EN 3631:2014
(Main)Aerospace series - Fluid fittings, flanged, 90° elbowed - Sealing by O-ring for 0,8 mm thick tubes
Aerospace series - Fluid fittings, flanged, 90° elbowed - Sealing by O-ring for 0,8 mm thick tubes
This European Standard specifies the characteristics of the fluid fittings, flanged, 90° elbowed, sealing by O-ring, for 0,8 mm thick tubes.
NOTE Flanged fitting installation hole and assembly, see EN 3633 and TR 3634.
Luft- und Raumfahrt - Rohrverbindungen mit Flansch, 90° - O-Ring-Dichtung für Rohre mit einer Dicke von 0,8 mm
Série aérospatiale - Raccords à bride à 90° - Étanchéité par joint torique pour tubes de 0,8 mm d'épaisseur
La présente Norme Européenne définie les caractéristiques des raccords à bride, à 90°, étanchéité par joint torique pour tubes de 0,8 mm d’épaisseur.
NOTE Trou d’implantation pour raccords à bride et montage, voir l’EN 3633 et le TR 3634.
Aeronavtika - Cevna napeljava, s prirobnicami, kotna 90° - Tesnilke O za cevi z debelino 0,8 mm
Ta evropski standard določa lastnosti cevne napeljave, s prirobnicami, kotna 90°, tesnilke O za cevi z debelino 0,8 mm.
OPOMBA: Luknja za vgradnjo cevne napeljave s prirobnico in sestav, glej standarda EN 3633 in TR 3634.
General Information
- Status
- Published
- Publication Date
- 30-Sep-2014
- Withdrawal Date
- 29-Apr-2015
- Technical Committee
- ASD-STAN - Aerospace
- Drafting Committee
- ASD-STAN/D 3 - Mechanical
- Current Stage
- 9093 - Decision to confirm - Review Enquiry
- Start Date
- 21-Jan-2025
- Completion Date
- 11-Feb-2026
Relations
- Effective Date
- 18-Sep-2013
- 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
- Effective Date
- 28-Jan-2026
- Effective Date
- 28-Jan-2026
Overview
EN 3631:2014 is a CEN European Standard that specifies the characteristics for aerospace fluid fittings, flanged 90° elbowed, sealed by O‑ring, specifically for tubes with a wall thickness of 0,8 mm. It defines configuration, dimensions, tolerances, materials and marking for both forged (Type A) and machined (Type B) flanged elbow fittings used in aerospace fluid systems.
Key topics and requirements
- Scope and geometry
- Covers flanged 90° elbow fittings designed to seal by O‑ring for 0,8 mm thick tubes (tube diameters from ∅4 up to ∅32 mm are covered in the tables and figures).
- Detailed configuration drawings and dimensional tables (Figures 1–8, Tables 1–5) define flange hole patterns, spot facings and weld lip relations.
- Materials and manufacture
- Acceptable materials referenced: EN 3487 or EN 3482.
- Fittings may be forged (see EN 2157‑3) or machined from specified bar/stock.
- Dimensions, tolerances and marking
- Precise dimensional tolerances and finish instructions are given for all diameter and hole codes; marking follows EN 2424 (Style A).
- Designation example: EN3631-140-2-A (standard‑number, diameter code, hole code, type).
- Assembly and installation
- Installation hole and assembly details are referenced to EN 3633 and assembly recommendations in TR 3634.
- Weld lip geometry linked to EN 3635.
- Quality and conformity
- Quality assurance is to follow EN 9100.
Practical applications and users
- Applications
- Design, manufacture and procurement of aircraft hydraulic, fuel and pneumatic tubing systems where compact 90° flanged elbows with O‑ring sealing are required.
- Standardized components for repairs, spares and retrofits in civil and military aerospace platforms.
- Who uses EN 3631:2014
- Aerospace OEMs, tier‑1 and tier‑2 suppliers, tube‑fitting manufacturers (forging and machining shops), design/lead engineers, quality and compliance teams, maintenance/repair organizations, and procurement specialists specifying compatible fittings.
- Benefits
- Ensures interchangeability, consistent sealing performance and traceable marking across suppliers.
- Reduces design ambiguity by providing standardized dimensions and assembly references.
Related standards
- EN 3633 - Installation hole for fluid fittings, flanged
- TR 3634 - Assembly recommendations for flanged fluid fittings
- EN 3635 - Weld lip geometrical configuration
- EN 2157‑3 - Forging stock and forgings (production)
- EN 3482 / EN 3487 - Specified steels for fittings
- EN 2424 - Marking of aerospace products
- EN 9100 - Quality management for aviation, space and defence
For engineers and procurement teams working with aerospace fluid fittings, EN 3631:2014 is the authoritative reference for specifying flanged 90° O‑ring elbow fittings for 0,8 mm tube systems.
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Frequently Asked Questions
EN 3631:2014 is a standard published by the European Committee for Standardization (CEN). Its full title is "Aerospace series - Fluid fittings, flanged, 90° elbowed - Sealing by O-ring for 0,8 mm thick tubes". This standard covers: This European Standard specifies the characteristics of the fluid fittings, flanged, 90° elbowed, sealing by O-ring, for 0,8 mm thick tubes. NOTE Flanged fitting installation hole and assembly, see EN 3633 and TR 3634.
This European Standard specifies the characteristics of the fluid fittings, flanged, 90° elbowed, sealing by O-ring, for 0,8 mm thick tubes. NOTE Flanged fitting installation hole and assembly, see EN 3633 and TR 3634.
EN 3631:2014 is classified under the following ICS (International Classification for Standards) categories: 49.080 - Aerospace fluid systems and components. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 3631:2014 has the following relationships with other standards: It is inter standard links to EN 3631:2008, EN 9100:2018, EN 2424:2008, EN 3633:2008, EN 3635:2014, EN 3487:2024, EN 2157-3:1993, EN 3482:2019. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 3631:2014 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aeronavtika - Cevna napeljava, s prirobnicami, kotna 90° - Tesnilke O za cevi z debelino 0,8 mmLuft- und Raumfahrt - Rohrverbindungen mit Flansch, 90° - O-Ring-Dichtung für Rohre mit einer Dicke von 0,8 mmSérie aérospatiale - Raccords à bride à 90° - Étanchéité par joint torique pour tubes de 0,8 mm d'épaisseurAerospace series - Fluid fittings, flanged, 90° elbowed - Sealing by O-ring for 0,8 mm thick tubes49.080Aerospace fluid systems and componentsICS:Ta slovenski standard je istoveten z:EN 3631:2014SIST EN 3631:2015en,fr,de01-januar-2015SIST EN 3631:2015SLOVENSKI
STANDARDSIST EN 3631:20081DGRPHãþD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 3631
October 2014 ICS 49.080 Supersedes EN 3631:2008English Version
Aerospace series - Fluid fittings, flanged, 90° elbowed - Sealing by O-ring for 0,8 mm thick tubes
Série aérospatiale - Raccords à bride à 90° - Étanchéité par joint torique pour tubes de 0,8 mm d'épaisseur
Luft- und Raumfahrt - Rohrverbindungen mit Flansch, 90° -O-Ring-Dichtung für Rohre mit einer Dicke von 0,8 mm This European Standard was approved by CEN on 4 January 2014.
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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 3631:2014 ESIST EN 3631:2015
Page Foreword .3 1 Scope .4 2 Normative references .4 3 Required characteristics .4 3.1 Configuration, dimensions, tolerances .4 3.1.1 Configuration .4 3.1.2 Dimensions and tolerances .4 4 Forging flanged fitting, Type A .4 5 Machined flanged fitting, Type B .8 6 Fitting . 11 6.1 Fitting for tubes ∅ ≤ 16. 11 6.2 Fitting for tubes ∅ > 16. 11 7 Cone and end fitting . 12 8 Designation . 13 9 Marking . 13 10 Quality assurance . 13
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