EN 14276-2:2007

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Pressure equipment for refrigerating systems and heat pumps - Part 2: Piping - General requirements]DKWHYHÉquipements sous pression pour systemes de réfrigération et pompes a chaleur - Partie 2: Tuyauteries - Exigences généralesDruckgeräte für Kälteanlagen und Wärmepumpen - Teil 2: Rohrleitungen - Allgemeine AnforderungenTa slovenski standard je istoveten z:EN 14276-2:2007SIST EN 14276-2:2007en;fr;de27.200Hladilna tehnologijaRefrigerating technology27.080Heat pumps23.020.30MHNOHQNHPressure vessels, gas cylindersICS:SLOVENSKI
STANDARDSIST EN 14276-2:200701-julij-2007

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14276-2May 2007ICS 23.020.30; 27.080; 27.200 English VersionPressure equipment for refrigerating systems and heat pumps -Part 2: Piping - General requirementsÉquipements sous pression pour systèmes de réfrigérationet pompes à chaleur - Partie 2: Tuyauteries - ExigencesgénéralesDruckgeräte für Kälteanlagen und Wärmepumpen - Teil 2:Rohrleitungen - Allgemeine AnforderungenThis European Standard was approved by CEN on 17 February 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, 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 STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14276-2:2007: E

DN System.28 Annex ZA (informative)
Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC.29 Bibliography.30

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 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, 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.

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

(ISO 4063:1998) EN ISO 10042:2005, Welding — Arc-welded joints in aluminium and its alloys — Quality levels for imperfections (ISO 10042:2005) 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 listed in
EN 378-1:2000, EN 764-1:2004, EN 764-2:2002, EN 764-3:2002, EN 764-4:2002, EN 764-5:2002,
EN 14276-1:2006 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
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 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. 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.

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):

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 Assembly and installation of piping N/A N/A EN 378-2 and EN 378-3 Permanent joint EN 14276-1 Non permanent joint EN 14276-1 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.

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 Z = 0,7 100 %
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