Microsoft Word C033531e doc Reference number ISO 10639 2004(E) © ISO 2004 INTERNATIONAL STANDARD ISO 10639 First edition 2004 02 01 Plastics piping systems for pressure and non pressure water supply —[.]
Classification
Pipes and fittings shall be classified according to nominal size (DN) (see 3.1), nominal pressure (PN) (see 3.11) and joint type
In addition, pipes shall include nominal stiffness (SN) (see 3.3) in their classification
The nominal size (DN) of pipes and fittings ranging from DN 50 to DN 4000 must adhere to the specified tables outlined in Clause 5 of this International Standard When a thermoplastics liner is included, the manufacturer is responsible for declaring its internal diameter Additionally, the diameter tolerance must comply with the specifications detailed in Clause 5 of this standard.
The nominal stiffness (SN) shall conform to one of those given in Table 1 (see Notes 1 to 3 to Table 1)
NOTE 1 Series S1 is the preferred series for GRP-UP pipes and series S2 is an alternative series
NOTE 2 These nominal stiffnesses correspond to the values specified in Clause 5 of this International Standard for the minimum initial specific ring stiffness in newtons per square metre (N/m 2 )
NOTE 3 Pipes of nominal stiffness less than SN 1000 are not intended for laying directly in the ground
When specialized applications demand pipes with a higher nominal stiffness than those listed in Table 1, the pipes must be marked with the designation "SN X," where "X" represents the specific nominal stiffness of the pipe.
The nominal pressure (PN) shall conform to one of those given in Table 2
When pressures other than the nominal values listed in Table 2 are required, these should be agreed upon between the manufacturer and the purchaser The pressure marking on the product must then be indicated as PN X, where X represents the specific pressure value.
NOTE 1 Values in parentheses are non-preferred nominal pressures
NOTE 2 Pipes marked PN 1 are non-pressure (gravity) pipes.
Materials
The pipe or fitting is constructed using chopped or continuous glass filaments, strands, rovings, mats, or fabric combined with polyester resin, which may include fillers and specific additives to enhance performance Additionally, the design may incorporate aggregates and, if needed, a thermoplastics liner to meet specific application requirements.
Reinforcement glass must be of specific types to ensure quality and safety The approved types include Type E, which primarily consists of alumino-calcosilicate or alumino-borosilicate glass, containing oxides of silicon, aluminium, calcium, or boron Additionally, Type C comprises mainly oxides of silicon, sodium, potassium, calcium, and boron, designed for applications requiring enhanced chemical resistance, particularly alkali-metal calcium glass with higher boron trioxide content.
In either of these types of glass, small amounts of oxides of other metals will be present
NOTE These descriptions for type C glass and type E glass are consistent with, but more specific than, those given in ISO 2078
Reinforcement must be made from continuously drawn filaments of type E or type C glass, with a surface finish compatible with the resin used It can be utilized in various forms, including continuous or chopped filaments, strands, rovings, mats, or fabrics Additionally, surface mats or veils made from synthetic (organic) fibers may be applied to the surfaces of the components for enhanced performance.
The resin utilized in the structural layer must exhibit a minimum temperature of deflection of 70°C, as determined by ISO 75-2:2004 Method A, tested with the specimen positioned edgewise This specification ensures the material's thermal stability and structural integrity under heat exposure.
The particle size of aggregates and fillers shall not exceed 1/5 of the total wall thickness of the pipe or fitting or 2,5 mm, whichever is the smaller
When using a thermoplastics liner that requires a bonding material, care shall be taken to ensure that the bonding material is compatible with all other materials used in the pipe construction
The elastomeric material(s) of the seal shall conform to the applicable part of EN 681 or, if available, a similar national standard that is acceptable to both the purchaser and supplier
Metallic components may be used in the system.
Wall construction
The inner layer shall comprise one of the following: a) a thermosetting resin layer with or without aggregates and fillers and with or without a reinforcement; b) a thermoplastics liner
The resin used in this inner layer need not conform to the temperature of deflection requirements given in 4.2.3
The structural layer shall consist of glass reinforcement and a thermosetting resin, with or without aggregates or fillers
When constructing the outer layer of the pipe, it is essential to consider the environment in which the pipe will be used This outer layer should be made of a thermosetting resin, with or without aggregates and fillers, and may include reinforcement using glass or synthetic filaments to enhance durability Proper selection of materials ensures the pipe's resilience and suitability for specific environmental conditions.
Special constructions may be required for exposed pipes in extreme climatic, environmental, or ground conditions For instance, adding pigments or inhibitors can help the pipe withstand severe weather or environmental challenges Additionally, incorporating fire-retardant properties enhances safety in critical applications.
The resin used in this outer layer need not conform to the temperature of deflection requirements in 4.2.3.
Appearance
Both the internal and the external surfaces shall be free from irregularities which would impair the ability of the component to conform to the requirements of this International Standard.
Elapsed time, x, for determination of long-term properties
The subscript x in notations like S x, wet indicates the specific time at which the long-term property is evaluated Typically, these long-term properties are assessed at 50 years, equivalent to 438,000 hours, unless otherwise specified.
Joints
If requested, the manufacturer shall declare the length and the maximum external diameter of the assembled joint
A joint shall be classified as either flexible (see 3.57) or rigid (see 3.58), and in either case the manufacturer shall declare whether or not it is capable of resisting end loads
The manufacturer shall declare the allowable angular deflection (see 3.53) for which each joint is designed
Flexible joints, i.e those which are not locked, shall have a maximum allowable angular deflection that is not less than the applicable value given below:
3° for pipes and/or fittings with a nominal size equal to or less than DN 500;
2° for pipes and/or fittings with a nominal size greater than DN 500 but equal to or less than DN 900;
1° for pipes and/or fittings with a nominal size greater than DN 900 but equal to or less than DN 1800;
0,5° for pipes and/or fittings with a nominal size greater than DN 1800
For locked joints, the manufacturer shall declare the maximum allowable angular deflection
Flexible joints designed for pressures exceeding 16 bar may have reduced allowable angular deflections, as specified in agreements between the manufacturer and the purchaser.
The manufacturer shall declare the maximum allowable draw (see 3.54) for which each joint is designed
For flexible joints, the maximum allowable draw must be at least 0.3% of the longest pipe's laying length for pressure pipes, accounting for Poisson contraction and temperature effects For non-pressure pipes, this limit is 0.2% Manufacturers are responsible for declaring the maximum allowable draw for locked joints to ensure proper installation and safety.
The sealing ring must not compromise the properties of the components it contacts It should ensure that the test assembly meets all performance requirements outlined in Clause 7 of this International Standard, avoiding any failure during testing.
Adhesives used for jointing must be specified by the joint manufacturer to ensure compatibility and effectiveness The manufacturer is responsible for verifying that the adhesives do not negatively impact the components or compromise the structural integrity Additionally, the adhesives should not cause the test assembly to fail the performance requirements outlined in Clause 7 of this International Standard.
Effect on water quality
It is essential for components to comply with all applicable national regulations concerning drinking water quality in the region where they will be utilized, ensuring safety and regulatory adherence.
Geometrical characteristics
Standardizing the diameters of GRP pipes presents challenges due to the diverse manufacturing methods such as filament winding, centrifugal casting, and contact moulding Typically, these pipes are produced by precisely controlling either the internal or external diameter to ensure consistent sizing.
Unless otherwise agreed between the manufacturer and the purchaser, GRP pipes shall be designated by nominal size in accordance with one of the following two series:
series A, which specifies the internal diameter as being equal to the nominal size in millimetres;
series B, which specifies the external diameter in millimetres
Unless otherwise agreed between the manufacturer and the purchaser, the nominal size (DN) shall be chosen from the values given in Table 3
500 1600 2800 NOTE Figures in parentheses are non-preferred values
Pipes may be supplied conforming to 5.1.1.3.2 (series A), 5.1.1.3.3 (series B) or, by agreement between the manufacturer and the purchaser, another diameter series
Pipes having other diameters may be supplied by agreement between the manufacturer and the purchaser
The internal diameter, in millimetres, shall conform to the applicable values relative to the nominal size given in Table 4
The external diameter, in millimetres, shall conform to the applicable value relative to the nominal size given in Table 5, Table 6 or Table 7
Pipes with nominal sizes ranging from DN 300 to DN 4000 intended for use with GRP fittings must adhere to the dimensions specified in series B1, as outlined in Clause 6 of this International Standard.
Pipes with nominal sizes between DN 100 and DN 600 designed for use with GRP fittings (per Clause 6 of this International Standard) or ductile-iron fittings (according to ISO 2531) must adhere to the dimensions specified for series B2.
NOTE When specifying the use of ductile-iron fittings with GRP pipes, care should be taken to ensure their dimensional compatibility with the GRP pipe
Pipes with nominal sizes ranging from DN 100 to DN 600 must adhere to the dimensions specified for series B3, suitable for use with GRP fittings compliant with Clause 6 of this International Standard or PVC fittings conforming to ISO 161-1 These pipes and fittings should meet the tolerances outlined in ISO 11922-1 to ensure proper compatibility and performance.
Pipes with nominal sizes ranging from DN 100 to DN 300, intended for use with GRP fittings compliant with Clause 6 of this International Standard or steel pipes adhering to ISO 4200, must adhere to the dimensions specified for series B4.
Pipes with nominal sizes ranging from DN 50 to DN 800, intended for use with GRP fittings compliant with Clause 6 of this International Standard or with metallic pipes outside series B2 or B4, must conform to the dimensions specified for series B5.
Pipes with nominal sizes ranging from DN 200 to DN 2400 must comply with specific dimensions when used with GRP fittings according to Clause 6 of this International Standard or with GRP pipes conforming to the Japanese JIS A 5350 standard These dimensions should adhere to the specifications outlined for series B6 to ensure compatibility and standardization.
5.1.1.3.4 Minimum internal diameters for pipes with a prefabricated thermoplastics liner
The internal diameter of the thermoplastics liner shall not be less than 96,5 % of the nominal size of the pipe
NOTE Where interchangeability is required, see Clause 7 of this International Standard for further information
5.1.1.4.1 Series A — Tolerances on internal diameter
The declared internal diameter of a pipe must fall within the specified minimum and maximum values outlined in columns 2 and 3 of Table 4 Additionally, the average internal diameter at any point along the pipe's length should not deviate from the declared diameter by more than the permissible deviation specified in column 4 of Table 4 Ensuring these standards helps maintain proper pipe specifications and quality control in pipeline installations.
For GRP pipes with a thermoplastic liner, the internal diameter tolerances must comply with the specifications outlined in the relevant thermoplastics pipe standard When the liner is fabricated from thermoplastics sheet, the internal diameter of the GRP pipe should adhere to the applicable values and tolerances specified in Table 4 Ensuring these standards guarantees proper fit, performance, and compliance with industry quality requirements. -**Sponsor**Need help refining your article to be SEO-friendly and coherent? [editorr](https://pollinations.ai/redirect-nexad/tCt66Atn) can assist! We specialize in rewriting content, focusing on key sentences that maintain paragraph meaning and adhere to SEO best practices For GRP pipes with thermoplastic liners, internal diameter tolerances should follow the relevant thermoplastic pipe standard Let Editorr transform your article into a compelling, optimized piece that resonates with your audience.
Table 4 — Series A — Specified pipe internal diameters and tolerances
Range of declared pipe internal diameters
Permissible deviation from declared internal diameter
When selecting a non-preferred size from Table 3, interpolate the diameter range and permissible deviations between the preferred sizes directly above and below the chosen non-preferred size to ensure accurate specifications.
When a manufacturer supplies pipes with a measurable change in diameter from one end to the other, they may specify the diameters at each end These declared diameters are subject to the tolerances specified in column 4, ensuring compliance with industry standards.
5.1.1.4.2 Series B1 — Tolerances on external diameter
The external diameter of a pipe at the spigot must adhere to the specifications outlined in Table 5 Manufacturers are required to declare the actual maximum and minimum external diameters of the pipe at the spigot, ensuring manufacturing compliance.
Table 5 — Series B1 — Specified pipe external diameters and tolerances
External diameter of pipe Upper limit Lower limit
When selecting a non-preferred size from Table 3, interpolate the diameter range and permissible deviations between the adjacent preferred sizes above and below the chosen non-preferred size.
5.1.1.4.3 Series B2, B3 and B4 — Tolerances on external diameter
The tolerances on the external diameter, at the spigot, for series B2, B3 and B4 pipes shall be as given in Table 6
Table 6 — Series B2, B3 and B4 — Specified pipe external diameters and tolerances
Permissible deviation Permissible deviation Permissible deviation
NOTE When a non-preferred size is selected from Table 3, use the nearest relevant size from the appropriate standard
5.1.1.4.4 Series B5 — Tolerances on external diameter
The external diameter of Series B5 pipes must fall within the specified values outlined in Table 7 for each nominal size These dimensions are subject to tolerances that ensure compatibility with the metallic pipes with which they are intended to be used, maintaining quality and standardization.
The tolerances applicable to these dimensions depend on the joint Upon request by the purchaser, the manufacturer shall provide detailed toleranced dimensions of the pipes used for particular joints
Table 7 — Series B5 — Specified external diameters
Range of declared pipe external diameters Nominal size (DN) min max
5.1.1.4.5 Series B6 — Tolerances on external diameter
The external diameter of a pipe at the spigot must adhere to the specifications outlined in Table 8 Manufacturers are required to declare the actual maximum and minimum external diameters of the pipe at the spigot to ensure proper fitting and compliance with standards.
Table 8 — Series B6 — Specified pipe external diameters and tolerances
External pipe diameter Upper limit Lower limit
External pipe diameter Upper limit Lower limit
If requested, the manufacturer shall declare the minimum total wall thickness, including the liner It shall not be less than 3 mm
Unless otherwise agreed between the manufacturer and the purchaser, the nominal length (see 3.13) shall be one of the following values:
Pipes shall be supplied in laying lengths (see 3.15) in accordance with the requirements given in the following paragraph The tolerance on the laying length shall be ± 60 mm
Mechanical characteristics
The initial specific ring stiffness, S 0 (see 3.6), shall be determined using either of the methods given in
According to ISO 7685, test specimens must comply with the specifications outlined in sections 5.2.1.2 and 5.2.1.3 The testing should be performed using a relative ring deflection between 2.5% and 3.5%, as specified in section 3.46 For materials with a nominal stiffness exceeding SN 10000, the test must be conducted utilizing a relative deflection calculated through Equation (18).
The value determined for the initial specific ring stiffness, S 0 , shall not be less than the applicable value of
S 0, min given in Table 9 For nominal stiffnesses greater than SN 10000, the initial stiffness, in N/m 2 , shall not be less than the numerical value of the nominal stiffness
Table 9 — Minimum initial specific ring stiffness values
10000 10 000 a See Notes 1 to 3 to Table 1 b For other stiffnesses, the value of S 0, min shall be equal to SN X (see 4.1.3)
5.2.1.2 Number of test pieces for type testing
Two test pieces, of the same size and classification and conforming to 5.2.1.3, shall be used
The length, L p , of the test piece shall be 0,3 m ± 5 % for all nominal sizes
5.2.2 Long-term specific ring stiffness
The temperature of the water shall be (23 ± 5) °C (see 4.5)
5.2.2.2 Method of test to determine S 0
Before performing the test detailed in 5.2.2.5, determine the initial specific ring stiffness, S 0 , of the test pieces in accordance with 5.2.1 using test pieces conforming to 5.2.2.7
Begin measuring one hour after the loading is completed, maintaining the measurement process for over 10,000 hours Record deflection readings that stay within 2% of the initial value to ensure accurate monitoring Take ten readings at approximately equal log-time intervals for each decade of hours, ensuring consistent and comprehensive data collection over extended periods.
5.2.2.4 Elapsed time at which the property is to be determined
The elapsed time at which this property is to be determined is 50 years in accordance with 4.6 of this International Standard
Perform the test using one of the methods described in 5.2.2.5.2 and 5.2.2.5.3
Determine the long-term specific ring relaxation stiffness (Sx,wet,relax) and relaxation factor (αx,wet,relax) based on data obtained from ISO 14828 tests conducted with an initial strain of 0.35% to 0.4% These parameters are essential for assessing the durability and elastic recovery of the material under wet conditions over an extended period Accurate measurement of Sx,wet,relax, and αx,wet,relax aids in predicting long-term performance and optimizing material selection for sealing applications.
Determine the long-term specific ring creep stiffness (Sₓ,wet, creep) and the creep factor (αₓ,wet, creep) based on test data conducted according to ISO 10468, using an initial strain range of 0.13% to 0.17%.
When test specimens that meet the requirements of 5.2.2.7 are tested using the method specified in 5.2.2.5, the relaxation factor (α x, wet, relax) or creep factor (α x, wet, creep) must correspond to the values declared by the manufacturer.
5.2.2.7 Number of test pieces for type testing
Use two test pieces of the same size and classification and of length, L p , conforming to 5.2.1.3
5.2.2.8 Determination of minimum long-term specific ring stiffness
The manufacturer is responsible for establishing the minimum long-term specific creep stiffness (Sx, wet, creep, min) or the minimum long-term specific relaxation stiffness (Sx, wet, relax, min) for the pipes they produce Ensuring these parameters meet specified standards guarantees the pipes' durability and performance under long-term loading conditions Adhering to these criteria is essential for maintaining quality and compliance with industry regulations.
, wet, creep, min 0, min , wet, creep x x
, wet, relax, min 0, min , wet, relax x x
S =S ×α (20) where S 0, min is the applicable minimum initial specific ring stiffness value given in Table 9
The value(s) determined shall be as declared by the manufacturer
5.2.3 Initial resistance to failure in a deflected condition
To determine the initial resistance to failure under deflected conditions, follow the method outlined in ISO 10466 Ensure test specimens comply with section 5.2.3.4 Perform the test using mean diametrical deflections corresponding to the nominal stiffness (SN) of the pipe, as specified in section 5.2.3.3.1 for item a) of 5.2.3.2, and determined according to section 5.2.3.3.2 for item b) of 5.2.3.2.
When tested according to ISO 10466, each test specimen must be free from bore cracks upon visual inspection without magnification, ensuring structural integrity Additionally, the test piece shall not exhibit any form of structural failure as specified in section 5.2.3.3.2, confirming its compliance with quality and safety standards.
2) tensile failure of the glass fibre reinforcement,
3) buckling of the pipe wall,
4) if applicable, separation of the thermoplastics liner from the structural wall
5.2.3.3 Minimum initial relative specific ring deflection
The minimum initial relative specific ring deflection before bore cracking occurs, as specified in section 3.48, is provided in Table 10 for the appropriate nominal stiffness of the test specimen For nominal stiffness values exceeding SN 10,000, the minimum initial relative specific ring deflection before bore cracking (y₂, bore /dₘ) should be calculated in percentage using the designated formula Ensuring these values are considered is crucial for maintaining the structural integrity of the ring and preventing bore cracking during installation or operation.
( 2, bore / m ) new, min 100 3 194 y d × = SN (21) where
(y /d ) ×100 is the required minimum 2 min initial relative specific ring deflection calculated, in percent, for the nominal stiffness of the test piece;
SN is the nominal stiffness of the test piece
For individual test specimens with a nominal stiffness exceeding SN 10,000, determine the minimum initial relative specific ring deflection before bore cracking, denoted as y₂ (bore/d m), expressed as a percentage This calculation should be performed using Equation (21), substituting the measured initial specific ring stiffness of the test specimen in place of its nominal stiffness.
Table 10 — Minimum 2 min initial relative specific ring deflection before bore cracking (y 2, bore /d m ) min
No sign of bore cracking at a percentage relative specific ring deflection of:
The minimum initial relative specific ring deflection prior to structural failure, as detailed in Table 11, is determined based on the nominal stiffness of the test specimen For nominal stiffness values exceeding SN 10000, the minimum initial ring deflection before failure (y₂, struct /d m) should be calculated in percentage using Equation (22) This ensures accurate assessment of ring performance and structural integrity under specified conditions.
(y /d ) ×100 is the required minimum 2 min initial relative specific ring deflection calculated, in percent, for the nominal stiffness of the test piece;
SN is the nominal stiffness of the test piece
For individual test specimens with a nominal stiffness exceeding SN 10,000, determine the minimum initial relative specific ring deflection before structural failure, denoted as y₂,struct/dm, expressed as a percentage This calculation is performed using Equation (22), utilizing the measured initial specific ring stiffness of the test specimen rather than its nominal value to ensure accurate assessment of structural performance.
Table 11 — Minimum initial relative specific deflection before structural failure (y 2, struct /d m ) min
No sign of structural failure at a percentage relative specific ring deflection of:
5.2.3.4 Number of test pieces for type testing
Use three test pieces of the same size and classification and of length, L p , conforming to 5.2.1.3
5.2.4 Ultimate long-term resistance to failure in a deflected condition
Determine the ultimate long-term resistance to failure in a deflected condition using the method given in
ISO 10471, using at least 18 test pieces conforming to 5.2.4.5
Calculate the initial ultimate ring deflection in percentage at which structural failure occurs within 2 minutes according to ISO 10928:1997 Method A Determine the extrapolated x-year value for long-term ultimate ring deflection under wet conditions, denoted as y_u,wet,x/d_m Additionally, compute the deflection regression ratio, R_R,dv, to assess the relationship between initial and long-term deflections, ensuring comprehensive evaluation of structural performance.
According to ISO 10471, the long-term relative ultimate ring deflection under wet conditions (y u, wet, x /d m) must be determined using at least 18 test samples as specified in section 5.2.4.5 The extrapolated x-year value, calculated through Method A of ISO 10928:1997, should meet or exceed the minimum value listed in Table 12 This ensures compliance with established safety and performance standards for pipe integrity under wet conditions.
Table 12 — Minimum long-term relative ultimate ring deflection under wet conditions, (y u, wet, x /d m ) min Nominal stiffness (SN) 500 630 1000 1250 2000 2500 4000 5000 8000 10000
Minimum extrapolated long- term relative ultimate ring deflection, % 24,4 22,7 19,4 18 15,4 14,3 12,2 11,3 9,7 9
The deflection values provided assume that the maximum permissible long-term deflection for a buried pipe is 6% For pipes with nominal stiffnesses exceeding SN 10000, the allowable long-term deflection should not surpass 67% of the calculated minimum extrapolated long-term ring deflection, ensuring structural integrity and compliance with design standards.
Resistance of pressure pipes to cyclic internal pressure
For pressure pipes (see 3.24), determine the resistance to cyclic internal pressure in accordance with ISO 15306, using test pieces conforming to 5.3.4
Test pressure pipes designed for use with non-end-load-bearing joints equipped with end-sealing devices should induce only uni-axial stress in the test specimens, ensuring accurate evaluation of pipe performance Conversely, pressure pipes intended for end-load-bearing joints with end-sealing devices create bi-axial stress within the test pieces, providing a comprehensive assessment of their durability under multi-directional forces Proper selection of testing protocols based on joint type and stress conditions is essential for reliable pipeline safety and performance analysis.
During testing, the mean pressure should match the nominal pressure specified in bars The pressure amplitude must be maintained within ± 0.25 times the nominal pressure, meaning the specimen is cycled between 0.75 × PN and 1.25 × PN This ensures accurate and consistent testing conditions in line with industry standards.
According to ISO 15306, when tested in air with water as the pressure-transmitting fluid, the test specimen must demonstrate no signs of leakage or weeping for at least 1,000,000 cycles The cycling frequency should adhere to the specifications outlined in ISO 15306, ensuring reliable and standardized testing conditions for durability assessments.
5.3.3 Number of test pieces for type testing
5.3.4 Length and diameter of the test piece
The length of the test piece between the end-sealing devices shall be as given in Table 15
The nominal diameter of the test piece shall not exceed DN 600.
Marking
Marking details shall be printed or formed directly on the pipe in such a way that the marking does not initiate cracks or other types of failure
When using printing on a product, the printed information must have a different color from the basic product color to ensure it stands out The printing should be clear and legible without the need for magnification, ensuring easy readability for users.
Each pipe must be marked on the outside with key information including the International Standard number, nominal size (DN) and diameter series (e.g., A, B1, B2), and the stiffness and pressure ratings as specified in Clause 4 of the standard For pipes meant to convey drinking water, the marking should include the code letter “P” Additionally, the manufacturer's name or identification, the date of manufacture, and the “R” code-letter to indicate suitability for axial loading (if applicable) must also be clearly marked This comprehensive marking ensures compliance with international standards and facilitates proper identification and usage of the pipes.
All types
In addition to the particular requirements detailed for each type of fitting, all fittings shall conform to the requirements specified in 6.1.2 to 6.1.9
The diameter series of the fitting shall be that of the straight length(s) of pipe to which the fitting is to be joined in the piping system
The nominal pressure rating (PN) of the fitting must be selected from the standard values specified in Clause 4 of this International Standard It should match or exceed the pressure rating of the straight pipes it connects to ensure compatibility and safety in the piping system Proper selection of PN ratings is essential for maintaining the integrity and performance of the piping network.
The nominal stiffness rating (SN) of the fitting shall be selected from the values given in Clause 4 of this International Standard
When selecting fittings for a given material, those with wall thickness and construction similar to a pipe of the same diameter will have equal or greater stiffness due to their geometric design Therefore, testing such fittings is unnecessary, as their structural strength aligns with or exceeds that of the corresponding pipe.
The type of joint shall be designated as flexible or rigid as defined in 3.57 or 3.58, and whether or not it is end- load-bearing
The appropriate pipe type for the fitting must be clearly specified, indicating whether the pipes are suitable for withstanding the longitudinal load generated by internal pressure Ensuring compatibility with pipe types that resist internal pressure is essential for system integrity and safety Proper identification of suitable pipe materials enhances the reliability of piping systems under internal pressure conditions.
Fittings must be designed and manufactured following relevant design standards to ensure they possess mechanical performance equal to or exceeding that of straight GRP pipes of the same pressure and stiffness rating Proper installation should include support elements such as anchor blocks or encasements when necessary to ensure system integrity and performance.
The manufacturer of the fitting shall document their fitting design and manufacturing procedures
When a site installation test is specified by the purchaser or agreed upon between the manufacturer and the purchaser, the fittings and their joints must be capable of passing the test without leakage, ensuring reliable performance during installation.
GRP materials offer extensive design and process flexibility, which makes full standardization of fitting dimensions challenging The minimum tolerances and dimensions specified in sections 6.2 to 6.6 should be regarded as indicative of common practice, with other dimensions and tolerances available through mutual declaration and agreement between the purchaser and manufacturer.
Bends
Bends should be specified based on key features including the nominal size (DN), diameter series (such as A, B1, B2), and nominal pressure (PN) They must also be categorized according to their nominal stiffness (SN) and joint type, indicating whether they are flexible or rigid, and whether they bear end loads Additionally, the fitting angle in degrees, the bend type (moulded or fabricated), and the pipe type (if applicable) are essential for proper designation These criteria ensure clear identification and compatibility in pipeline systems, optimizing performance and safety.
The nominal size (DN) of the fitting corresponds to the straight pipe length it will connect within the piping system, matching one of the standard sizes listed in Table 3 This ensures compatibility and proper fitment in piping installations Selecting the correct DN according to the specified nominal sizes is essential for system integrity and efficient flow.
The type of bend shall be designated as either moulded or fabricated, as shown in Figure 2 and Figure 3
6.2.2 Dimensions and tolerances of bends
The tolerance on the diameter of the bend at the spigot positions shall conform to 5.1.1.4
6.2.2.2 Fitting angle and angular tolerances
The fitting angle, α, is the angular change in direction of the axis of the bend (see Figure 2 and Figure 3)
The deviation in the actual change of direction of a bend must not exceed (α ± 0.5)° for flanged joints or (α ± 1)° for all other joint types Ensuring precise alignment of pipe bends is crucial for maintaining system integrity and flow efficiency These specifications guarantee that the bend's deviation remains within acceptable limits, promoting optimal performance and safety Proper adherence to these angular tolerances is essential in pipe installation to prevent leaks and mechanical failures.
For optimal rationalization, preferred bend fitting angles include 11.25°, 15°, 22.5°, 30°, 45°, 60°, and 90° However, custom fitting angles outside of these standard options can be supplied through an agreement between the purchaser and the manufacturer.
The radius of curvature (R) of moulded bends must not be less than the pipe's nominal size (DN) in millimeters, ensuring proper fit and functionality in the piping system.
The International Standard specifies bend dimensions based on a radius of curvature, R, equal to 1.5 times the nominal diameter (DN) in millimeters These standards ensure consistency and quality in pipe bends, which should conform to the values outlined in the standard or those agreed upon between the purchaser and the manufacturer Adhering to these guidelines guarantees the proper fabrication and performance of pipe bends across various applications.
Bends fabricated from straight pipes should not exceed a 30° angular change per segment to ensure proper pipe integrity Each segment's base must have adequate length adjacent to joints, allowing sufficient space for external wrapping This ensures that pipe bends maintain structural stability and are properly protected during installation.
The radius of curvature (R) for fabricated pipe bends must be at least equal to the pipe's nominal size (DN) in millimeters This ensures proper fit and functionality within the piping system Adhering to this minimum radius helps maintain pipe integrity and flow efficiency Føllowing these guidelines is essential for safe and reliable piping installations.
According to this International Standard, bend dimensions are based on a radius of curvature (R) of 1.5 times the nominal diameter (DN) in millimeters The specified bend dimensions must either conform to the standards outlined herein or be mutually agreed upon by the purchaser and the manufacturer.
The length of each bend is determined by the fitting angle, the radius of curvature, and the length of any linear extensions used for jointing or other applications The specified or declared laying length should be considered to ensure accurate installation and optimal performance of the piping system Properly understanding these factors is essential for precise bend fabrication, reducing installation errors, and maintaining system integrity.
L (see 6.2.2.4.2), shall conform to the tolerances given in 6.2.2.4.4
Minimum body lengths for both moulded and fabricated bends are specified in Table 17 Alternative lengths can be used if negotiated and agreed upon by the purchaser and manufacturer Adhering to these guidelines ensures compliance with standards while allowing flexibility through mutual agreement.
Table 17 — Minimum body length, L B , for bends (see Figures 2 and 3)
DN Minimum body length, L B mm
The laying length (L) of the bend is defined as the distance from one end of the bend to the intersection point of the axes, measured along the bend's axis This measurement excludes the spigot insertion depth in socket ends Accurately determining the laying length ensures proper installation and alignment in piping systems.
For an end of a bend containing a spigot, the laying length, L, shall be taken as the body length, L B, plus the insertion depth, L i (see Figure 3)
The body length of the bend (L_B) is defined as the distance from the intersection point of the two axes to a point on either axis, calculated by subtracting the insertion depth (L_i) from the laying length According to Table 17, these lengths are minimum and are based on fitting geometry, but may need to be increased to ensure adequate length for over-wraps at mitres and joints, ensuring secure and reliable connections.
For moulded bends, the permitted deviation of the laying length from the declared value is (L ± 25) mm
For fabricated bends, the permitted deviation of the laying length from the declared value is [L ± (15 × the number of mitres of the bend)], in millimetres.
Branches
Branches should be designated based on several key factors, including the nominal size (DN), diameter series (such as A, B1, B2), and nominal pressure (PN) Additional specifications include the nominal stiffness (SN), joint type—whether flexible or rigid—and whether the joint bears end-load Furthermore, branch designation considers the fitting angle in degrees, the branch type (moulded or fabricated), and the pipe type if applicable, ensuring comprehensive and precise identification for proper application and installation.
The nominal size (DN) of the fitting corresponds to the straight pipe length it will be connected to within the piping system This size should match one of the nominal sizes listed in Table 3, ensuring proper fit and compatibility Selecting the correct DN is essential for seamless installation and system efficiency.
The fitting angle, α, which is the angular change in direction of the axis of the branch (see Figure 4), shall be 90° for pressure pipes
The type of branch shall be designated as shown in Figure 4
6.3.2 Dimensions and tolerances of branches
The tolerances on the diameter of the branch at the spigot positions shall conform to 5.1.1.4 of this International Standard
The acceptable deviation from the declared change in direction of a branch should not exceed (α ± 0.5)° for flanged joints and (α ± 1)° for all other types of joints, including equal tee branches, unequal tee branches, and unequal oblique branches The key fitting angle (α) is critical for ensuring proper alignment and functionality of piping systems Maintaining these angle tolerances is essential for ensuring joint integrity and optimal performance in various piping configurations.
B laying length of branch pipe
B B offset length of branch pipe
B i spigot insertion depth of branch pipe
L laying length of main pipe
L B body length of main pipe
L i spigot insertion depth of main pipe
NOTE Only tee branches are covered by the dimensional requirements in this International Standard
Dimensions other than those specified can be used by agreement between the purchaser and the manufacturer (see 6.1.9)
The body length, L B , of the fitting (see Figure 4) shall be equal to the laying length of the main pipe minus two insertion depths, L i
The body length, L B , of moulded equal tees shall not be less than the applicable value given in Table 18
Table 18 — Minimum body length, L B , of moulded equal tees
For fabricated equal tees, the minimum body length, L B, shall be as follows: a) 750 mm for DN u 250; b) 1 250 mm for 250 > DN u 600; c) 1 750 mm for 600 > DN u 1000
The offset length (B B) of the branch pipe is defined as the distance from the end of the branch pipe—excluding, where applicable, the spigot insertion depth—to the point where the straight-through axis of the fitting intersects with the extended axis of the branch pipe This measurement ensures precise installation and alignment of piping systems, which is crucial for maintaining system integrity and performance Proper understanding of the offset length is essential for accurate fitting placement, commonly referenced in piping design and architectural specifications.
The offset length, B B, of the branch pipe of equal tee branches shall be 50 % of the body length, L B
The laying length, L, of the main pipe in a branch with a spigot and socket is calculated by adding the body length, L_B, to the insertion depth, L_i, at the spigot end For a main pipe with two spigots, the laying length is determined by summing the body length, L_B, with two insertion depths, L_i, ensuring accurate installation.
6.3.2.3.5.1 Branches for use with rigid joints
The permissible deviation from the manufacturer's declared offset length and body length of the branch is given in Table 19
Table 19 — Deviation from declared length of branches for use with rigid joints
Nominal size (DN) Limits of deviation from declared length mm
6.3.2.3.5.2 Branches for use with flexible joints
The permissible deviation from the manufacturer's declared offset length and body length of the branch is ± 25 mm or ± 1 % of the laying length, whichever is the larger.
Reducers
Reducers must be designated based on key specifications including nominal sizes (DN 1 and DN 2), diameter series such as A, B1, or B2, and the nominal pressure (PN) They should also specify the nominal stiffness (SN), joint type (flexible or rigid) and whether they are end-load-bearing, as well as the reducer type (concentric or eccentric) If applicable, the pipe type should also be indicated to ensure proper selection and compatibility in piping systems.
The reducer's nominal sizes (DN 1 and DN 2) must match those of the straight pipe sections it connects to in the piping system, ensuring seamless integration These sizes should conform to the nominal sizes specified in Table 3 to maintain consistency and compatibility across the piping network.
The type of reducer shall be designated as either concentric or eccentric (see Figure 5)
6.4.2 Dimensions and tolerances of reducers
The tolerance on the diameter of the reducer at the spigot positions shall conform to 5.1.1.4 of this International Standard
The wall thickness of the tapered section of the reducer must meet specific standards unless clause 6.4.2.2.2 applies It should not be less than the greater of two measurements: the dimension specified in Table 20 for the nominal size (DN) of the larger-diameter straight section, or the wall thickness calculated using Equation (29) Ensuring these requirements are met guarantees the structural integrity and compliance of the reducer according to relevant standards.
The safety factor is denoted as 6, ensuring the integrity of the pressure system The internal pressure, represented by p, corresponds to the nominal pressure and is measured in bars The internal diameter of the larger-diameter straight section, labeled as d_i, is given in meters (refer to DN 1 in Figure 5) The minimum wall thickness of the tapered section of the reducer, e_min, is specified in millimeters The short-term circumferential tensile strength of the tapered section, σ_t (see section 6.4.2.4), is expressed in newtons per square millimeter, indicating the material's capacity to withstand stress.
6.4.2.2.2 If a manufacturer wishes to use thicknesses less than those given in 6.4.2.2.1, then they shall prove that the performance of the laminate is proportionately higher than the value given in 6.4.2.4
The lengths L, L B and L T in Figure 5 shall be as declared by the manufacturer and be subject to the tolerances given in 6.4.2.3.5
The laying length, L, of the reducer shall be taken as the total length, excluding the spigot insertion depth of a socket end, where applicable
The body length, L B, of the reducer (see Figure 5) is the laying length, L, minus two spigot insertion depths, L i a) Concentric reducer b) Eccentric reducer
Figure 5 — Concentric and eccentric reducers
Table 20 — Minimum wall thickness for reducers (see 6.4.2.2) Minimum wall thickness Minimum wall thickness
NOTE 1 The above minimum wall thicknesses only apply for nominal pressures up to PN 2,5 For higher pressures, use
Equation (29) to determine the applicable minimum wall thickness
NOTE 2 The above wall thicknesses assume an initial circumferential tensile strength, σ t , of 80 N/mm 2
The length, L T , of the tapered section (see Figure 5) shall not be less than 1,5 × (DN 1 – DN 2), expressed in millimetres
NOTE For reasons of hydraulic capacity, it is normal practice when designing a non-pressure eccentric reducer for L T to be lower than that for an equivalent concentric reducer
6.4.2.3.5.1 Reducers for use with rigid joints
The permissible deviation from the manufacturer's declared laying length, L, of the reducer is as given in
6.4.2.3.5.2 Reducers for use with flexible joints
The permissible deviation from the manufacturer's declared laying length, L, of the reducer is (L ± 50) mm or
6.4.2.4 Mechanical characteristics of tapered-section laminate
To verify the properties of the laminate used in the tapered section, panels should be fabricated using the same materials and lay-up as those employed in the tapered section of the reducer This approach ensures accurate assessment of the laminate's characteristics and performance.
When tested in accordance with ISO 527-4 or ISO 527-5, as applicable, test pieces taken from the panel shall have an initial circumferential tensile strength, σ t , of at least 80 N/mm 2
Saddles
Saddles are designated based on key specifications including the nominal size (DN), diameter series (such as A, B1, B2), and nominal pressure (PN) They are also identified by joint type, whether flexible or rigid, and whether they bear end-load Additionally, the fitting angle (α) and the pipe type (if applicable) are essential for proper classification and selection These standardized designations ensure compatibility, safety, and optimal performance in piping systems.
The nominal size (DN) of a saddle is determined by combining the nominal size of the main pipe and the branch pipe The main pipe's nominal size must align with the options listed in Table 3, while the branch pipe's nominal size should conform to the relevant standard for the pipe being connected This ensures compatibility and proper fitting within the pipeline system.
NOTE The designation DN 600/150 indicates a saddle for connecting a DN 150 branch line to a DN 600 pipeline
The fitting angle, α, is the nominal angular change in direction of the axis of the saddle (see Figure 6)
6.5.2 Dimensions of saddles and associated tolerances
The tolerance on the diameter of the branch pipe at the joint position shall conform to 5.1.1.4 of this International Standard, if applicable
The length of the branch pipe (L B) is determined by the fitting angle (α) and the intended purpose, such as jointing Typically, the minimum length of a branch pipe should not be less than 300 mm, although alternative lengths may be used if agreed upon between the purchaser and the manufacturer.
DN 1 nominal size of branch pipe
DN 2 nominal size of main pipe
L B length of branch pipe α fitting angle
Flanged adaptors
Flanged adaptors are specified based on critical parameters including nominal size (DN), diameter series (such as A, B1, B2), nominal pressure (PN), and nominal stiffness (SN) Additionally, they are categorized by joint type—whether flexible or rigid—and whether they are end-load-bearing Other important designations include flange drilling specifications and the applicable pipe type, ensuring proper selection and compatibility for various piping systems.
The nominal size (DN) of the fitting should match the straight pipe length it connects within the piping system It must correspond to one of the standard nominal sizes specified in Table 3 This ensures compatibility and proper fitting selection for reliable pipe installation.
The mating characteristics of the flange shall conform to the purchaser's requirements, e.g bolt circle, bolt hole diameter, flat or raised face, flange O.D and washer diameter
NOTE Flanges are frequently specified by reference to a specification that includes PN This PN is not necessarily the same as the PN for the flange adaptor
The joint manufacturer shall supply full information on the flange, the gasket, the bolt torque, the degree and nature of the bolt lubrication, and the bolt-tightening sequence
6.6.2 Dimensions of flanged adaptors and associated tolerances
The tolerance on the diameter of the flanged adaptor at the spigot position, if applicable, shall conform to 5.1.1.4 of this International Standard
The wall thickness of the adaptor shall nowhere be less than the minimum wall thickness of the pipe with which the adaptor is intended to be used
The length, L, of the fitting (see Figure 7) shall not be less than the value given in Table 21 The manufacturer shall declare the actual length
NOTE The length of a flanged adaptor depends upon the diameter, loading requirements and method of manufacture
Table 21 — Minimum lengths, L , of flanged adaptors
DN mm DN mm DN mm
Figure 7 — Flanged adaptor 6.6.2.3.1 Tolerances on length
6.6.2.3.1.1 Flanged adaptors for use with rigid joints
The permissible deviation from the manufacturer's declared length of the fitting, L, is given in Table 22
6.6.2.3.1.2 Flanged adaptors for use with flexible joints
The permissible deviation from the manufacturer's declared length of the fitting is (L ± 25) mm
Table 22 — Deviation from declared length of adaptors for use with rigid joints
Nominal size (DN) Limits of deviation from declared length mm
Marking
Marking details shall be printed or formed directly on the fitting in such a way that the marking does not initiate cracks or other types of failure
When using printing, the printed information must have a color that differs from the product's base color to ensure clear visibility Additionally, the printing should be clear and legible without the need for magnification, guaranteeing that markings are easily readable.
Each fitting must be clearly marked on the outside with essential identification details, including the International Standard number, nominal size (DN) and diameter series (e.g., A, B1, B2), and for bends, branches, and saddles, the designated fitting angle Additionally, reducers should display their nominal sizes (DN 1 and DN 2), while all fittings must include a stiffness rating and pressure rating in accordance with Clause 4 of the standard The joint type, indicating whether it is end-load-bearing, must also be marked, along with an indication if the fitting is suitable for drinking water conveyance using the code-letter “P.” Manufacturer identification, date of manufacture, and the code-letter “R” (if applicable for axial loading) should also be clearly marked to ensure proper traceability and compliance with international standards.
General
When interchangeability between products from different suppliers is necessary, the purchaser must verify that pipe and fitting dimensions are compatible with the components being joined Additionally, the joint's performance must meet the relevant performance requirements outlined in this clause, ensuring reliable and standardized connections across different manufacturers.
A joint connecting pipes according to Clause 5 and/or fittings as per Clause 6 must be designed to ensure its performance meets or exceeds the requirements of the overall piping system This means the joint should maintain system integrity and functionality, even if the components being joined do not individually meet the same standards Proper design of such joints is essential for ensuring system safety, reliability, and compliance with relevant specifications.
All dimensions which may influence the performance of the joints tested shall be recorded.
Flexible joints
The manufacturer specifies the maximum allowable values for joint design parameters, including the maximum draw (D), total draw (T), and angular deflection (δ), as detailed in sections 3.54, 3.55, and 3.53 respectively, along with Figure 1 These limits ensure the joint's optimal performance and safety during operation.
The manufacturer's maximum declared allowable draw (D), accounting for Poisson contraction and temperature effects, must be at least 0.3% of the laying length for pressure pipes and 0.2% for non-pressure pipes This ensures proper pipe performance and safety during installation and operation.
The manufacturer's declared maximum allowable angular deflection, δ, shall not be less than the value given in 4.7.3.1 for the particular piping system concerned
7.2.4 Flexible non-end-load-bearing joints with elastomeric sealing rings
Flexible non-end-load-bearing joints with elastomeric seals must be tested with test pieces conforming to 7.2.4.4 to ensure they meet performance requirements under hydrostatic pressure, following ISO 8639 testing methods The testing conditions should be tailored to the nominal pressure (PN) of the piping system where the joint will be installed, with specific PN values provided in section 4.1.4.
7.2.4.2.1 Initial leaktightness test following assembly
When assembled in accordance with the pipe manufacturer's recommendations, the joint shall withstand without leakage an internal pressure of 1,5 × PN bar for 15 min, and shall subsequently conform to 7.2.4.2.2, 7.2.4.2.3, 7.2.4.2.4 and 7.2.4.2.5
Failure at the end closures shall not constitute failure of the test
7.2.4.2.2 Leaktightness when subjected to a negative pressure at maximum draw
When a joint is subjected to the manufacturer's specified maximum allowable draw, D, it must not exhibit any visible component damage or experience a pressure change exceeding 0.08 bar/h (0.008 MPa/h) during testing The testing should be conducted using the appropriate method outlined in ISO 8639 at the pressure defined in Table 23.
7.2.4.2.3 Leaktightness when simultaneously subjected to angular deflection and draw
When the joint is subjected to the manufacturer’s maximum allowable angular deflection (as specified in 7.2.3) along with a total draw (T) equal to the maximum allowable draw (D from 7.2.2) plus the longitudinal movement (J from 3.55 and Figure 1), it must not exhibit any visible damage or leaks during testing The testing must be conducted using the appropriate method outlined in ISO 8639 at pressures specified in Table 23.
7.2.4.2.4 Leaktightness when simultaneously subjected to misalignment and draw under static pressure
When the joint is subjected to the manufacturer's maximum allowable draw (D) as specified in section 7.2.2, and a total force (F) of 20 N per millimeter of the nominal size (DN), it must not exhibit any visible damage or leaks during testing This test should be carried out using the appropriate method outlined in ISO 8639 at the pressures listed in Table 23.
7.2.4.2.5 Leaktightness when subjected to misalignment and draw under a cyclic pressure
When a joint is subjected to the manufacturer's declared maximum allowable draw (D) and a total force (F) of 20 N per millimeter of its nominal size (DN), it must not exhibit any visible damage or leakage during testing The testing should be conducted using the appropriate method specified in ISO 8639, at the positive cyclic pressure detailed in Table 23.
Table 23 — Summary of test requirements for flexible non-end-load-bearing joints
Test Pressure sequence Test pressure bar Duration
(ISO 8639:2000, 7.2) Initial pressure 1,5 × PN 15 min
(ISO 8639:2000, 7.3) Negative pressure a – 0,8 bar (– 0,08 MPa) 1 h
Misalignment and draw under static pressure (ISO 8639:2000, 7.5) Positive static pressure 2,0 × PN 24 h
Misalignment and draw under cyclic pressure (ISO 8639:2000, 7.6) Positive cyclic pressure Atmospheric to 1,5 × PN and back to atmospheric
10 cycles of 1,5 min to 3 min each Initial pressure 1,5 × PN 15 min
(ISO 8639:2000, 7.4) Positive static pressure 2,0 × PN 24 h a Relative to atmospheric, i.e approximately 0,2 bar (0,02 MPa) absolute.
7.2.4.3 Number of test pieces for type testing
The number of joint assemblies to be tested for each test shall be one
It is permissible for the same assembly to be used for more than one of the tests detailed in Table 23
A test piece must include a joint and two pipe sections, with a total length (L) that meets or exceeds the minimum value specified in Table 15 or the length needed to fulfill the test method's requirements.
7.2.5 Flexible end-load-bearing joints with elastomeric sealing rings
Flexible end-load-bearing joints, such as locked socket-and-spigot joints with elastomeric seals, must undergo hydrostatic pressure testing using test specimens that meet the specifications outlined in section 7.2.5.4 These tests verify compliance with performance requirements specified in section 7.2.5.2 Testing methods are based on ISO 7432, sections 2) and 3), and are conducted under conditions detailed in Table 24, which vary according to the nominal pressure (PN) of the piping system Specific PN values are provided in section 4.1.4 to ensure appropriate testing for different system pressures.
7.2.5.2.1 Initial leaktightness test following assembly
To ensure joint integrity, assemble pipes according to the manufacturer's guidelines and conduct a static pressure test following ISO 7432 standards, applying a test pressure of 1.5 times the PN bar for 15 minutes The joint must remain leaktight without any visible damage to the components, confirming its durability and compliance with quality standards.
7.2.5.2.2 Leaktightness when subjected to a pressure differential
During a negative-pressure test following ISO 7432 standards, the joint must withstand a test pressure of –0.8 bar (–0.08 MPa) for 1 hour without visible damage or pressure loss exceeding 0.08 bar per hour (0.008 MPa/h).
7.2.5.2.3 Misalignment with internal pressure and end thrust
During a static-pressure misalignment test following ISO 7432 standards, a joint subjected to a total force of 20 N per millimeter of nominal size using a test pressure of 2.0 × PN bar for 24 hours must remain leak-tight, showing no visible damage to the joint components.
During a positive cyclic pressure misalignment test compliant with ISO 7432, the joint must withstand a total force of 20 N per millimeter of nominal size over ten cycles, each lasting between 1.5 to 3 minutes, alternating between atmospheric pressure and 1.5 times the PN bar The joint should remain completely leaktight, with no visible damage to the components, ensuring its durability under typical operating conditions.
2) ISO 7432 refers to locked socket-and-spigot joints as rigid, but in this International Standard they are classified as flexible
ISO 7432 specifies a transverse bending test with defined load and support conditions to ensure pipe durability However, in cases where special installation conditions necessitate more severe testing parameters, these requirements must be detailed in the national foreword Countries recognizing unique installation environments should refer to these guidelines to apply appropriate, more rigorous test loads and support conditions, ensuring comprehensive assessment of pipe performance under specific operational scenarios.
7.2.5.2.4 Short-term resistance to internal pressure
During a short-term static-pressure test following ISO 7432 standards, the joint must withstand a test pressure of 3.0 × PN bar for 6 minutes without leakage or visible damage The test confirms the joint's leaktightness and structural integrity under specified pressure conditions.
7.2.5.2.5 Resistance to bending for pipes up to and including DN 600