1、BRITISH STANDARDBS EN ISO 11844-3:2008Corrosion of metals and alloys Classification of low corrosivity of indoor atmospheres Part 3: Measurement of environmental parameters affecting indoor corrosivityICS 77.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44
2、g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 11844-3:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 May 2006 BSI 2008ISBN 978 0 580 60546 8National forewordTh
3、is British Standard is the UK implementation of EN ISO 11844-3:2006. It is identical with ISO 11844-3:2006. It supersedes BS ISO 11844-3:2006 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/NFE/8, Corrosion of metals and alloys. A list of organiza
4、tions represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations
5、.Amendments/corrigenda issued since publicationDate Comments29 August 2008 This corrigendum renumbers BS ISO 11844-3:2006 as BS EN ISO 11844-3:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 11844-3April 2008ICS 77.060English VersionCorrosion of metals and alloys - Classification of low co
6、rrosivityof indoor atmospheres - Part 3: Measurement of environmentalparameters affecting indoor corrosivity (ISO 11844-3:2006)Corrosion des mtaux et alliages - Classification de lacorrosivit faible des atmosphres dintrieur - Partie 3:Mesurage des paramtres environnementaux affectant lacorrosivit de
7、s atmosphres dintrieur (ISO 11844-3:2006)Korrosion von Metallen und Legierungen - Einteilung derKorrosivitt in Rumen mit geringer Korrosivitt - Teil 3:Messung der Umgebungsparameter, die Korrosivitt inRumen beeinflussen (ISO 11844-3:2006)This European Standard was approved by CEN on 21 March 2008.CE
8、N members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on appli
9、cation 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has
10、 the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portug
11、al,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means rese
12、rvedworldwide for CEN national Members.Ref. No. EN ISO 11844-3:2008: Eii Foreword The text of ISO 11844-3:2006 has been prepared by Technical Committee ISO/TC 156 “Corrosion of metals and alloys” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 11844-3:20
13、08 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings” the secretariat of which is held by BSI. 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 October 2008, and conflicting
14、national standards shall be withdrawn at the latest by October 2008. 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
15、CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania
16、, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 11844-3:2006 has been approved by CEN as a EN ISO 11844-3:2008 without any modification. iiiContents Page Introduction v 1 Sc
17、ope . 1 2 Normative references . 1 3 Principle. 1 4 Environmental parameters 2 5 Humidity and temperature parameters. 2 5.1 Relative humidity 2 5.2 Temperature 2 5.3 Temperaturehumidity complex . 2 6 Airborne gas contaminants . 3 6.1 Principle. 3 6.2 Placing of measuring equipment 3 6.3 Measuring me
18、thods and duration. 3 7 Airborne particle contaminants. 6 7.1 Principle. 6 7.2 Volumetric measurements. 6 7.3 Measurement of particle deposits. 7 Annex A (informative) Reagents used for both passive and active samplers. 8 Bibliography . 10 BS EN ISO 11844-3:2008blankvIntroduction This part of ISO 11
19、844 deals with environmental parameters for the characterisation of indoor atmospheres and methods of measurement. The environmental parameters for the characterisation of indoor atmospheres include more airborne contaminants than are normally used for the characterisation of the outdoor environment
20、. Measurement of environmental parameters is a way of characterising the corrosivity of the indoor atmosphere and will always be required if it is necessary to consider measures for reducing the corrosivity. BS EN ISO 11844-3:2008blank1Corrosion of metals and alloys Classification of low corrosivity
21、 of indoor atmospheres Part 3: Measurement of environmental parameters affecting indoor corrosivity 1 Scope This part of ISO 11844 describes methods for measuring the environmental parameters used to classify the corrosivity of indoor atmospheres on metals and alloys. 2 Normative references The foll
22、owing 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. ISO 7708:1995, Air quality Particle size fraction definit
23、ions for health-related sampling ISO 9225:1992, Corrosion of metals and alloys Corrosivity of atmospheres Measurement of pollution ISO 11844-1, Corrosion of metals and alloys Classification of low corrosivity of indoor atmospheres Part 1: Determination and estimation of indoor corrosivity EN 12341:1
24、998, Air quality Determination of the PM10fraction of suspended particulate matter Reference method and field test procedure to demonstrate reference equivalence of measurement methods 3 Principle Different combinations of parameters affect the corrosivity of indoor atmospheres. Knowledge about poss
25、ible sources of environmental effects must be obtained before decisions regarding the type of measurements needed are taken. The characterisation of indoor atmospheric corrosivity using environmental parameters is more complicated than measuring the corrosivity with metal specimens. However, in many
26、 cases, measurement of environmental parameters can give a good indication of how to establish the corrosivity of an environment and will, in combination with the information given in ISO 11844-1, give a good indication of the corrosivity categories for the materials in the selected environment. BS
27、EN ISO 11844-3:20082 4 Environmental parameters In indoor atmospheres, corrosion processes are characterised by a more complex group of parameters than in outdoor atmospheres. In general, two groups of parameters should be measured: humidity and temperature; airborne contaminants, such as gases and
28、particles. Fluctuation in the temperature and humidity, particularly at higher humidity levels, may cause condensation on cooler surfaces. The frequency and time of condensation is an important factor for indoor corrosion. The corrosion effects from these groups of parameters are usually interdepend
29、ent. A particular level of humidity is needed before corrosion begins, and this can vary for different contaminants. Combinations of contaminants might accelerate the corrosion processes. 5 Humidity and temperature parameters 5.1 Relative humidity Use continuous measuring devices such as hygrographs
30、, thermohygrographs or logging hygrometers. The measuring period is preferably one year, to cover seasonal variations. If shorter measuring periods are needed, select a measuring period where large variations in the relative humidity are expected. The period shall be at least one month per season. T
31、he data shall be reported as monthly values. The average, maximum and minimum values for each month shall be reported. The calculation of time with relative humidity in given intervals represents useful information. 5.2 Temperature Use continuous measuring devices such as thermohygrographs or loggin
32、g thermometers. The measuring period is preferably one year, to cover seasonal variations. If shorter measuring periods are needed, select a measuring period where large variations in the temperature are expected. The period shall be at least one month per season. The data shall be reported as month
33、ly values. The average, maximum and minimum values for each month shall be reported. The calculation of time with temperature in given intervals represents useful information. 5.3 Temperaturehumidity complex Continuous measurements of temperature and humidity give data for the calculation of frequen
34、cy and time with condensation. BS EN ISO 11844-3:200836 Airborne gas contaminants 6.1 Principle The gas concentration or deposition can be measured by several techniques: continuous gas-concentration measuring instruments; average gas concentration with an active sampler and air pump; average gas co
35、ncentration with a passive sampler; average gas-deposition equipment. The results from concentration measurements are typically given in g/m3and for deposition measurements as mg/m2.d. The results obtained from the two types of measurements can be difficult to compare. 6.2 Placing of measuring equip
36、ment The corrosivity of the indoor atmosphere may vary dramatically from one point to another in a room. Cooler areas may have moisture condensation with a high corrosion effect. Corners often have higher contaminant concentrations and lower air circulation than the rest of the room. If the problem
37、is located in a specific area, measurements shall be performed in that location. If the problem is more general, then measurements should be made in a central open area in the room. 6.2.1 Continuous gas-measuring instruments The instrument shall be placed so it is protected from unauthorised people.
38、 Polyethylene or polytetrafluoroethene (PTFE) tubing can be used to collect the air sample from the selected area of the room. The length of the tubing should not exceed 2 m. 6.2.2 Active sampler The active sampler shall be placed according to the same rules as the continuous gas-measuring instrumen
39、t. 6.2.3 Passive sampler The passive sampler shall be placed in a part of the room where there is free movement of air. The sampling device shall be placed with the open end facing downward. 6.2.4 Gas-deposition equipment The equipment shall be placed in a part of the room where there is free moveme
40、nt of air. The equipment shall be sheltered from settling particles that can interfere with the analyses of the gases. 6.3 Measuring methods and duration 6.3.1 Continuous measurement The measurements shall preferably be carried out for one year to record the seasonal variation of the gas pollutants.
41、 The data from continuous measuring instruments shall be reported as monthly average values, together with the maximum and minimum values of the month. Standard instruments have detection limits in a range from 4 105to 1 106volume fractions. Specially designed instruments may have detection limits o
42、f one-tenth of these values. BS EN ISO 11844-3:20084 6.3.2 Measurement and calculation with the active sampler The methods are based on pumping air through an absorption unit with a reactive surface or liquid, with subsequent laboratory analysis of the amount absorbed. The result will be given as an
43、 average concentration for the sampling period. The sampling time shall be one week or longer. The sampling period is preferably one year, or at least one month for each season of the year. With active samplers, the volume of air (V) is known. The average concentration (C) is then mCV= (1) where C i
44、s the average concentration, in g/m3; m is the gas absorbed, in g; V is the air passed through the absorption unit, in m3. The data shall be collected weekly and reported as average weekly values, and converted to average monthly values for four weeks. The maximum and minimum values for the period s
45、hall also be reported. NOTE The detection limits for air concentrations depend on the sensitivity of the analysing instruments and the duration of the sampling. The normal sensitivity for the instrument is 0,01 g/cm3and weekly mean values with detection limits better than 0,1 g/m3can easily be obtai
46、ned. 6.3.3 Measurement and calculation with the passive sampler Mean gas concentrations can be calculated using passive sampling devices. The principle used for passive sampling is shown in Figure 1. Key 1 absorbent 2 tube 3 permeable screen for gases C1is the ambient concentration of gas C0is the c
47、oncentration of gas at the absorbent equal zero Figure 1 Principle of construction of a passive-sampling device BS EN ISO 11844-3:20085The basic idea for the use of passive samplers is that Ficks first law for gas diffusion applies inside the tube. Ficks first law is valid if the air inside the tube
48、 is stagnant and the absorbent in the upper end of the tube will completely absorb the gas that reaches the surface. 11ddCFDz= (2) where F1is the flux of gas(amount of net transported gas per time and area); D1is the diffusion coefficient for gasin area per time; dC/dz is the concentration gradient
49、that is negative to the flow direction. When D1is known and the absorbed amount (Q) of gas pollutant is measured, Ficks law can be transformed to 11QzCD At=(3) where Q is the total amount of gas absorbed, in g; C1is the concentration of gas in air, in g/cm3; A is the area of absorbent, in cm2; t is the exposure time, in seconds; D1is the diffusion coefficient for gas, in cm2/s;z is the length of diffusion, in cm. D1for gases in air is temperature dependent. However the adjustment is minor in normal climates. The
