October 2025 Monthly Overview: Fluid Systems Standards

Looking back at October 2025, the Fluid Systems sector experienced a pivotal month in standardization, marked by the release of five influential standards. This period brought renewed focus to polyethylene-based gaseous fuel supply systems, highlighted through the comprehensive EN 1555 series updates, alongside critical advancements in composite storage solutions with FprEN 13121-3. For professionals responsible for compliance, engineering, procurement, or research, this in-depth overview offers both consolidation of knowledge and practical guidance on the month's publications—helping you benchmark, strategize, and stay current with regulatory shifts.

Monthly Overview: October 2025

October 2025 saw significant developments in standards for fluid systems and components. This month, the sector was defined by two central themes:

• Systematization and Harmonization: The EN 1555 series updates (Parts 1–4) provide a unified, clear framework for the design, installation, and maintenance of polyethylene (PE) piping systems used in the conveyance of gaseous fuels. These revisions reflect Europe’s push for harmonization and improved safety across national energy infrastructures.

• Future-Focused Materials and Applications: The formalization of FprEN 13121-3 for GRP (glass-reinforced plastic) tanks and vessels underscores the critical role composite materials play in above-ground fluid storage. Both areas address market drivers such as hydrogen and biogas utilization, enhanced durability, and new performance expectations.

Compared to previous cycles, October 2025’s output stands out not only for the volume of cross-referenced standards but for the tightening integration of material, testing, safety, and installation guidance. This trend reflects a broader shift: standards are aligning with the sector’s ambitions for safer, more versatile, and sustainable infrastructure in energy and industrial projects.

Standards Published This Month

EN 1555-1:2025 - General Principles for Polyethylene Gas Piping Systems

Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 1: General

EN 1555-1:2025 establishes the foundation for all PE-based piping systems designed for gaseous fuel transport. It details the essential material characteristics, system design parameters, applicable pressure and temperature ranges, and test criteria for compliance. The standard covers the full spectrum of gaseous fuels—including natural gas, hydrogen, methane, and various admixtures.

Crucially, it sets a maximum operating pressure (MOP) of up to 10 bar at 20 °C, and clearly defines the performance envelope for safe operation between −20 °C and 40 °C. The document harmonizes color requirements, material stress factors, and prescribes derating protocols for higher temperatures. Annexes in this edition introduce new recommendations for PE 100-RC installations and hydrogen blending compatibility, reflecting the sector’s move towards alternative energy carriers.

Stakeholders—specifiers, installers, and regulatory authorities—are directly impacted, as this document dictates not only technical compliance but also the selection and approval of connected components and materials.

Key highlights:

• Materials and design coefficients for multi-fuel gas systems
• Installation and material requirements for new energy vectors (hydrogen/biogas)
• Updated test parameters and jointing guidance for component interoperability

Access the full standard:View EN 1555-1:2025 on iTeh Standards

EN 1555-2:2025 - Polyethylene Pipes for Gaseous Fuels

Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 2: Pipes

EN 1555-2:2025 provides a technical specification for PE pipes used in gas distribution networks. It details material compound requirements, dimensions, minimum wall thicknesses, ovality and tolerances, marking conventions, and types of permissible co-extruded or peelable-layers (protective layers for installation and environmental resilience).

This revision enhances guidance on the use of PE 100-RC grades for improved slow-crack growth resistance, integrates the nuances of hydrogen service, and mandates stricter marking for traceability. The standard enforces conformity testing—tensile, pressure, and physical tests—for safe operation at up to 10 bar MOP. Multiple types of pipes are covered: standard solid wall, co-extruded, and peelable-coated variants, allowing engineers flexibility in balancing protection versus ease of installation.

Utilities, contractors, and design engineers must ensure compliant pipe procurement and system assembly, particularly as hydrogen-ready infrastructure becomes a policy imperative.

Key highlights:

• Technical parameters for PE pipe design, including dimensions and colour coding
• Updated installation requirements for hydrogen and PE 100-RC applications
• Enhanced test and conformity assessment protocols

Access the full standard:View EN 1555-2:2025 on iTeh Standards

EN 1555-3:2025 - Fittings for Polyethylene Gas Piping Systems

Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 3: Fittings

With EN 1555-3:2025, the requirements for both fusion and mechanical fittings within PE gas supply systems are harmonized. This part addresses dimensions, material compatibility, fusion characteristics (e.g., electrofusion socket/saddle fittings, spigot ends for butt fusion), and mechanical joining methods, ensuring integrated system performance.

Important innovations in this edition include updated references to hydrogen compatibility, harmonization with new ISO standards for joint geometry, clear delineation of mechanical versus fusion fitting design, and explicit marking for system recognition. Extendable to a variety of fitting types—including couplers, tees, reducers, elbows, end caps—this standard directly impacts manufacturers, utilities, and installers responsible for gas network expansions or retrofits.

EN 1555-3:2025 enforces rigorous performance, tensile, and pressure tests for both electrofusion and mechanical joints, aiming to minimize risk in multi-fuel gas transport scenarios. The increased emphasis on cross-compatibility is essential due to the sector’s transition towards greater use of hydrogen and biogas mixtures.

Key highlights:

• Requirements for fusion and mechanical fittings, including performance testing
• Provisions for hydrogen admixtures and advanced PE materials
• Harmonized geometrical and marking conventions for network asset traceability

Access the full standard:View EN 1555-3:2025 on iTeh Standards

EN 1555-4:2025 - Polyethylene Valves for Gaseous Fuel Piping Systems

Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE) - Part 4: Valves

EN 1555-4:2025 delineates the requirements for PE valves (unidirectional and bidirectional) intended for fusion with PE pipes or fittings. It establishes geometric, physical, and mechanical property parameters for valve bodies, end connections, and integrated components—ensuring reliable isolation and operation in PE gas grids.

This document expands on past editions by referencing requirements for hydrogen service, defining allowable body sizes (up to DN400), and updating protocols for external/internal leaktightness. It also details test conditions for valve-seat packing, tensile load resistance, pressure integrity, and actuation functionality.

Operators, asset owners, and procurement professionals benefit from strengthened quality assurance, particularly as national networks require valves to serve mixed-fuel—including high hydrogen—applications. The transition to hydrogen-compatible gas infrastructure is closely supported by these expanded performance demands.

Key highlights:

• Technical requirements for PE valve bodies and fusion couplings for gas piping
• Updated leaktightness, ease-of-operation, and tensile load test methods
• Mandatory marking and traceability for valve identification and installation compliance

Access the full standard:View EN 1555-4:2025 on iTeh Standards

FprEN 13121-3 - GRP Tanks and Vessels: Design and Workmanship

GRP tanks and vessels for use above ground - Part 3: Design and workmanship

In parallel to the EN 1555 series, FprEN 13121-3 establishes detailed rules for the design, fabrication, inspection, and quality assurance of glass-reinforced plastic (GRP) tanks and vessels intended for above-ground fluid storage or processing. Covering working pressures up to 10 bar and operating temperatures from −40 °C to 120 °C, this standard is relevant across chemicals, water, and process industries.

The document prescribes requirements for material selection (including thermoplastic linings), laminate construction and thickness, design analysis (stress, strain, buckling criteria), and verification/inspection protocols. Excluded are tanks for transport, underground storage, abnormal shapes, or those subject to explosive/radioactive environments.

Manufacturers and end-users benefit from clarified documentation responsibilities, engineering calculations, quality control steps, and normative annexes that support complete lifecycle management—from design intent through to installation and operational verification.

Key highlights:

• Comprehensive design and quality guidelines for above-ground GRP tanks/vessels
• Engineering criteria for advanced composite structures (mechanical, thermal, resistance)
• Expanded scope for documentation, inspection, and performance verification

Access the full standard:View FprEN 13121-3 on iTeh Standards

Common Themes and Industry Trends

A review of the October 2025 publications reveals several clear patterns and emergent themes shaping the fluid systems sector:

• Hydrogen Readiness: All EN 1555 updates explicitly address hydrogen and its admixtures, reflecting policy and market shifts towards low-carbon and renewable gases. Performance and material selection are increasingly tested for hydrogen resistance and compatibility.

• Harmonization Across the Value Chain: Requirements for pipes, fittings, and valves are now tightly integrated, ensuring compatibility and easing cross-border project execution. Unified marking and traceability support both quality assurance and regulatory compliance.

• Composite Material Engineering: The evolution of FprEN 13121-3 underlines the move towards lightweight, corrosion-resistant composite tanks and vessels, enabling longer service lives and adaptability to aggressive environments.

• Enhanced Performance & Safety Metrics: Expanded testing regimes and mechanical performance requirements (e.g., tensile tests, leaktightness, slow crack growth resistance) are now baseline expectations for both polymeric and composite components.

Industries most impacted include gas utilities, energy infrastructure, chemical processing, and any operator transitioning assets toward hydrogen or biogas service. Together, these standards indicate a strong regulatory and technical shift towards safer, more adaptable, and future-ready fluid systems.

Compliance and Implementation Considerations

Organizations affected by the October 2025 suite should consider the following for swift, effective compliance:

1. Gap Assessment: Review existing specifications for pipes, fittings, valves, and tanks against the revised EN 1555 and FprEN 13121-3 requirements. Pay particular attention to MOP, hydrogen readiness, and joint compatibility.

2. Procurement & Specification Updates: Ensure product tenders and procurement criteria are aligned with the new dimensional, marking, and performance clauses.

3. Installation Practice Alignment: Reference EN 12007-2 for installation best practices and validate contractor training/competence on new jointing and testing methods (especially for hydrogen service).

4. Document Control and Traceability: Update documentation/marking systems to match new traceability and conformity marking requirements.

5. Implementation Timeline: Many standards specify a withdrawal period for conflicting national standards by April 2026, giving a transition window for planning upgrades or inventory changeover.

6. Engage Suppliers: Collaborate with manufacturers and suppliers to verify third-party certification, conformity, and quality management to new standards.

7. Continuous Education: Stay informed via platforms like iTeh Standards for the latest official documents, guidance notes, and assessment tools.

Conclusion: Key Takeaways from October 2025

October 2025 set a benchmark month for the Fluid Systems sector, delivering vital regulatory and technical clarity through both the EN 1555 series (updated for hydrogen, integration, and performance) and FprEN 13121-3 for composite tanks/vessels. These standards will drive improvements in asset safety, multi-fuel adaptability, and lifecycle management across the gas supply and process industries.

For industry professionals, the imperative is clear: review your systems, update your procurement and installation practices, and engage with suppliers to ensure full compliance. Familiarize yourself with these standards now—leveraging resources at iTeh Standards—to future-proof your investments and support resilient, low-carbon infrastructure.

Explore the detailed standards documents directly for actionable specifications and compliance guidance via the provided iTeh Standards links.