SIST EN 3902:2017

Overview

SIST EN 3902:2017 is a European Standard developed by CEN, specifying the requirements for washers used in rivet assemblies made from anodized aluminium alloy, within the metric series. Designed for aerospace applications, these washers are suitable for environments with operating temperatures up to 120°C. The standard ensures alignment with recognized aerospace quality management systems and consistent product performance across the industry.

Key Topics

• Material Specification: SIST EN 3902:2017 applies specifically to washers manufactured from aluminium alloys, which must be anodized. The referenced alloys and anodizing processes ensure lightweight strength and enhanced corrosion resistance for aerospace usage.
• Design Features: Washers under this standard follow metric sizing, with detailed requirements for configuration, dimensions, masses, and tolerances. Precise dimensions after surface treatment guarantee washer compatibility in rivet assemblies.
• Surface Treatment: All washers are subject to an anodizing process for increased durability and oxidation resistance, aligning with industry standards for aerospace-grade aluminium components.
• Quality Control: Manufacturers must adhere to stringent marking and traceability methods as well as the requirements of recognized quality assurance frameworks, such as EN 9100 for aerospace organizations.
• Designation System: Standardized identification for washers, including clear coding for product type and size (for example, EN3902-025), enhancing supply chain clarity and traceability.

Applications

SIST EN 3902:2017 is primarily intended for use in the aerospace sector, where high standards for reliability, weight efficiency, and durability are essential. Key application areas include:

• Aircraft Assembly: Used in rivet assemblies for airframe sections, control surfaces, and other aircraft structures requiring lightweight yet robust fastening.
• Aerospace Components Manufacturing: Compliance with this standard is often required in the production of subassemblies and structural aerospace parts, particularly where aluminium rivets are used.
• Maintenance, Repair, and Overhaul (MRO): Ensures consistency for replacement washers in servicing aerospace systems, supporting long-term airworthiness and industry compliance.

Related Standards

To ensure full compliance and optimal integration, SIST EN 3902:2017 references and aligns with several related standards, including:

• EN 2090: Aerospace series - Aluminium alloy AL-P2024- T3 Clad sheet and strip
• EN 2091: Aerospace series - Aluminium alloy 2024-T4 Clad sheet and strip
• EN 2284: Aerospace series - Sulphuric acid anodizing of aluminium and wrought aluminium alloys
• EN 2320: Aerospace series - Aluminium alloy 2024-T4 Drawn bar
• EN 2321: Aluminium alloy 2024-T3 Bars and sections (aerospace series)
• EN 2424: Marking of aerospace products
• EN 9100: Quality Management Systems - Requirements for Aviation, Space and Defence Organizations

These standards provide detailed requirements for materials, treatments, manufacturing processes, marking, and quality systems relevant to aerospace fasteners and associated components.

SIST EN 3902:2017 ensures that washers for rivet assemblies in aerospace applications meet rigorous requirements for safety, performance, and traceability. Adherence to this standard supports supply chain efficiency, product reliability, and global standardization in aerospace manufacturing and maintenance.