SIST EN 3855:2004

SIST EN 3855:2004 Overview

SIST EN 3855:2004 is a European standard that defines specifications for caps used in aerospace pipe couplings with a 60° spherical design, manufactured from titanium alloy TI-P64001. Developed by the European Committee for Standardization (CEN), this standard is essential for ensuring consistent quality, dimensional accuracy, and material integrity in aerospace fluid systems. It is intended to be used alongside related standards EN 3851, EN 3852, and EN 3853, which cover corresponding components of the pipe coupling system.

This standard addresses the critical requirements for manufacturing caps that fit aerospace-grade pipe couplings, emphasizing dimensional tolerances, material quality, assembly procedures, and marking for traceability. It facilitates the integration of high-performance titanium alloy components in aerospace hydraulic and fluid systems.

Key Topics Covered

• Material Requirements
  Caps must be fabricated from titanium alloy TI-P64001 compliant with EN 2530, ensuring high strength and corrosion resistance essential for aerospace fluid systems.

• Dimensional Specifications
  The standard details exact configuration, dimensions, and tolerances in millimeters, ensuring interchangeability and precision fit. Figures and tables define tube diameters, thread sizes, and radius specifications.

• Cap Assembly Instructions
  Guidelines include staking procedures for securing swivel nuts as per EN 3851, recommendations to avoid material defects during assembly, and minimum push-out forces for mechanical integrity.

• Marking and Identification
  Marking provisions follow EN 2424 requirements to ensure clear traceability of parts within aerospace inventory and maintenance systems.

• Quality Assurance
  Compliance with EN 2000 assures manufacturers maintain rigorous quality control management systems for aerospace products, emphasizing product reliability and safety.

Applications

SIST EN 3855:2004 caps are integral components in aerospace fluid system pipe couplings, where reliability, durability, and low weight are paramount. Key applications include:

• Hydraulic Systems
  Providing leak-proof seals in pipe couplings to maintain system pressure and prevent contamination.

• Fuel and Lubrication Lines
  Ensuring secure connections in sensitive fluid circuits where titanium alloy offers corrosion resistance and strength.

• Aircraft and Spacecraft Manufacturing
  Supporting the assembly of critical fluid conduits in both commercial and military aerospace platforms.

• Maintenance and Repair Operations
  Standardized components simplify replacement, inspection, and certification of aerospace pipe fittings.

Related Standards

SIST EN 3855:2004 is designed for use with the following complementary standards, which together define the entire pipe coupling system in titanium alloy TI-P64001:

• EN 3851 – Swivel nuts for 60° spherical pipe couplings in titanium alloy
• EN 3852 – Straight unions, welded and threaded, for 60° spherical pipe couplings
• EN 3853 – Straight unions, threaded, for 60° spherical pipe couplings

Additionally, normative references incorporated include:

• EN 2530 – Specifications for titanium alloy TI-P64001 bars (annealed condition)
• EN 2000 – Quality assurance for aerospace product manufacturing systems
• EN 2424 – Marking standards for aerospace products
• ISO 286-2 – System of limits and fits for dimensional tolerances

Keywords: aerospace pipe couplings, titanium alloy caps, 60-degree spherical pipe coupling, TI-P64001 standard, aerospace fluid systems, EN 3855 certification, pipe coupling quality assurance, aerospace pipe fittings, titanium aerospace components, pipe coupling manufacturer standards.