SIST EN 12502-5:2005
(Main)Protection of metallic materials against corrosion - Guidance on the assessment of corrosion likelihood in water distribution and storage systems - Part 5: Influencing factors for cast iron, unalloyed and low alloyed steels
Protection of metallic materials against corrosion - Guidance on the assessment of corrosion likelihood in water distribution and storage systems - Part 5: Influencing factors for cast iron, unalloyed and low alloyed steels
This document reviews the influencing factors for the corrosion likelihood of bare unalloyed or low alloyed ferrous materials (mild steels and cast irons) used as tubes, tanks and equipment in water distribution and storage systems, except for water intended for human consumption.
NOTE See EN 12502-1.
Korrosionsschutz metallischer Werkstoffe - Hinweise zur Abschätzung der Korrosionswahrscheinlichkeit in Wasserverteilungs- und speichersystemen - Teil 5: Einflussfaktoren für Gusseisen, unlegierte und niedriglegierte Stähle
Dieses Dokument gibt einen Überblick über die Einflussfaktoren für die Korrosionswahrscheinlichkeit von unlegierten und niedriglegierten Eisenwerkstoffen (Stahl und Gusseisen), die als Rohre, Behälter und Apparate in Wasserverteilungs- und -speichersystemen mit Ausnahme von Wässern, die für den menschlichen Gebrauch bestimmt sind, eingesetzt werden.
ANMERKUNG Siehe prEN 12502-1:2004.
Protection des matériaux métalliques contre la corrosion - Recommandations pour l'évaluation du risque de corrosion dans les installations de distribution et de stockage d'eau - Partie 5 : Facteurs a considérer pour la fonte, les aciers non alliés et faiblement alliés
Le présent document étudie les facteurs d'influence du risque de corrosion des tubes, réservoirs et équipements composés de matériaux ferreux (aciers doux et fontes) non alliés ou faiblement alliés, sans revetement, dans les installations de distribution et stockage d'eau, excepté l'eau destinée a la consommation humaine
NOTE Voir prEN 12502-1.
Protikorozijska zaščita kovinskih materialov - Navodilo za ocenjevanje verjetnosti nastanka korozije v porazdeljeni vodi in skladiščnih sistemih - 5. del: Vplivni dejavniki za lito železo, nelegirana in malolegirana jekla
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Korrosionsschutz metallischer Werkstoffe - Hinweise zur Abschätzung der Korrosionswahrscheinlichkeit in Wasserverteilungs- und
speichersystemen - Teil 5: Einflussfaktoren für Gusseisen, unlegierte und niedriglegierte StähleProtection des matériaux métalliques contre la corrosion - Recommandations pour l'évaluation du risque de corrosion dans les installations de distribution et de stockage d'eau - Partie 5 : Facteurs a considérer pour la fonte, les aciers non alliés et faiblement alliésProtection of metallic materials against corrosion - Guidance on the assessment of corrosion likelihood in water distribution and storage systems - Part 5: Influencing factors for cast iron, unalloyed and low alloyed steels91.140.60Sistemi za oskrbo z vodoWater supply systems77.060Korozija kovinCorrosion of metals23.040.99Drugi sestavni deli za cevovodeOther pipeline componentsICS:Ta slovenski standard je istoveten z:EN 12502-5:2004SIST EN 12502-5:2005en01-marec-2005SIST EN 12502-5:2005SLOVENSKI
STANDARD
SIST EN 12502-5:2005
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12502-5December 2004ICS 77.060; 23.040.99; 91.140.60English versionProtection of metallic materials against corrosion - Guidance onthe assessment of corrosion likelihood in water distribution andstorage systems - Part 5: Influencing factors for cast iron,unalloyed and low alloyed steelsProtection des matériaux métalliques contre la corrosion -Recommandations pour l'évaluation du risque de corrosiondans les installations de distribution et stockage d'eau -Partie 5 : Facteurs à considérer pour la fonte, les aciersnon alliés et faiblement alliésKorrosionsschutz metallischer Werkstoffe - Hinweise zurAbschätzung der Korrosionswahrscheinlichkeit inWasserverteilungs- und
speichersystemen - Teil 5:Einflussfaktoren für Gusseisen, unlegierte undniedriglegierte StähleThis European Standard was approved by CEN on 22 November 2004.CEN 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 application to the Central Secretariat 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 Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2004 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12502-5:2004: ESIST EN 12502-5:2005
EN 12502-5:2004 (E) 2 Contents Page Foreword.3 Introduction.4 1 Scope.5 2 Normative references.5 3 Terms, definitions, and symbols.5 3.1 Terms and definitions.5 3.2 Symbols.5 4 Types of corrosion.5 4.1 General.5 4.2 Uniform corrosion.6 4.3 Pitting corrosion.7 4.4 Selective corrosion.8 4.5 Bimetallic corrosion.9 4.6 Erosion corrosion.10 5 Assessment of corrosion likelihood.11 Bibliography.12
SIST EN 12502-5:2005
EN 12502-5:2004 (E) 3 Foreword This document (EN 12502-5:2004) has been prepared 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 June 2005, and conflicting national standards shall be withdrawn at the latest by June 2005. This standard is in five parts: Part 1: General Part 2: Influencing factors for copper and copper alloys Part 3: Influencing factors for hot dip galvanised ferrous materials
Part 4: Influencing factors for stainless steels Part 5: Influencing factors for cast iron, unalloyed and low alloyed steels Together these five parts constitute a package of interrelated European Standards with a common date of withdrawal (dow) of 2005-06. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
SIST EN 12502-5:2005
EN 12502-5:2004 (E) 4 Introduction This document mainly results from investigations into and experiences gained of the corrosion of unalloyed and low alloyed ferrous materials (steels and cast irons) in contact with supply waters and raw waters in once-through flow systems. The corrosion likelihood of unalloyed and low alloy ferrous materials (steels and cast irons) in contact with water depends on the layers built up from corrosion products that might or might not be protective. When layers are present that are not protective, tuberculation can appear on the walls of the components and can lead to corrosion effects such as: sludge in water, colouring (red or black water), reduction of free section of pipes or even wall perforation.
As a result of the complex interactions between the various influencing factors, the extent of corrosion can only be expressed in terms of likelihood. This document is a guidance document and does not set explicit rules for the use of unalloyed and low alloy ferrous materials in water systems. It can be used to minimize the likelihood of corrosion damages occurring by: assisting in designing, installing and operating systems from an anti-corrosion point of view; evaluating the need for additional corrosion protection methods for a new or existing system; assisting in failure analysis, when failures occur in order to prevent repeat failures occurring. However, a corrosion expert, or at least a person with technical training and experience in the corrosion field is required to give an accurate assessment of corrosion likelihood or failure analysis.
SIST EN 12502-5:2005
EN 12502-5:2004 (E) 5 1 Scope This document reviews the influencing factors for the corrosion likelihood of bare unalloyed or low alloyed ferrous materials (mild steels and cast irons) used as tubes, tanks and equipment in water distribution and storage systems, except for water intended for human consumption.
NOTE See EN 12502-1. 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 12502-1:2004, Protection of metallic materials against corrosion — Guidance on the assessment of corrosion likelihood in water distribution and storage systems — Part 1: General. EN ISO 8044:1999, Corrosion of metals and alloys — Basic terms and definitions (ISO 8044:1999). 3 Terms, definitions, and symbols 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in EN ISO 8044:1999 and EN 12502-1:2004 apply. 3.2 Symbols c(O2)
concentration of oxygen in mmol/l c(HCO3-)
concentration of hydrogen carbonate ions in mmol/l c(Ca2+)
concentration of calcium ions in mmol/l 4 Types of corrosion 4.1 General The most common types of corrosion are described in EN 12502-1:2004, Clause 4.
The types of corrosion considered for steels and cast irons are the following: uniform corrosion; pitting corrosion; selective corrosion; bimetallic corrosion; erosion corrosion. SIST EN 12502-5:2005
EN 12502-5:2004 (E) 6 For each type of corrosion, the following influencing factors (described in EN 12502-1:2004, Table 1 and Clause 5) are considered: characteristics of the metallic material; characteristics of the water; design and construction; pressure testing and commissioning; operating conditions. 4.2 Uniform corrosion 4.2.1 General Uniform corrosion of steel and cast iron is associated with the transfer of iron (II) ions into the water (metal loss). These ions dissolved in the water can react with oxygen to form less soluble iron (II)-(III)-hydroxy compounds leading to turbidity and sludge formation. These corrosion effects usually do not lead to corrosion damages. Under flowing conditions with waters containing sufficient amounts of calcium carbonate, protective layers consisting of calcium carbonate and hydrated iron oxides can be formed if the intensity of localized corrosion is low enough. With similar waters under stagnant conditions, localized corrosion always occurs. 4.2.2 Influence of the characteristics of the metallic material The chemical composition and microstructure of these materials as well as the cold deformation have virtually no influence on uniform corrosion. 4.2.3 Influence of the characteristics of the water In oxygen containing waters, corrosion damage because of uniform corrosion only occurs when protective layers cannot form. The precondition for the formation of a protective layer is a water composition with: c(O2)
> 3 mg/l
and pH
> 7,0
and c(HCO3-)
> 2 mmol/l and c(Ca2+)
> 1 mmol/l
The type and concentration of natural components (e.g. phosphates, aluminosilicates) dissolved in the water can play an important part in the formation of protective layers. In the absence of protective layers, the corrosion rate is determined by the concentration of oxidizing agents and/or acidic agents, e.g. carbon dioxide. The uniform corrosion rate is very low if: c(O2)
< 0,1 mg/l and
pH
> 8,5 SIST EN 12502-5:2005
EN 12502-5:2004 (E) 7 4.2.4 Influence of design and construction In water lines designed for water under mainly stagnant conditions, e.g. sprinkler systems, the oxygen concentration rapidly drops under 1 mg/l as a consequence of corrosion. At the same time the pH value increases above 8. The rate of uniform corrosion is insignificant under these condi
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.