EN 334:2005+A1:2009

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
  3.4 Terms, symbols and definitions related to design
      and tests
4 Construction requirements
  4.1 Basic requirements
  4.2 Materials
  4.3 Strength of housings
5 Functional requirements
  5.1 General
  5.2 Shell strength, external tightness and internal sealing
  5.3 Control classifications
  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
  6.3 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
8 Documentation
  8.1 Documentation related to type test
  8.2 Documentation related to the routine tests
  8.3 Documentation related to production surveillance
      in accordance with 7.6
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.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.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.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

This document specifies 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 °C to +60 °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.
"Gas pressure regulators" hereafter will be called "regulators" except in the titles.
For standard regulators when used in pressure regulating stations complying with EN 12186 or EN 12279, Annex ZA lists all applicable Essential Requirements except the external corrosion resistance in case of environmental conditions where corrosion is likely to occur.
This document considers the following classes/types of regulators:
-class 1: operating temperature range from 10 °C to 60 °C;
-class 2: operating temperature range from 20 °C to 60 °C;
-type IS: (integral strength type);
-type DS: (differential strength type).
This document applies to regulators which use the pipeline gas as a source of control energy unassisted by any external power source.
The regulator may incorporate a creep (venting) relief device, complying with the requirements in Annex F.
The regulators complying with the requirements of this document may be declared as "in compliance with EN 334" and bear the marking "EN 334".
This document does not apply to:
-regulators upstream from/on/in domestic gas consuming appliances which are installed downstream of domestic gas meters;
-regulators incorporated into pressure-regulating devices used in service lines with volumetric flow rate