation of the specimens 7.1 Number and dimensions of the test specimens The test specimens shall have a regular shape such as cubes or cylinders. They shall have minimum dimensions on any side of 10 mm. Large samples give greater
33、 experimental accuracy. 1) FEPA Federation of European Producers of Abrasives BS EN 16322:2013EN 16322:2013 (E) 7 The number and dimensions of specimens are dependent on the heterogeneity of the material. Each series shall consist of at least 3 specimens. In case of anisotropy, each series shall alw
34、ays be tested according to the same orientation, if any. All dimensions should not differ by 0,5 mm. In case of non homogeneous materials such as mortars containing coarse aggregates, the dimensions shall be at least three times (and preferably five times) that of the largest grain size. In cases wh
35、ere sampling constraints exist the number and dimensions of samples may need to vary from the requirements given above, however every effort should be made to ensure that the minimum requirements for reliability are satisfied. 7.2 Pre-conditioning of the specimens The test surface shall be flat and
36、wet or dry polished with sand paper (6.6). After polishing, the specimens shall be washed with water, gently brushed with a soft brush and immersed in deionised water for 30 min. In case of water-sensitive materials, for example gypsum containing materials, only dry polishing and compressed air shal
37、l be used. The above procedure does not apply to treated specimens or specimens taken from exposed surfaces. Specimens are saturated with water by capillary rising absorption for 24 h and then total immersion until constant mass in achieved. Constant mass is reached when the difference between two s
38、uccessive weightings at an interval of 24 h is not greater than 0,1 % of mass of the specimen. After this immersion the surface of the specimens is patted dry. All faces, except the test surface, are then sealed with a water impermeable (both in liquid and vapour form) material such as latex, alumin
39、ium foil, etc. 8 Test procedure Specimens prepared according to Clause 7 are placed in a climatic chamber at temperature (23 1) C and relative humidity (50 3)% in such a way that drying occurs through the upper side. The drying behaviour is recorded by periodic weighing. As the air flow conditions h
40、ave significant influence on the drying rate during the first drying phase, these conditions should be kept constant and reproducible. The influence is illustrated in Annex B. The first weight reading at t = 0 is mmax.In order to obtain enough data during the first drying phase, the measurement inte
41、rval at the beginning of the drying shall be chosen in accordance with the specimen height and the materials under investigation. The following figure indicates this influence showing drying curves obtained under standard conditions for different materials. BS EN 16322:2013EN 16322:2013 (E) 8 Key X
42、time d Y water content kg/m2 A weathered granite B concrete C historic lime plaster D sand stone E clinker clay brick F clay brick Figure 1 Drying curves for different materials with different length of the first drying phase; calculation results for specimens of 5 cm height dried under standard con
43、ditions BS EN 16322:2013EN 16322:2013 (E) 9 The above graphs indicate the following: materials with a low liquid conductivity (dense materials, e.g. concrete) generally show a short first drying phase materials with a high liquid conductivity (porous materials as clay brick) generally show a distinc
44、t and long first drying phase In addition, a smaller specimen height can lead to a shorter first drying phase. In the first hour of the experiment procedure a minimum of 5 measurements should be taken at set time intervals. After the first hour, measurements should be taken on an hourly basis for th
45、e next 7 h. Subsequent measurements should then be taken twice a day with at least 6 h between two successive weightings. The experiment is carried out until the final mass of the sealed specimen at time tf(mf) is reached. 9 Expression of results 9.1 Determination of the drying curve The residual am
46、ount of water present in the specimen per unit area (expressed as kg/m2) at time tiis calculated as follows: AmmMfii= The calculated values of Miare reported as a function of time expressed in h. 9.2 Calculation of the drying rate 9.2.1 Calculation of the drying rate corresponding to the first dryin
47、g phase D1The drying rate corresponding to the first drying phase (see Figure A.1) is the negative slope of the initial linear part of the drying curve and shall be calculated by linear regression, using at least 5 successive aligned points. 9.2.2 Calculation of the drying rate corresponding to the
48、second drying phase D2For the determination of the drying rate corresponding to the second drying phase the calculated values of Miare reported in a graph as a function of the square root of time (ti1/2). The drying rate corresponding to the second drying phase (see Figure A.2) is the negative slope
49、 of the linear section of the drying curve plotted against ti1/2and shall be calculated by linear regression, using at least 5 successive aligned points. 9.2.3 Determination of the knick-point While mathematically there are two intersection points between the curves, the knick-point (tk) corresponds to the greatest of the two possible time values. A worked example of knick-point determination is illustrated in Annex A. BS EN 16322:2013EN 16322:2013 (E) 10 9.3 Calculation of drying index The drying index is a valuable aid to characterise the
