EN ISO 4126-2:2003

SLOVENSKI STANDARD
01-julij-2003
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PHPEUDQDPL,62
Safety devices for protection against excessive pressure - Part 2: Bursting disc safety
devices (ISO 4126-2:2003)
Sicherheitseinrichtungen gegen unzulässigen Überdruck - Teil 2:
Berstscheibeneinrichtungen (ISO 4126-2:2003)
Dispositifs de sécurité pour la protection contre les pressions excessives - Partie 2:
Dispositifs de sureté a disque de rupture (ISO 4126-2:2003)
Ta slovenski standard je istoveten z: EN ISO 4126-2:2003
ICS:
13.240 Varstvo pred previsokim Protection against excessive
tlakom pressure
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 4126-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2003
ICS 13.240
English version
Safety devices for protection against excessive pressure - Part
2: Bursting disc safety devices (ISO 4126-2:2003)
Dispositifs de sécurité pour la protection contre les Sicherheitseinrichtungen gegen unzulässigen Überdruck -
pressions excessives - Partie 2: Dispositifs de sûreté à Teil 2: Berstscheibeneinrichtungen (ISO 4126-2:2003)
disque de rupture (ISO 4126-2:2003)
This European Standard was approved by CEN on 9 September 2002.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 4126-2:2003 E
worldwide for CEN national Members.

Contents
page
Foreword.4
Introduction .5
1 Scope .5
2 Normative references .5
3 Terms and definitions.7
4 Materials.9
4.1 Selection of materials.9
4.2 Material specifications .10
4.3 Protection from corrosion.10
5 Types of bursting discs.10
5.1 Conventional domed bursting discs (forward acting) .10
5.2 Reverse domed bursting discs (reverse acting).11
5.3 Flat bursting discs .11
5.4 Other types and designs.13
6 Bursting disc holders .13
6.1 Design .13
6.2 Types.13
6.3 Connections .15
7 Back pressure supports.16
7.1 General.16
7.2 Opening back pressure supports.16
7.3 Non-opening back pressure supports.16
8 Temperature shields.16
9 Stiffening rings.16
10 Gaskets/seals .16
11 Assembly of bursting disc safety devices .16
11.1 General.16
11.2 Bursting disc safety devices with replaceable bursting disc assemblies.17
11.3 Bursting disc safety devices with non-replaceable bursting disc assemblies.17
12 Specified bursting pressure requirements .17
13 Inspection by the manufacturer .19
14 Test procedures .19
14.1 General.19
14.2 Pressure testing.19
14.3 Burst testing.19
14.4 Leak testing .21
14.5 Non-destructive examination.21
15 Certification .21
16 Product designation .22
17 Marking .22
17.1 General.22
17.2 Bursting discs/bursting disc assemblies.23
17.3 Bursting disc holders.23
17.4 Bursting disc safety devices with non-replaceable bursting disc assemblies.24
17.5 Ancillary components .24
17.6 Omission of markings .24
18 Preparation for storage and transportation .25
18.1 General.25
18.2 Marking of packages .25
18.3 Provision of assembly and installation instructions .25
18.4 Provision of documents, loose identification plates etc. .25
Annex A (normative)  Materials .26
Annex B (informative)  Materials.28
Annex ZA (informative)  Clauses of this European Standard addressing essential requirements or
other provisions of EU Directives.33
Bibliography .34
Foreword
This document (EN ISO 4126-2:2003) has been prepared by Technical Committee CEN/TC 69 "Industrial valves",
the secretariat of which is held by AFNOR, in collaboration with ISO/TC 185 "Safety devices for protection against
excessive pressure".
This European Standard EN ISO 4126-2:2003 shall be given the status of a national standard, either by publication
of an identical text or by endorsement, at the latest by July 2003, and conflicting national standards shall be
withdrawn at the latest by July 2003.
This document 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(s).
For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document.
This standard for safety devices for protection against excessive pressure consists of seven parts of which this is
Part 2. The various parts are:
 Part 1: Safety valves.
 Part 2: Bursting disc safety devices.
 Part 3: Safety valves and bursting disc safety devices in combination.
 Part 4: Pilot operated safety valves.
 Part 5: Controlled safety pressure relief systems (CSPRS).
 Part 6: Application, selection and installation of bursting disc safety devices.
 Part 7: Common data.
Part 7 contains data that is common to more than one of the parts of this standard to avoid unnecessary repetition.
Annex A is normative. Annex B is informative.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal,
Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
A bursting disc safety device is a non-reclosing pressure relief device used to protect pressure equipment such as
pressure vessels, piping, gas cylinders or other enclosures from excessive pressure and/or excessive vacuum.
A bursting disc safety device typically comprises an assembly of components including a bursting disc, a bursting
disc holder and, where necessary, other components such as back pressure supports, stiffening rings etc.
The bursting disc is a pressure-containing and pressure-sensitive part of the bursting disc safety device and is
designed to open by bursting at a pre-determined pressure. There are many different types of bursting disc safety
devices manufactured in corrosion resistant materials, both metallic and non-metallic, to cover a wide range of
nominal sizes, burst pressures and temperatures.
1 Scope
This part of this European Standard specifies the requirements for bursting disc safety devices.
It includes the requirements for the design, manufacture, inspection, testing, certification, marking, and packaging.
The requirements for the application, selection and installation of bursting disc safety devices are given in Part 6 of
this European Standard.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the
publication referred to applies (including amendments).
EN 485-1, Aluminium and aluminium alloys – Sheet, strip and plate – Part 1: Technical conditions for inspection
and delivery.
EN 485-2, Aluminium and aluminium alloys – Sheet, strip and plate – Part 2: Mechanical Properties.
EN 485-3, Aluminium and aluminium alloys – Sheet, strip and plate – Part 3: Tolerances on shape and dimensions
for hot-rolled products.
EN 485-4, Aluminium and aluminium alloys – Sheet, strip and plate – Part 4: Tolerances on shape and dimensions
for cold-rolled products.
EN 573-3, Aluminium and aluminium alloys – Chemical composition and form of wrought products – Part 3:
Chemical composition.
EN 573-4, Aluminium and aluminium alloys – Chemical composition and form of wrought products – Part 4: Forms
of products.
EN 1092-1, Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN designated –
Part 1: Steel flanges.
EN 1333, Pipework components - Definition and selection of PN.
EN 1652, Copper and copper alloys – Plate, sheet, strip and circles for general purposes.
EN 1653, Copper and copper alloys – Plate, sheet and circles for boilers, pressure vessels and hot water storage
units.
EN 10028-1, Flat products made of steels for pressure purposes – Part 1: General requirements.
EN 10028-7, Flat products made of steels for pressure purposes – Part 7: Stainless steels.
EN 10088-1, Stainless steels – Part 1: List of stainless steels.
EN 10095, Heat resisting steels and nickel alloys.
EN 10222-1, Steel forgings for pressure purposes – Part 1: General requirements for open die forgings.
EN ISO 6708, Pipework components - Definition and selection of DN (nominal size) (ISO 6708:1995).
DIN 17740, Wrought nickel – Chemical composition.
DIN 17742, Wrought nickel alloy with chromium – Chemical composition.
DIN 17743, Wrought nickel alloys with copper – Chemical composition.
DIN 17744, Wrought nickel alloys with molybdenum and chromium – Chemical composition.
DIN 17850, Titanium – Chemical composition.
SEW 400, Rolled and forged stainless steels.
BS 3072, Specification for nickel and nickel alloys – Sheet and plate.
BS 3073, Specification for nickel and nickel alloys – Strip.
ASTM A240/A240M, Standard specification for chromium and chromium-nickel stainless steel plate, sheet and strip
for pressure vessels and for general applications.
ASTM B127, Standard specification for nickel-copper alloy (UNS N04400) plate, sheet, and strip.
ASTM B162, Standard specification for nickel plate, sheet and strip.
ASTM B168, Standard specification for nickel-chromium-iron alloys (UNS N06600, N06601, N06603, N06690,
N06025, and N06045) and nickel-chromium-cobalt-molybdenum alloy (UNS N06617) plate, sheet and strip.
ASTM B209, Standard specification for aluminium and aluminium-alloy sheet and plate.
ASTM B265, Standard specification for titanium and titanium alloy strip, sheet and plate.
ASTM B333, Standard specification for nickel-molybdenum alloy plate, sheet and strip.
ASTM B424, Standard specification for Ni-Fe-Cr-Mo-Cu alloy (UNS N08825 and UNS N08221), plate, sheet and
strip.
ASTM B443, Standard specification for nickel-chromium-molybdenum-columbium alloy (UNS N06625) and nickel-
chromium-molybdenum-silicon alloy (UNS N06219), plate, sheet and strip.
ASTM B569, Standard specification for brass strip in narrow widths and light gauge for heat-exchanger tubing.
ASTM B575, Specification for low-carbon nickel-molybdenum-chromium, low-carbon nickel-chromium-
molybdenum, low-carbon nickel-chromium-molybdenum-copper, low-carbon nickel-chromium-molybdenum-
tantalum, low-carbon nickel-chromium-molybdenum-tungsten alloy plate, sheet and strip.
ASTM B708, Standard specification for tantalum and tantalum alloy, plate, sheet and strip.
3 Terms and definitions
For the purposes of this European Standard, the following terms and definitions apply.
3.1
bursting disc safety device
non-reclosing pressure relief device actuated by differential pressure and designed to function by the bursting of
the bursting disc(s), and which is the complete assembly of installed components including, where appropriate, the
bursting disc holder
3.2
bursting disc assembly
complete assembly of components which are installed in the bursting disc holder to perform the desired function
3.3
bursting disc
pressure-containing and pressure-sensitive component of a bursting disc safety device
3.4
bursting disc holder
part of a bursting disc safety device which retains the bursting disc assembly in position
3.5
conventional domed bursting disc (also referred to as: forward-acting)
bursting disc which is domed in the direction of the bursting pressure (i.e. where the bursting pressure is applied to
the concave side of the bursting disc, see Figure 1)
3.6
slotted lined bursting disc
bursting disc made up of two or more layers, at least one of which is slit or slotted to control the bursting pressure
of the bursting disc
3.7
reverse domed bursting disc (also referred to as: reverse-acting)
bursting disc which is domed against the direction of the bursting pressure (i.e. where the bursting pressure is
applied to the convex side of the bursting disc, see Figure 2)
3.8
flat bursting disc
bursting disc having one or more layers which is flat when installed. It may be made of a ductile or brittle material
3.9
graphite bursting disc
bursting disc manufactured from graphite, impregnated graphite, flexible graphite or graphite composite and
designed to burst due to bending or shearing forces
NOTE The following definitions apply:
a) graphite. A crystalline form of the element carbon;
b) impregnated graphite. Graphite in which the open porosity is impregnated with a filler material;
c) flexible graphite. A graphite structure formed by the compression of thermally exfoliated graphite intercalation
compounds;
d) graphite composite. Made up of two or more distinct materials and having different properties to those of the
separate materials and in which the proportion of graphite is over 50 per cent by weight.
3.10
bursting pressure
value of the differential pressure between the upstream side and the downstream side of the bursting disc when it
bursts
3.11
specified bursting pressure
bursting pressure quoted with a coincident temperature when defining the bursting disc requirements (used in
conjunction with a performance tolerance, see 3.15)
3.12
specified maximum bursting pressure
maximum bursting pressure quoted with a coincident temperature when defining the bursting disc requirements
(used in conjunction with specified minimum bursting pressure, see 3.13)
3.13
specified minimum bursting pressure
minimum bursting pressure quoted with a coincident temperature when defining the bursting disc requirements
(used in conjunction with specified maximum bursting pressure, see 3.12)
3.14
coincident temperature
temperature of the bursting disc associated with a burst pressure (see 3.11, 3.12 and 3.13) and which is the
expected temperature of the bursting disc when it is required to burst
3.15
performance tolerance
range of pressure between the specified minimum bursting pressure and the specified maximum bursting pressure,
or the range of pressure in positive and negative percentages or quantities which is related to the specified bursting
pressure (see Figure 9)
3.16
operating pressure
pressure existing at normal operating conditions within the system being protected
3.17
differential back pressure
differential pressure across a bursting disc in the opposite direction to the direction of the bursting pressure, which
is the result of pressure in the discharge system from other sources and/or a result of vacuum on the upstream side
of the bursting disc
3.18
vent area
cross-section area available for discharge of fluid
3.19
batch
quantity of bursting discs or bursting disc safety devices made as a single group of the same type, size, materials
and specified bursting pressure requirements where the bursting discs are manufactured from the same lot of
material (see 3.20)
3.20
lot of material
a) metal. Material of the same specification coming from the same heat number, heat treatment batch and
specified thickness with tolerances to an appropriate standard;
b) graphite and flexible graphite. Material of the same specification grade and quality coming from the same
graphite manufacturer and the same manufacturing process;
c) impregnated graphite. Graphite of the same lot impregnated with a specific grade of filler material by the
same manufacturing process;
d) graphite composite. Graphite and specific grades of other constituents coming from the same mix
3.21
back pressure support
component of a bursting disc safety device which prevents damage to the bursting disc due to differential back
pressure
NOTE A back pressure support which is intended to prevent damage to the bursting disc when the system pressure falls
below atmospheric pressure is sometimes referred to as a vacuum support.
3.22
stiffening ring
component of a bursting disc assembly used primarily for reinforcing fragile bursting discs, so as to prevent
damage
3.23
coating
layer of metallic or non-metallic material applied to components of a bursting disc safety device by a coating
process
3.24
lining
additional sheet or sheets of metallic or non-metallic material forming part of a bursting disc assembly or bursting
disc holder
3.25
plating
metal layer applied to a bursting disc or bursting disc holder by a plating process
3.26
muffled outlet
component of a bursting disc safety device which disperses the discharge
3.27
temperature shield
device which protects a bursting disc from excessive temperature
4 Materials
4.1 Selection of materials
The selection of materials used for the components of bursting disc safety devices shall take into account:
a) suitability with regard to manufacture;
b) compatibility with the process fluid, the adjoining components and the chemical and physical conditions to
which the bursting disc safety device will be subjected when in service.
NOTE The use of corrosion-resistant materials for the downstream side of the bursting disc device is recommended
because corrosion of these parts can cause damage which can impair the performance of the bursting disc safety device.
4.2 Material specifications
The material specification for the bursting disc safety devices shall be according to annex A (normative) and annex
B (informative).
They shall have uniform chemical and physical properties and shall be free from defects, which would cause the
bursting disc safety device to malfunction.
4.3 Protection from corrosion
Bursting disc safety devices are frequently required to operate in corrosive environments and, therefore,
components manufactured from materials affected by corrosion shall, where appropriate, be protected by coating,
plating or lining.
Coatings and plating shall be applied to give an even and homogeneous coating to the surfaces to be protected.
Linings shall be seamless and supplied with the bursting disc safety device so as to preserve them as a set or
integral unit.
The corrosion protection shall be supplied only by the manufacturer.
The corrosion protection shall not impair the performance of the bursting disc safety device.
5 Types of bursting discs
5.1 Conventional domed bursting discs (forward acting)
Conventional domed bursting discs shall be designed so that they burst due to tensile stresses when the bursting
pressure is applied to the concave side of the bursting disc (see Figure 1).
Key
1 Flat seat
2 Angle seat
3Flow
Figure 1 — Conventional domed bursting disc (forward acting)
They shall be domed by a means sufficient to cause a permanent set such that no further plastic flow will occur
initially when the bursting disc is subjected to its intended operating condition.
Conventional domed bursting discs include the following types:
a) conventional simple domed. This type of bursting disc shall have one or more layers, the bursting pressure
of which is controlled by the ultimate tensile strength of the material(s);
b) conventional slotted domed. This type of bursting disc shall have two or more layers at least one of which
shall have slits or slots so as to reduce its strength and to control the bursting pressure;
c) conventional scored simple domed. This type of bursting disc shall be scored such that when the bursting
pressure is reached, the bursting disc opens along the score;
d) conventional simple domed with knife blades. This type of bursting disc shall open by being cut by the knife
blades when the bursting pressure is reached.
5.2 Reverse domed bursting discs (reverse acting)
Reverse domed bursting discs shall be designed to function due to buckling, bending or shearing stresses when
the bursting pressure is applied to the convex side of the bursting disc (see Figure 2).
Key
1Flow
Figure 2 — Reverse domed bursting disc (reverse acting)
Reverse domed bursting discs include the following types:
a) reverse domed scored. This type of bursting disc shall be scored such that, when the dome reverses at the
bursting pressure, the bursting disc opens along the score. The bursting disc may also have areas of
weakness which determine the pressure at which the bursting disc reverses;
b) reverse domed having slip or tear-away design. This type of bursting disc shall function by being expelled
downstream from the bursting disc holder;
NOTE A catching device can be provided for this type of bursting disc.
c) reverse domed with knife blades. This type of bursting disc shall open by being cut by knife blades during
reversal of the dome;
d) reverse domed that function by shearing. This type of bursting disc shall have one or more layers which
upon reversal opens due to shearing forces;
e) reverse domed composite or multi-layered. This type of bursting disc shall have two or more layers at least
one of which shall contain areas of weakness of such a configuration as to determine the pressure at which
the bursting disc reverses.
5.3 Flat bursting discs
Flat bursting discs shall have one or more layers. According to the type, they may require a bursting disc holder, or
be fitted directly between installation flanges.
Flat bursting discs include the following types:
a) graphite replaceable element. This type of bursting disc shall be plane or recessed and used in conjunction
with a bursting disc holder. They shall be designed to burst due to bending or shearing forces, (see Figure 3);
Key
1 Back pressure support (where required)
2Flow
Figure 3 — Typical replaceable element graphite bursting disc and holder
b) graphite monobloc. This type of bursting disc shall be designed so as to fit directly between the installation
flanges. They may be recessed on one or both sides according to the bursting pressure and the direction in
which it is to be applied (see Figure 4). Graphite monobloc bursting discs may be reinforced with an external
armour ring. This design may be provided with a lining on the pressure side;
Key
1 Armour ring (optional)
2Flow
Figure 4 — Monobloc graphite bursting discs - different configurations
The pressure containing capability of graphite monobloc bursting discs, after bursting, shall be determined by one
of the methods given in 6.1.1.
NOTE For this design of graphite monobloc bursting disc, the diameter of the downstream piping adjacent to the bursting
disc should follow the manufacturer's instructions. Normally this diameter will be greater than the inside diameter of the recess.
c) flat slotted lined. This type of bursting disc shall have two or more layers. At least one of the layers shall have
for example, slits or slots so as to reduce its strength and to control the bursting pressure. According to the
design it may be necessary for the bursting disc to be used in conjunction with a bursting disc holder.
5.4 Other types and designs
Other types and other designs of bursting discs are permitted providing that they meet the requirements of this
standard.
6 Bursting disc holders
6.1 Design
6.1.1 Pressure containing capability
The pressure containing capability of bursting disc holders shall be determined by either:
a) calculation generally according to design rules for flanged connections such as EN 1092-1; or
b) other established design methods of the manufacturer; or
c) experimental design procedure(s) developed by the manufacturer, carried out on prototypes, or on
representative production samples.
6.1.2 Other design requirements
The design of the bursting disc holder shall ensure:
a) the accurate positioning of the bursting disc assembly;
b) the bursting disc assembly, where applicable, can only be fitted the correct way round;
c) the ability to apply or transmit a clamping load appropriate to the particular bursting disc assembly;
d) where appropriate, the correct fitting of a back pressure support (see clause 8);
e) that, when installed in accordance with the manufacturer's installation instructions, it provides adequate
pressure containment under the specified service conditions;
f) the position of any holes for pre-assembly screws is compatible with the specified gaskets used between the
bursting disc holder and the installation flanges;
g) the accurate positioning within the pressure system connection including direction of flow;
h) its suitability for the specified service conditions;
i) correct functioning of the bursting disc assembly.
NOTE It is recommended that the bursting disc holder is so designed as to protect the bursting disc assembly during
installation and removal. With domed bursting discs this can be achieved by ensuring that the dome does not protrude beyond
the bursting disc holder. Other methods may be used subject to agreement between the purchaser and the manufacturer.
6.2 Types
The type of bursting disc holder shall be appropriate to the particular type of bursting disc and suitable for its
intended use.
Bursting disc holders include the following types:
a) insert/capsule. Insert/capsule bursting disc holders shall have an inlet and outlet member, with or without
fasteners and shall fit within the installation flange bolting (see Figure 5);
Figure 5 — Typical insert / capsule bursting disc holder
b) full face flange. Full face flange bursting disc holders shall have an inlet and outlet member, with or without
fasteners and shall have holes/slots to suit the installation flange bolting (see Figure 6).
NOTE The outside diameter is normally the same as the outside diameter of the installation flanges.
Figure 6 — Typical full face flange bursting disc holder
c) union. Union bursting disc holders shall have an inlet and outlet member connected by a union nut (see Figure
7);
Key
1 Muffled outlet (optional)
Figure 7 — Typical union bursting disc holders
d) plug/screw. Plug/screw bursting disc holders shall have an inlet and outlet member which are screwed
together. The outlet member may be a muffled outlet design (see Figure 8);
Figure 8 — Typical plug / screw bursting disc holders
e) other. Other types of bursting disc holders are permitted providing that they meet the requirements of this
standard.
6.3 Connections
Where bursting disc holders fit between installation flanges, for example, insert/capsule and full face flange types,
the facing and surface finish of the bursting disc holder shall be compatible with that of the purchaser's piping
specifications.
For other types (see 6.2) the connections to the installation may be threaded, welded, proprietary etc., according to
the purchaser's requirements.
7 Back pressure supports
7.1 General
Where a bursting disc is to be subjected in service to a differential back pressure it shall be supported by a back
pressure support unless the bursting disc is capable of withstanding the back pressure.
The back pressure support shall be supplied by the manufacturer either permanently attached to the bursting disc,
or it shall form part of a bursting disc safety device that ensures the back pressure support can only be assembled
to the correct side of the bursting disc.
The back pressure support shall be free from all burrs or similar imperfections which would cause a bursting disc to
function incorrectly.
7.2 Opening back pressure supports
The opening back pressure support shall fit closely against and give adequate support to the bursting disc. The
support shall be of a design such that the pressure in the system is transmitted to the bursting disc.
When the bursting disc has burst, the back pressure support shall open when subjected to a pressure not
exceeding the specified minimum bursting pressure or the specified bursting pressure minus the negative tolerance
at the coincident temperature of the associated bursting disc.
7.3 Non-opening back pressure supports
The non-opening back pressure support shall fit closely against and give adequate support to the bursting disc.
The support shall have openings to allow the discharge of fluid.
8 Temperature shields
The temperature shields shall be designed and manufactured so as to reduce the temperature at the bursting disc
in order to avoid incorrect functioning of the bursting disc. They shall be used when specified, and shall be supplied
by the manufacturer.
9 Stiffening rings
Stiffening rings shall provide reinforcement to, and protection of, the seating area of the bursting disc without
interfering with the correct functioning of the bursting disc. They shall be permanently attached to the bursting disc.
10 Gaskets/seals
Gaskets/seals forming part of the bursting disc safety device shall be compatible with the chemical, thermal and
mechanical demands of the application (see 4.1)
The use, type, material (see 4.2) and dimensions shall be as specified by the manufacturer.
11 Assembly of bursting disc safety devices
11.1 General
Instructions for the assembly, installation, use and maintenance of the bursting disc safety device shall be provided
by the manufacturer.
The requirements for the assembly of bursting disc safety devices are dependent upon whether:
a) the bursting disc assembly is retained in the bursting disc holder in such a way that the bursting disc assembly
can readily be replaced (see 11.2);
or
b) the bursting disc assembly is permanently retained in the bursting disc holder as an integral assembly (see
11.3).
11.2 Bursting disc safety devices with replaceable bursting disc assemblies
The bursting disc safety device shall be such that following initial assembly of the bursting disc assembly in the
bursting disc holder, it can readily be dis-assembled, a replacement bursting disc assembly fitted and then re-
assembled.
The components of the bursting disc safety device may be assembled either by the manufacturer or the purchaser.
The bursting disc holders and the bursting disc assemblies shall be subjected to testing before assembly in
accordance with clause 14.
Prior to assembly, the manufacturer's model/type reference for the bursting disc holder, marked on the bursting
disc assembly, shall be checked to ensure that it coincides with that marked on the bursting disc holder (see clause
17).
The performance of the bursting disc safety device is determined by the interaction of its components and shall be
assembled in accordance with the manufacturer's instructions.
11.3 Bursting disc safety devices with non-replaceable bursting disc assemblies
The components of the bursting disc safety devices shall be assembled by the manufacturer.
They shall be permanently joined together using welding, crimping, adhesion or other permanent joining process.
Joining materials such as welding materials, brazing materials, solders, adhesives and cements shall be
compatible with the materials of the components being joined and be suitable for the duty. The joining shall be
carried out by suitably experienced/qualified personnel using approved written procedures. The completed joint
shall form an effective seal and pressure containment when installed.
Bursting disc safety devices with non-replaceable bursting disc assemblies shall be manufactured as a batch with
the bursting discs being manufactured from the same lot of material.
The testing and marking shall comply with clauses 14 and 17.
12 Specified bursting pressure requirements
The specified bursting pressure shall be expressed as follows, (see Figure 9):
a) by using specified maximum bursting pressure and specified minimum bursting pressure with a coincident
temperature (see Figure 9a);
or
b) by using specified bursting pressure and performance tolerance with a coincident temperature (see Figure 9b).
MAXIMUM LIMIT OF BURSTING PRESSURE
SPECIFIED MAXIMUM BURSTING PRESSURE (see 3.12)
PERFORMANCE
TOLERANCE
(see 3.15)
ABOVE MINIMUM BURSTING
PRESSURE THE DISC SHALL BURST AT
ANY POINT WITHIN PERFORMANCE
TOLERANCE
SPECIFIED MINIMUM BURSTING PRESSURE (see 3.13)
MINIMUM LIMIT OF BURSTING PRESSURE
SUITABLE
MARGIN
OPERATING PRESSURE (see 3.16) DISC TO REMAIN INTACT
Figure 9 a — Specified maximum bursting pressure and specified minimum bursting pressure with
coincident temperature
MAXIMUM LIMIT OF BURSTING PRESSURE
POSITIVE PERCENTAGE
OR QUANTITY
SPECIFIED BURSTING PRESSURE
PERFORMANCE
(see 3.11)
TOLERANCE
(see 3.15)
NEGATIVE PERCENTAGE
ABOVE MINIMUM BURSTING
OR QUANTITY
PRESSURE THE DISC SHALL BURST AT
ANY POINT WITHIN PERFORMANCE
TOLERANCE
MINIMUM LIMIT OF BURSTING PRESSURE
SUITABLE
MARGIN
OPERATING PRESSURE (see 3.16) DISC TO REMAIN INTACT
Figure 9 b — Specified bursting pressure and performance tolerance with coincident temperature
Figure 9 — Methods for specifying bursting pressure
13 Inspection by the manufacturer
Inspection of components during manufacture shall be carried out in accordance with the manufacturer's
requirements.
On completion of manufacture, all components shall be visually inspected for defects. Any components having
defects, which would cause incorrect functioning, shall be discarded or rectified.
14 Test procedures
14.1 General
The verification of the pressure integrity of bursting disc holders, when required is described in 14.2. The
verification of the specified bursting pressure requirements of bursting discs/bursting disc safety devices with non-
replaceable bursting disc assemblies shall be carried out in accordance with 14.3.
NOTE Additional testing requirements necessitated by a particular application should, where required, be specified by the
purchaser (see 14.4 and 14.5).
14.2 Pressure testing
14.2.1 Bursting disc safety devices with replaceable bursting disc assemblies
When required the manufacturer shall subject each bursting disc holder to an hydrostatic test. The test fluid shall
normally be water. Other fluids may be used providing the appropriate safety precautions are observed.
In order to carry out the pressure test, the bursting disc holder shall be assembled using an appropriate sealing
device in place of a bursting disc and a clamping load sufficient to sustain the test pressure shall be applied.
The test pressure (see 6.1.1.b) shall be maintained at the required value for a sufficient period of time to permit a
visual examination to be made. Any bursting disc holder showing visible signs of leakage or permanent
deformation shall be rejected.
14.2.2 Bursting disc safety devices with non-replaceable bursting disc assemblies
The test pressure for bursting disc safety devices with non-replaceable bursting disc assemblies shall be the
specified bursting pressure.
14.3 Burst testing
14.3.1 General
A number of bursting discs/bursting disc safety devices with non-replaceable bursting disc assemblies shall be
selected at random from each batch (see Table 1) and be subjected to burst testing in accordance with 14.3.2 to
14.3.4 in order to verify that the bursting pressure(s) is (are) in accordance with the specified requirements.
Bursting tests carried out during the manufacture of the batch of bursting discs/bursting disc safety devices with
non-replaceable bursting disc assemblies, i.e. discarded and trial bursts, shall not be considered as part of the
batch.
14.3.2 Coincident temperature in the range 15 °C to 30 °C
Th
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