IS 14439 : Part 4 : 2025 Legal Metrology - Gas Volume Meters - Part 4 Thermal Mass Flow Based Gas Meters - Specification

ICS 17.120.10

PGD 26

1 SCOPE

This standard specifies requirements and tests for the construction, performance, safety and production of battery powered class 1.5, capillary thermal-mass flow sensor gas meters [here in after referred to as meter(s)]. This applies to meters having two pipe connections, which are used to measure volumes of 2nd and/or 3rd family of gases, as given in IS 15127.

In general, the term 'thermal mass flow meters' applies to a flow-measuring device using heat transfer to measure and indicate gas flow rate. NOTE - Although the word 'mass' is present in the definition of the measurement principle, gas meters covered by this standard provide measurement of gas at base conditions of temperature and pressure.

These meters have a maximum working pressure not exceeding 0.5 bar and a maximum flow rate not exceeding 40 m3/h over a minimum ambient temperature range of -10 °C to 55 °C and a gas temperature range as specified by the manufacturer with a minimum range of 55 °C.

This standard applies to meters indicating volume at base conditions, which are installed in locations with vibration and shocks of low significance. It applies to meters in closed locations (indoor or outdoor with protection, as specified by the manufacturer) with condensing humidity or non-condensing humidity, or, if specified by the manufacturer, open locations (outdoor without any covering) with condensing humidity or noncondensing humidity, and in locations with electromagnetic disturbances likely to be found in residential, commercial and light industrial use.

For meters which indicate unconverted volume, reference may be made to Annex D.

Unless otherwise stated, all pressures given in this standard are gauge pressures.

NOTE - 1 bar = 105 Pa.

2 REFERENCES

The standards listed in Annex A contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of these standards.

IS No./Other Publications	Title
IS/CISPR 32 : 2015	Electromagnetic compatibility of multimedia equipment - Emission Requirements
IS 101 (Part 5/Sec 3) : 2019/ISO 6272-1 : 2011	Methods of sampling and test for paints, varnishes and related products: Part 5 Mechanical tests, Section 3 Impact resistance - Fallingweight test, large-area indenter (fifth revision)
IS 554 : 1999/ISO 7-1 : 1994	Pipe threads where pressuretight joints are made on the threads - Dimensions, tolerances and designation (fourth revision)
IS/ISO 834-1 : 1999	Fire-resistance tests - Elements of building construction: Part 1 General requirements
IS 2643 : 2005/ISO 228-1 : 2000	Pipe threads where pressuretight joints are not made on the threads - Dimensions, tolerances and designation (third revision)
IS 5528 : 2024/ISO 9227 : 2022	Corrosion test in artificial atmospheres - Salt spray tests (second revision)
IS 5572 : 2009/IEC 60079-10 : 2002	Classification of hazardous areas (Other than mines) having flammable gases and vapours for electrical installation (third Revision)
IS 6303 : 2018	Primary batteries - General (second Revision)
(Part 4) : 2023/IEC 60086-4 : 2019	Safety of lithium batteries (third Revision)
IS 14700	Electromagnetic compatibility (EMC):
(Part 4)	Testing and measurement techniques,
(Sec 2) : 2018/IEC 61000-4-2 : 2008	Electrostatic discharge immunity test (second revision
(Sec 3) : 2023/IEC 61000-4-3 : 2020	Radiated, radio-frequency, electromagnetic field immunity test (second revision)
Sec 8) : 2018/IEC 61000-4-8 : 2009	Power frequency magnetic field immunity test (second revision)
Sec 9) : 2019/IEC 61000-4-9 : 2016	Impulse magnetic field immunity test (second revision)
(Part 6)	Generic standards,
Sec 1) : 2019/IEC 61000-6-1 : 2016	Immunity standard for residential, commercial and light-industrial environments (first revision)
Sec 2) : 2019/IEC 61000-6-2 : 2016	Immunity standard for industrial environments (first revision)
IS 15127 : 2024/ISO 13686 : 2013	Natural gas - Quality designation (first revision)
IS 15305 (Part 2) : 2019/ISO 12213-2 : 2006	Natural gas - Calculation of compression factor: Part 2 Calculation using molarcomposition analysis (first revision)
IS/IEC 60079-0 : 2017	Explosive atmospheres: Part 0 Equipment - General requirements (first revision)
IS/IEC 60079-11 : 2023	Explosive atmospheres: Part 11 Equipment protection by intrinsic safety “i” (second revision)
IS/IEC 60079-15 : 2017	Explosive atmospheres: Part 15 Equipment protection by type of protection "n" (second revision)
IS/IEC 60529 : 2001	Degrees of protection provided by enclosures (IP Code)
IS/IEC 60695-11-5 : 2016	Fire hazard testing: Part 11 Test flames, Section 5 Needle - Flame test method - Apparatus, Confirmatory test arrangement and guidance (first revision)
IS/IEC 60695-11-10 : 2013	Fire hazard testing: Part 11 Test flames, Section 10 50 W horizontal and vertical flame test methods
IS/IEC 60730-1 : 1999	Automatic electrical controls for household and similar use: Part 1 General requirements
IS/IEC 62056-21 : 2002	Electricity metering - Data exchange for meter reading, tariff and load control: Part 21 Direct local data exchange
ISO 1518-1 : 2023	Paints and varnishes - Determination of scratch resistance: Part 1 Constantloading method
ISO 2409 : 2020	Paints and varnishes - Cross-cut test
ISO 2812-1 : 2017	Paints and varnishes - Determination of resistance to liquids: Part 1 Immersion in liquids other than water
ISO 4628-2 : 2016	Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and size of defects, and of intensity of uniform changes in appearance: Part 2 Assessment of degree of blistering
ISO 4628-3 : 2024	Paints and varnishes - Evaluation of quantity and size of defects, and of intensity of uniform changes in appearance: Part 3 Assessment of degree of rusting
ISO 4892-3 : 2024	Plastics - Methods of exposure to laboratory light sources: Part 3 Fluorescent UV lamps
ISO 6270-1 : 2017	Paints and varnishes - Determination of resistance to humidity: Part 1 Condensation (single-sided exposure)
ISO 14511 : 2019	Measurement of fluid flow in closed conduits - Thermal mass flowmeters
ASME B1. 20.1 : 2013	Pipe threads, general purpose, inch
BS 746 : 2014	Specification for gas meter unions and adaptors
EN 437 : 2021	Test gases - Test pressures - Appliance categories
EN 549 : 2019	Rubber materials for seals and diaphragms for gas appliances and gas equipment
EN 1092-1 : 2018	Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN designated - Part 1 Steel flanges
EN 16314 : 2013	Gas meters - Additional functionalities
EN 50561-1 : 2013	Power line communication apparatus used in low-voltage installations - Radio disturbance characteristics - Limits and methods of measurement: Part 1 Apparatus for in-home use