UNI EN 13786 : 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
      5.3.8 Non return valves
  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 Change over pressure
      6.3.2 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.1.4 Test methods
           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.2.3 Performance characteristics
           A.2.4 Test methods
      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.5.4 Users and maintenance instructions
Annex B (normative) - Special requirements for automatic
        change over devices and automatic change over
        device systems for caravans, motor caravans or
        fresh water boats
Annex C (normative) - Special requirements for low
        pressure automatic change over devices under
        extreme temperature conditions (temperatures
        below - 20 degrees 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 bench
      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 diaphragms
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 J (normative) - Automatic change over device and
        change over device systems for LPG cylinders
        to supply appliances installed in seawater boats
      J.1 Scope
      J.2 General
      J.3 Maximum guaranteed rate
      J.4 Change over device and change over device
           systems fitted with a pressure relief valve
      J.5 Vent
      J.6 Connections
      J.7 Material
      J.8 Resistance to corrosion
           J.8.1 General
           J.8.2 Requirement
           J.8.3 Test method
      J.9 Marking
      J.10 Instructions for use and maintenance
Annex ZA (informative) - Clauses of this European
         Standard addressing essential requirements
         or other provisions of EU Directives
Bibliography

Describes 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.