SIST EN 3050:2026

Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Technical specification

This document specifies the characteristics, qualification and acceptance requirements for O-rings in low compression set fluorocarbon rubber (FKM) in accordance with EN 2798.

Luft- und Raumfahrt - O-Ringe aus Fluorcarbon-Elastomer (FKM) mit niedrigem Druckverformungsrest - Technische Lieferbedingungen

Série aérospatiale - Joints toriques, en élastomère fluorocarbone (FKM), à faible déformation rémanente après compression - Spécification technique

Le présent document spécifie les caractéristiques, et les exigences de qualification et de réception des joints toriques en élastomère fluorocarbone (FKM), à faible déformation rémanente après compression, conformes à l’EN 2798..

Aeronavtika - Tesnilni obročki O, izdelani iz fluoroogljikove gume (FKM) z nizko stopnjo kompresije - Tehnična specifikacija

Ta dokument določa značilnosti ter zahteve glede ustreznosti in sprejemljivosti tesnilnih obročkov O, izdelanih iz fluoroogljikove gume (FKM) z nizko stopnjo kompresije, v skladu s standardom EN 2798.

General Information

• Status: Published
• Public Enquiry End Date: 11-Sep-2024
• Publication Date: 07-Jan-2026
• ICS: 49.080 - Aerospace fluid systems and components
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Jan-2026
• Due Date: 12-Mar-2026
• Completion Date: 08-Jan-2026
• Ref Project: EN 3050:2025 - Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Technical specification

Relations

• Replaces: SIST EN 3050:2001 - Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Technical specification
• Effective Date: 01-Feb-2026
• Refers: SIST EN 12767:2019+A1:2025 - Passive safety of support structures for road equipment - Requirements and test methods
• Effective Date: 28-Jan-2026
• Refers: SIST EN 2798:2019 - Aerospace series - Fluorocarbon rubber (FKM) - Low compressions set - Hardness 80 IRHD
• Effective Date: 28-Jan-2026
• Refers: SIST-TS CEN/TS 1852-2:2016 - Plastics piping systems for non-pressure underground drainage and sewerage - Polypropylene (PP) - Part 2: Guidance for the assessment of conformity
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3049:2001 - Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Hardness 80 IRHD
• Effective Date: 28-Jan-2026
• Referred By: SIST EN 3049:2026 - Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Hardness 80 IRHD
• Effective Date: 28-Jan-2026

Overview

SIST EN 3050:2026, "Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set - Technical specification," establishes the technical requirements, qualification procedures, and acceptance criteria for O-rings manufactured from fluorocarbon rubber (FKM) with a low compression set. Developed by the Slovenian Institute for Standardization (SIST), this standard aligns with the European EN 3050:2025 and specifically addresses the needs of aerospace hydraulic and fluid systems.

Fluorocarbon (FKM) O-rings are widely used in aerospace applications where resistance to high temperatures, aggressive fluids, and low compression set (minimizing permanent deformation) is essential. This standard provides manufacturers and suppliers with clear guidelines for producing reliable, high-quality sealing components that meet rigorous aerospace industry requirements.

Key Topics

• Material Requirements: O-rings must be made from FKM elastomer conforming to EN 2798, ensuring consistent performance under demanding conditions.
• Qualification & Acceptance: The standard defines stringent qualification and acceptance protocols. Manufacturers must implement an aerospace-approved quality management system (e.g., EN 9100).
• Testing Procedures: Includes tests for dimensions and tolerances, hardness (ISO 48-2), density (ISO 2781), compression set (ASTM D1414), ageing (ISO 188), fluid resistance (ISO 1817), and surface condition (ISO 3601-3).
• Batch and Lot Control: Requirements for traceability and clearly defined production batches and inspection lots to maintain product consistency.
• Packaging: Specifies water-, vapor-, oil-, ozone-, and grease-proof individual and collective packaging to maintain product quality during storage and transport. Marking for traceability, shelf life (unlimited), and handling instructions is required.

Applications

SIST EN 3050:2026 is crucial in the design, manufacture, and quality assurance of O-rings for:

• Aerospace Fluid and Hydraulic Systems: Ensures long-lasting and reliable seals, preventing fluid leaks in critical aircraft systems.
• Aerospace Component Manufacturing: Used by OEMs and parts suppliers to meet qualification and contractual obligations for aerospace clients.
• Maintenance, Repair, and Overhaul (MRO): Provides a standard reference for the selection and verification of O-rings in service and during aircraft maintenance.
• Regulatory and Contract Compliance: Helps organizations demonstrate conformity to European and international aerospace standards.

By adhering to this standard, stakeholders ensure optimal performance, enhanced safety, and regulatory compliance in aerospace environments where reliability is paramount.

Related Standards

SIST EN 3050:2026 refers to several other important standards relevant to aerospace sealing technology:

• EN 2798: Specifies properties for FKM elastomer used in aerospace applications.
• EN 9100: Quality management systems for aviation, space, and defense organizations.
• ISO 48-2: Methods for determining rubber hardness.
• ISO 188: Accelerated aging and heat resistance testing for rubber materials.
• ISO 1817: Procedures for assessing effect of liquids on rubber.
• ISO 2781: Density determination for rubber products.
• ISO 3601-3: Quality acceptance criteria for O-rings.
• ISO 27996: Storage and shelf life for elastomer seals in aerospace applications.
• ASTM D1414: Standard test methods for rubber O-rings.
• ISO 2859-1: Sampling procedures for inspection by attributes.

By integrating these standards, SIST EN 3050:2026 delivers a harmonized and comprehensive approach to FKM O-ring quality and reliability for aerospace applications.

Keywords: aerospace O-rings, fluorocarbon rubber, FKM O-ring standard, low compression set, EN 3050, aerospace sealing, quality assurance, O-ring testing, hydraulic systems, aerospace components.

Standards Content (Sample)

SLOVENSKI STANDARD
01-februar-2026
Nadomešča:
SIST EN 3050:2001
Aeronavtika - Tesnilni obročki O, izdelani iz fluoroogljikove gume (FKM) z nizko
stopnjo kompresije - Tehnična specifikacija
Aerospace series - O-rings, in fluorocarbon rubber (FKM), low compression set -
Technical specification
Luft- und Raumfahrt - O-Ringe aus Fluorcarbon-Elastomer (FKM) mit niedrigem
Druckverformungsrest - Technische Lieferbedingungen
Série aérospatiale - Joints toriques, en élastomère fluorocarbone (FKM), à faible
déformation rémanente après compression - Spécification technique
Ta slovenski standard je istoveten z: EN 3050:2025
ICS:
49.080 Letalski in vesoljski Aerospace fluid systems and
hidravlični sistemi in deli components
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 3050
EUROPEAN STANDARD
NORME EUROPÉENNE
December 2025
EUROPÄISCHE NORM
ICS 49.080 Supersedes EN 3050:1998
English Version
Aerospace series - O-rings, in fluorocarbon rubber (FKM),
low compression set - Technical specification
Série aérospatiale - Joints toriques, en élastomère Luft- und Raumfahrt - O-Ringe aus Fluorcarbon-
fluorocarbone (FKM), à faible déformation rémanente Elastomer (FKM) mit niedrigem Druckverformungsrest
après compression - Spécification technique - Technische Lieferbedingungen
This European Standard was approved by CEN on 29 September 2025.

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 CEN-CENELEC 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 CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 3050:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Quality assurance . 5
4.1 Qualification . 5
4.1.1 General. 5
4.1.2 Hardness Test . 5
4.2 Acceptance. 5
4.2.1 Conditions . 5
4.2.2 Responsibility . 6
4.2.3 Inspection and test report . 6
5 Requirements . 6
Annex A (normative) Packaging . 9
A.1 General. 9
A.2 Material of the individual package . 9
A.3 Dimensions of the individual packages . 9
A.4 Identification . 10
A.5 Collective packaging . 10
Bibliography . 11

European foreword
This document (EN 3050:2025) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2026, and conflicting national standards shall be
withdrawn at the latest by June 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 3050:1998.
This document includes the following significant technical changes with respect to EN 3050:1998:
— normative references were updated;
— subclause 4.1.1 was updated to include further information on qualification;
— subclause 4.1.2, Hardness Test, was added;
— Bibliography was added.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
1 Scope
This document specifies the characteristics, qualification and acceptance requirements for O-rings in
low compression set fluorocarbon rubber (FKM) in accordance with EN 2798.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendm
...