UNI EN 334 : 2009

Foreword
1 Scope
2 Normative references
3 Terms, definitions and symbols
  3.1 General terms and definitions of types of gas pressure
      regulators
  3.2 Terms and definitions of components of gas pressure
      regulators
  3.3 Terms, symbols and definitions of components of
      functional performance
      3.3.7 Terms, symbols and definitions of functional
            performance
  3.4 Terms, symbols and definitions related to design
      and tests
4 Construction requirements
  4.1 Basic requirements
      4.1.1 General
      4.1.2 Gas pressure regulators with associated safety
            devices
      4.1.3 End connections
      4.1.4 Flange ratings
      4.1.5 Nominal sizes and face-to-face dimensions
      4.1.6 Sealing of the adjusting device
      4.1.7 Springs
      4.1.8 Replaceable parts that amy be affected by
            erosion or abrasion
  4.2 Materials
      4.2.1 Requirements for metallic materials
      4.2.2 Requirements for elastomers (including
            vulcanized rubbers)
      4.2.3 Requirements for non metallic materials
            different from those in 4.2.2
  4.3 Strength of housings
      4.3.1 Body and its inner metallic partition walls
      4.3.2 Flanges
      4.3.3 Other pressure containing parts
      4.3.4 Inner metallic partition walls
      4.3.5 Minimum values of safety factor
      4.3.6 Welded joint coefficient
5 Functional requirements
  5.1 General
      5.1.1 Mounting position
      5.1.2 Sound emission
  5.2 Shell strength, external tightness and internal sealing
      5.2.1 Shell strength
      5.2.2 External tightness
      5.2.3 Internal sealing
  5.3 Control classifications
      5.3.1 Accuracy under stable conditions
      5.3.2 Lock-up behaviour
      5.3.3 Stable conditions
  5.4 Final visual inspection
  5.5 Fail-close conditions
6 Gas pressure regulator sizing
  6.1 Flow behaviour
  6.2 Sizing equations for the calculation of volumetric
      flow rates of a gas pressure regulator with its
      control member in its mechanically fully open position
      6.2.1 Normal calculations
      6.2.2 Practical calculations
      6.2.3 Simplified calculations
  6.3 Calculation of the maximum accuracy flow rate
  6.4 Inherent flow characteristics
  6.5 Calculation of volumetric flow rates for partially
      open gas pressure regulators
  6.6 Flow coefficient
7 Testing
  7.1 General
  7.2 Tests
  7.3 Type test
  7.4 Selection of test samples
  7.5 Routine tests
  7.6 Production surveillance
  7.7 Test and verification methods
      7.7.1 Dimensional check and visual inspection
      7.7.2 Materials check
      7.7.3 Verification of the strength of pressure
            containing parts and inner metallic partition
            walls
      7.7.4 Shell and inner metallic partition walls
            strength test
      7.7.5 Alternative shell and inner metallic partition
            walls strength test
      7.7.6 External tightness test
      7.7.7 Functional tests
      7.7.8 Final visual inspection
8 Documentation
  8.1 Documentation related to type test
      8.1.1 Documentation required prior to type test
      8.1.2 Test report
  8.2 Documentation related to the routine tests
      8.2.1 Documentation provided at the request of the
            customer
      8.2.2 Documentation provided with the regulator
  8.3 Documentation related to production surveillance
      in accordance with 7.6
      8.3.1 Documentation to be available for production
            surveillance
      8.3.2 Production surveillance report
9 Marking
  9.1 General requirements
  9.2 Markings for the various connections
  9.3 Marking of integrated safety devices
Annex A (informative) Alternative methods for the
        determination of the accuracy class, the lock-up
        pressure class, the maximum accuracy flow rate,
        the flow coefficients and the verification of the
        hysteresis band
      A.1 General
      A.2 Test methods
          A.2.1 Direct acting gas pressure regulator
          A.2.2 Pilot controlled gas pressure regulators
      A.3 Determination of flow coefficients for larger
          capacity regulators
Annex B (informative) Inspection certificate
Annex C (informative) Acceptance test
Annex D (informative) Compliance evaluation
      D.1 General
      D.2 Introduction
      D.3 Procedure
      D.4 Manufacturer's compliance evaluation
      D.5 Issue of the certificate of compliance
Annex E (informative) Seat leakage (alternative requirement)
Annex F (normative) Creep (venting) relief device
      F.1 General
      F.2 Terms and definitions
      F.3 Requirements
          F.3.1 Construction
          F.3.2 Functional requirements
      F.4 Testing
      F.5 Type test
      F.6 Routine tests
      F.7 Documentation
      F.8 Marking
Annex G (informative) Order specification
      G.1 General
      G.2 Minimum specifications
          G.2.1 Details of construction
          G.2.2 Dimensions
          G.2.3 Performance
      G.3 Optional specifications
Annex H (normative) Materials
      H.1 Steel materials for pressure containing parts and
          inner metallic partition walls
      H.2 Metallic materials different from steel materials
          for pressure containing parts and inner metallic
          partition walls
      H.3 Materials for fixtures, integral process and
          sensing lines, connectors and fasteners
Annex I (informative) Glossary
Annex ZA (informative) Relationship between this European
         Standard and the Essential Requirements of EU
         Directive 97/23/EC
Bibliography

Describes constructional, functional, testing and marking requirements, sizing and documentation of gas pressure regulators used in the pressure regulating stations in accordance with EN 12186 or EN 12279: - for inlet pressures up to 100 bar and nominal diameters up to DN 400; - for an operating temperature range from -20 degree C to +60 degree C, which operate with fuel gases of the 1st and 2nd family in accordance with EN 437 in transmission and distribution networks and also in commercial and industrial installations.