Machinery safety
EN ISO 13849-1/-2
Design safety-related parts of control systems to a required Performance Level (Part 1) and validate them (Part 2).
Safety of machinery — Safety-related parts of control systems (Part 1: General principles for design; Part 2: Validation)
- Category
- Machinery safety
- Scope
- International
- Edition / refs
- ISO 13849-1:2023 · ISO 13849-2:2012
MSA output
- PLr / SIL calculations
- Validation protocols
- Fault injection tests
- Device test records
What is EN ISO 13849-1/-2?
ISO 13849-1 applies to safety-related parts of control systems (SRP/CS) of any technology — electrical, electronic, hydraulic, pneumatic and mechanical. Each safety function is assigned a required Performance Level (PLr), from PL a to PL e, typically using a risk graph based on severity of injury (S), frequency and/or duration of exposure (F) and possibility of avoiding the hazard (P).
The achieved PL is estimated from the designated architecture (Category B, 1, 2, 3 or 4), the mean time to dangerous failure of each channel (MTTFd), the average diagnostic coverage (DCavg) and measures against common cause failure (CCF), together with requirements for systematic failures and safety-related software.
ISO 13849-2 covers validation: a validation plan, validation by analysis and testing, fault lists and criteria for fault exclusion, confirming that each safety function meets its specification, Category and PL.
Who it applies to
- Machine builders designing safety functions such as interlocked guards, emergency stops, light curtains and safe speed monitoring
- System integrators combining machines and safety controllers into cells and lines
- Control and safety engineers specifying and verifying SRP/CS
- Validation engineers preparing evidence for the Technical File
Key requirements
- 01
Specify the safety functions
Define each safety function, its trigger, required response and PLr in a safety requirements specification.
- 02
Determine PLr
Derive the required Performance Level from the risk assessment using the S, F and P parameters, or an equivalent justified method.
- 03
Design to a Category
Select an architecture (B, 1, 2, 3 or 4) with the fault tolerance and diagnostics the PLr demands.
- 04
Quantify reliability
Estimate MTTFd per channel and DCavg, and score CCF measures — at least 65 points are required for Categories 2, 3 and 4.
- 05
Verify PL ≥ PLr
Confirm the achieved PL meets the PLr for every safety function, including systematic aspects and software.
- 06
Validate (Part 2)
Plan and record validation by analysis and testing, including fault lists and justified fault exclusions.
Summary for orientation only. Always refer to the current official text of EN ISO 13849-1/-2 and any applicable legislation.
MSA for EN ISO 13849-1/-2
What MSA generates
Evidence produced from your engineering inputs, traceable end to end and exported to Word, PDF or Excel.
PLr / SIL calculations
PLr determined per safety function and linked back to the hazard in the EN ISO 12100 risk assessment.
Validation protocols
Validation plans and records for each safety function, ready for the Technical File.
Fault injection tests
Test procedures that inject faults and record the observed response of the safety function.
Device test records
Per-device records for the sensors, logic and actuators that make up each safety function.
Frequently asked questions
What is the difference between PLr and PL?
PLr is the required Performance Level, determined from the risk assessment. PL is the level the designed control system actually achieves. Verification must show PL ≥ PLr for each safety function.
How do Performance Levels map to SIL?
Based on the average probability of dangerous failure per hour: PL e corresponds to SIL 3, PL d to SIL 2, and PL b and PL c to SIL 1. PL a has no SIL equivalent.
Do I need SISTEMA to comply with ISO 13849?
No. SISTEMA is a free calculation tool published by the German IFA. The standard does not require any particular tool; it requires the method to be applied correctly and documented.
Can MSA replace the validation tests themselves?
No. MSA generates the validation plan, test procedures and records. The tests are still carried out on the real machine, and the results are recorded against each safety function.
Generate EN ISO 13849-1/-2 evidence from your own data
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