IEC 61779-6:1999

FOREWORD
INTRODUCTION
1 General
   1.1 Scope
   1.2 Normative references
2 Definitions
3 Measuring principles
   3.1 Catalytic sensor
   3.2 Thermal conductivity sensor
   3.3 Electromagnetic radiation absorption sensor -
        usually infrared
   3.4 Semi-conductor sensor
   3.5 Electrochemical sensors
   3.6 Flame ionization detectors (FID)
4 Selection of apparatus
   4.1 General
   4.2 Selection criteria
   4.3 Miscellaneous factors affecting selection of
        apparatus
5 Behaviour of gas releases
   5.1 Nature of a release
   5.2 Outdoor sites and open structures
   5.3 Buildings and enclosures
   5.4 Environmental considerations
6 Installation of fixed gas detection apparatus
   6.1 Basic considerations for the installation of fixed
        systems
   6.2 Location of sensors
   6.3 Installation of sensors
   6.4 Timing of installation during construction operations
   6.5 Safety in fixed systems
   6.6 Environmental conditions
   6.7 Sample lines
   6.8 Access for calibration and maintenance
   6.9 Commissioning
   6.10 Operating instructions, plans and records
7 Use of portable and transportable flammable gas detection
   apparatus
   7.1 General
   7.2 Initial and periodic check procedures for portable
        and transportable instrumentation
   7.3 Guidance on the use of portable and transportable
        apparatus
8 Special precautions for fixed and portable apparatus
9 Maintenance, routine procedures and general
   administrative control
   9.1 General
   9.2 Operational checks
   9.3 Maintenance
   9.4 Sensors
   9.5 Flow systems
   9.6 Readout devices
   9.7 Alarms
   9.8 Workshop calibration test
   9.9 Routine tests and re-calibration procedures
   9.10 General administrative control
10 Training
Annex A (informative) Flammability limits (LFL and UFL) of
        certain flammable gases and vapours
Annex B (informative) Environmental and application
        check-list for flammable gas detectors (typical)
Annex C (informative) Instrument maintenance record for
        flammable gas detectors (typical)
Annex D (informative) Minimum environmental demands for
        IEC 61779-4 (group II 100 % LFL) and IEC 61779-5
        (group II 100 % (v/v) gas)

Gives guidance on the selection, installation, use and maintenance of electrically operated group II apparatus for the detection and measurement of flammable gases complying with the requirements of IEC 61779-1 to IEC 61779-5. For the purpose of this standard, flammable gases shall include flammable vapours. This standard applies only to group II apparatus intended for use in industrial and commercial safety applications, involving areas classified in accordance with IEC 60079-10.