SIST EN 4804:2017

Overview

SIST EN 4804:2017 is a European standard developed by CEN under the Aerospace and Defence Industries Association of Europe (ASD-STAN). This standard specifies the design, materials, dimensions, and performance requirements for swivel flanges with 4 fastening holes made from nickel alloy. These swivel flanges are intended for aerospace pipe coupling applications using the inch series. The standard ensures interchangeability, reliability, and safety for aerospace fluid systems by defining clear specifications for flange couplings subjected to nominal pressures up to 21,000 kPa, depending on the assembly conditions.

Key Topics

• Scope and Application: Covers swivel flanges with four fastening holes, manufactured from nickel alloy, designed explicitly for aerospace inch series pipe couplings.
• Materials: Specifies the use of nickel-based heat-resistant alloys compliant with related EN standards (EN 3671, EN 4376, EN 4377, EN 4379, EN 4380) ensuring high durability and corrosion resistance typical of aerospace environments.
• Dimensioning and Tolerances: Provides detailed dimensional tables and tolerances to guarantee precision and proper fit in aerospace systems.
• Surface Treatment: Mandates passivation treatment according to EN 2516 for corrosion resistance and enhanced longevity.
• Pressure Ratings: Flanges rated for nominal pressures up to 21,000 kPa contingent on seal types, tube materials, tube diameters, and wall thicknesses (refer to EN 4814 for assembly details).
• Marking and Traceability: Identification markings comply with EN 2424 to maintain traceability and quality control.
• Quality Assurance: Manufacturers must comply with stringent aerospace quality management systems as per EN 9100.

Applications

SIST EN 4804:2017 swivel flanges are essential components in aerospace fluid systems, particularly for:

• Aircraft hydraulic and fuel line connections requiring secure, high-strength flange joints.
• Aerospace pipeline systems where nickel alloy's corrosion resistance and mechanical strength are critical.
• High-pressure fluid transfer applications within the aviation and defense industry, ensuring safe and reliable sealing under demanding operating conditions.
• Maintenance, repair, and manufacturing of aerospace equipment where standardized flange coupling components promote interchangeability and system integrity.

Using swivel flanges compliant with EN 4804 enhances system reliability, reduces assembly errors, and supports overall aerospace safety standards by providing components that meet uniform international specifications.

Related Standards

• EN 4814: Aerospace flange couplings - Inch series technical specifications, complementing EN 4804 by covering associated seals and assembly conditions.
• TR 4815: Aerospace flange couplings design guidelines for inch series, providing deeper design and assembly references.
• EN 2424: Marking requirements for aerospace products ensuring traceability.
• EN 2516: Passivation and surface treatment standards for corrosion-resistant steels and nickel alloys.
• EN 9100: Quality management systems specific to aviation, space, and defense organizations, governing manufacturing approvals and controls.
• EN 3671, EN 4376, EN 4377, EN 4379, EN 4380: Nickel alloy material standards defining acceptable compositions, treatments, and stock forms for aerospace applications.

SIST EN 4804:2017 is a crucial standard for aerospace engineers, manufacturers, and quality assurance personnel focusing on the integrity and safety of nickel alloy flange couplings used in high-pressure inch series pipelines. Adhering to this standard helps ensure aerospace fluid system components perform reliably under rigorous service conditions, ultimately supporting mission success and operational safety.