PREN 50402 : DRAFT 2013

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 General requirements
5 Functional modules and elements - Characterisation
   and requirements
6 Software
7 Combining Functional Modules to Safety Functions
8 Determination of Hardware Failure Rates for each
   Safety Function
9 Gas detection as Part of an overall Safety Function
10 Information requirements
11 Validation
12 Functional safety management
13 Functional safety assessment
14 Documentation
Annex A (normative) - Transformation of the SIL-capabilities
        of gas detection systems
Annex B (normative) - Transformation from generic standard
        requirements to modules
Annex C (normative) - Determination of SIL-capability of
        a safety function of the gas detection system
Annex D (informative) - Failure Modes for Specific
        Measuring Principles
Bibliography

Pertains to fixed gas detection systems for the detection and measurement of flammable or toxic gases or vapours or oxygen.