SIST EN 4051:2004

• Abstract:

  This standard specifies the characteristics of port connection for pipe couplings, 60°, spherical, in titanium alloy, for aerospace applications.; It is applicable to 60°Ispherical tube coupling in titanium alloy defined by the EN 3853 standard, to be mounted with O-ring defined in accordance with the TR 4052.

• Status: Published
• Publication Date: 30-Apr-2004
• ICS: 49.080 - Aerospace fluid systems and components
• Technical Committee: I08 - Imaginarni 08
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-May-2004
• Due Date: 01-May-2004
• Completion Date: 01-May-2004
• Ref Project: EN 4051:2002 - Aerospace series - Pipe couplings, 60°, spherical, in titanium alloy - Port connection

• Refers: SIST EN 3853:2004 - Aerospace series - Pipe couplings, 60°, spherical, in titanium alloy TI-P64001 - Straight unions, threaded
• Effective Date: 28-Jan-2026
• Refers: oSIST prEN 415-2:2022 - Safety of packaging machines - Part 2: Packaging machines for pre-formed rigid containers
• Effective Date: 28-Jan-2026

SIST EN 4051:2004 is the Slovenian national standard identical to EN 4051:2002 from CEN. It specifies the port connection for 60° spherical pipe couplings in titanium alloy for aerospace applications, including the dimensions, thread form, drawing indication and designation used by manufacturers and users. It is aimed at people who design, make, specify, or inspect aerospace fluid system fittings.

What does SIST EN 4051:2004 specify?

SIST EN 4051:2004 specifies the characteristics of the port connection for pipe couplings, 60°, spherical, in titanium alloy. In practice, it tells you how the connection interface is defined so that a coupling can be selected, machined, and referenced consistently in aerospace work.

The standard applies to the 60° spherical tube coupling in titanium alloy defined by EN 3853, and it is intended to be mounted with an O-ring defined in accordance with TR 4052. That matters because the port connection has to match both the coupling body and the sealing arrangement.

The document is organized into five clauses:

• Scope
• Normative references
• Required characteristics
• Indication on drawing
• Designation

The required characteristics are shown in Figure 1 and Table 1, with dimensions and tolerances in millimetres.

What are the key requirements of SIST EN 4051:2004?

SIST EN 4051:2004 standardizes the port connection geometry for a defined family of aerospace pipe couplings. The key practical point is that the port interface must match the coupling, the thread, and the O-ring arrangement named in the standard.

The coupling family is fixed by reference

SIST EN 4051:2004 applies only to the titanium-alloy 60° spherical tube coupling defined by EN 3853. This limits the standard to a specific coupling type, so users should check that their part belongs to that family before applying the document.

The thread form is controlled by a normative reference

SIST EN 4051:2004 uses MJ threads, with the limit dimensions taken from ISO 5855-3. That means the thread geometry is not left to local practice, and the thread callout on a drawing must align with the aerospace MJ system.

Figure 1 defines the geometric features

SIST EN 4051:2004 identifies the port connection by named dimensions in Figure 1, including height, pitch diameter and thread. This is the information needed when checking a design or verifying machining, because the port connection is defined by geometry rather than by a generic description.

Table 1 links diameter codes to the port dimensions

SIST EN 4051:2004 uses diameter codes and associated tube nominal diameters, thread designations and limit dimensions in Table 1. In practice, this is the selection and ordering rule: the code on a drawing or in a part designation identifies the correct port connection variant.

The drawing indication is standardized

SIST EN 4051:2004 gives a drawing indication in Clause 4, and Figure 2 shows how the tapping is identified. This helps designers place the correct callout on drawings and helps suppliers manufacture the correct feature without ambiguity.

The designation format is fixed

SIST EN 4051:2004 defines a designation using the standard number plus the diameter code, as shown in Clause 5. This matters for procurement, marking, and part lists because the designation ties the part directly to the exact port connection variant.

What terms does SIST EN 4051:2004 define?

• Port connection - the connection feature at the pipe-coupling interface, used to join the coupling to the mating fluid-system part.
• Pipe couplings, 60°, spherical - the specific coupling family covered by the standard, identified by a 60° spherical form.
• Titanium alloy - the material named for the coupling family and port connection covered by the standard.
• O-ring - the sealing element used with the coupling, defined by TR 4052.
• MJ threads - the aerospace thread system whose limit dimensions are taken from ISO 5855-3.
• Diameter code - the code used in Table 1 and in the designation to identify the port connection variant.
• Tapping - the threaded port feature shown in the drawing indication example.

Who uses SIST EN 4051:2004?

SIST EN 4051:2004 is used by aerospace design engineers, suppliers of fluid-system fittings, machining and production teams, and quality inspectors. Buyers and specification writers use it when they need to order or approve a port connection that matches a defined aerospace coupling family. It is also useful for drawing control and part designation in procurement and configuration management.

Which standards are used with SIST EN 4051:2004?

• ISO 5855-3 - provides the limit dimensions for MJ threads used for fittings for fluid systems.
• EN 3853 - defines the 60° spherical tube coupling in titanium alloy that this port connection applies to.
• TR 4052 - provides the assembly recommendations and the O-ring definition used with the coupling.

What does the SIST EN 4051:2004 document contain?

SIST EN 4051:2004 contains a scope, a list of normative references, and a clause on required characteristics supported by Figure 1 and Table 1. It also includes a drawing-indication clause with an example in Figure 2 and a designation clause showing the identification format. The technical content is focused on the port connection geometry, thread identification, diameter coding, and the way the part is called out on a drawing or in a part designation.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Aerospace series - Pipe couplings, 60°, spherical, in titanium alloy - Port connectionLuft- und Raumfahrt - Rohrverschraubungen mit Kugelbuchsen, 60°, aus Titanlegierung - EinschraublöcherSérie aérospatiale - Raccords, sphériques, 60°, en alliage de titane - Logement d'implantationAerospace series - Pipe couplings, 60°, spherical, in titanium alloy - Port connection49.080Aerospace fluid systems and componentsICS:Ta slovenski standard je istoveten z:EN 4051:2002SIST EN 4051:2004en01-maj-2004SIST EN 4051:2004SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 4051November 2002ICS 49.080English versionAerospace series - Pipe couplings, 60°, spherical, in titaniumalloy - Port connectionSérie aérospatiale - Raccords sphériques, 60°, en alliagede titane - Logement d'implantationThis European Standard was approved by CEN on 19 August 2002.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 4051:2002 ESIST EN 4051:2004
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