BS-EN-12501-1-2003.pdf

british standard bs en 12501-1:2003 protection of metallic materials against corrosion corrosion likelihood in soil part 1: general the european standard en 12501-1:2003 has the status of a british standard ics 77.060 ? licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi bs en 12501-1:2003 this british standard was published under the authority of the standards policy and strategy committee on 6 may 2003 bsi 6 may 2003 isbn 0 580 41802 2 national foreword this british standard is the official english language version of en 12501-1:2003. the uk participation in its preparation was entrusted to technical committee ise/nfe/8, corrosion of metals and alloys, which has the responsibility to: a list of organizations represented on this committee can be obtained on request to its secretary. cross-references the british standards which implement international or european publications referred to in this document may be found in the bsi catalogue under the section entitled “international standards correspondence index”, or by using the “search” facility of the bsi electronic catalogue or of british standards online. 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 does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/european committee any enquiries on the interpretation, or proposals for change, and keep the uk interests informed; monitor related international and european developments and promulgate them in the uk. summary of pages this document comprises a front cover, an inside front cover, the en title page, pages 2 to 13 and a back cover. the bsi copyright date displayed in this document indicates when the document was last issued. amendments issued since publication amd. no. datecomments licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi european standard norme europenne europische norm en 12501-1 april 2003 ics 77.060 english version protection of metallic materials against corrosion - corrosion likelihood in soil - part 1: general protection des matriaux mtalliques contre la corrosion - risque de corrosion dans les sols - partie 1: gnralits korrosionsschutz metallischer werkstoffe - korrosionswahrscheinlichkeit in bden - teil 1: allgemeines this european standard was approved by cen on 21 february 2003. 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 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 management centre has the same status as the official versions. cen members are the national standards bodies of austria, belgium, czech republic, denmark, finland, france, germany, greece, hungary, iceland, ireland, italy, luxembourg, malta, netherlands, norway, portugal, slovakia, spain, sweden, switzerland and united kingdom. european committee for standardization comit europen de normalisation europisches komitee fr normung management centre: rue de stassart, 36 b-1050 brussels 2003 cenall rights of exploitation in any form and by any means reserved worldwide for cen national members. ref. no. en 12501-1:2003 e licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 2 contents page foreword3 introduction.4 1scope 4 2normative references 4 3terms and definitions4 4general concepts.5 4.1principles5 4.2assessment of the corrosion load in soil .5 4.3classification of the corrosion load in soil.5 4.4risk of appearance of corrosion damage in soil6 5factors influencing the corrosion of buried structures 6 5.1general6 5.2soils and backfill materials.6 5.3structures and metals .7 5.4environment.7 annex a (normative) procedure for assessing the corrosion load in soil8 a.1procedure .8 a.2preliminary inquiry 9 a.3site survey9 a.4soil sampling9 annex b (informative) examples of factors influencing the corrosion of buried structures 10 b.1soil and backfill material.10 b.2structure.10 b.3environment.10 annex c (informative) principal function of a buried structure and main type of corrosion to be considered12 bibliography13 licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 3 foreword this document (en 12501-1:2003) 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 october 2003, and conflicting national standards shall be withdrawn at the latest by october 2003. according to the cen/cenelec internal regulations, the national standards organizations of the following countries are bound to implement this european standard: austria, belgium, czech republic, denmark, finland, france, germany, greece, hungary, iceland, ireland, italy, luxembourg, malta, netherlands, norway, portugal, slovakia, spain, sweden, switzerland and the united kingdom. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 4 introduction corrosion analysis of a buried structure is complex due to the interactions of various factors of the corrosion system, such as soil, type of metallic material, characteristics of the structure and environment. consequently, identification and assessment of the factors pertaining to a given corrosion likelihood as defined in this european standard are too complex for precise results to be expected solely from the use of this european standard. therefore this european standard has to be supplemented by expertise and scientific training. the european standard comprises two parts: part 1: general part 2:low alloyed and non alloyed ferrous materials. 1 scope this european standard provides a basis for assessing the corrosion likelihood in soil of buried metallic structures such as pipelines, sheathed metallic cables, storage tanks, sheet pilings, support anchors, culverts and earth reinforcement. this part of this european standard defines the general concepts for the assessment method and lists the main factors influencing the corrosion of buried structures. 2 normative references this european standard incorporates by dated or undated reference, provisions from other publications. these normative references are cited at the appropriate places in the text, and the publications are listed hereafter. for dated references, subsequent amendments to or revisions of any of these publications apply to this european standard only when incorporated in it by amendment or revision. for undated references the latest edition of the publication referred to applies (including amendments). en 12501-2protection of metallic materials against corrosion corrosion likelihood in soil part 2: low alloyed and non alloyed ferrous materials en iso 8044:1999, corrosion of metals and alloys basic terms and definitions (iso 8044:1999). 3 terms and definitions for the purpose of this european standard, the terms and definitions given in en iso 8044:1999 and the following apply. 3.1 corrosion load sum of all the effects of a corrosive environment licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 5 3.2 foreign cathode element of the environment in contact with the structure, with a more positive electrochemical potential than the structure, leading to the formation of a galvanic cell 4 general concepts 4.1 principles the assessment of the corrosion likelihood of buried metallic structures defined in figure 1 takes into consideration: soil parameters; characteristics of the structure in the absence of protection; environmental factors. soil parameterscharacteristics of the structureenvironmental factors assessment of the corrosion load in soil(table 1) this standard design function risk of appearance of corrosion damage (table 2) serviceability durability in combination with product standards protection figure 1 diagram for assessing the corrosion likelihood in soil 4.2 assessment of the corrosion load in soil a practical procedure for the assessment of the corrosion load in soil is given in annex a. it is a step by step method comprising three main steps: preliminary enquiry, site survey, soil sampling. 4.3 classification of the corrosion load in soil for a given metal, table 1 defines three classes of corrosion load in soil. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 6 table 1 classes of corrosion load in soil classes of corrosion load classification in terms of probability lowlow probability that the corrosion rate will be above a threshold value or that a specific corrosion effect will occur. mediumhigh probability that the corrosion rate will be between the upper and lower threshold values. highhigh probability that the corrosion rate will exceed a threshold value or that a specific corrosion effect will occur. notea specific corrosion effect relates to types of corrosion such as pitting, crevice corrosion, bimetallic corrosion, hydrogen embrittlement, corrosion fatigue or stress corrosion cracking. if such types are expected, the corrosion load should always be assumed as high because quantitative assessment of such effects is not possible. 4.4 risk of appearance of corrosion damage in soil the risk of appearance of corrosion damage can be estimated from the class of corrosion load in soil in combination with the requirements concerning the function of the structure, its design (material, thickness, .), its serviceability and its durability. the assessment of the risk of the appearance of corrosion damage is not detailed in this standard. standards dealing with protective systems of specific buried metallic structures are to be used in combination with the corrosion load in soil. some guidance is given in table 2. table 2 risk of appearance of corrosion damage and service life requirements risk of appearance of corrosion damage service life requirements comments lowfulfilledcorrosion resistance adequate. no additional corrosion protection measure required. moderatenot always ensuredcorrosion resistance not always adequate. monitoring is recommended to assess risks of corrosion damage and to decide whether additional corrosion protection measures are necessary. highnot fulfilledcorrosion resistance inadequate. additional corrosion protection measures required. 5 factors influencing the corrosion of buried structures 5.1 general examples of factors to be considered are given in annex b. 5.2 soils and backfill materials this standard only applies to soils and backfill materials in direct contact with the structure. these materials can be divided into the following categories based on their origin: native soils, either disturbed or undisturbed; imported soils (backfill materials): natural soils (sand, gravel, crushed limestone .); licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 7 artificial soils : by-products (granules, ), industrial refuse (ashes, cinders, .), etc . the main physical and chemical parameters of soils and backfill materials are considered in en 12501-2. 5.3 structures and metals the corrosion of a structure in a given soil depends on numerous parameters specific to each structure, for example geometry, complexity and operational conditions. moreover, for existing structures, corrosion products have to be considered as a part of the corrosion system. when considering the corrosion of a buried structure, the impairment of its functions should be taken into account in relation to the expected type of corrosion. the main types of corrosion to be considered in relation to the principal function are given in annex c. metals and their alloys considered in this standard can either constitute the material used for the structure or the protective system for that structure. 5.4 environment environmental factors are discussed in en 12501-2 and include special factors such as electrical interference within the soil and foreign cathodes. this standard does not consider in detail: cathodic protection measures (see en 12954 and en 13509); corrosion in soil due to stray currents from electrical direct current (dc) systems (see pren 50162); corrosion in soil due to influences from electrical alternating current (ac) systems. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 8 annex a (normative) procedure for assessing the corrosion load in soil a.1 procedure actionassessment soil and backfill materials environment structure yespreliminary inquiry sufficient information (criteria) no no yessite survey sufficient information (criteria) no criteriasoil sampling corrosion load in soil after each step, the decision whether to stop or to continue can be taken. the possible lack of information is counterbalanced by accepting a higher corrosion load. the criteria to be taken into account during this assessment depend on the metal and structure. they are considered in detail in en 12501-2. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 9 a.2 preliminary inquiry the inquiry is mainly performed with data gathered from the design documents: profile, maps (geological, hydrological, etc.), structure definition, other buried structures in the vicinity, electrical environment, etc. a.3 site survey the site survey is performed in order to gather data concerning the physico-chemical characteristics of soils, pollution indicators and the presence of voltage gradients in the ground. a.4 soil sampling investigations on soil samples will give additional information for the assessment of the corrosion load in soil. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 10 annex b (informative) examples of factors influencing the corrosion of buried structures b.1 soil and backfill material type of soil, texture (permeability to oxygen, etc.) type of backfill material resistivity ph, acidity-alkalinity water content, water table salts : sulfates, sulfides, chlorides, etc. bacterial activity (sulfate reducing bacteria) soil homogeneity (vertical, horizontal) b.2 structure orientation (horizontal-vertical) electrical continuity length, surface area material complexity (geometry, materials, etc.) earthing operating conditions: temperature and variation pressure and variation, etc. coating (no, yes, type, etc.) b.3 environment backfilling process corrosion cell by differential aeration dc influence, for example: licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 11 cathodic protection of other structures dc railways high voltage dc transmission industry using dc etc. ac influence, for example: high voltage power lines ac railways etc. influence of foreign cathodes (e.g. steel partly in concrete and partly in soil, or copper earthing electrodes) influence of telluric currents. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 12 annex c (informative) principal function of a buried structure and main type of corrosion to be considered structure principal functionexamplemain type of corrosion to be considered leaktightnesspipelines vessels localised corrosion mechanical strengthpylons steel foundations piles sheet pilings uniform corrosion longitudinal electrical conductivity earth electrodes electrical cables localised corrosion licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi en 12501-1:2003 (e) 13 bibliography en 12954, cathodic protection of buried or immersed metallic structures - general principles and application for pipelines. en 13509, cathodic protection measurement techniques. pren 50162, protection against corrosion by stray current from dc systems. licensed copy: sheffieldun sheffieldun, na, sat oct 28 07:06:06 gmt+00:00 2006, uncontrolled copy, (c) bsi bs en 12501-1:2003 bsi 389 chiswick high road london w4 4al bsi british standards institution bsi is the independent national body responsible for preparing british standards. it presents the uk view on standards in europe and at the international level. it is incorporated by royal charter. revisions british standards are updated by amendment or revision. users of british standards should make sure that they possess the latest amendments or editions. it is the constant aim of bsi to improve the quality of our products and services. we would be grateful if anyone finding an inaccuracy or ambiguity while using this british standard would inform the secretary of the technical committee responsible, the identity of which can be found on the inside front cover. tel: +44 (0)20 8996 9000. fax: