BS EN 12261:2018 pdf download

BS EN 12261:2018 pdf download.Gas meters – Turbine gas meters
1 Scope
This document specifies the measuring conditions, requirements and tests for the construction,performance and safety of class 1,0 axial and radial turbine gas meters with mechanical indicating devices, herein after referred to as a meter(s), having in-line pipe connections for gas flow measurement.
This document applies to turbine gas meters used to measure the volume of fuel gases of the 1st and 2nd gas families, the composition of which is specified in EN 437 at maximum working pressures up to 420 bar, actual flow rates up to 25 000 m3/h over a gas temperature range of at least 40 K and for a climatic environmental temperature range of at least 50 K.
This document applies to meters that are installed in locations with vibration and shocks of low significance and in closed locations (indoor or outdoor with protection as specified by the manufacturer) with condensing or with non-condensing humidity or, if specified by the manufacturer,open locations [outdoor without any covering) with condensing humidity or with non-condensing humidity and in locations with electromagnetic disturbances.
Unless otherwise specified in this document:
一all pressures used are gauge;
一all influence quantities, except the one under test, are kept relatively constant at their reference value.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 10204, Metallic products一Types of inspection documents
EN 22768-1:1993, General tolerances一Part 1: Tolerances for linear and angular dimensions without individual tolerance indications (ISO 2768-1:1989)
EN 60079-0, Explosive atmospheres一Part 0: Equipment一General requirements (IEC 60079-0)
EN 60079-11, Explosive atmospheres一Part 11: Equipment protection by intrinsic safety “4” (IEC 60079-11)
EN 60529, Degrees of protection provided by enclosures (IP Code) (IEC 60529)
EN 60947-5-6, Low-voltage switchgear and controlgear一Part 5-6: Control circuit devices and switching elements一DC interface for proximity sensors and switching amplifiers (NAMUR) (IEC 60947-5-6)
EN 62246-1, Reed switches一Part 1: Generic specification (IEC 62246-1)
EN ISO 5167-1:2003, Measurement ofluid flow by means of pressure differential devices inserted in circular cross-section conduits running full一Part 1: General principles and requirements (ISO 5167-1:2003)
ISO/IEC Guide 98-3, Uncertainty of measurement一Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)
4.3 Connections and dimensions
The inlet and outlet of the meter shall have the same nominal diameter and connection type. The preferred overall length in millimetres of the meter between inlet and outlet connections is 3 DN. Tolerances are given in EN 22768-1:1993, “Designation c”. The preferred length in millimetres of 3 DN for the meter shall not be exceeded. For shorter meters the manufacturer shall be able to provide a“make up spool piece” to bring their body lengths up to the preferred length, where requested. The maximum overall distance in millimetres measured from the extremity of the protruding parts to the meter axis should not exceed 150 plus 1,5 DN. For flange connections refer to Table 2.