1、BRITISH STANDARDBS EN ISO 11844-2:2008Corrosion of metals and alloys Classification of low corrosivity of indoor atmospheres Part 2: Determination of corrosion attack in indoor atmospheresICS 77.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g5
2、9g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 11844-2:2008This British Standard was published under the authority of the Standards Policy and Strategy Committee on 25 January 2006 BSI 2008ISBN 978 0 580 60545 1National forewordThis Britis
3、h Standard is the UK implementation of EN ISO 11844-2:2008. It is identical with ISO 11844-2:2005. It supersedes BS ISO 11844-2:2005 which is withdrawn.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 organizations rep
4、resented 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.Amendmen
5、ts/corrigenda issued since publicationDate Comments29 August 2008 This corrigendum renumbers BS ISO 11844-2:2005 as BS EN ISO 11844-2:2008EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 11844-2April 2008ICS 77.060English VersionCorrosion of metals and alloys - Classification of low corrosivity
6、of indoor atmospheres - Part 2: Determination of corrosionattack in indoor atmospheres (ISO 11844-2:2005)Corrosion des mtaux et alliages - Classification de lacorrosivit faible des atmosphres dintrieur - Partie 2:Dtermination de lattaque par corrosion dans lesatmosphres dintrieur (ISO 11844-2:2005)K
7、orrosion von Metallen und Legierungen - Einteilung derKorrosivitt in Rumen mit geringer Korrosivitt - Teil 2:Bestimmung der korrosiven Belastung in Rumen (ISO11844-2:2005)This European Standard was approved by CEN on 21 March 2008.CEN members are bound to comply with the CEN/CENELEC Internal Regulat
8、ions 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 application to the CEN Management Centre or to any CEN member.This Europ
9、ean 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 the same status as theofficial versions.CEN members are the nation
10、al 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, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and Unit
11、ed 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 reservedworldwide for CEN national Members.Ref. No. EN ISO 11844-2:2008
12、: Eii Foreword The text of ISO 11844-2:2005 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 11844-2:2008 by Technical Committee CEN/TC 262 “Metallic and other inorganic
13、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 national standards shall be withdrawn at the latest by October 2008
14、. 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 organizati
15、ons 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, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania
16、, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 11844-2:2005 has been approved by CEN as a EN ISO 11844-2:2008 without any modification. iiiContents Page Introduction v 1 Scope 1 2 Normative references 1 3 Principle1 4 Methods 1 Annex A (no
17、rmative) Determination of corrosion rate by mass change measurement 4 Annex B (normative) Determination of corrosion rate by electrolytic cathodic reduction .7 Annex C (informative) Determination of corrosion rate by resistance measurements .9 Bibliography 11 BS EN ISO 11844-2:2008blankvIntroduction
18、 This part of ISO 11844 describes standard specimens, their exposure and evaluation for the derivation of the indoor corrosivity categories. The determination of the corrosion attack is, at the present state of knowledge, the most reliable way, and usually also an economical way, for evaluation of c
19、orrosivity taking into account all main local environmental influences. BS EN ISO 11844-2:2008blank1Corrosion of metals and alloys Classification of low corrosivity of indoor atmospheres Part 2: Determination of corrosion attack in indoor atmospheres 1 Scope This part of ISO 11844 specifies methods
20、for determination of corrosion rate with standard specimens of metals in indoor atmospheres with low corrosivity. For this direct method of evaluation of corrosivity, different sensitive methods can be applied using standard specimens of the following metals: copper, silver, zinc and steel. The valu
21、es obtained from the measurements are used as classification criteria for the determination of indoor atmospheric corrosivity. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For u
22、ndated references, the latest edition of the referenced document (including any amendments) applies. IEC 60654-4:1987, Operating conditions for industrial-process measurement and control equipment Part 4: Corrosive and erosive influences ANSI/ISA-S71.04:1985, Environmental conditions for Process, Me
23、asurement and Control Systems: Airborne Contaminants 3 Principle The corrosivity of the indoor location, e.g. control rooms, electric boxes, storage rooms, during transportation, in museums, etc., is determined from the corrosion rate calculated from the mass change or resistance change per unit are
24、a of standard specimens of metals after exposure for a certain time period. Different materials are sensitive to different environmental parameters or their combinations. 4 Methods The following methods described in Annexes A and B are available for evaluation of the corrosion attack: Determination
25、of corrosion rate by mass change measurements (Annex A) Determination of corrosion rate by electrolytic cathodic reduction (Annex B) The method described in informative Annex C is suitable for continuous or periodic monitoring of the corrosion attack: Determination of corrosion rate by resistance me
26、asurements (Annex C) BS EN ISO 11844-2:20082 Special features of the methods, such as sensitivity, possibility for continuous or periodic assessment of corrosion attack, available space, etc., should be considered when choosing the most suitable methods. Examples of suitable racks for exposure of sp
27、ecimens are given in Figure 1. Dimensions in millimetres Key 1 specimens 2 support 15 a) Sketch of a rack for sheltered exposure of specimens Figure 1 Examples of exposure racks with suggested dimensions BS EN ISO 11844-2:20083Dimensions in millimetres Key 1 specimens 2 distance pins 3 plastic plate
28、s 4 open air flow 5 plastic screws b) Sketch of a mounting plate for unsheltered exposure of specimens Figure 1 (continued) BS EN ISO 11844-2:20084 Annex A (normative) Determination of corrosion rate by mass change measurement A.1 Principle Mass increase measurements can be performed on all metals a
29、nd comparatively large surfaces can be evaluated. The technique is relatively easy to operate. The mass loss determination gives a best estimate of the corrosion effect. The method is not yet applicable to all metals. Both mass increase and mass loss determination using an ultramicro-balance has a p
30、recision of about 10 mg/m2with the method described below. Due to the difficulty of distinguishing corrosion effects from other surface-related phenomena, such as sorption and contamination by particulate matter, the specimens should preferably be exposed under shelter. A.2 Specimens It is preferabl
31、e to use rectangular specimens in the form of flat sheets, as they can be readily weighed. A convenient specimen size is 10 mm 50 mm. Specimens may be larger provided that they can be accurately weighed. The specimen thickness may preferably be 0,5 mm. The materials used to prepare the specimens are
32、 of the following quality, Silver: 99,98 % min. Copper: ISO 1336-1337, Cu-DHP, 99,85 % min. Zinc: 99,45 % min. Carbon steel: ISO 3574, CR 1, max. 0,15 % C, max. 0,04 % P, max . 0,05 % S, max. 0,6 % Mn The specimens should, before weighing, be prepared as follows: a) A hole with diameter 4 mm is cut
33、at the upper side of the specimen. b) Abrading1) Silver and copper with silicon carbide paper to 1 200 P (600 grit). Zinc and carbon steel to 500 P (320 grit). c) Cleaning in deionised water. d) Degreasing in ethanol in an ultrasonic bath for 5 min. e) Drying. 1) To avoid risk of contamination, an a
34、brading paper must not be used for polishing specimens of different metals. BS EN ISO 11844-2:20085f) Store in plastic tubes with a hole in the top. The plastic tubes are placed in a desiccator or sealed into plastic bags with desiccant before and after the weighing and the exposure. After final sur
35、face cleaning before exposure, it is important that limited handling occurs. Before and after weighing, the specimens are placed in tubes and are only handled with a clean pair of tweezers. To avoid marking on the specimens, the identity of the specimens may preferably be marked on the tubes. A.3 Ex
36、posure The specimens shall be exposed vertically, either with or without a shelter against settling particles (see Figure 1). The specimens shall be mounted between plastic plates or racks to permit free air circulation. A distance of a minimum of 10 mm between the surfaces and/or the surface and th
37、e mounting plate is recommended. The plastic racks or mounting plates are placed at a site with free air circulation, preferably at a height of 1 m above the floor. The exposure should be performed in an area with airflow rates characteristic of the site. A map of specimen identity on the plastic ra
38、ck, exposure date and location of the exposure rack should be established. The type of exposure, with or without a shelter, should be noted. The test specimens (at least three) should be exposed preferably for one year but at least for six months. A.4 Mass increase The specimens shall be weighed on
39、a micro-balance, with an accuracy of 0,1 g. Each test specimen is weighed twice in relation to a reference balance standard of stainless steel having a similar mass to the specimen. The difference between the first mass of the test specimen m1and the reference balance standard mr,1is calculated as (
40、mr,1 m1), and the difference between the second masses (mr,2 m2) is calculated in the same way. The mass of the test specimen is calculated in relation to the reference specimen as the average of the differences (m): r,1 1 r,2 2()( )2mm m mm+ = where m is the mass of the test specimen in relation to
41、 the reference balance standard, in mg; m1is the mass of the test specimen at first weighing, in mg; m2is the mass of the test specimen at second weighing, in mg; mr,1is the mass of the reference balance standard at first weighing, in mg; mr,2is the mass of the reference balance standard at second w
42、eighing, in mg. The same weighing procedure is performed both before and after the exposure of the specimens. After the exposure, the specimens should be carefully blown with oil-free compressed air or nitrogen to remove dust before the weighing. The rate of mass increase for each metal is given by
43、the following equation: ae bemimmrAt=BS EN ISO 11844-2:20086 where rmiis the rate of mass increase in mg/m2a maeis the mass of the test specimen in relation to the reference balance standard after exposure, in mg; mbeis the mass of the test specimen in relation to the reference balance standard befo
44、re exposure, in mg; A is the surface area including both sides and edges, in m2; t is the exposure time; in years (with the unit symbol a). A.5 Mass loss The specimens shall be weighed on a micro-balance, with an accuracy of 0,1 g. The specimens are weighed in relation to a reference balance standar
45、d of stainless steel before exposure, see the description in Clause 3. After the exposure, the specimens are pickled in the following solutions: Silver: 750 ml hydrochloric acid (HCl, density = 1,18 g/ml). Distilled water to make up to 1 000 ml Copper: aqueous amidosulfonic acid (sulfamic acid) with
46、 a volume fraction of 5 % Zinc: saturated glycine solution Carbon steel: concentrated hydrochloric acid, 20 g/l Sb2O3, 50 g/l SnCl2. Measurement of the mass after repetitive cleaning cycles is the normal method for determining the mass loss of corroded specimens (see ISO 8407). In this part of ISO 1
47、1844, however, a simplified procedure with the use of a blank is recommended, since the weighing of specimens on a micro-balance requires significant time compared to the usual weighing procedure. The pickling time depends on the severity of the corrosion attack but is usually 1 min to 2 min. The ti
48、me should be long enough to ensure that the sample is clean and all corrosion products have been removed. During the pickling, an unexposed specimen (blank) of each material shall be included. After the pickling, the specimens are weighed on the micro-balance, using the same procedure as before expo
49、sure. The mass loss of the unexposed specimen, which shows the loss of base material during the pickling, should be withdrawn from the mass loss of the pickled specimens. The corrosion rate is given by the following equation: be ap bp-blank ap-blankcorr()( )mm m mrAt =where rcorris the corrosion rate, in mg/m2a; mbeis the mass of the specimen in relation to the reference specimen before exposure, in mg; mapis the mass of the specimen in relation to the reference specimen after pickling, in mg; mbp-blankis the mass of the bl
