EN 10226-1:2004
(Main)Pipe threads where pressure tight joints are made on the threads - Part 1: Taper external threads and parallel internal threads - Dimensions, tolerances and designation
General Information
- Abstract
This part of EN 10226 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1/16 to 6 inclusive, for joints made pressure tight by the mating of the threads. These threads are taper external (designated by R) and parallel internal (designated by Rp) and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipments interconnected by threaded joints.
- Status
- Published
- Publication Date
- 13-Jul-2004
- Technical Committee
- ECISS/TC 110 - Steel tubes, and iron and steel fittings
- Drafting Committee
- ECISS/TC 29/SC 6 - Tube threads and service tubes
- Current Stage
- 9093 - Decision to confirm - Review Enquiry
- Start Date
- 03-Dec-2024
- Completion Date
- 17-Sep-2026
- Directive
- Not Harmonized97/23/EC - Pressure equipment
Overview - EN 10226-1:2004 (pipe threads, taper ext. / parallel int.)
EN 10226-1:2004 is a CEN standard that specifies the requirements for pipe threads where pressure‑tight joints are made on the threads. This Part 1 covers taper external threads (designated R) and parallel internal threads (designated Rp) for sizes 1/16 to 6 inclusive. The standard defines the required thread form, dimensions, tolerances and designation for threaded joints that become pressure‑tight by the mating of the threads and are intended for use with pipes, valves, fittings and other pipeline equipment suitable for threading.
Key topics and technical requirements
- Thread form: geometric shape and profile of taper external (R) and parallel internal (Rp) threads used for pressure-tight joints.
- Dimensions: nominal sizes covered (1/16 to 6) and the dimensional data required to manufacture mating threads.
- Tolerances: permitted dimensional and form tolerances to ensure reliable, pressure‑tight engagement when threads are assembled.
- Designation: how threads are identified and marked (designation conventions for R and Rp threads) so components can be specified and matched.
- Intended application: use with pipes suitable for threading and with valves, fittings or other pipeline equipment interconnected by threaded joints.
Note: EN 10226-1 focuses on the thread geometry and fit required to make a pressure‑tight joint by the threaded interface itself.
Applications - practical use cases
- Specification and manufacture of threaded pipe ends, nipples and couplings for fluid and gas pipelines.
- Design and production of valves and fittings that require compatibility with taper external (R) and parallel internal (Rp) threaded connections.
- Procurement and inspection checklists for construction, oil & gas, water distribution, HVAC and industrial piping systems where threaded, pressure‑tight joints are required.
- Quality control and acceptance testing: verifying thread dimensions and tolerances to ensure leak‑free joints without reliance on non‑threaded sealing methods.
Who uses this standard
- Pipe, valve and fitting manufacturers
- Mechanical and piping engineers specifying threaded connections
- Quality assurance, inspection and metrology laboratories
- Procurement and compliance officers ensuring component interchangeability and safety
- Installers and maintenance teams working with threaded pipelines
Related standards
- This document is Part 1 of the EN 10226 series and complements other national and international standards covering pipe threads and jointing practices. For comprehensive specification, consult other relevant EN or ISO standards and manufacturer technical data.
Keywords: EN 10226-1:2004, pipe threads, taper external threads, parallel internal threads, thread dimensions, thread tolerances, pressure-tight joints, R threads, Rp threads, threaded pipe joints.
Relations
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 22-Apr-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Referred By
EN 419-1:2009 - Non-domestic gas-fired overhead luminous radiant heaters - Part 1: Safety - Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Referred By
EN 30-1-1:2008+A3:2013 - Domestic cooking appliances burning gas - Part 1-1: Safety - General - Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
- Referred By
EN 15502-1:2012+A1:2015 - Gas-fired heating boilers - Part 1: General requirements and tests - Effective Date
- 28-Jan-2026
Frequently Asked Questions
EN 10226-1:2004 is a standard published by the European Committee for Standardization (CEN). Its full title is "Pipe threads where pressure tight joints are made on the threads - Part 1: Taper external threads and parallel internal threads - Dimensions, tolerances and designation". This standard covers: This part of EN 10226 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1/16 to 6 inclusive, for joints made pressure tight by the mating of the threads. These threads are taper external (designated by R) and parallel internal (designated by Rp) and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipments interconnected by threaded joints.
This part of EN 10226 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1/16 to 6 inclusive, for joints made pressure tight by the mating of the threads. These threads are taper external (designated by R) and parallel internal (designated by Rp) and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipments interconnected by threaded joints.
EN 10226-1:2004 is classified under the following ICS (International Classification for Standards) categories: 21.040.30 - Special screw threads. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 10226-1:2004 has the following relationships with other standards: It is inter standard links to EN 10226-3:2005, EN ISO 228-1:2003, EN 18126:2026, EN 50465:2015, EN 12007-3:2000, EN 10255:2004+A1:2007, EN 12007-5:2024, EN 419-1:2009, EN 806-4:2010, EN 30-1-1:2008+A3:2013, EN 1254-20:2021, EN ISO 23553-1:2014, EN 1254-20:2021+A1:2025, EN 484:2019, EN 15502-1:2012+A1:2015. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 10226-1:2004 is associated with the following European legislation: EU Directives/Regulations: 97/23/EC; Standardization Mandates: M/071. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Rohrgewinde für im Gewinde dichtende Verbindungen - Teil 1: Kegelige Außengewinde und zylindrische Innengewinde - Maße, Toleranzen und BezeichnungFiletage de tuyauterie pour raccordement avec étanchéité par le filetage - Partie 1: Filetages extérieurs coniques et filetages intérieurs cylindriques - Dimensions, tolérances et désignationPipe threads where pressure tight joints are made on the threads - Part 1: Taper external threads and parallel intern
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