Conservation of Cultural Property - Procedures and instruments for measuring temperatures of the air and the surfaces of objects

This European Standard recommends the procedures for measuring the temperature of the air and of the surfaces of cultural property in indoor and outdoor environments, as well as specifying the minimum characteristics of instruments for such measurements. This document contains recommendations for accurate measurements to ensure the safety of objects and it is addressed to any people with the responsibility of the environment, its diagnosis, the conservation or maintenance of buildings, collections, or single object.

Erhaltung des kulturellen Erbes - Verfahren und Geräte zur Messung der Temperatur der Luft und der Oberflächen von Gegenständen

Dieses Dokument legt die Verfahren zur Messung der Temperatur der Luft und der Oberflächen von Gegenständen des kulturellen Erbes in Innen  und Außenumgebungen sowie die mindestens erforderlichen Merkmale der für diese Messungen angewendeten Geräte fest.
Die Norm enthält Angaben für genaue Messungen, die gleichzeitig die höchste Sicherheit für Gegenstände des kulturellen Erbes sicherstellen.

Conservation des biens culturels - Méthodes et instruments de mesure de la température de l'air et de la surface des objets

Le présent document stipule les méthodes de mesure de la température de l’air et de la surface des biens culturels se trouvant dans des environnements intérieurs ou extérieurs, tout en spécifiant les caractéristiques minimales des instruments destinés à effectuer ces mesures.
La norme fournit des indications relatives à des mesurages précis qui garantissent en même temps une protection maximale des objets appartenant au patrimoine.

Ohranjanje kulturne dediščine - Postopki in instrumenti za merjenje temperature zraka in površine predmetov

Ta evropski standard priporoča postopke za merjenje temperature zraka in površine kulturne dediščine v notranjih ali zunanjih okoljih, poleg tega pa določa minimalne karakteristike instrumentov za taka merjenja. Ta dokument vsebuje priporočila za natančne meritve, da se zagotovi varnost predmetov, in je namenjen vsem ljudem, ki so odgovorni za okolje, njegovo diagnozo, konservatorstvo ali vzdrževanje stavb ali posamezen predmet.

General Information

Status
Published
Public Enquiry End Date
30-Apr-2008
Publication Date
07-Nov-2010
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
15-Oct-2010
Due Date
20-Dec-2010
Completion Date
08-Nov-2010

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Erhaltung des kulturellen Erbes - Verfahren und Geräte zur Messung der Temperatur der Luft und der Oberflächen von GegenständenConservation des biens culturels - Méthodes et instruments de mesure de la température de l'air et de la surface des objetsConservation of Cultural Property - Procedures and instruments for measuring temperatures of the air and the surfaces of objects97.195Umetniški in obrtniški izdelkiItems of art and handicrafts17.200.20Instrumenti za merjenje temperatureTemperature-measuring instrumentsICS:Ta slovenski standard je istoveten z:EN 15758:2010SIST EN 15758:2010en,fr,de01-december-2010SIST EN 15758:2010SLOVENSKI

STANDARD
SIST EN 15758:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 15758
September 2010 ICS 97.195 English Version

Conservation of Cultural Property -Procedures and instruments for measuring temperatures of the air and the surfaces of objects

Conservation des biens culturels - Méthodes et instruments de mesure de la température de l'air et de la surface des objets

Erhaltung des kulturellen Erbes - Verfahren und Geräte zur Messung der Temperatur der Luft und der Oberflächen von Gegenständen This European Standard was approved by CEN on 23 July 2010.

CEN members are bound to comply with the CEN/CENELEC 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 the CEN Management Centre 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 CEN Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 15758:2010: ESIST EN 15758:2010

EN 15758:2010 (E) 2 Contents Page Foreword ..............................................................................................................................................................3Introduction .........................................................................................................................................................41 Scope ......................................................................................................................................................52 Normative references ............................................................................................................................53 Terms and definitions ...........................................................................................................................54 Recommendations relating to measuring methods ...........................................................................84.1 Measurement of air temperature ..........................................................................................................84.2 Measurement of the effective temperature including radiant contribution .....................................84.2.1 Black-globe thermometer .....................................................................................................................84.2.2 Measuring temperature with a blackbody strip target .......................................................................85 Measurement of surface temperature .................................................................................................95.1 General ....................................................................................................................................................95.2 Thermometers with contact sensors ...................................................................................................95.3 Infrared thermometers (remote temperature sensors) ................................................................... 105.4 Quasi-contact thermometers ............................................................................................................. 106 Recommendations relating to variations in space of the thermal quantities .............................. 116.1 General ................................................................................................................................................. 116.2 Recommendations relating to variations in time of the thermal quantities ................................. 116.3 Specifications relating to measuring instruments .......................................................................... 117 Calibration ........................................................................................................................................... 11Annex A (normative)

Characteristics of measuring instruments ............................................................... 13Bibliography ..................................................................................................................................................... 14 SIST EN 15758:2010

EN 15758:2010 (E) 3 Foreword This document (EN 15758:2010) has been prepared by Technical Committee CEN/TC 346 “Conservation of Cultural Property”, 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 text or by endorsement, at the latest by March 2011, and conflicting national standards shall be withdrawn at the latest by March 2011. 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 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 15758:2010

EN 15758:2010 (E) 4 Introduction This standard is intended to assist in providing an acceptable environment for tangible cultural heritage. The temperature of the air and of object surfaces constitute important aspects of that environment. Temperature is one of the factors which can have a profound effect on the preservation of objects. Physical characteristics of materials change as they absorb or release heat. Objects expand and contract as the temperature changes, become rigid and brittle if the temperature falls below the glass transition temperature, or are mechanically damaged by the melting and freezing of water. The rates of some important chemical reactions, such as the degradation of cellulose (paper, textiles) increase with rising temperature. Temperature influences the activity of fungi and insects responsible for the bio-deterioration of organic materials. Temperature may affect some minerals and masonry crystallisation. Temperature also has an important indirect effect: a rise in temperature causes lowering of the relative humidity, which results in the drying of moisture absorbing materials such as wood, paper or leather. Such drying may lead to shrinkage and embrittlement. When direct radiation from sun, lamps or radiant heaters reaches objects, the consequent temperature rise causes drying even when the relative humidity of the surrounding air remains constant. Whatever the air temperature, the water vapour may condense on cold surfaces if their temperature drops below the dew point. The control of levels and variability of temperature contributes to a proper environment for cultural property and thereby reduces the risk of deterioration. Such control is an important preventive measure which will minimise the need for future conservation interventions. This standard recommends procedures for measuring the temperature of the air and of the surfaces of cultural property in indoor and outdoor environments as well as specifying the minimum characteristics of instrument for such measurements. Although standards exist for measuring the air or surface temperature in other fields like meteorology, industry or medicine, this standard focuses on the specific requirements of cultural property. One of the main concerns has been the use of non-contact or remote methods to make possible measuring temperatures of fragile and precious surfaces without any physical contact. However, taking measurements of the object surface, whether using contact or non-contact methods, involves a degree of risk to the object and should not be undertaken without clear justification nor without consultation with a suitably qualified and experienced conservator, preferably as part of an interdisciplinary team. This document is one of the series of European Standards intended for use in the study of environments of cultural property. Any measuring system which meets or exceeds the requirements of this European Standard can be used. The description or listing of certain instruments signifies only that they are recommended. It is up to users to analyze the quality of instruments available on the market and verify whether they conform to this document. SIST EN 15758:2010

EN 15758:2010 (E) 5 1 Scope This European Standard recommends the procedures for measuring the temperature of the air and of the surfaces of cultural property in indoor and outdoor environments, as well as specifying the minimum characteristics of instruments for such measurements. This document contains recommendations for accurate measurements to ensure the safety of objects and it is addressed to any people with the responsibility of the environment, its diagnosis, the conservation or maintenance of buildings, collections, or single object. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 7726:2001, Ergonomics of the thermal environment

Instruments for measuring physical quantities (ISO 7726:1998) 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 air temperature

T temperature read on a thermometer which is exposed to air in a position sheltered from direct solar radiation or other energy sources

NOTE This is expressed in degrees Celsius (°C). 3.2 black-globe thermometer thermometer consisting of a black globe in the centre of which is placed a temperature sensor, and which records the effective air-radiant temperature which results from a thermal balance between air temperature, radiation coming from the different heat sources and convective motions 3.3 blackbody strip target low thermal inertia, blackbody target, like a strip of black textile, which assumes an effective air-radiant temperature resulting from a thermal balance between air temperature, radiation coming from light, heat sources and convective motions

NOTE The surface temperature of the blackbody target is then measured with a quasi-contact or a remote thermometer. 3.4 blackbody body which absorbs all the ultraviolet, visible and infrared radiation impinging on it, i.e. having surface emissivity 1 3.5 contact sensor sensor placed in direct physical contact with the surface and devised to reach thermal equilibrium with it

SIST EN 15758:2010

EN 15758:2010 (E) 6 NOTE The sensor may be pressed against the surface or coupled to it with a glue or paste in order to improve the heat exchange and achievement of the thermal equilibrium. 3.6 dew-point temperature temperature to which air is cooled at constant pressure and constant water vapour content in order for saturation to occur

NOTE This is expressed in degrees Celsius (°C). 3.7 emissivity relative power of a surface to emit heat by radiation expressed as the ratio of the radiant energy emitted by a surface to that emitted by a blackbody at the same temperature

NOTE This ranges from 0 to 1. 3.8 infrared thermometer thermometer which permits remote measurements of surface temperature by measuring the flux of infrared radiation emitted and reflected from the target 3.9 measuring range interval of values that are intended to be measured, or that are potentially measurable, or that have been measured, specified by their upper and lower limits 3.10 probe small device placed in or on the object to make measurements or to protect the sensor

NOTE This is usually designed not to influence significantly the result. 3.11 quasi-contact thermometer total radiation thermometer measuring the surface temperature of a target which comprises a sensor located in the focal point of a concave mirror, shielded against the infrared radiation from the surrounding sources

NOTE The thermometer is placed close to the target but not in contact with it. It measures and converts into the temperature the flux of infrared radiation emitted by the target. 3.12 radiometric temperature temperature measured with an infrared thermometer

NOTE This is expressed in degrees Celsius (°C). 3.13 repeatability ability of the measuring instrument to reproduce the same output when successively measuring the same value of the air or the surface under investigation, taken under the same conditions

NOTE This is expressed as ± percent of the range. 3.14 resolution smallest difference between indications of a displaying device that can be meaningfully distinguished SIST EN 15758:2010

EN 15758:2010 (E) 7 3.15 response time time interval between the instant when the air, or the surface temperature, is subjected to a specified abrupt change and the instant when the response reaches and remains within specified limits around its final steady value

NOTE The response time is typically expressed as the time needed to reach 63,2 % of the final value and in this case is called time constant, or 90 % or 95 % of it. The 90 % response time is 2,3 times longer than the time constant and the 95 % response time is three times longer. The response time is independent of the span of the output change. 3.16 sensor device that senses either the absolute value or a change in a physical quantity and converts it into a useful input signal for an information-gathering system 3.17 stability ability of a measuring instrument to keep its metrological characteristics constant over a period of time

NOTE Stability should be expressed in terms of variation of temperature response in a year (°C/yr). 3.18 surface temperature

TS temperature of a given surface of an object

NOTE This can be measured with contact thermometers, quasi-contact total radiation thermometers or remote infrared thermometers. The surface temperature is generally different from the air temperature, and varies between different objects and different places on the same object. It is expressed in degrees Celsius (°C). In general, the measured surface temperature is not representative of the whole object. 3.19 target surface surface being in thermal equilibrium with the sensor

3.20 thermometer instrument to measure temperature which comprises a sensor which is placed in thermal equilibrium with the air (if it measures the air temperature) or the surface, sometimes a probe that contains and protects the sensor, and a system that transforms the input from the sensor into an output expressed in degrees Celsius (°C) 3.21 time constant time interval between the instant when the air, or the surface temperature, is subjected to a specified abrupt change and the instant when the response reaches 1 – 1/e = 0,632 (63,2 %) and remains within specified limits around its final steady value

NOTE See also response time. 3.22 uncertainty (of measurement) uncertainty is a non-negative parameter characterizing the dispersion of the values attributed to a measured quantity SIST EN 15758:2010

EN 15758:2010 (E) 8 4 Recommendations relating to measuring methods 4.1 Measurement of air temperature Measurements should only be taken to answer questions which will help to solve environmental or conservation problems and they should always form part of an overall plan for environmental improvement. Air temperature is monitored to establish a cause-and-effect relationship between atmospheric variables and the response of cultural heritage objects. When measuring air temperature precautions should be taken to reduce the effect of thermal radiation and inertia of the probe. Particular care should be taken to shield the air temperature sensors from radiation sources at different temperature levels, e.g.: direct solar radiation, incandescent lamps or radiant heaters. Screens should be made from reflecting materials and should have adequate natural or forced ventilation as described in EN ISO 7726:2001, Annex A. A thermom

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