Explosion resistant equipment

This European Standard specifies requirements for explosion resistant equipment which will be able to withstand an internal explosion without rupturing and will not give rise to dangerous effects to the surroundings. It is applicable to equipment (vessels and systems) where explosions are considered to be an exceptional load case.
There are two types of explosion resistant equipment: explosion pressure resistant and explosion pressure shock-resistant equipment (see Figure 1).
(...)
Explosion pressure resistant equipment is designed to withstand the explosion pressure without permanent deformation and will not give rise to dangerous effects to the surroundings. Since the design and calculation methods for explosion pressure resistant equipment are similar to those described in EN 13445-1 to -6 "Unfired pressure vessels" they are not repeated in this standard.
For explosion pressure shock resistant equipment permanent deformation is allowed provided the equipment will not give rise to dangerous effects to the surroundings. This design has been developed especially for explosion protection purposes. This standard focusses on the requirements for explosion pressure shock resistant equipment.
This standard is valid for atmospheres having absolute pressures ranging from 800 mbar to 1 100 mbar and temperatures ranging from −20 °C to +60 °C. This standard may also be helpful for the design, construction, testing and marking of equipment intended for use in atmospheres outside the validity range stated above, as far as this subject is not covered by specific standards.
This standard applies to equipment and combinations of equipment where deflagrations may occur and is not applicable to equipment and combination of equipment where detonations may occur. In this case, different design criteria for the required explosion resistance are applicable which are not covered by this standard.
It is not applicable to equipment which is designed according to type of protection, flameproof enclosures "d" (EN 13463-3 or EN 60079-1).
This standard does not apply to offshore situations.
This standard is only applicable for equipment where metallic materials provide the explosion resistance. This standard does not cover fire risk associated with the explosions, neither with the materials processed nor with the materials used for construction.

Explosionsfeste Geräte

Diese Europäische Norm legt die Anforderungen an explosionsfeste Geräte fest, die einer im Innern erfolgenden Explosion standhalten werden, ohne zu bersten und ohne gefährliche Auswirkungen auf die Umgebung hervorzurufen. Sie ist auf Geräte (Behälter und Systeme) anwendbar, bei denen Explosionen eine außergewöhnliche Belastung darstellen.
Es gibt zwei Arten explosionsfester Geräte: explosionsdruckfeste und explosionsdruckstoßfeste Geräte (siehe Bild 1).
Explosionsdruckfeste Geräte sind so gebaut, dass sie dem Explosionsdruck standhalten, ohne sich bleibend zu verformen und ohne gefährliche Auswirkungen auf die Umgebung hervorzurufen. Da die Auslegungs- und Berechnungsverfahren explosionsdruckfester Geräte den in EN 13445 Teil 1 bis 6 "Unbefeuerte Druckbehälter" beschriebenen ähnlich sind, werden sie in dieser Norm nicht erneut aufgeführt.
Bei explosionsdruckstoßfesten Geräten ist eine dauerhafte Verformung zulässig, sofern diese Geräte keine gefährlichen Auswirkungen auf die Umgebung hervorrufen. Diese Bauweise wurde speziell für Explosionsschutzzwecke entwickelt. Diese Norm stellt die Anforderungen an explosionsdruckstoßfeste Geräte in den Mittelpunkt.
Diese Norm gilt für Atmosphären mit Absolutdrücken im Bereich von 800 mbar bis 1 100 mbar und Temperaturen im Bereich von −20 °C bis +60 °C. Diese Norm kann auch für die Auslegung, Konstruktion, Prüfung und Kennzeichnung von Geräten von Nutzen sein, die für Atmosphären außerhalb des oben festgelegten Anwendungsbereiches vorgesehen sind, sofern dieses Thema nicht durch spezifische Normen abgedeckt ist.
Diese Norm ist auf Geräte und Gerätekombinationen anwendbar, in denen sich Deflagrationen ereignen können. Sie ist nicht auf Geräte und Gerätekombinationen anwendbar, in denen Detonationen vorkommen können. In solchen Fällen sind für die erforderliche Explosionsfestigkeit andere Auslegungskriterien anwendbar, die in dieser Norm nicht behandelt werden.
Sie ist nicht anwendbar auf Geräte, die nach der Zündschutzart "Druckfeste Kapselung" "d" (EN 13463-3 oder EN 60079-1) konstruiert sind.
Diese Norm gilt nicht für Offshore-Anwendungen.
Diese Norm ist nur auf Geräte anwendbar, deren Explosionsfestigkeit durch die Verwendung metallischer Werkstoffe erreicht wird. Diese Norm behandelt nicht die mit den Explosionen einhergehende Brandgefahr, weder bezüglich der verarbeiteten noch der für die Konstruktion verwendeten Werkstoffe.

Appareil résistant à l'explosion

La présente Norme européenne spécifie les exigences applicables aux appareils résistants à l'explosion qui devront supporter une explosion intérieure sans rompre et sans engendrer d'effets dangereux pour le milieu environnant. Elle s'applique aux appareils (enceintes et systèmes) dans lesquels les explosions sont considérées comme un cas de charge accidentelle.
Il existe deux types d'appareils résistants à l'explosion : les appareils résistants à la pression d'explosion et les appareils résistants au choc de pression de l'explosion (voir Figure 1).
Un appareil résistant à la pression d'explosion est conçu pour supporter la pression d'explosion sans déformation permanente et sans engendrer d'effets dangereux pour le milieu environnant. La conception et les méthodes de calcul des appareils résistants à la pression d'explosion étant similaires à celles décrites dans l'EN 13445-1 à -6, « Récipients sous pression non soumis à la flamme », elles ne sont pas reprises dans la présente norme.
Pour les appareils résistants au choc de pression de l'explosion, une déformation permanente est admise à condition que l'appareil n'engendre pas d'effets dangereux pour le milieu environnant. Cette conception a été développée spécialement à des fins de protection contre l'explosion. La présente norme est axée sur les exigences applicables aux appareils résistants au choc de pression de l'explosion.
La présente norme concerne les atmosphères dont la pression absolue est comprise entre 800 mbar et 1 100 mbar et la température entre −20 °C et + 60 °C. Il est possible de s’aider de la présente norme lors de la conception, de la construction, des essais et du marquage d’appareils destinés à être utilisés dans des atmosphères dont les caractéristiques sont différentes de celles citées ci-dessus et ce, tant que le sujet ne fait pas l’objet de normes spécifiques.
La présente norme s’applique aux appareils et combinaisons d’appareils dans lesquels peut se produire une déflagration et n’est pas applicable aux appareils et combinaisons d’appareils dans lesquels peuvent se produire des détonations. Dans ce cas, des critères de conception différents, non traités dans la présente norme, sont applicables pour la résistance à l'explosion requise.
Elle ne s’applique pas aux appareils conçus selon un type de protection par enveloppe antidéflagrante « d » (EN 13463 -3 ou EN 60079 -1).
La présente norme ne s'applique pas aux situations en mer (offshore).
La présente norme s’applique uniquement aux appareils dans lesquels des matériaux métalliques assurent la résistance à l’explosion. La présente norme ne traite pas du risque d'incendie associé aux explosions, aux matériaux traités ou aux matériaux utilisés pour la construction.

Eksplozijsko vzdržljiva oprema

Ta standard določa zahteve za opremo, ki je odporna na tlak pri eksploziji in šok zaradi tlaka pri eksploziji. Ta standard se uporablja za procesne posode in sisteme. Ne uporablja se za posamezne elemente opreme, kot so motorji in menjalniki, ki so lahko izdelani tako, da so odporni na notranjo eksplozijo, in so zajeti v standardu EN 13463-3. Ta standard velja za atmosfere s tlaki od 800 hPa do 1100 hPa in temperaturami od -20 °C do +60 °C. Ta standard se uporablja za opremo in kombinacije opreme, kjer lahko pride do eksplozije, in ne velja za opremo in kombinacije opreme, kjer lahko pride do detonacije. Ta standard je nujno uporabljati samo za opremo, narejeno iz kovinskih materialov.

General Information

Status
Published
Publication Date
30-Jan-2018
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
06-Dec-2017

RELATIONS

Effective Date
13-Nov-2010
Effective Date
08-Jun-2022

Buy Standard

Standard
EN 14460:2018
English language
36 pages
sale 10% off
Preview
sale 10% off
Preview
e-Library read for
1 day

Standards Content (sample)

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eksplozijsko vzdržljiva opremaExplosionsfeste GeräteAppareil résistant à l'explosionExplosion resistant equipment29.260.20Electrical apparatus for explosive atmospheres13.230Varstvo pred eksplozijoExplosion protectionICS:Ta slovenski standard je istoveten z:EN 14460:2018SIST EN 14460:2018en,fr,de01-maj-2018SIST EN 14460:2018SLOVENSKI

STANDARDSIST EN 14460:20061DGRPHãþD
SIST EN 14460:2018
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14460
January
t r s z ICS
s uä t u râ
t {ä t x rä t r Supersedes EN
s v v x rã t r r xEnglish Version
Explosion resistant equipment Appareil résistant à l 5explosion
Explosionsfeste Geräte This European Standard was approved by CEN on
s y December
t r s yä

egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä

translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä

CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre:
Rue de la Science 23,
B-1040 Brussels

t r s z CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN

s v v x rã t r s z ESIST EN 14460:2018

EN 14460:2018 (E) 2 Contents Page European foreword ....................................................................................................................................................... 4 Introduction .................................................................................................................................................................... 5 1 Scope .................................................................................................................................................................... 6 2 Normative references .................................................................................................................................... 7 3 Terms and definitions ................................................................................................................................... 7 4 Explosion pressure shock resistant equipment ................................................................................... 7 4.1 General ................................................................................................................................................................ 7 4.2 Design procedure ............................................................................................................................................ 8 4.3 Design pressure ............................................................................................................................................... 8 4.4 Design temperature ....................................................................................................................................... 8 4.5 Additional loads ............................................................................................................................................... 9 4.6 Wall thickness allowance ............................................................................................................................. 9 5 Materials for pressure shock resistant design ..................................................................................... 9 5.1 General ................................................................................................................................................................ 9 5.2 Criteria for ductile materials ...................................................................................................................... 9 5.3 Criteria for brittle materials .................................................................................................................... 10 6 Explosion pressure shock resistant design ........................................................................................ 10 6.1 General ............................................................................................................................................................. 10 6.2 Design ............................................................................................................................................................... 10 6.2.1 Definition of permissible stresses ......................................................................................................... 10 6.2.2 Weld seam factor .......................................................................................................................................... 11 6.2.3 Flanges ............................................................................................................................................................. 11 6.3 Type testing of pressure shock resistant equipment ...................................................................... 12 6.3.1 General ............................................................................................................................................................. 12 6.3.2 Pressure test .................................................................................................................................................. 12 6.3.3 Explosion test ................................................................................................................................................ 12 6.4 Special requirements for bolted structures ....................................................................................... 13 6.5 Documentation of design and testing of pressure shock resistant equipment ..................... 13 6.5.1 Documentation of Design by Finite Element Methods .................................................................... 13 6.5.2 Documentation of Design by engineering standards ...................................................................... 14 6.5.3 Documentation of testing .......................................................................................................................... 14 7 Documentation of quality of explosion pressure shock resistant equipment ....................... 14 7.1 General ............................................................................................................................................................. 14 7.2 Materials .......................................................................................................................................................... 14 7.3 Welding ............................................................................................................................................................ 15 7.4 Quality test procedure for explosion pressure shock resistant design .................................... 15 7.4.1 Standard procedure (routine test) ........................................................................................................ 15 7.4.2 Alternative procedure in specific cases ............................................................................................... 16 8 Information for use ..................................................................................................................................... 17 8.1 Marking ............................................................................................................................................................ 17 8.2 Accompanying documents ........................................................................................................................ 17 Annex A (informative)

Calculation of design pressure for single vessels ............................................. 19 Annex B (informative)

Explosion in pipes and interconnected vessels ................................................ 20 SIST EN 14460:2018

EN 14460:2018 (E) 3 B.1 General ............................................................................................................................................................. 20 B.2 Design for the maximum explosion pressure .................................................................................... 20 B.3 Venting and Suppression ........................................................................................................................... 20 B.4 Explosions in pipes....................................................................................................................................... 21 B.5 Use of numerical models for estimating the design pressure ...................................................... 21 Annex C (normative)

Use of Finite Element Analysis (FEA) for the design of explosion pressure shock resistant equipment ..................................................................................................... 23 C.1 Software ........................................................................................................................................................... 23 C.2 Validation ........................................................................................................................................................ 23 Annex D (informative)

Definition of permissible stresses ......................................................................... 24 D.1 General ............................................................................................................................................................. 24 D.2 Verification by Typical Design Rules ..................................................................................................... 24 D.3 Yield line method .......................................................................................................................................... 25 D.4 Equivalent Stress Theories ....................................................................................................................... 26 D.4.1 General ............................................................................................................................................................. 26 D.4.2 The “von Mises Theory” .............................................................................................................................. 26 D.4.3 The “Tresca Theory” .................................................................................................................................... 27 D.4.4 The “Rankine Theory” ................................................................................................................................. 27 D.5 Permissible Stress ........................................................................................................................................ 28 Annex E (informative)

Examples for limitation of stress concentration ............................................... 29 Annex F (informative)

Significant changes between this European Standard and EN 14460:2006 .............................................................................................................................................. 31 Annex ZA (informative)

Relationship between this European Standard and the Essential Requirements of EU Directive 2014/34/EU aimed to be covered .............................................. 34 Bibliography ................................................................................................................................................................. 35

SIST EN 14460:2018

EN 14460:2018 (E) 4 European foreword This document (EN 14460:2018) has been prepared by Technical Committee CEN/TC 305 “Potentially explosive atmospheres - Explosion prevention and protection”, the secretariat of which is held by DIN. 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 July 2018, and conflicting national standards shall be withdrawn at the latest by July 2018. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN not be held responsible for identifying any or all such patent rights. This document supersedes EN 14460:2006. This document has been prepared under a standardization request given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 14460:2018

EN 14460:2018 (E) 5 Introduction The principles of integrated explosion safety include the following measures the manufacturer needs to take: a) prevention of formation of explosive atmospheres; b) prevention of the ignition of the explosive atmospheres and; c) if an explosion nevertheless occurs, to halt it immediately and/or to limit the range of explosion flames and explosion pressures to a sufficient level of safety. If the ignition hazard assessment of the equipment shows that the prevention of ignition sources does not fulfil the requirements of the category for the intended use of the equipment, it is essential that methods according to c) are used. This standard specifies requirements for equipment that shall be explosion resistant. Explosion resistance is the term applied to the construction of an enclosure so that it can withstand an expected explosion pressure without rupture. The term “explosion resistance” may be applied to equipment, components and protective systems. SIST EN 14460:2018

EN 14460:2018 (E) 6 1 Scope This European Standard specifies requirements for explosion resistant equipment which will be able to withstand an internal explosion without rupturing and will not give rise to dangerous effects to the surroundings. It is applicable to equipment (vessels and systems) where explosions are considered to be an exceptional load case. There are two types of explosion resistant equipment: explosion pressure resistant and explosion pressure shock-resistant equipment (see Figure 1).

Figure 1 — Explosion resistant equipment Explosion pressure resistant equipment is designed to withstand the explosion pressure without permanent deformation and will not give rise to dangerous effects to the surroundings. Since the design and calculation methods for explosion pressure resistant equipment are similar to those described in EN 13445-1 to -6 “Unfired pressure vessels” they are not repeated in this standard. For explosion pressure shock resistant equipment permanent deformation is allowed provided the equipment will not give rise to dangerous effects to the surroundings. This design has been developed especially for explosion protection purposes. This standard focusses on the requirements for explosion pressure shock resistant equipment. This standard is valid for atmospheres having absolute pressures ranging from 800 mbar to 1 100 mbar and temperatures ranging from

« t r °C to +60 °C. This standard may also be helpful for the design, construction, testing and marking of equipment intended for use in atmospheres outside the validity range stated above, as far as this subject is not covered by specific standards. This standard applies to equipment and combinations of equipment where deflagrations may occur and is not applicable to equipment and combination of equipment where detonations may occur. In this case, different design criteria for the required explosion resistance are applicable which are not covered by this standard. It is not applicable to equipment which is designed according to type of protection, flameproof enclosures “d” (EN 13463-3 or EN 60079-1). This standard does not apply to offshore situations. This standard is only applicable for equipment where metallic materials provide the explosion resistance. This standard does not cover fire risk associated with the explosions, neither with the materials processed nor with the materials used for construction. SIST EN 14460:2018

EN 14460:2018 (E) 7 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 10204:2004, Metallic products — Types of inspection documents EN 13018, Non-destructive testing — Visual testing — General principles EN 13237:2012, Potentially explosive atmospheres — Terms and definitions for equipment and protective systems intended for use in potentially explosive atmospheres EN ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature (ISO 6892-1) EN ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel (ISO 9712) EN ISO/IEC 80079-34, Explosive atmospheres — Part 34: Application of quality systems for equipment manufacture (ISO/IEC 80079-34) 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 13237:2012 and the following apply. 3.1 bolted structure structures with bolted connections of which the design is not covered in published standards Note 1 to entry: Bolted structures will be distinguished from flanged structures which can be designed according to engineering standards. Examples for bolted structures in the sense of this standard are rectangular flanges, fixing of metal sheets with bolts to a steel frame or overlapping sheet constructions. 3.2 maximum allowable explosion pressure pexmax maximum explosion pressure which the equipment will withstand 4 Explosion pressure shock resistant equipment 4.1 General This standard focusses on the requirements for explosion-pressure-shock resistant equipment. With explosion-pressure-shock resistant equipment permanent deformation is allowed provided the equipment will not give rise to dangerous effects to the surroundings. The tolerable extent of effects on the surroundings depends on the intended use of the equipment. Formation of missiles or the rupture of individual parts of the equipment (e.g. gaskets) shall be considered as dangerous effects under any condition. In general, a distinction is made between the following designs: —

design for the maximum explosion pressure; SIST EN 14460:2018
EN 14460:2018 (E) 8 —

design for the reduced explosion pressure in combination with explosion venting or explosion suppression. NOTE If explosions are part of the normal operation (allowed operation pressure) the design rules of this standard do not apply. 4.2 Design procedure The procedure for explosion pressure shock resistant design is as follows: — define geometry; — define design pressure, temperature and loads (see 4.3, 4.4, 4.5); — choose materials (see Clause 5); — define safety factors for material properties (see 6.2.1); — calculate according to state of the art with engineering standards or finite element methods or prove design by testing. NOTE See additional information in Bibliography. 4.3 Design pressure The design pressure shall not be less than the maximum gauge pressure occurring in the equipment, when subjected to explosion or reduced explosion conditions. If the inside of the equipment is divided into sections (e.g. vessels connected by pipes or containing baffles or surge plates) and an explosion is initiated in one of the sections the pressure in the other sections of the equipment will be increased. As a result, an explosion in these sections will occur at an elevated initial pressure and/or a higher turbulence level. Explosion pressures will thus be higher than the value expected under atmospheric conditions. In the case of such arrangements, appropriate measures shall be taken, either explosion isolation techniques or explosion resistant design derived from representative explosion tests or validated explosion modelling (see informative Annex B). NOTE 1 Pressures quoted are gauge pressures unless otherwise stated. NOTE 2 If an explosion is initiated at pressures higher than atmospheric pressure, the maximum explosion pressure will rise proportionally to the initial pressure. NOTE 3 For guidance on the derivation of design pressure for single vessels see Annex A, for interconnected vessels and pipes see Annex B. For explosion venting, the design pressure is derived from EN 14491 and EN 14994 for dust and gas explosions respectively. For explosion suppression, the design pressure is given by the manufacturer of the explosion suppression system according to EN 14373. 4.4 Design temperature In case of an explosion the vessel walls will generally not heat up significantly. Therefore, the intended operating temperatures (minimum and maximum) at the initial pressure shall be used as the design temperatures. The effect of higher gas temperatures caused by exothermic reactions (e.g. subsequent fire) should be considered for gaskets and bolts. Depending on the dimensions of the equipment fully contained light-metal dust explosions could give rise to elevated wall temperatures which should be assessed. SIST EN 14460:2018

EN 14460:2018 (E) 9 4.5 Additional loads Loads which are due to an activation of a venting device, due to product load and/or to hydrostatic load shall be considered. In addition any other load that can occur at the same time as an explosion e.g. wind load, snow load, shall be considered. If brittle material (see 5.3) is used for pressure shock-resistant apparatus and components, care shall be taken to avoid excessive or uneven stressing during assembly. 4.6 Wall thickness allowance Corrosion and/or erosion allowances shall be implemented according to the intended use (see Clause 8). This shall be deducted from the design wall thicknesses before design calculations are carried out. 5 Materials for pressure shock resistant design 5.1 General Yield and rupture stress for materials may be taken from engineering tables. Alternatively, values from material certification according to EN 10204:2004, 3.1 may be used to define the permissible design stresses. The material certification may also be used to classify the material with respect to ductility. Material certification is required for quality documentation depending on the chosen values (see Clause 7). The material of gaskets or seals shall withstand the explosion pressure and impact of flames during explosion. This includes the avoidance of failure due to mechanical forces and the thermal impact of flames and hot gases. Dangerous effects to the surroundings shall be prevented. 5.2 Criteria for ductile materials For explosion pressure shock resistant design, only materials shall be used which fulfil the mechanical, thermal and chemical requirements of the design and intended use of the equipment. Minimum requirements for the materials shall be valid over the complete range of temperatures for the intended use. Special attention shall be given to brittle behaviour at low temperatures. Ductile materials in the sense of EN 14460 are: a) steel (ferritic or austenitic) and spheroidal graphite castings with 1) rupture elongation A5

· 14 %, test temperature 20 °C; and NOTE 1 For further information on A5 see EN ISO 6892-1. 2) notch impact energy

· 27 J, ISO V-notch. The test temperature shall not be higher than the lowest intended operating temperature and shall not exceed 20 °C. NOTE 2 For further information on ISO V-notch see EN ISO 148-1. The term “steel” covers e.g. ferrite, austenitic and cast steel. The material properties of these shall be assessed against the given criteria for ductility. b) aluminium with SIST EN 14460:2018

EN 14460:2018 (E) 10 1) rupture elongation A5

· 20 %, test temperature 20 °C; and 2) notch impact energy not relevant. 5.3 Criteria for brittle materials For materials not fulfilling the criteria of 5.2 the design stresses for brittle materials in 6.2.1 shall be used. NOTE Typical brittle materials are flake graphite castings, cast aluminium G-Al Mg 5 and G-Al Si Mg wa. For testing, brittle materials may be subdivided into two groups: — materials with high notch impact energy: Materials with minimum notch impact energy of 14 J (mean value of three tests), single values shall not be less than 11 J; — materials with low notch impact energy: Materials not fulfilling notch impact energy criteria. 6 Explosion pressure shock resistant design 6.1 General Explosion pressure shock resistant equipment shall be designed such that it can withstand the maximum or reduced explosion pressure without rupturing, but may become permanently deformed [see 8.2 i)]. Explosion pressure shock resistant equipment shall be designed or tested either by a) design according to 6.2, documentation of quality according to 7.2, 7.3 and 7.4 for each item, or b) pressure or explosion test as a type test according to 6.3, documentation of quality according to 7.2, 7.3 and 7.4 for each item. 6.2 Design 6.2.1 Definition of permissible stresses NOTE 1 During short durational loading, the yield stress of metals increases, but the ultimate strength is hardly effected. The actual increase in yield stress depends on the strain rate (1/s) and the characteristics of the metal involved. For explosion pressure resistant design the strain rate is typically in the order of 10 «4 – 10 «2 1/s. For carbon steel only a minor increase in yield stress will arise at such loading rates ((0 – 15) %). However, the duration of the loading is rather long (typically 0,1 s – > 1 s) and the increase in yield stress will be even lower. As a consequence, for explosion protection, it is a correct and safe approach to apply the normal yield stress. It is possible to use verification by engineering rules or finite element methods. NOTE 2 See Bibliography for further references. Detailed design features which can lead to cracking shall be avoided. This requires limitation of stress concentrations (for examples see Annex E). If design is done according to technical standards (membrane or two-dimensional stress), the permissible stresses are as follows: Ductile ferritic material ()ϑ=021,/dfpfR Ductile austenitic material ()ϑ=21%/dafR SIST EN 14460:2018

EN 14460:2018 (E) 11 Brittle materials (see 5.3): ()ϑ=+1100/BrmZfR If design is done according to finite element methods (three-dimensional stress), the permissible stresses are as follows: Ductile ferritic material ()ϑ=×02151,,/dfpfR Ductile austenitic material ()ϑ=×2151%,/dafR Brittle materials (see 5.3): ()ϑ=+1100/BrmZfR If R2 % is not known for austenitic material, R1 % +10 % may be used. The variables are as follows: f permissible stress df ductile ferritic da ductile austenitic Br brittle Rp0,2 (equivalent) yield stress R2 % or R1 % 2 % or 1 % strain limit Rm maximum tensile stress Z necking before fracture The maximum permissible stresses shall not exceed the rupture stress of the material. Further information on the definition of permissible stresses is given in Annex D. It is allowed to use other permissible stresses if the calculation method is validated by testing according to 6.3.2 or 6.3.3. Test requirements for individual testing shall be taken into account in this case. 6.2.2 Weld seam factor If the equipment undergoes a qualification test according to 7.4.1 (pressure test) a weld seam factor of 1,0 may be used. If the equipment undergoes a qualification test according to 7.4.2 (omission of pressure test) the following applies: — A weld seam factor of 1,0 may be used if automatic, certified welding systems are used. — For manual welding a weld seam factor of 0,85 or less shall be applied. 6.2.3 Flanges The calculation according to technical rules shall be for assembly (initial deformation of the gasket) and for the load given by the explosion pressure. Pipe flanges manufactured as in EN 1092-1 may be used without checking for explosion pressure shock resistant equipment. SIST EN 14460:2018

EN 14460:2018 (E) 12 6.3 Type testing of pressure shock resistant equipment 6.3.1 General As an alternative to the design procedure as defined in 6.2 the explosion pressure shock resistance can be proven by a hydrostatic or pneumatic pressure test or alternatively by an explosion test. Permanent deformation is allowed in the type test but shall not lead to rupture and dangerous effects. For vital parts of equipment material certification shall be as specified in EN 10204:2004, 3.1. The ratio [Rp0,2 (Test)/Rp0,2 (Production)] of the properties of the materials used for the type testing [Rp0,2 (Test), as given in the material certification] and t

...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.