1、BSI Standards PublicationBS EN 16795:2015Plastics Method forestimating heat build up offlat surfaces by simulated solarradiationBS EN 16795:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16795:2015.The UK participation in its preparation was entrusted to T
2、echnicalCommittee PRI/21, Testing of plastics.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 British Standar
3、ds Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 87749 0ICS 83.080.01Compliance 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 December 2015.Amen
4、dments issued since publicationDate Text affectedBS EN 16795:2015EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16795 December 2015 ICS 83.080.01 English Version Plastics - Method for estimating heat build up of flat surfaces by simulated solar radiation Plastiques - Mthode destimation de lcha
5、uffement de surfaces planes par rayonnement solaire simul Kunststoffe - Verfahren mit simulierter Sonnenstrahlung zur Bewertung der Aufheizung auf ebenen Oberflchen This European Standard was approved by CEN on 7 November 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulation
6、s 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 the CEN-CENELEC Management Centre or to any CEN member. Th
7、is 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 CEN-CENELEC Management Centre has the same status as the official versions. CEN mem
8、bers are the national standards bodies of Austria, 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, Portu
9、gal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any for
10、m and by any means reserved worldwide for CEN national Members. Ref. No. EN 16795:2015 EBS EN 16795:2015EN 16795:2015 (E) 2 Contents Page European foreword . 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions . 5 4 Abbreviations . 5 5 Principle . 5 6 Apparatus . 6 6.1 Genera
11、l 6 6.2 Test chamber 6 6.3 Laboratory radiation source . 6 6.4 Radiometer 7 6.5 Test chamber temperature and relative humidity . 7 6.6 Surface temperature measurement device . 7 6.7 Black and white standard thermometer 8 6.8 Defined airflow directed across the sample 9 6.9 Specimen holders 9 7 Test
12、specimens . 9 7.1 Form, shape and preparation . 9 7.2 Number of test specimens 9 8 Exposure conditions . 9 8.1 Radiation 9 8.2 Black and white standard thermometer 9 8.3 Chamber air temperature . 10 8.4 Relative humidity of chamber air. 10 8.5 Wind speed . 10 8.6 Sets of exposure conditions 10 9 Pro
13、cedure 10 9.1 General . 10 9.2 Mounting the test specimens . 10 9.3 Exposure 10 9.4 Measurement of the surface temperature 11 10 Test report 11 Bibliography . 12 BS EN 16795:2015EN 16795:2015 (E) 3 European foreword This document (EN 16795:2015) has been prepared by Technical Committee CEN/TC 249 “P
14、lastics”, the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2016 and conflicting national standards shall be withdrawn at the latest by June 2016. Atten
15、tion 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 for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations of
16、the following countries are bound to implement this European Standard: Austria, 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, Nethe
17、rlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16795:2015EN 16795:2015 (E) 4 Introduction Solar radiation causes the temperature of irradiated surfaces to rise substantially above the temperature of the surrounding air.
18、 The resulting surface temperature depends on the climatic parameters at the location in question, the spectral absorption of the surface, the geometric dimensions and on the specific structure of the object. Generally, the darker the colour, the more the suns energy is absorbed and the higher is th
19、e heat build-up. The performance characteristics of most of the materials are also defined by the in service temperature. Such materials can be window profiles or other polymeric carrier materials. The micro climate at house walls is also essential defined by the absorbed solar radiation (depending
20、on the material properties). The same applies for interior room and automobile temperatures. The examples reveal the significance of the knowledge of the temperature of sun irradiated surfaces. If the temperature magnitude is estimated to be critical, provisions can be taken to optimize the in-servi
21、ce micro climate, e.g. reduction of the in-service temperature by improvement of the spectral reflection characteristics or appropriate change in design and improving the air conditioning. BS EN 16795:2015EN 16795:2015 (E) 5 1 Scope This European Standard specifies a method for estimating the temper
22、ature increase of a flat polymer surface, due to its solar radiant energy absorption, compared to the ambient temperature. For that purpose, a specimen and black and white reference plates are exposed to simulated solar radiation under specified conditions (simulated solar radiation, ambient air tem
23、perature, convective flow). For opaque specimens, a thermally sensitive electrical element at the backside or a pyrometer is used to measure the surface temperature. For translucent specimens, a pyrometer is used to measure surface temperature. NOTE Some specific polymeric materials are translucent
24、(transparent) and might have a transmittance window in a wavelength range where the used pyrometer is sensitive (e.g. polyethylene). The surface temperature of these materials cannot be measured with the contact and the contactless method. 2 Normative references The following documents, in whole or
25、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 amendments) applies. EN ISO 4892-1, Plastics - Methods of exposur
26、e to laboratory light sources - Part 1: General guidance (ISO 4892-1) ISO 9370, Plastics - Instrumental determination of radiant exposure in weathering tests - General guidance and basic test method 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 937
27、0 apply. 4 Abbreviations BST black-standard thermometer CHT chamber air temperature RTD resistance temperature detector WST white-standard thermometer 5 Principle 5.1 A xenon or metal halide arc lamp, fitted with filters, is used to simulate the spectral irradiance of global solar radiation. 5.2 Spe
28、cimens are exposed to various levels of simulated global solar radiation, heat, and relative humidity and air flow under controlled environmental conditions, including: a) the irradiance level; b) the air flow directed over the test specimen; c) the ambient air temperature during the exposure to sim
29、ulated global solar radiation; BS EN 16795:2015EN 16795:2015 (E) 6 d) the relative humidity in the chamber during the exposure to simulated global solar radiation. 5.3 The procedure may include measurements of the global irradiance in the plane of the specimens. 5.4 The procedure includes measuremen
30、ts of the surface temperature in the plane of the specimens. 5.5 It is recommended to expose simultaneously with the test specimens a black standard (BST) and white standard (WST) thermometer as specified in EN ISO 4892-1 to provide a standard for comparative purposes. 5.6 Comparison of results obta
31、ined from specimens exposed in different apparatus should not be made unless an appropriate statistical relationship has been established between the apparatuses for the particular material exposed. 6 Apparatus 6.1 General The equipment comprises a test chamber, an ozone-free radiation source which
32、generates UV, visible, and infrared radiation similar to solar radiation. A contactless surface temperature device (pyrometer) or contact temperature measuring systems may be part of the device. 6.2 Test chamber The design of the test chamber may vary, but it shall be constructed from inert material
33、 and shall be equipped with a blower which generates a defined airflow to be directed across the specimens. In addition to the controlled lamp wattage, the test chamber shall provide for control of ambient temperature. For exposures that require control of humidity, the test chamber shall include hu
34、midity-control facilities that meet the requirements of EN ISO 4892-1. NOTE 1 If the lamp system (one or more lamps) is centrally positioned in the chamber, the effect of any eccentricity of the lamp(s) on the uniformity of exposure can be reduced by using a rotating frame carrying the specimens or
35、by repositioning or rotating the lamps. NOTE 2 The required irradiance level can be adjusted by means of the lamp wattage. In this case, the lamp wattage is controlled not the irradiance. 6.3 Laboratory radiation source 6.3.1 General The radiation source shall comprise one or more xenon-arc or metal
36、 halide radiation sources which emit radiation from below 270 nm in the ultraviolet through the visible spectrum and into the infrared. In order to simulate global solar radiation, filters shall be used to remove short-wavelength UV radiation (800 nm) may be used to prevent unrealistic heating of th
37、e test specimens. 6.3.2 Spectral irradiance of xenon and metal halide arc lamps with global solar radiation filters Table 1 specifies the minimum and maximum levels of the relative spectral irradiance, in the visible and infrared wavelength range. Filters are a useful tool to achieve these values. I
38、n order to simulate global solar radiation, filters shall be used to remove short-wavelength UV radiation (800 nm) may be used to prevent unrealistic heating of the test specimens. BS EN 16795:2015EN 16795:2015 (E) 7 NOTE Solar spectral irradiance for a number of different atmospheric conditions is
39、described in CIE Publication No. 85 1. The benchmark global solar irradiance used in this standard is that defined in Table 4 in CIE No. 85:1989. Table 1 Relative spectral irradiance of laboratory radiation sources simulating global solar radiation Spectral passband ( = wavelength in nm) Relative sp
40、ectral portiona% 290 800 60 9 800 3 000 40 9 aThe minimum and maximum tolerance will not necessarily sum to 100 % because they represent tolerance of the measurement data used. For any individual spectral irradiance, the percentages calculated for the passbands in this table will sum to 100 %. For a
41、ny individual simulated global solar radiation, the calculated percentage in each passband shall fall within the minimum and maximum limits given. Contact the manufacturer of the simulated global solar radiation apparatus for specific spectral irradiance data. 6.3.3 Irradiance uniformity The irradia
42、nce at any position in the area used for specimen exposure shall be at least 80 % of the maximum irradiance. NOTE The surface temperature might vary with the irradiance uniformity on sample level. 6.4 Radiometer The radiometer used shall comply with the requirements given in ISO 9370. 6.5 Test chamb
43、er temperature and relative humidity The chamber temperature sensor shall be located, radiation-shielded, possibly combined with a sensor which measures the relative humidity close to the exhaust air duct. For exact calibration of the chamber temperature and relative humidity sensor it is necessary
44、to move a calibrated working reference standard and the instrument sensor to about the same position so that a balanced temperature and humidity can be set for the measuring sensors and the ambient air. Calibration takes place as soon as the whole system is in thermal balance. NOTE Typically, the th
45、ermal equilibrium is achieved after 30 min up to 1 h. 6.6 Surface temperature measurement device 6.6.1 Pyrometer 6.6.1.1 Minimum requirements for the pyrometer A pyrometer may be used to measure the surface temperature of the test specimen on sample level. The minimum requirements for the pyrometer
46、are the following: a) temperature range: 20 C to 150 C (traceably calibrated by a black body radiator); b) spectral response: 8 m to 14 m; c) IR detector: e.g. silicon based thermopile; d) uncertainty: 0,6 % (in the considered temperature range); BS EN 16795:2015EN 16795:2015 (E) 8 e) spot size (dia
47、meter): maximum 30 mm. 6.6.1.2 Calibration of the pyrometer The pyrometer shall be calibrated to a traceable national or international standard. Re-calibration by a qualified national or international calibration laboratory should be done at appropriate intervals (e.g. annually). 6.6.1.3 Emissivity
48、of material The temperature of a given object can only be measured correctly if its exact emissivity () in the wavelength range between 8 m and 14 m is known and the pyrometer is set up accordingly. The emissivity () is the ratio between the radiation emitted by a particular surface and that by a ra
49、diated black body at the same temperature. The emissivity () of a coated surface can be measured by an appropriate laboratory. In principle the emissivity () depends on wavelength, temperature and angle 2. NOTE 1 The emissivity of a material depends on the recording angle of the pyrometer. The observation angle of the pyrometer shall be perpendicular with respect to the specimen to be evaluated. If the specimen to be evaluated is not perpendicular to the observation angle of the pyrometer, a cosine-correction shall be applied. The emissivi
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