ISO 25119-3:2018

Overview

ISO 25119-3:2018 - part of the ISO 25119 series - provides principles and requirements for the design, series development, hardware and software of safety-related parts of control systems (SRP/CS) used on tractors, agricultural and forestry machinery, self‑propelled ride-on machines and mounted/semi‑mounted/trailed implements. It applies mainly to electrical/electronic/programmable electronic systems (E/E/PES) as they relate to mechatronic safety functions and their malfunctioning behaviour. The standard complements machine risk assessment (e.g., ISO 12100) but does not itself assign application performance levels (AgPL) except where type‑C standards specify them.

Key topics and requirements

• Scope and exclusions: Focuses on hazards caused by malfunctioning of E/E/PES and interactions between safety systems; excludes non‑E/E/PES systems (hydraulic, mechanical, pneumatic) and hazards unrelated to E/E/PES malfunctions (e.g., generic corrosion, nominal electromagnetic radiation).
• System design: Structuring safety requirements, defining technical safety concepts and prerequisites (hazard identification and risk analysis).
• Hardware: Hardware categories, prerequisites and required work products for safe series development of SRP/CS.
• Software lifecycle: Detailed guidance on software planning, safety requirements specification, architecture, component design and implementation, testing (component, integration, safety testing), and software‑based parameterisation.
• Verification and work products: Emphasis on documented work products, test specifications and reports to demonstrate compliance and traceability through the safety lifecycle.
• Supplementary material: Annex A (example agenda for functional safety assessment) and normative Annex B (independence by software partitioning) support practical implementation.

Applications and who should use it

ISO 25119-3 is intended for:

• Manufacturers and designers of tractors, agricultural and forestry machinery, and mobile municipal equipment looking to develop SRP/CS that meet recognized functional safety practices.
• Functional safety engineers responsible for E/E/PES architecture, hardware categorisation and software lifecycle activities.
• Test engineers and quality teams preparing verification, validation and certification evidence for SRP/CS.
• Regulatory bodies and certification bodies assessing compliance of safety‑related control systems in agricultural and municipal vehicles.

Practical use cases include designing safe electronic control units, implementing safety software for emergency stop or interlocks, protecting hybrid electrical systems from insulation failures, and ensuring electromagnetic compatibility of SRP/CS.

Related standards

• ISO 12100 - general machinery safety and risk assessment principles (prerequisite).
• Other parts of the ISO 25119 series for complementary functional safety lifecycle guidance and application‑specific requirements.

Keywords: ISO 25119-3, SRP/CS, safety-related parts of control systems, tractors, agricultural machinery, E/E/PES, functional safety, hardware and software development, AgPL, ISO 12100.