SIST ISO 7268:2001/AMD 1:2001

Pipe components - Definition of nominal pressure - Amendment 1

The amendment refers to clause 2 'definition' and states: delete the text and substitute: nominal pressure (PN): A numerical designation which is a convenient round number for reference purposes. All equipent of the same nominal size (DN) designated by the same PN number shall have compatible mating dimensions. Gives additionally two notes.

Tuyauterie — Définition de la pression nominale — Amendement 1

Cevne komponente - Definicija imenskega tlaka - Dopolnilo 1

General Information

• Status: Published
• Publication Date: 31-Aug-2001
• ICS: 23.040.01 - Pipeline components and pipelines in general
• Technical Committee: TLP - Pressure vessels
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Sep-2001
• Due Date: 01-Sep-2001
• Completion Date: 01-Sep-2001
• Ref Project: ISO 7268:1983/Amd 1:1984 - Pipe components - Definition of nominal pressure - Amendment 1

Relations

• Amends: SIST ISO 7268:2001 - Pipe components -- Definition of nominal pressure
• Effective Date: 06-Jun-2022
• Child: ISO 7268:1983 - Pipe components - Definition of nominal pressure
• Effective Date: 12-May-2008
• Child: SIST ISO 7268:2001 - Pipe components -- Definition of nominal pressure
• Effective Date: 18-Apr-2008

Overview

SIST ISO 7268:2001/AMD 1:2001 is an important international standard amendment that clarifies the definition of nominal pressure (PN) for pipe components. Developed by ISO Technical Committee ISO/TC 5 focused on ferrous metal pipes and metallic fittings, this amendment refines how nominal pressure should be understood and applied across pipeline components. Published in 1984, it enhances compatibility and interoperability within piping systems by standardizing the designation and dimensioning principles associated with nominal pressure and nominal size (DN).

Key Topics

• Nominal Pressure (PN) Definition
  This amendment replaces the previous clause 2 with a precise and simplified definition:

  Nominal pressure (PN) is a numerical designation which is a convenient rounded number for reference purposes.
  This makes it clear that PN values serve as standardized reference points rather than exact pressure limits.

• Compatibility Based on PN and DN
  All equipment with the same nominal size (DN) and designated by the same PN number must have compatible mating dimensions. This ensures that components such as pipes, flanges, and fittings can be reliably connected without issues arising from dimension mismatches.

• Guidance Notes

  • The maximum allowable working pressure for a component depends on the material, design, and operating temperature. Correct pressure ratings should be selected from specific pressure/temperature rating tables provided in appropriate standards.
  • The nominal pressure designation uses the letters “PN” followed directly by the assigned reference number, for example, PN10, PN16.

Applications

This amendment is essential for industries involving pipeline construction, maintenance, and design to ensure proper selection and compatibility of pipe components:

• Pipeline Engineering
  Enables engineers to specify pressure classes clearly, ensuring that pipes and fittings will fit properly and safely handle intended pressures.

• Manufacturing of Pipe Components
  Manufacturers apply the PN designation to standardize product ranges, simplifying inventory, quality control, and interchangeability.

• Pressure Rating Selection
  Assists designers and safety inspectors in choosing correct components that meet not only dimensional but also performance requirements at given operating conditions.

• Standardization in Construction Projects
  Facilitates international and cross-sector projects by creating a common language and reference for nominal pressure and pipe sizing.

Related Standards

SIST ISO 7268:2001/AMD 1:2001 works in conjunction with other key standards in the field of piping and pressure components, including:

• ISO 7268:1983 – Original standard for pipe component pressure designations.
• ISO/TC 5 Series Standards – Cover ferrous metal pipes and fittings with related specifications.
• ISO Pressure-Temperature Rating Tables – Provide detailed guidance for selecting allowable working pressures based on material and temperature.
• ISO 6708 – Defines nominal size (DN) designations to complement PN definitions.

Summary

SIST ISO 7268:2001/AMD 1:2001 clarifies the concept of nominal pressure (PN) as a practical, rounded reference number enabling consistent classification and interoperability of pipe components across various industries. By standardizing dimension compatibility and encouraging proper pressure rating selection, it enhances pipeline safety, reliability, and simplifies component specification. This amendment remains a cornerstone for manufacturers, engineers, and standards bodies working with pressure piping systems internationally.

Keywords: ISO 7268 amendment, nominal pressure PN, pipe components, nominal size DN, pressure rating, pipeline standards, piping compatibility, pipe flange standards, pressure-temperature ratings, ISO pipe standards.

Standards Content (Sample)

INTERNATIONAL STANDARD IS0 7268=1983/AMENDMENT 1
Published 1984-07-15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEX~YHAPO~HAR OPTAHM3AUMR IlO CTAH~APTM3AlJ4WORGANlSATlON INTERNATIONALE DE NORMALISATION
Pipe components - Definition of nominal pressure
AMENDMENT 1
Tu yau terie - DMnition de la pression nominale
Amendement 7
Amendment 1 to International Standard IS0 72684973 was developed by Technical Committee ISO/TC 5, Ferrous metalpipes and
metalljc fittings. It was submitted directly to the IS0 Council, in accordance with clause 6.11.2, part 1 of the Directives for the
technical work of /SO.
Page I
Clause 2 Definition
Delete the text and substitute :
nominal pressure (PN) : A numerical designation which is a convenient r
...

NORME INTERNATIONALE ISO 7268=1983/AMENDEMENT 1
Publié 1984-07-15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEX)(nYHAPO~HAR OPrAHM3ALJMfl fl0 CTAH~APTM3AL&lM~RGANISATION INTERNATIONALE DE NORMALISATION
Tuyauterie - Définition de la pression nominale
AMENDEMENT 1
Pipe components - Definition of nominal pressure
Amendment 7
L’Amendement 1 à la Norme internationale BO 72684983 a été élaboré par le comité technique ISO/TC 5, Tuyauteries en métaux
ferreux et raccords méta//iques. II a été soumis directement au Conseil de I’ISO, conformément au paragraphe 6.11.2, partie 1 des
Directives pour les travaux techniques de NSO.
Page 1
Chapitre 2 Définition
I
Remplacer le texte par le suivant :
pression nominale (PN) : Désignation numérique exprimée par un nombre arrondi utilisé à des fins de références.
Tous les équipements
...

NORME INTERNATIONALE ISO 7268=1983/AMENDEMENT 1
Publié 1984-07-15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEX)(nYHAPO~HAR OPrAHM3ALJMfl fl0 CTAH~APTM3AL&lM~RGANISATION INTERNATIONALE DE NORMALISATION
Tuyauterie - Définition de la pression nominale
AMENDEMENT 1
Pipe components - Definition of nominal pressure
Amendment 7
L’Amendement 1 à la Norme internationale BO 72684983 a été élaboré par le comité technique ISO/TC 5, Tuyauteries en métaux
ferreux et raccords méta//iques. II a été soumis directement au Conseil de I’ISO, conformément au paragraphe 6.11.2, partie 1 des
Directives pour les travaux techniques de NSO.
Page 1
Chapitre 2 Définition
I
Remplacer le texte par le suivant :
pression nominale (PN) : Désignation numérique exprimée par un nombre arrondi utilisé à des fins de références.
Tous les équipements
...

SLOVENSKI STANDARD
01-september-2001
Cevne komponente - Definicija imenskega tlaka - Dopolnilo 1
Pipe components - Definition of nominal pressure - Amendment 1
Ta slovenski standard je istoveten z: ISO 7268:1983/Amd 1:1984
ICS:
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL STANDARD IS0 7268=1983/AMENDMENT 1
Published 1984-07-15
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MEX~YHAPO~HAR OPTAHM3AUMR IlO CTAH~APTM3AlJ4WORGANlSATlON INTERNATIONALE DE NORMALISATION
Pipe components - Definition of nominal pressure
AMENDMENT 1
Tu yau terie - DMnition de la pression nominale
Amendement 7
Amendment 1 to International Standard IS0 72684973 was developed by Technical
...