SIST EN 14276-2:2007+A1:2011
(Main)Pressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General requirements
Pressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General requirements
1.1 This European Standard specifies the requirements for material, design, manufacturing, testing and documentation for stationary piping intended for use in refrigerating systems, heat pumps and secondary cooling and heating systems. These refrigerating systems and heat pump systems are referenced in this standard as refrigerating systems as defined in EN 378-1.
1.2 This European Standard applies to piping including welded or brazed attachments up to and including the flanges, screwed, welded or brazed connectors or to the edge to be welded or brazed at the first circumferential joint connecting piping or other elements.
1.3 This European Standard applies to the selection, application and installation of safety accessories intended to protect the piping during the various phases of the refrigeration cycle.
1.4 This European Standard applies to the following piping:
heat exchanger consisting of piping for the purpose of cooling or heating air where piping aspects are predominant;
piping incorporated into an assembly (e.g. self contained system, condensing unit);
field erected piping.
1.5 This European Standard applies to piping with an internal pressure down to – 1 bar, to account for the evacuation of the piping prior to charging with refrigerant.
1.6 This European Standard applies to both the mechanical loading conditions and thermal conditions as defined in EN 13480-3 associated with refrigerating systems. It applies to piping subject to the maximum allowable temperatures for which nominal design stresses for materials are derived using EN 14276-1:2006+A1" or as specified in this European Standard. In addition piping designed to this standard needs to have a maximum design temperature not exceeding 200 °C and a maximum design pressure not exceeding 64 bar. Outside of these limits, EN 13480 should be used for the design construction and inspection of the piping. Under these circumstances the unique nature of a refrigerating plant, as indicated in the introduction of !EN 14276-1:2006+A1", needs also to be taken into account.
1.7 This European Standard applies to piping where the main pressure bearing parts are manufactured from metallic ductile materials as defined in Clause 4 and in !EN 14276-1:2006+A1".
Druckgeräte für Kälteanlagen und Wärmepumpen - Teil 2: Rohrleitungen - Allgemeine Anforderungen
1.1 Diese Europäische Norm legt die Anforderungen an Werkstoffe, Konstruktion, Herstellung, Prüfung und Dokumentation für ortsfeste Rohrleitungen für Kälteanlagen, Wärmepumpen und indirekte Kühl- und Heiz-systeme fest. Diese Kälteanlagen und Wärmepumpen werden in der vorliegenden Norm als Kälteanlagen nach EN 378-1 bezeichnet. 1.2 Diese Europäische Norm gilt für Rohrleitungen mit angeschweißten oder angelöteten Bauteilen, einschließlich Flansche, Schraub-, Schweiß- oder Lötverbindungen oder der ersten Schweiß- oder Lötnaht für den Anschluss von Rohrleitungen oder anderen Teilen. 1.3 Diese Europäische Norm gilt für die Auswahl, Anwendung und den Einbau von Ausrüstungsteilen mit Sicherheitsfunktion zum Schutz der Rohrleitungen während der verschiedenen Phasen des Kältemittelkreislaufs. 1.4 Diese Europäische Norm gilt für folgende Rohrleitungen: ⎯ Wärmeaustauscher, bestehend aus Rohrleitungen zum Kühlen oder Erhitzen von Luft, bei maßgebenden Aspekten von Rohrleitungen; ⎯ Rohrleitungen innerhalb einer Baugruppe (z. B. Kältesatz, Verdichtungssatz); ⎯ vor Ort montierte Rohrleitungen. 1.5 Diese Europäische Norm gilt für Rohrleitungen mit einem Innendruck bis – 1 bar, um der Entleerung der Rohrleitung vor dem Befüllen mit Kältemittel Rechnung zu tragen. 1.6 Diese Europäische Norm gilt sowohl für die mechanischen Belastungen als auch die thermischen Beanspruchungen nach den Festlegungen in EN 13480-3, die im Zusammenhang mit Kälteanlagen auftreten. Sie gilt für Rohrleitungen mit den maximal zulässigen Temperaturen, für die die zulässigen Nennspannungen für die Werkstoffe nach !EN 14276-1:2006+A1" abgeleitet werden oder in dieser Europäischen Norm festgelegt sind. Ferner müssen Rohrleitungen, die nach dieser Norm ausgelegt sind, eine maximale Auslegungstemperatur von 200 °C und einen maximalen Auslegungsdruck von 64 bar aufweisen. Außerhalb dieser Grenzwerte sollte für die Konstruktion, Herstellung und Prüfung der Rohrleitungen EN 13480 herangezogen werden.
Equipements sous pression pour systèmes de réfrigération et pompes à chaleur - Partie 2: Tuyauteries - Exigences générales
1.1 La présente Norme européenne spécifie les exigences relatives aux matériaux, à la conception,
à la fabrication, aux essais et à la documentation concernant les tuyauteries fixes destinées à être utilisées dans des
systèmes de réfrigération, des pompes à chaleur et des systèmes de refroidissement et de chauffage secondaires.
Ces systèmes de réfrigération et systèmes de pompes à chaleur sont désignés dans la présente norme par le terme
systèmes de réfrigération défini dans l’EN 378-1.
1.2 La présente Norme européenne s’applique aux tuyauteries comportant les fixations soudées ou brasées
y compris les brides, les raccords vissés, soudés ou brasés ou, d’autre part, au bord à souder ou à braser au premier
joint circulaire de raccordement à la tuyauterie ou à d’autres éléments.
1.3 La présente Norme européenne traite de la sélection, de l’application et de l’installation des accessoires
de sécurité destinés à protéger les tuyauteries sous pression au cours des diverses phases du cycle de réfrigération.
1.4 La présente Norme européenne s’applique aux tuyauteries suivantes :
- les échangeurs thermiques constitués de tuyaux et destinés au refroidissement ou au réchauffement de l'air,
où les aspects liés à la tuyauterie prédominent ;
- les tuyauteries incorporées dans un ensemble (par exemple système autonome, unité de condensation) ;
- les tuyauteries montées sur site.
1.5 La présente Norme européenne s’applique aux tuyauteries soumises à une pression intérieure jusqu’à – 1 bar
nécessaire pour réaliser la vidange de la tuyauterie avant de charger le fluide frigorigène.
1.6 La présente Norme européenne concerne les conditions de chargement mécanique et les conditions
thermiques définies dans l’EN 13480-3 associées aux systèmes de réfrigération. Elle s’applique aux tuyauteries
soumises aux températures maximales admissibles pour lesquelles des contraintes nominales de calcul applicables
aux matériaux sont déterminées à l’aide de l’!EN 14276-1:2006+A1" o
Tlačna oprema za hladilne sisteme in toplotne črpalke - 2. del: Cevovodi - Splošne zahteve
Ta evropski standard določa zahteve za material, načrtovanje, proizvodnjo, preskušanje in dokumentacijo fiksnih cevovodov za uporabo v hladilnih sistemih, toplotnih črpalkah in sekundarnih hladilnih in grelnih sistemih. Ti hladilni sistemi in toplotne črpalke so navedeni v tem standardu kot hladilni sistemi, kot je določeno v EN 378-1.
1.2 Ta evropski standard velja za cevovode vključno s privarjenimi ali pritrjenimi priključki do prirobnic za šobe in vključno z njimi, za privite, privarjene ali pritrjene konektorje ali na rob privarjene ali pritrjene priključke pri prvem obodnem spoju, ki povezuje cevi na druge elemente.
1.3 Ta evropski standard velja za izbor, uporabo in inštalacijo varnostnih dodatkov za zaščito cevovoda med različnimi fazami hladilnega cikla.
1.4 Ta evropski standard velja za naslednje cevovode:
Izmenjevalnike toplote, sestavljene iz cevovodov, za namen hlajenja ali segrevanja zraka, kjer so vidiki cevovodov prevladujoči;
cevovodi, vgrajeni v sklop (npr. samostojni sistem, enota za kondenzacijo);
na terenu postavljeni cevovodi.
1.5 Ta evropski standard velja za cevovode z notranjim negativnim tlakom do –1 bar, ob upoštevanju praznjenje cevovoda pred polnjenjem s hladilom.
1.6 Ta evropski standard velja za mehanske nakladalne razmere in toplotne razmere, kot je določeno v EN 13480-3, povezane s hladilnimi sistemi. Velja za cevovode, izpostavljene maksimalnim dovoljenim temperaturam, za katere so nominalne načrtovane obremenitve za materiale izpeljane iz EN 14276-1:2006+A1 ali kot je določeno v tem evropskem standardu. Poleg tega cevovodi, načrtovani v skladu s tem standardom, morajo imeti maksimalno načrtovano temperaturo manjšo od 200 °C in maksimalni načrtovani tlak nižji od 64 barov. Zunaj teh omejitev je pomembno, da se EN 13480 uporablja za načrtovanje, gradnjo in pregled cevovodov. V teh okoliščinah je pomembno, da se edinstvena narava hladilne naprave, kot je navedena v uvodu iz EN 14276-1:2006+A1, prav tako upošteva.
1.7 Ta evropski standard velja za cevovode, kjer so deli, ki nosijo glavni tlak, proizvedeni iz raztegljivih kovinskih materialov, kot je določeno v klavzuli 4 in v EN 14276-1:2006+A1.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.]DKWHYHDruckgeräte für Kälteanlagen und Wärmepumpen - Teil 2: Rohrleitungen - Allgemeine AnforderungenEquipements sous pression pour systèmes de réfrigération et pompes à chaleur - Partie 2: Tuyauteries - Exigences généralesPressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General requirements27.200Hladilna tehnologijaRefrigerating technology27.080Heat pumps23.020.30MHNOHQNHPressure vessels, gas cylindersICS:Ta slovenski standard je istoveten z:EN 14276-2:2007+A1:2011SIST EN 14276-2:2007+A1:2011en,fr,de01-maj-2011SIST EN 14276-2:2007+A1:2011SLOVENSKI
STANDARD
SIST EN 14276-2:2007+A1:2011
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14276-2:2007+A1
February 2011 ICS 23.020.30; 27.080; 27.200 Supersedes EN 14276-2:2007English Version
Pressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General requirements
Equipements sous pression pour systèmes de réfrigération et pompes à chaleur - Partie 2: Tuyauteries - Exigences générales
Druckgeräte für Kälteanlagen und Wärmepumpen - Teil 2: Rohrleitungen - Allgemeine Anforderungen This European Standard was approved by CEN on 17 February 2007 and includes Amendment 1 approved by CEN on 13 December 2010. 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 CEN-CENELEC 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 CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14276-2:2007+A1:2011: ESIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 2 Contents Page Foreword .3Introduction .41Scope .52Normative references .63Terms, definitions, symbols, quantities and units .74Material .85Piping classification .96Design . 117Manufacturing . 178Testing and inspection . 17Annex A (informative)
DN System . 27Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC . 28Bibliography . 29 SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 3 Foreword This document (EN 14276-2:2007+A1:2011) has been prepared by Technical Committee CEN/TC 182 “Refrigerating systems, safety and environmental requirements”, 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 August 2011, and conflicting national standards shall be withdrawn at the latest by August 2011. This document includes Amendment 1, approved by CEN on 2010-12-13. This document supersedes EN 14276-2:2007. The start and finish of text introduced or altered by amendment is indicated in the text by tags ! ". Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports Essential Requirements of EU Directive 97/23/EC concerning pressure equipment. For relationship with EU Directive 97/23/EC, see informative Annex ZA, which is an integral part of this document. This document consists of the following parts under the general title Pressure equipment for refrigerating systems and heat pumps: Part 1: Vessels — General requirements; Part 2: Piping — General requirements. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 4 Introduction This European Standard recognises the unique nature of piping for refrigerating systems or heat pumps and is intended to address the specific needs of the refrigeration and heat pump industry. This European Standard should be read in conjunction with the various parts of EN 13480 and !EN 14276-1:2006+A1". The unique nature of a refrigerating system is defined in the introduction of !EN 14276-1:2006+A1". SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 5
1 Scope 1.1 This European Standard specifies the requirements for material, design, manufacturing, testing and documentation for stationary piping intended for use in refrigerating systems, heat pumps and secondary cooling and heating systems. These refrigerating systems and heat pump systems are referenced in this standard as refrigerating systems as defined in EN 378-1. 1.2 This European Standard applies to piping including welded or brazed attachments up to and including the flanges, screwed, welded or brazed connectors or to the edge to be welded or brazed at the first circumferential joint connecting piping or other elements. 1.3 This European Standard applies to the selection, application and installation of safety accessories intended to protect the piping during the various phases of the refrigeration cycle. 1.4 This European Standard applies to the following piping: heat exchanger consisting of piping for the purpose of cooling or heating air where piping aspects are predominant; piping incorporated into an assembly (e.g. self contained system, condensing unit); field erected piping. 1.5 This European Standard applies to piping with an internal pressure down to – 1 bar, to account for the evacuation of the piping prior to charging with refrigerant. 1.6 This European Standard applies to both the mechanical loading conditions and thermal conditions as defined in EN 13480-3 associated with refrigerating systems. It applies to piping subject to the maximum allowable temperatures for which nominal design stresses for materials are derived using
!EN 14276-1:2006+A1" or as specified in this European Standard. In addition piping designed to this standard needs to have a maximum design temperature not exceeding 200 °C and a maximum design pressure not exceeding 64 bar. Outside of these limits, EN 13480 should be used for the design construction and inspection of the piping. Under these circumstances the unique nature of a refrigerating plant, as indicated in the introduction of !EN 14276-1:2006+A1", needs also to be taken into account. 1.7 This European Standard applies to piping where the main pressure bearing parts are manufactured from metallic ductile materials as defined in Clause 4 and in !EN 14276-1:2006+A1". SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 6 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 378-1:2008+A1:2010, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 1: Basic requirements, definitions, classification and selection criteria EN 378-2:2008+A1:2009, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 2: Design, construction, testing, marking and documentation EN 378-3:2008, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 3: Installation site and personal protection EN 378-4:2008, Refrigerating systems and heat pumps — Safety and environmental requirements — Part 4: Operation, maintenance, repair and recovery" EN 571-1:1997, Non destructive testing — Penetrant testing — Part 1: General principles EN 583-4:2002, Non-destructive testing — Ultrasonic examination — Part 4: Examination for discontinuities perpendicular to the surface EN 764-1:2004, Pressure equipment — Terminology — Part 1: Pressure, temperature, volume, nominal size EN 764-2:2002, Pressure equipment — Part 2: Quantities, symbols and units EN 764-3:2002, Pressure equipment — Part 3: Definition of parties involved EN 764-4:2002, Pressure equipment — Part 4: Establishment of technical delivery conditions for metallic materials EN 764-5:2002, Pressure equipment — Part 5: Compliance and inspection documentation of materials EN 970:1997, Non-destructive examination of fusion welds — Visual examination
EN 1289:1998, Non-destructive examination of welds — Penetrant testing of welds — Acceptance levels
EN 1435:1997, Non-destructive examination of welds — Radiographic examination of welded joints EN 1653:1997, Copper and copper alloys — Plate, sheet and circles for boilers, pressure vessels and hot water storage units EN 1712:1997, Non-destructive examination of welds — Ultrasonic examination of welded joints — Acceptance levels EN 1714:1997, Non-destructive examination of welds — Ultrasonic examination of welded joints EN 10204:2004, Metallic products — Types of inspection documents EN 10246-9:2000, Non-destructive testing of steel tubes — Part 9: Automatic ultrasonic testing of the weld seam of submerged arc welded steel tubes for the detection of longitudinal and/or transverse imperfections EN 10246-16:2000, Non-destructive testing of steel tubes — Part 16: Automatic ultrasonic testing of the area adjacent to the weld seam of welded steel tubes for the detection of laminar imperfections
SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 7 EN 12178:2003, Refrigerating systems and heat pumps — Liquid level indicating devices — Requirements, testing and marking EN 12517-1:2006, Non-destructive testing of welds — Part 1: Evaluation of welded joints in steel, nickel, titanium and their alloys by radiography — Acceptance levels EN 12735-1:2001, Copper and copper alloys — Seamless, round copper tubes for air conditioning and refrigeration — Part 1: Tubes for piping systems EN 12735-2:2001, Copper and copper alloys — Seamless, round copper tubes for air conditioning and refrigeration — Part 2: Tubes for equipment !EN 13445-3:2009, Unfired pressure vessels — Part 3: Design" EN 13480-2:2002, Metallic industrial piping — Part 2: Materials EN 13480-3:2002, Metallic industrial piping — Part 3: Design and calculation !EN 14276-1:2006+A1:2011, Pressure equipment for refrigerating systems and heat pumps — Part 1: Vessels — General requirements" EN 22553:1994, Welded, brazed and soldered joints — Symbolic representation on drawings
(ISO 2553:1992) !EN ISO 4063:2009, Welding and allied processes
Nomenclature of processes and reference numbers
(ISO 4063:2009)" EN ISO 10042:2005, Welding — Arc-welded joints in aluminium and its alloys — Quality levels for imperfections (ISO 10042:2005) !EN ISO 23277:2009, Non-destructive testing of welds — Penetrant testing of welds — Acceptance levels
(ISO 23277:2006)" ISO 817:2005, Refrigerants — Designation system 3 Terms, definitions, symbols, quantities and units !For the purposes of this document, the terms, definitions, symbols, quantities and units given in
EN 378-1:2008+A1:2010, EN 764-1:2004, EN 764-2:2002, EN 764-3:2002, EN 764-4:2002, EN 764-5:2002,
EN 14276-1:2006+A1:2011 and the following apply." 3.1 Terms and definitions 3.1.1 coil heat exchanger consisting of pipe or tubing (more particularly made from one or more bent pipes) used to cool or heat air
NOTE see Figure 1 SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 8
a) Coil with straight tubes and elbows b) Coil with elbow and headers Figure 1 — Coil 3.2 Symbols, quantities and units Symbols, quantities and units used in this standard are listed in Table 1. Table 1 — Symbols, quantities and units Symbol Quantity Unit DNa Nominal diameter — De External diameter of tube mm f Nominal design stress at design temperature
MPa Pc Calculation pressure (in formula, Pc can be replaced by P) MPa or bar b Pd Design pressure MPa or bar b PS Maximum allowable pressure
MPa or bar b Ptest Test pressure MPa or bar b R Radius of curvature for tube mm tc Calculation temperature
°C td Design temperature
°C z Joint coefficient for welds — a See also Annex A
b 1 bar = 100 000 Pa = 0,1 MPa = 0,1 N/mm2
4 Material 4.1 General The materials referenced in this European Standard shall meet the requirements of
!EN 14276-1:2006+A1" unless modified by the subclauses of this clause. It is permitted to use non-metallic materials (e.g. gaskets, coatings, insulating materials, sight glasses) provided they are compatible with the other materials, refrigerants and lubricants present. SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 9 Sight glasses shall comply with EN 12178 for pressure bearing requirements. 4.2 Requirements for materials to be used for pressurised parts Materials listed in this European Standard have been identified for use in refrigerating piping. If it is required to utilise a material not listed in this European Standard, the requirements of EN 13480-2 shall be followed where applicable and the unique nature of refrigerating plant requirements shall also be taken into account. 4.3 Materials 4.3.1 Piping manufactured from the following materials satisfies the requirements of this European Standard for the pressurised parts: 4.3.1.1 Where mechanical properties may be modified by the piping manufacturing process, the material shall be selected from the following material groups as defined in !EN 14276-1:2006+A1:2011, Annex I": steel groups: St 1.1, St 1.2, St 8.1; aluminium and aluminium alloys groups: 21, 22; copper groups: 31, 32, 33, 34, 35 included in EN 1653, EN 12735-1, EN 12735-2. When materials do not comply with the above requirements, it is also permitted to use materials which comply with European Approval of Material (EAM) or with particular appraisal according to EN 764-4. 4.3.1.2 Where the piping manufacturing process does not modify mechanical properties, metallic materials other than those quoted in 4.3.1.1 can be used if they comply with European Approval of Material (EAM) or with particular appraisal according to EN 764-4. 4.3.2 Special considerations The requirements of !EN 14276-1:2006+A1:2011, 4.3.3" shall apply. 4.4 Requirements for the prevention of brittle fracture The requirements of !EN 14276-1:2006+A1:2011, 4.4" shall apply. NOTE The brittle fracture should be determined only when the material thickness can permit to make a test piece according to EN 10045-1 with a minimum section size 5 mm x 10 mm. 4.5 Material documentation The requirements of !EN 14276-1:2006+A1:2011, 4.5" shall apply. 4.6 Materials for non-pressure retaining parts The requirements of !EN 14276-1:2006+A1:2011, 4.6" shall apply. 5 Piping classification 5.1 Category of piping The pressure piping is classified into 2 categories according to Table 2 in accordance with the following: a) the product of maximum allowable pressure PS (in bar) times DN; SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 10 b) the fluid classification as defined in !EN 14276-1:2006+A1:2011, 5.2"; c) the fluid state: 1) gases, liquefied gases, gases dissolved under pressure and those liquids whose vapour pressure at the maximum allowable temperature is greater than 0,5 bar; 2) liquids having a vapour pressure at the maximum allowable temperature of not more than 0,5 bar. For this European Standard, the refrigerant containing parts are always considered as a gas circuit. Table 2 — Classification of piping by categories Category Fluid !EN 14276-1:2006+A1:2011, 5.2" Criteria X Group 1 PS < 0,5 bars, no limit of DN or 0,5 bar < PS ≤ 10 bar, DN ≤ 100 or 10 bar < PS ≤ 40 bar: PS × DN ≤ 1 000 or PS > 40 bar, DN ≤ 25 Group 2 PS < 0,5 bar, no limit of DN or 0,5 bar < PS ≤ 35 bar, PS × DN ≤ 3 500 or PS > 35 bar, DN ≤ 100 Y Group 1 Other than criteria for category X group 1 Group 2 Other than criteria for category X group 2
NOTE Where refrigerating systems are subject to the Low Voltage Directive and/or the Machinery Directive, exclusion in Article 1.3.6 of the Pressure Equipment Directive (PED) may apply. In these cases, piping of category X is not subject to PED requirements. 5.2 Piping typology In refrigerating systems, the following 3 types of pressure equipment can be classified as piping: type A: heat exchangers where air is the secondary fluid (they are used in air conditioning and heat pumps) and where the piping aspects are predominant defined as coil (see Figure 1); NOTE The predominant aspect of piping is defined in Guideline 2/4. type B: piping incorporated into an assembly (e.g. self contained system, condensing unit); type C: field erected piping; type C1: with pre-fabricated piping; type C2: totally built on site. For the different types of piping, the following requirements shall apply (if applicable): SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 11 Table 3 — Applicable requirements per piping type
Type A Type B Type C Item Coils Piping Pre-fabricated piping Totally built on site piping Pressure and temperature determination Clause 6 Pressure stress
Clause 6 Other loads/fixations N/A N/A EN 378-2 and EN 378-3 Forming !EN 14276-1:2006+A1" Assembly and installation of piping N/A N/A EN 378-2 and EN 378-3 Permanent joint !EN 14276-1:2006+A1" Non permanent joint !EN 14276-1:2006+A1" Final inspection Clause 8
6 Design 6.1 General This clause covers pressure piping constructed of materials as defined in clause 4. The dimensions of pressurised parts shall be designed at the design pressure (Pd) at the design temperature (td). 6.2 Corrosion, corrosion protection 6.2.1 General The corrosion allowances specified in this subclause are based on the assumption that the piping will be maintained as prescribed in EN 378-2. If other corrosion allowances are used, the manufacturer shall indicate the value in the documentation. 6.2.2 Internal corrosion For surfaces in contact with refrigerants listed in EN 378-1, internal corrosion is negligible and the minimum corrosion allowance may be taken to be 0 mm. Other values, greater than zero, may be selected by the manufacturer. 6.2.3 External corrosion External corrosion allowance shall be either: 1) 0 mm for pressurised parts, if appropriate protection (e.g. paint, zinc plating, vapour barriers, non corrosive materials) is applied prior to putting into service, and the protection is properly maintained by the end user during the operational lifetime and checked at least according to EN 378-2. 2) not less than 1 mm if pressurised parts are not protected during the operational life time as prescribed above. SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 12 6.3 Loading The normal load of piping covered in this European Standard is: internal/external pressure; ambient and operational temperatures; static pressure and mass of contents in operating and test conditions; reaction forces and moments from the supports, attachments; corrosion and erosion, fatigue etc. The requirements of EN 378-2 shall apply for piping support and attachments. NOTE 1 The fluids used in a refrigerating system are not considered as unstable fluids. NOTE 2 For traffic, wind, earthquake loading, if applicable, refer to EN 13480-3. Maximum allowable pressure PS, design pressure Pd and calculation pressure P or Pc. The maximum allowable PS shall be specified by the manufacturer. The design pressure Pd and the calculation pressure P or Pc shall not be less than PS. 6.4 Design temperature td and minimum material temperature The maximum design temperature of the pressurised refrigerant containing parts shall not be less than the maximum allowable temperature TSmax. TSmax shall not be less than the saturated temperature (dew point temperature) corresponding to PS of the fluid and the maximum continuous operating temperature. Localised high temperatures (e.g. super heated refrigerant) shall be taken into account in the relevant pressure piping area. The minimum design temperature shall not be more than the minimum allowable temperature TSmin. TSmin is the minimum temperature which can occur during operation or during standstill conditions. This temperature shall be used to select materials to avoid brittle fracture. TSmin shall not be greater than 20 °C. Localised low temperatures associated with the rapid charging of refrigerants/refrigerant blends (expanding a volatile liquid into a vacuum) shall be taken into account in the relevant area of the piping. The requirements for impact test properties shall be considered in this localised area. 6.5 Calculation temperature tc 6.5.1 General The calculation temperature tc is used to determine the appropriate design stress for the selected material. SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 13 6.5.2 Piping without heater The calculation temperature, unless determined on the basis of detailed calculations or tests based on measurements, shall be determined as follows: Thermally insulated piping: tc equal TSmax Piping is not thermally insulated: when fluid temperature is less than 40 °C, tc is TSmax; when fluid temperature is greater or equal to 40 °C, tc is TSmax with the exception for bolts where tc
is equal to 80 % of TSmax. 6.5.3 Piping with heater When the piping is equipped with a heater, the calculation temperature shall be determined by test or taken to be equal to the temperature determined in 6.5.2 + 50 K. The manufacturer when selecting the heater shall quantify the risk that exists of overheating for the fluid or for the material and shall take appropriate measures to restrict this risk by for example the inclusion of safety accessories and/or the inclusion of appropriate warning labels and/or adding instructions to the documentation. 6.6 Joint coefficient for welds The joint coefficient for welds “z” takes into account the risk associated with the introduction of a weld as well as the risk of a defect remaining undetected due to the level of Non Destructive Testing (NDT) conducted on the joint. The joint coefficient for welds applies for longitudinal and helical welded joints in piping, longitudinal joints in conical piping and the main joints between plates used to fabricate dished heads. The joint coefficient for welds does not apply to non governing joints such as circumferential joints on piping, conical sections, nozzle to shell joints or any type of joint where only compressive stresses are present. The manufacturer shall select one of the following values: 1 for equipment subjected to destructive and non-destructive tests that confirm that 100 % of the joint is defect free; 0,85 for equipment subject to random non-destructive testing equivalent to 10 % of the joint length; 0,7 for equipment where no non-destructive testing has been carried out other than the visual inspection of the joint. Table 4 — Extent of NDT for longitudinal welding joint coefficient for welds Z
VT MT or PT RT or UT Z = 1 100 % 100 100 Z = 0,85 100 %
10
10 Z = 0,7 100 %
0
0
SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 14 When assessing exceptional situations e.g. below atmosphere pressure, no joint coefficient for welds is necessary for calculation purposes. In this European Standard, the brazed joints are applicable only for circular joint. In this case, the joint factor is 1,0. 6.7 Design stress The value of design stress shall take into account the design and tests conditions. The requirements of
!EN 14276-1:2006+A1:2011, 6.12" shall apply when the materials are not subjected to creep. When materials are subjected to creep, all requirements of EN 13480-3 shall apply. The values of yield and tensile strength of the material shall be those which apply to the materials in the final fabricated condition, and shall conform to the values given in the appropriate design specification. These values can be used for design purposes unless heat treatment is known to lead to lower values. For metallic material, the value at 20 °C may be used for temperatures up to and including 50 °C. If the weld or brazed metal gives lower strength values after fabrication, then these values shall be used instead. When assessing exceptional conditions (e.g. vacuum – 1 bar), the design stress shall be taken for the test condition with the temperature of material taken to be that existing at the exceptional condition. The design stresses shall be in accordance with !EN 14276-1:2006+A1:2011, Table 4". 6.8 Access and inspection openings, venting and draining provisions, filling and discharge provisions and handling devices 6.8.1 Access and inspection openings No provisions are required for access and inspection openings other than the connections used on the piping. In case of corrosive fluids, the manufacturer shall indicate in the instruction documentation, the recommended periodic inspection schedule and methods. 6.8.2 Venting and draining provisions The design of the piping shall ensure provision for adequate venting of air during the pressure test and draining of the test fluid after the hydraulic test. 6.8.3 Filling and discharge provisions The provision given in EN 378 parts 2, 3 and 4 shall apply to prevent the risk of refrigerant emission during the filling or discharging of the refrigerating system. If the piping is used for refrigerant storage, the documentation shall recommend the maximum liquid level and the use of safety accessories to avoid any over-pressure. 6.8.4 Handling devices For piping, there is no requirement for additional handling devices. SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 15 6.9 Design methods 6.9.1 General The basic design method is the design by formula (DBF) method. In addition two other methods can be used to either supplement or replace DBF: a) design by analysis (DBA); the rules are given in EN 13480-3; b) experimental techniques; the rules are given in !EN 14276-1:2006+A1:2011, Annex E". For piping in category X, alternative methods are given in 8.9.4.1.2 and 8.9.4.1.3. 6.9.2 Design by formula (DBF) 6.9.2.1 Straight piping The minimum required thickness without corrosion allowance, for a straight pipe shall be determined as follows: PzfDPte×+×××=8,02 6.9.2.2 Bend piping The minimum required thickness without corrosion allowance, for a bend pipe shall be determined as follows: +×+×××=RDPzfDPtee418,02 SIST EN 14276-2:2007+A1:2011
EN 14276-2:2007+A1:2011 (E) 16
Key De External diameter of tube R Radius of curvature for tube Figure 2 — Bend piping 6.9.2.3 Other piping components !For other piping components such as fabricated elbow, reducers, end cap, opening etc., the appropriate requirements of EN 13480-3:2002, Clauses 6 to 8 or equivalent clauses of EN 13445-3:2009, as given in Table 5, shall apply. Table 5 — Correspondence between EN 13480-3 and EN 13445-3 Subject Clause of
EN 13480-3:2002 Clause of
EN 13445-3:2009 Cone 6.4.3 to 6.4.6 7.6 Flange 6.6 11 or Annex G Hemispherical end 7.1.2 7.5.2 Torispherical end 7.1.3 7.5.3 Elliptical end 7.1.4 7.5.4 Circular flat end
7.2 10 Opening
8 9 External pressure 9 8 Fatigue 10 17 and 18 " 6.9.3 Joint design The requirements of !EN 14276-1:2006+A1:2011, 6.14.3" s
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