DIN 50934-2-2000 Corrosion of metals - Methods for evaluation of efficiency of water treatment apparatus for corrosion protection - Part 2 Apparatus for decreasing of emission of c.pdf

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1、ICS 77.060Korrosion der Metalle Verfahren zur Beurteilung der Wirksamkeit von Wasserbehandlungsanlagen zumKorrosionsschutz Teil 2: Anlagen zur Verminderung der Abgabe von Korrosionsprodukten an das Trink-wasserForewordThis standard has been prepared by Technical Committee Korrosion und Korrosionssch

2、utz of the Normen-ausschuss Materialprfung (Materials Testing Standards Committee).Ref. No. DIN 50934-2 : 2000-04English price group 05 Sales No. 010503.01DEUTSCHE NORM April 200050934-2Continued on pages 2 to 4. No part of this translation may be reproduced without the prior permission ofDIN Deutsc

3、hes Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).Methods of evaluating the effectiveness of watertreatment equipment for corrosion controlPart 2: Equipment for reducing the release of corrosion productsin

4、to drinking waterTranslation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.All dimensions are in millimetres.1 ScopeThe standard specifies a method of evaluating the effectiveness of water treatment equipment used toreduce the rele

5、ase of corrosion products (scale) from system components into the drinking water. Suchcomponents include valves, tanks and reservoirs, pipes and pipe fittings.Since this type of treatment equipment can be used for more than one component material, the effectivenessof the equipment is to be tested se

6、parately for each material.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the titles of the publications arelisted below. For dated references, subsequ

7、ent amendments to or revisions of any of these publicationsapply to this standard only when incorporated in it by amendment or revision. For undated references, thelatest edition of the publication referred to applies.DIN 2440 Medium-weight threaded steel pipesDIN 17457 Welded circular austenitic st

8、ainless steel tubes subject to special requirements Technicaldelivery conditionsDIN 17458 Seamless circular austenitic stainless steel tubes subject to special requirements Techni-cal delivery conditionsDIN 50930-1 Corrosion behaviour of metallic materials in contact with water GeneralDIN 50930-2 Co

9、rrosion behaviour of metallic materials in contact with water Assessing unalloyed andlow-alloy ferrous materialsDIN 50930-3 Corrosion behaviour of metallic materials in contact with water Assessing hot-dip galva-nized ferrous materialsDIN 50930-4 Corrosion behaviour of metallic materials in contact

10、with water Assessing stainless steelDIN 50930-5 Corrosion behaviour of metallic materials in contact with water Assessing copper andcopper alloysDIN 50931-1 Corrosion testing of drinking water distribution systems Determining changes to the com-position of drinking waterDIN 50934-1 Methods of evalua

11、ting the effectiveness of water treatment equipment for corrosion control GeneralIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.Page 2DIN 50934-2 : 2000-04DIN EN 1057 Copper an

12、d copper alloys Seamless, round copper tubes for water and gas in sanitary andheating applicationsDIN EN 10240 Internal and/or external protective coatings for steel tubes Specification for hot dip galva-nized coatings applied in automatic plantsDIN EN ISO 8044 Corrosion of metals and alloys Basic t

13、erms and definitions (ISO 8044 : 1999)Trinkwasserverordnung (German Drinking Water Regulation), as of 5 December 1990, BGBl. (German FederalLaw Gazette) I, No. 66, pp. 26132629, amended by BGBl. I, 1991, No.7, p.2273 ConceptsFor the purposes of this standard, the concepts defined in DIN EN ISO 8044,

14、 DIN 50930-1 to DIN 50930-5 andDIN 50934-1 apply, as well as the following.Water treatment equipmentAll components and media used to inhibit corrosion within a drinking water system.4 Effects of corrosion on water-related parametersThe concentration of corrosion products in water not only depends on

15、 the water-related parameters andtemperature, and the characteristics of materials used in the system, but also to a greater extent on thelength of time water stagnates in the system. The age of the system is also an influencing factor. An evaluationof the effectiveness of corrosion control equipmen

16、t must therefore expressly consider stagnation and systemage. In general, it may be assumed that the concentration of corrosion products in the water is greater in newersystems than in older ones. Single values obtained in water analyses are unsuitable for evaluation, which shouldbe based, instead,

17、on several values obtained under specified conditions; this principle extends to the testmethod described here.Another factor which influences the concentration of corrosion products is the ratio of the component surfacearea to the water volume, which is generally determined by the pipe diameter. Pi

18、pe diameters and specimendimensions are therefore specified here.Testing is to be performed using cold water.5 Test pipes, specimens, and reagent water5.1 Test pipesStandardized, commercially available pipes are to be used for testing the pipe material.5.1.1 Hot dip galvanized steel pipesSteel pipes

19、 of a nominal size as in DIN 2440, hot dip galvanized as in DIN EN 10240, shall be used.5.1.2 Copper pipesTest pipes shall be 15 mm 1 mm copper pipes of tensile strength hard (R290) as in DIN EN 1057.5.2 SpecimensWhen testing the material of components other than pipes, specimens shall be of the rel

20、evant material, and havea 120 mm length and an internal diameter of 17 mm (cf. figure 1).5.3 Reagent water5.3.1 GeneralThe concentrations of components of the reagent water should lie as close to the critical limits of the operatingrange as possible, while still lying within the range (cf. DIN 50930

21、), ensuring that the strongest effects to beexpected will occur during testing.Since this is a comparison test, all parameters not specified in subclauses 5.3.2 and 5.3.3 may be freelyselected, although they are to lie within the limits prescribed in the Trinkwasserverordnung.The reagent water may b

22、e taken from the public system, provided it meets the requirements of subclause 5.3.2or 5.3.3, or has been adjusted to meet these requirements.5.3.2 Reagent water for hot dip galvanized steelReagent water for testing hot dip galvanized steel materials shall have the following parameters:Base capacit

23、y, KB8,20,5 mmol/lpH 6,5 or higherElectrical conductivity between 250 mS/cm and 1000 mS/cmOrthophosphate content lower than 0,3 mg/l (as )Zinc content 0,2 mg/l or lower-34POPage 3DIN 50934-2 : 2000-045.3.3 Reagent water for copper or copper alloysReagent water for testing copper materials shall have

24、 the following parameters:Base capacity, KB8,21,0 mmol/lpH 6,5 or higherElectrical conductivity between 250 mS/cm and 1000 mS/cmOrthophosphate content lower than 0,3 mg/l (as -34PO )Copper content 0,05 mg/l or lower6 Procedure6.1 Test assembliesSeveral assemblies are to be set up simultaneously. The

25、 assemblies for testing pipe materials shall comprisea (3 t 0,1) m long pipe as specified in subclause 5.1.When testing nonferrous metals, five specimens as in subclause 5.1.2 shall be assembled together with shortpipe sections of grade X6CrNiMoTi17-12-2 steel (material no. 1.4571) as in DIN 17457 a

26、nd DIN 17458 to formone specimen with a (3 t 0,1) m total length. Include plastic insulating pieces to prevent contact corrosion.Arrange the assemblies so that they are parallel, with an inclination of (4 t 2) cm/m. Introduce the reagent waterinto the upper end of the assembly, with a pressure no gr

27、eater than 2,5 bar. Ensure that the pressure is the samefor both assemblies.Install the water treatment equipment under test between the tank containing the reagent water and the testassemblies (at least two), following the manufacturers instructions. At the same time, feed untreated water intothe s

28、ame number and same type of assemblies, taking care that the hydraulic conditions are the same for eachassembly (i.e. by using a pressure equalizing device). The tank with the reagent water is to have an outlet forsampling.Mount a drain valve at the bottom end of each assembly, through which water w

29、ill flow while the assembly isbeing operated. The valve shall be opened and closed by means of a time switch. In addition, there is to be asampling point located upstream of the valve.The surfaces of all valves and fittings which come in contact with the water shall be made of an inert material(e.g.

30、 plastic or stainless steel).6.2 Operating test assembliesA time switch at the outlet valve shall control the operation of the test assemblies, according to a specifiedschedule, such as that given in table 1 of DIN 50931-1, which approximates operating conditions in practicewhen a water tap is used

31、regularly throughout one day.Figure 1: Specimen assemblyPage 4DIN 50934-2 : 2000-046.3 Sampling6.3.1 Sampling of reagent waterSampling frequency and the analytical method used will depend on the system under test. To monitor the qualityof the reagent water, continually measure its temperature, pH va

32、lue and conductivity.6.3.2 Sampling of stagnant water6.3.2.1 ProcedureSampling may be performed with the system pressurized or unpressurized. In the latter case, the valve betweenthe test assembly and the supply line or storage tank shall be closed, the appropriate air release valve opened,and the s

33、ample taken.Each sample should have a volume equivalent to the volume of the relevant assembly, taking care to maintainthe flow at the rate specified in table 1 of DIN 50931-1. It is essential that the volumes of the samples taken fromthe test assembly and from the assembly to which it is compared a

34、re the same. The quantities taken shall berecorded for each assembly.6.3.2.2 Time and frequency of samplingSampling of stagnant water shall be as specified in Appendix A or B of DIN 50931-1, and shall be carried outat three intervals of one week, starting at six months after commissioning of the sys

35、tem. Between samplingintervals, operation of the test assemblies shall be continued, as specified in subclause 5.3 of DIN 50931-1.If the water is stagnant for more than 16 hours, analysis shall not be carried out.7 Evaluation of resultsTo determine the extent to which the release of corrosion produc

36、ts into the water has been reduced, determinethe amounts of the relevant metals in the samples of stagnant water taken as in subclause 6.3.2.8 Test reportThe test report shall refer to this standard and contain the following information:a) type of water treatment equipment tested;b) type of material used for testing;c) corrosion products tested for;d) number of test assemblies used;e) analysis of reagent water;f) effectiveness of water treatment equipment determined.