SN EN 13786 : 2004 + A1 2009

Foreword
1 Scope
2 Normative references
3 Terms and definitions
  3.1 General terms and definitions
  3.2 Terms and definitions concerning gas
  3.3 Terms and definitions concerning pressures
  3.4 Terms and definitions concerning rates
4 Types of automatic change over devices
  4.1 Introduction
  4.2 Automatic change over devices for installations where the
      final regulator supplies a pressure specified in EN 437
  4.3 Other automatic change over devices installation
5 Constructional characteristics
  5.1 General
  5.2 Materials
  5.3 Special requirements
      5.3.1 Pressure sensing subassembly
      5.3.2 Regulation subassembly
      5.3.3 Back pressure subassembly
      5.3.4 Connection subassembly
      5.3.5 Supply-reserve indicator
      5.3.6 Knob for selection of the operational cylinder
      5.3.7 Fixing onto a wall
  5.4 Mechanical strength
      5.4.1 Resistance to pressure
      5.4.2 Strength of connections
  5.5 Soundness
  5.6 Mechanical endurance
  5.7 Resistance to humidity changes
  5.8 Resistance to corrosion
6 Performance characteristics
  6.1 General
      6.1.1 Introduction
      6.1.2 Supply pressure
  6.2 Operational limit characteristics (regulation
      function)
  6.3 Operational limit characteristics (Change over
      function)
      6.3.1 Gas flow safety
      6.3.2 Change over pressure
      6.3.3 Selection of the operating cylinder
7 Test methods
  7.1 General conditions
      7.1.1 Type of test gas
      7.1.2 Test conditions
      7.1.3 Equivalence formulae
      7.1.4 Test samples
  7.2 Verification of constructional characteristics
      7.2.1 Resistance to pressure
      7.2.2 Mechanical strength of connections
      7.2.3 Regulation subassembly
      7.2.4 Soundness
      7.2.5 Endurance
      7.2.6 Resistance to humidity changes
      7.2.7 Resistance to corrosion
  7.3 Verification of performance characteristics
      7.3.1 General
      7.3.2 Plotting of regulation curves
8 Marking, packaging, instructions
  8.1 General
  8.2 Marking of the device
  8.3 Packaging
  8.4 Instructions for use and maintenance
Annex A (normative) Special requirements for automatic change
                    over devices fitted with pressure or rate
                    operated safety valves
  A.1 Change over devices fitted with an over-pressure relief
      A.1.1 Definition
      A.1.2 Constructional characteristics
      A.1.3 Performance characteristics
            A.1.3.1 Automatic change over devices having a
                    maximum regulated pressure of up to and
                    including 150 mbar
            A.1.3.2 Automatic change over devices having a
                    maximum regulated pressure exceeding 150
                    mbar
      A.1.4 Test methods
            A.1.4.1 Automatic change over devices having a
                    maximum regulated pressure of up to and
                    including 150 mbar
            A.1.4.2 Automatic change over devices having a
                    maximum regulated pressure exceeding 150 mbar
      A.1.5 Automatic change over device marking
  A.2 Automatic change over device fitted with an over-pressure
      shut off safety valve
      A.2.1 Definition
      A.2.2 Constructional characteristics
            A.2.2.1 General
            A.2.2.2 Closing force
            A.2.2.3 Diaphragm strength
      A.2.3 Performance characteristics
            A.2.3.1 Automatic change over devices with a
                    maximum regulated pressure of up to and
                    including 150 mbar
            A.2.3.2 Automatic change over devices with a
                    maximum regulated exceeding 150 mbar
      A.2.4 Test methods
            A.2.4.1 Test for the components transmitting the
                    closing forces
            A.2.4.2 Test for diaphragm strength
            A.2.4.3 Performance test
  A.3 Automatic change over device fitted with an under-pressure
      shut off safety device
      A.3.1 Definition
      A.3.2 Constructional and performance characteristics
      A.3.3 Test methods
  A.4 Automatic change over devices fitted with an excess flow
      valve
      A.4.1 Definition
      A.4.2 Performance characteristics
      A.4.3 Complementary tests for the automatic change over
            devices - Test methods
      A.4.4 User and maintenance instructions
  A.5 Automatic change over devices fitted with a regulated
      pressure limiter
      A.5.1 Definition
      A.5.2 Constructional and performance characteristics
      A.5.3 Test methods
            A.5.3.1 Test conditions
            A.5.3.2 Measurement of the maximum regulated
                    pressure
            A.5.3.3 Measurement of the pressure drop
      A.5.4 Users and maintenance instructions
Annex B (normative) Special requirements for automatic change
                    over devices and automatic change over
                    devices systems for caravans and leisure
                    vehicles
Annex C (normative) Special requirements for low pressure
                    automatic change over devices under extreme
                    temperature conditions (temperatures below -
                    20 degree C)
Annex D (normative) Method for measuring leaks at test pressures
                    less than or equal to 16 bar
  D.1 Scope
  D.2 Diagram of the test
  D.3 Coefficient K
      D.3.1 Method
      D.3.2 Calculations
  D.4 Measurement of the leak
      D.4.1 Method
      D.4.2 Calculations
  D.5 Checks
Annex E (normative) Complementary test requirements for non
                    metallic thermoplastic or thermal setting
                    materials used in the construction of
                    automatic change over devices
  E.1 Scope
  E.2 Materials
  E.3 Special conditions for carrying out the test mentioned in
      the body of the standard
      E.3.1 Resistance to impact
      E.3.2 Mechanical resistance of connections
      E.3.3 Soundness
  E.4 Special requirements
      E.4.1 Resistance to hydrocarbons
      E.4.2 Resistance to cracking under stress and when chemical
            agents are present
      E.4.3 Characteristics relating to fire resistance
      E.4.4 Accelerated ageing
  E.5 Sampling and order of tests
Annex F (normative) Requirements for elastomeric reinforced
                    diaphgrams
Annex G (normative) Inlet connections
Annex H (normative) Outlet connections
Annex I (normative) Test method for resistance to corrosion
  I.1 Principle
  I.2 Reagents
      I.2.1 Saline solution
      I.2.2 Compressed air
      I.2.3 Salt mist
  I.3 Apparatus
      I.3.1 Spraying chamber
      I.3.2 Sprayers
      I.3.3 Heating device
      I.3.4 Salt solution supply device
      I.3.5 Compressed air supply device
      I.3.6 Mist collectors
  I.4 Test method
      I.4.1 Method of exposure of automatic change over device
      I.4.2 Duration of tests
      I.4.3 Checks
      I.4.4 Cleaning of automatic change over device
  I.5 Results
Annex ZA (informative) Clauses of this European Standard addressing
                       essential requirements or other provisions of
                       EU Directives
Bibliography

Defines the constructional and operational characteristics, the safety requirements and test methods, and the marking of automatic change over devices with a capacity of less than or equal to 100 kg/h and having a maximum regulated pressure of less than or equal to 4 bar for butane, propane or their mixtures only in the vapour phase.