BS-EN-12952-3-2001.pdf

british standard bs en 12952 3 2001 water tube boilers and auxiliary installations part 3 design and calculation of pressure parts the european standard en 12952 3 2001 has the status of a british standard ics 27 040 no copying without bsi permission except as permitted by copyright law licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi bs en 12952 3 2001 this british standard having been prepared under the direction of the engineering sector policy and strategy committee was published under the authority of the standards policy and strategy committee on 28 may 2002 bsi 28 may 2002 isbn 0 580 38354 7 national foreword this british standard is the official english language version of en 12952 3 2001 it partially supersedes bs 1113 1999 which will be withdrawn when parts 1 2 3 5 6 7 10 and 11 of bs en 12952 are all published when reference to this part of the european standard has been published in the official journal of the european communities oj compliance with it will confer a presumption of conformity with the essential safety requirements of the pressure equipment directive covered by this part of the standard the uk participation in its preparation was entrusted to technical committee pve 2 water tube boilers which has the responsibility to a list of organizations represented on this committee can be obtained on request to its secretary additional information the united kingdom voted against the acceptance of this european standard at the formal vote stage the principal uk objections were as follows a there is no reference in the en foreword to cr 12952 17 water tube boilers and auxiliary installations part 17 guidelines for the involvement of an inspection body independent of the manufacturer b cen tc 269 passed a resolution that parts 1 2 3 5 6 and 7 be published as a package necessary for the design construction and safety of water tube boilers but no mention of this is given in the en foreword c 5 5 covers cyclic loading and gives a requirement that in equation 5 5 1 m 4 or if there is any doubt that the value is conservative the exact value of m shall be taken from figure 13 4 5 or figure 13 4 7 however there is no reference to m in figure 13 4 7 d 5 6 1 covers design requirements the last paragraph of this subclause gives a requirement that for major components operating in the creep range facilities shall be provided for monitoring the creep in relation to operation however there is no specific instruction about what constitutes a major component for example no limiting diameter is specified e 5 8 1 covers internal metal wastage and gives a requirement that the magnetite layer shall be protected in accordance with 13 4 1 1 however no such subclause exists within this part of en 12952 2001 f 5 8 2 covers external metal wastage and gives a requirement that in the special case of chemical recovery boilers it shall be permitted to provide for wastage by means of metallurgically bonded composite material tubing with corrosion resistant layers this implies that this technique is only suitable for chemical recovery boilers when in fact it is also suitable for other types of boilers 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 amendments issued since publication amd no datecomments licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi bs en 12952 3 2001 bsi 28 may 2002 i g table 6 3 1 and table 6 3 2 give material strength values k and related safety factors s for use in determining design stress footnote a in each table states that if creep rupture strength values rmttc for times in excess of 100 000 h are not available 100 000 h data may be used with s 1 5 this is inconsistent with the different values of s used in the two tables h equation 7 3 10 of 7 3 4 is used in the evaluation of ligament stress for inclined ligaments in drums however the term pb0 of this equation is not defined i 7 5 cover stress in cylindrical shells the first paragraph of this subclause gives a requirement that in addition to the requirements of 7 3 and 8 1 1 other local stresses shall also be considered however there is no specific instruction about what other local stresses are to be considered j 8 1 1 1 gives a list of requirements for the ligament efficiency of the main body of cylindrical shells with openings and branches item d of the list states that reinforcing pads analogous to item a shall be used it then states that the requirements of clause 13 are not applicable to this type of reinforcement this implies that reinforcing pads are good in fatigue situation and do not need checking it is felt that the opposite is true in which case there needs to be a requirement that precludes the use of reinforcing pads in locations subject to fatigue k figure 8 1 1 shows reinforcement by increased wall thickness of a cylindrical shell main body with opening however the arrow for the effective width of the reinforcing line dis is incorrectly pointing to the outside diameter instead of the bore of the body l figure 8 1 2 shows reinforcement by set through and full penetration welded branch but the effective length of inner projection of set through branch is incorrectly labelled as lrb1 instead of lrbi m figure 8 1 8 shows an opening with reinforcing pad and full penetration set through and set on welded branch however there are no dimensions for the effective length of the reinforcing pad lrp n 8 1 2 covers effective lengths for the calculation of efficiencies and compensations the fourth line introduces equations for the effective length of the branch lrb and the effective length of the main body lrbi it is stated that these equations are to be used for nozzles with 45 however they can also be used for branches with 45 o 8 1 3 gives a requirement that adjacent openings in cylindrical shells shall be treated as isolated openings if for the centre distance p in accordance with figure 8 3 3 equation 8 1 4 is satisfied figure 8 3 3 refers to adjacent branches arranged with an angle to the axis of the shell however equation 8 1 4 differs in that it refers to angle p 8 1 4 3 gives requirements for the design of extruded branches however it refers to figure 8 1 5 which shows a die forged branch q figure 8 3 2 shows a load diagram for cylindrical shells with a non radial branch however there are no dimensions for the angle 1 r 8 3 3 7 gives requirements for the design of cylindrical shells as forged fittings and refers to figure 8 3 6 figure 8 3 6 shows a tee piece this means that the reference to elbow in the title of 8 3 3 7 and the reference to angle do not make sense s 8 4 1 gives general requirements for bolted connections the fourth and fifth paragraphs are indented and appear to make requirements for only reduced shank bolts when they could also apply to highly loaded bolts in the fourth paragraph the symbol ds is defined as the shank diameter however this symbol has already been defined in part 1 of en 12952 2001 as the stay diameter t table 8 4 1 defines c3 as the symbol for manufacturing tolerances however this same symbol is referred to in 8 4 3 3 as representing design allowance tolerances table 8 4 1 also defines ds as the symbol for shank diameter however this symbol has already been defined in part 1 of en 12952 2001 as the stay diameter u 8 5 3 refers to socket welded connections however the second paragraph gives a requirement about flanges licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi bs en 12952 3 2001 ii bsi 28 may 2002 v 10 2 1 gives requirements for spherical shells and dished ends and states that the equations shown in this clause shall be applied this implies that the equations of clause 10 shall be applied when in fact it is only referring to the equations in subclause 10 2 w the diagrams in figure 10 2 6 are used in the determination of pressure and stress loaded areas in spherical shells and dished ends all the diagrams are incorrectly labelled diagram a is labelled as not being reinforced when it is in fact reinforced by virtue of the increased wall thickness x 10 3 1 gives requirements for unstayed flat ends it states that for flat ends of the type referred to in item b made from a plate and machined and butt welded to the shell plate materials with a z3 quality in accordance with the relevant material standard shall be used however this information is irrelevant for flat ends of the type referred to in item b and is already covered in items e and f 10 3 1 also states that for flat ends of the type referred to in items e and f machined from a plate materials with a z3 quality in accordance with en 10164 shall be used however there are no materials of z3 quality in en 10164 y figure 10 3 1 is labelled as showing diagrams of unstayed flat ends however diagrams f and g do not show unstayed flat ends z 13 3 gives requirements for when a fatigue analysis need not be required 13 3 4 states that a fatigue analysis shall not be required in such cases as exceptional operating conditions however there is no specific instruction as to what constitutes an exceptional operating condition aa 13 4 covers stress analysis for fatigue calculation 13 4 3 gives a requirement that the magnetite layer on the inside of boiler components made from ferritic or martensitic steel shall be protected by the restrictions given in equation 13 4 5a and equation 13 4 5b however there is no reference to the fact that equation 13 4 5a gives a restriction for tensile strength and equation 13 4 5b gives a restriction for compressive strength 13 4 5 gives requirements for the circumferential stress caused by pressure at the inside corner of a bore item c of 13 4 5 refers to figure 13 4 3c however no such figure exists within this part of en 12952 2001 13 4 7 gives requirements for thermal stresses the third paragraph of 13 4 7 refers to t in equation 13 4 9 however there is no such term in this equation 13 4 11 gives a requirement that components with oblique and or non radial branches shall be treated as components with radial branches and gives an instruction to see above but lists no specific subclause to refer to bb table d 1 table d 2 and table d 3 give the physical properties of steels for certain steel groups it is unclear whether the steel groups have been checked with cr iso 15608 textual errors the textual errors set out below were discovered when the english language version of en 12952 3 2001 was adopted a the national standard they have been reported to cen in a proposal to amend the text of the european standard in the title read auxilliary as auxiliary in the second paragraph of 6 1 1 insert be between shall and the so that it reads the reference temperature tor shall be the mean fluid temperature of the component under construction which is to be expected during use in the first paragraph of 6 1 9c delete tube before diameter and insert of the tube after diameter so that it reads do is the outside diameter of the tube in the second paragraph of 8 3 4 4 insert the value between fb1 fs or fb2 fs 1 and shall so that it reads if fb1 fs or fb2 fs 1 the value shall not be used in the calculation in 8 5 1d insert if between or and the and is between pressure and greater so that it reads seal welding shall be applied if the temperature is greater than 220 c or if the pressure is greater than 2 n mm2 in the title of figure 11 5 3 insert of the between loading and attachment so that it reads allowable compressive loading of the attachment the equations of figure 13 4 5 are not clearly presented read the equations as follows am fmax podms 2ems 2 2ea b licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi bs en 12952 3 2001 bsi 28 may 2002 iii where a 1 14 b 0 326 in the first paragraph of 13 4 7 read figure 14 4 8 as figure 13 4 8 in the first paragraph of a 3 move shall be to after on the intrados of the bend so that it reads the required wall thickness on the intrados of the bend shall be in the second paragraph of a 3 insert the required wall thickness before on the extrados of the bend and insert shall be at the end so that it reads the required wall thickness on the extrados of the bend shall be 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 of this publication are responsible for their correct application compliance with a british standard does not of itself confer immunity from legal obligations summary of pages this document comprises a front cover an inside front cover pages i to iii a blank page the en title page 2 to 141 and a back cover the bsi copyright date displayed in this document indicates when the document was last issued dmb dms dms 2ems embems 0 89 2 embems 1 43 embems 0 59 2 embems 1 08 licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi blank licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi european standard norme europ enne europ ische norm en 12952 3 december 2001 ics 27 040 english version water tube boilers and auxilliary installations part 3 design and calculation for pressure parts chaudi res tubes d eau et installations auxiliaires partie 3 conception et calcul des parties sous pression wasserrohrkessel und anlagenkomponenten teil 3 konstruktion und berechnung f r drucktragende teile this european standard was approved by cen on 25 july 2001 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 iceland ireland italy luxembourg netherlands norway portugal spain sweden switzerland and united kingdom european committee for standardization comit europ en de normalisation europ isches komitee f r normung management centre rue de stassart 36 b 1050 brussels 2001 cenall rights of exploitation in any form and by any means reserved worldwide for cen national members ref no en 12952 3 2001 e licensed copy sheffieldun sheffieldun na sat oct 28 06 34 52 gmt 00 00 2006 uncontrolled copy c bsi en 12952 3 2001 e contents pagepage foreword 1scope 2normative references 3terms and definitions 4symbols and abbreviations 5general 5 1purpose 5 2dimensions of pressure parts 5 3strength of pressure parts 5 4design by analysis 5 5cyclic loading 5 6general design requirements 5 7design and calculation pressures 5 8metal wastage 5 9attachments on pressure parts 6calculation temperature and nominal design stress 6 1calculation temperature 6 2maximum through the wall temperature difference and maximum flue gas temperature for heated drums and headers 6 3design stress 7cylindrical shells of drums and headers under internal pressure 7 1shell thickness 7 2basic calculation 7 3combined stresses in drum and header shells 7 4boiler drum supports 7 5other stresses in cylindrical shells 8openings and branches in cylindrical shells of drums and headers and integral tubes 8 1general 8 2efficiency factor calculation by way of approximation and maximum diameter of unreinforced openings 8 3design of openings and branches in cylindrical shells efficiency and reinforcement 8 4bolted connections 8 5screwed connections 9headers and plain tubes of rectangular section 9 1general 9 2symbols and abbreviations 9 3required wall thickness 10ends and spherical shells 10 1symbols and abbreviations 10 2spherical shells and dished ends 10 3unstayed flat ends 10 4flat unstayed closures 11tubes 11 1symbols and abbreviations 11 2thickness of straight boiler tubes 11 3thickness of tube bends and elbows 11 4flexibility of integral tubing tube systems 11 5structural attachments to tubes 11 6fitting and joining of heated tubes 11 7joining of unheated tubes 12pressure parts of irregular shape 12 1hydrostatic test for determining the allowable internal pressure 12 2numerical methods 13fatigue 13 1general 13 2symbols and abbreviations 13 3exemption rule for fatigue analysis 13 4stress analysis for fatigue calculation 13 5example calculations annex a normative calculation of tube bends and elbows a 1general a 2symbols and abbreviations a 3required wall thickness a 4calculation annex b normative fatique cracking design to allow for fluctuating stress b 1general b 2conditions b 3symbols and abbreviations b 4cyclic stress range and mean cyclic stress in the case of uniaxial and multiaxial fluctuating stress b 5correction factors for taking into account the influences of surface finish and weldments b 6controlling stress range b 7permissible stress range with a known number of load cycles annex c informative examples of calculating the effects of fatigue c 1general c 2calculation of the admissible number of load cycles c 3calculation of the admissible temperatur