SIST EN 4550-1:2015

Overview

SIST EN 4550-1:2015 is a European Standard developed by CEN that specifies the dimensions and tolerances for the male sealing end of inch series pipe couplings with a 37° spherical design, specifically intended for aerospace applications. This standard ensures consistency, compatibility, and reliability within aerospace fluid systems by standardizing the design configuration of pipe coupling components. It supersedes the previous version EN 4550-1:2003 and mandates compliance by national standards bodies across Europe.

The matched fluid system component for these male sealing ends must correspond to the female sealing ends defined under EN 4550-4, facilitating proper integration and leak-proof connection in critical aerospace fluid systems.

Key Topics

• Design Configuration: Focuses on the 37° spherical design for male sealing ends used in inch series pipe couplings.
• Dimensional Accuracy: Defines precise dimensions and tolerances in millimeters to maintain uniformity and interchangeability.
• Aerospace Application: Targets aerospace fluid system components requiring high reliability and leak-tightness under extreme conditions.
• Thread Specifications: Incorporates thread standards according to ISO 3161 for UNJ threads ensuring compatibility.
• Concentricity Requirements: Outer surfaces must maintain concentricity within a 0.1 mm diameter tolerance relative to the inner sealing diameter.
• Designation System: Uses a dimensional code representing nominal diameter as a multiple of 1/16 inch increments.
• Standard Evolution: Document updates reflect corrections in dimensional representation to align with aerospace quality and safety demands.

Applications

SIST EN 4550-1:2015 pipe coupling specifications are critical for:

• Aerospace Fluid Systems: Ensuring secure connections in fuel, hydraulic, and pneumatic lines where tight sealing and safety are vital.
• Aircraft Manufacturing and Maintenance: Providing manufacturers and maintenance crews with standardized components that fit precisely with complementary parts.
• Aerospace Component Production: Assisting suppliers in producing male sealing end components that meet global aerospace requirements.
• Leak Prevention: Reducing risks associated with fluid leakage in high-pressure aerospace environments through well-defined sealing geometry.
• International Collaboration: Facilitating harmonization of aerospace parts across multiple countries through CEN-wide adoption of standards.

Related Standards

• EN 4550-4: Covers the female sealing ends complementing the male ends defined in EN 4550-1, ensuring matched components.
• ISO 3161: Specifies the UNJ threads general requirements and dimensional limits that the pipe coupling threads must comply with.
• Aerospace Fluid System Standards: Other EN and ISO standards governing aerospace hydraulic and fluid components contribute to a comprehensive regulatory framework supporting EN 4550-1.
• CEN Aerospace Standards: Collaboration under ASD-STAN ensures this standard aligns with related aerospace and defense industry requirements.

By adhering to SIST EN 4550-1:2015, aerospace manufacturers and suppliers guarantee component consistency, system integrity, and operational safety essential for modern aircraft fluid systems. This standard plays a pivotal role in supporting the aerospace industry's needs for reliable, high-precision pipe couplings that meet demanding performance criteria.