Handbook

Safety-critical standards (blueprint)

**Purpose:** Guidance on safety-critical engineering standards and their impact on software development practices. Each standard entry covers scope, safety integrity levels, required activities, and e

Safety-critical standards (blueprint)

Purpose: Guidance on safety-critical engineering standards and their impact on software development practices. Each standard entry covers scope, safety integrity levels, required activities, and engineering constraints.

Why functional safety is non-negotiable: For systems where failure can harm people or the environment, process and evidence matter as much as code. Standards such as IEC 61508 and ISO 26262 define lifecycle activities, independence, and integrity levels so claims about risk reduction are auditable. Skipping them shifts unbounded liability to the organization and blocks market access in regulated domains. Align blueprint reading with EMBEDDED-IOT.md for real-time and firmware context, and Embedded / IoT ↔ SDLC ↔ PDLC bridge for certification impact on phases.

Audience: Teams adopting Embedded / IoT Engineering for safety-critical applications; project-specific safety documentation stays in docs/safety/.

Safety standard family (conceptual)

flowchart TB IEC[IEC 61508<br/>E/E/PE functional safety] IEC --> ISO26262[ISO 26262<br/>Road vehicles] IEC --> EN50128[EN 50128 / EN 50657<br/>Rail / road vehicles] IEC --> IEC61511[IEC 61511<br/>Process industry] IEC --> IEC62061[IEC 62061<br/>Machinery] IEC --> IEC62304[IEC 62304<br/>Medical device software] ISO26262 -.->|+ cybersecurity| ISO21434[ISO/SAE 21434]
Standard Domain Focus Deep dive
IEC 61508 General Functional safety of E/E/PE safety-related systems — SIL 1–4, V-model, failure modes iec-61508.md
ISO 26262 Automotive Road vehicle functional safety — ASIL A–D, HARA, HSI, FMEA, production iso-26262.md
DO-178C Aerospace Software considerations in airborne systems — DAL A–E, objectives, verification, tool qualification EMBEDDED-IOT.md
IEC 62304 Medical devices Medical device software lifecycle — safety classes A/B/C, risk management integration, maintenance EMBEDDED-IOT.md
MISRA C / C++ Coding standards Safe subset of C/C++ for critical systems — rule categories (mandatory, required, advisory), deviation process EMBEDDED-IOT.md §2
EN 50128 Railway Railway software — SIL allocation, coding standards, formal methods, independent verification EMBEDDED-IOT.md

For each standard, guides cover: - Scope and applicability criteria - Safety integrity / assurance levels and their engineering implications - Required activities by SDLC phase (analysis, design, coding, testing, traceability) - Tool qualification requirements - Common pitfalls and practical guidance

Core knowledge: EMBEDDED-IOT.md — real-time systems, firmware development, safety engineering competency.

Bridge: Embedded / IoT ↔ SDLC ↔ PDLC bridge — safety certification impact on lifecycle phases.

Keep project-specific safety documentation in docs/safety/ and hazard analyses in docs/security/, not in this file.

Canonical source

Edit https://github.com/autowww/blueprints/blob/main/disciplines/engineering/embedded-iot/safety/README.md first; regenerate with docs/build-handbook.py.