untitled BRITISH STANDARD BS EN 14276 2 2007 Pressure equipment for refrigerating systems and heat pumps — Part 2 Piping — General requirements ICS 23 020 30; 27 080; 27 200 ��������� � ���� ���������[.]
Trang 1Pressure equipment for refrigerating systems and heat pumps —
Part 2: Piping — General requirements
ICS 23.020.30; 27.080; 27.200
Trang 2National foreword
This British Standard is the UK implementation of
EN 14276-2:2007+A1:2011 It supersedes BS EN 14276-2:2007, which is withdrawn
The UK participation in its preparation was entrusted to Technical Committee RHE/18, Refrigeration safety
A list of organizations represented on this committee can be obtained on request to its secretary
This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application
Compliance with a British Standard cannot confer immunity from legal obligations.
Amendments/corrigenda issued since publication
30 June 2011 Implementation of CEN amendment A1:2011
This British Standard was
published under the authority
of the Standards Policy and
Strategy Committee
on 31 August 2007
© BSI 2011
Trang 3NORME EUROPÉENNE
ICS 23.020.30; 27.080; 27.200 Supersedes EN 14276-2:2007
English 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
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
C O M I T É E U R O P É E N D E N O R M A L I S A T I O N
E U R O P Ä I S C H E S K O M I T E E FÜ R N O R M U N G
Management Centre: Avenue Marnix 17, B-1000 Brussels
Trang 4Contents Page
Foreword 3
Introduction 4
1 Scope 5
2 Normative references 6
3 Terms, definitions, symbols, quantities and units 7
4 Material 8
5 Piping classification 9
6 Design 11
7 Manufacturing 17
8 Testing and inspection 17
Annex A (informative) DN System 27
Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC 28
Bibliography 29
Trang 5Foreword
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
Trang 6Introduction
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"
Trang 71 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"
Trang 82 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
Trang 9EN 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
Trang 10a) 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
f Nominal design stress at design temperature MPa
Pc Calculation pressure (in formula, Pc can be replaced by P) MPa or bar b
PS Maximum allowable pressure MPa or bar b
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
Trang 11Sight 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;
Trang 12b) 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
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):
Trang 13Table 3 — Applicable requirements per piping type
Type A Type B Type C
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"
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
Trang 146.3 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
Trang 156.5.2 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, t c 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
Trang 16When 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