NBN EN 50402 : 2006 AMD 1 2009

Introduction
1 Scope
2 Normative references
3 Definitions
4 General requirements
  4.1 Introduction
  4.2 Functional safety characteristics of modules
5 Modules and elements - Characterisation and requirements
  5.1 General requirements
  5.2 Gas sampling
  5.3 Sensor
  5.4 Signal-transmission
  5.5 Input of control unit
  5.6 Signal processing in the control unit
  5.7 Output of the control unit
6 Characterisation of safety requirement
  6.1 General
  6.2 Characterisation of safety function
  6.3 Characterisation of safety integrity
  6.4 Determination of SIL-capabilities for a safety function
  6.5 Determination of hardware failure rates for a safety function
  6.6 Safety performance requirements
7 Information requirements
  7.1 Information delivered by the manufacturer of the gas
      detection system
  7.2 Information delivered by the user of the gas detection system
8 Validation
Annex A (informative) Gas detection systems as part of a
                      safety-related system
Annex B (normative) Transformation of the SIL-capabilities of
                      gas detection systems
Annex C (normative) Transformation from generic standard
                      requirements to modules
Annex D (normative) Management of functional safety
Annex E (informative) Determination of SIL-capability of a
                      safety function of the gas detection system

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