Industry Standard Update 119

IGEM/GM/5 Edition 4 Electronic gas meter volume conversion systems
Date issued: 20 June 2023

This Industry Standard Update provides an overview of the recently published revised Industry Standard IGEM/GM/5 Edition 4 – Electronic gas meter volume conversion systems, and highlights areas of significant change that the revision has introduced.

Introduction

During April 2023, IGEM published a revision to IGEM/GM/5 Edition 3 Electronic gas meter volume conversion systems⁽¹⁾. IGEM/GM/5 Edition 4 (Communication 1817)⁽²⁾ supersedes Edition 3 (Communication 1730), which is now obsolete.

The revision to this standard comes into effect immediately.

To allow registered businesses time to carry out internal update training to reflect the technical requirements of the amended standard, Gas Safe Register will inspect to the new requirements of this standard from 1 October 2023.

However, this should not restrict businesses from applying the specification sooner. The following is a brief overview of the amendments made to IGEM/GM/5 Edition 4.

General

Table 1 in Section 2 has been updated to include Electronic Index and Advanced Meters.

Due to the devolution of power to the Scottish, Welsh and Northern Irish assemblies, Section 3.1.1 highlights that there may be variations to the legislation for each of them and consideration of their requirements.

Section 3.1.6 states that certification for explosion protection should now conform to DSEAR Regulations as opposed to the ATEX Directive in the previous document.

Section 4: Rules for selection and configuration of electronic volume conversion system (EVCS)

Guidance is given in Sections 4.1 and 4.2 on the considerations that should be taken when selecting the appropriate correction device and advises that Table 1 can be used to aid in the selection.

Section 4.3 gives guidance on how to set the correct pulse output significance on any EVCS to match the pulse input significance.

The Automatic Meter Reading (AMR) provider should be contacted to confirm what options are available if the meter pulse significance cannot be used, as per Section 4.3.1.2.

The width of pulses for reed relays and for electronic switches is given in Section 4.3.2.

Commissioning procedure has been added if GSM system is used to communicate between the device and a head-end system. This configuration should be developed and tested with the head-end system to ensure the correct configuration, as errors would result in further site visits.

The pre-installation tests added to Section 4.4.1 state that it’s optional to carry out preinstallation tests: however, if completed, they should always be carried out in a non-hazardous area on site. Any changes to the programme identified during testing after installation should be recorded.

The full procedure for pre-installation checks is given in Section 4.4.2.

It may be possible to program conversion systems with several parameters, by using an external computer, as stated in Section 4.4.3.

Section 5: Design and installation

Section 5.1.2 advises that access to any part of the meter should not be unduly impeded by the electrical circuit, and that the meter index or any statutory labels must not be rendered difficult to read. Pipework and wiring should be arranged in a way that doesn’t create a hazard or restrict access for service and maintenance work, as stated in Section 5.3.1.3.

Section 5.4.2 adds that if the additional outputs are used, then DSEAR must be followed and IGEM/GM/7A Electrical connections for gas metering equipment (communication 1731)⁽³⁾ and IGEM/GM/7B

Hazardous area classifications for gas metering equipment (communication 1732)⁽⁴⁾ shall be followed. The manufacturer’s instructions should be followed to protect the device from incorrect use of the outputs. If the conversion device is certified for use in hazardous areas, then its outputs should be treated as if they were in a hazardous area.

Figure 4 has been added, showing sealing points.

Section 6: Commissioning

This commissioning procedure assumes that the EVCS being installed complies with BS EN 12405-1:2021 Gas meter – Conversion devices Volume conversion⁽⁵⁾. See Section 8: Monitoring, if using an older EVCS.

Section 6.5.1 advises that the operating temperature and pressure of the installation shall be observed by the person carrying out the checks, and judgement should be used to confirm the operation effectiveness of the system by checking the volume input, temperature and pressure values indicated by the device. Section 6.5.2 and 6.5.3 should be consulted if there are any doubts about the effectiveness of the transducers.

Values of acceptance criteria are given in Section 6.5.2 as no changes in pulses for LF systems and a tolerance of less than +/- 0.001% of pulses for HT systems.

Operatives shall ensure there are no gas escapes on the instrumentation pipework and all wiring terminations have been reconnected with covers correctly fitted to all units as per Section 6.6.1.

The conversion device shall be disabled and protected by a seal, as stated in Section 6.6.3.

Section 8: Monitoring, inspection and maintenance

Section 8.2.1 has added that, when checking for intrinsic safety, factors relating to results of previous inspections, signs of deterioration and classification of the area should all be considered.

Unless an expert documented analysis has been conducted, the inspection period shall not exceed three years, as stated in Section 8.2.2.

Additional checks required for equipment during maintenance have been added to Section 8.2.4, including barriers for equipment in hazardous areas, casings and displays are in good condition, weather protection is adequate, and earth bonding is suitable. Also confirm that the serial number relates to the make and model of the device and contact the meter asset manager for guidance if there are any issues.

Section 8.3.1 states that the owner of any electrical equipment connected to or installed on a gas meter shall be responsible for the safe and efficient operation of the equipment.

Appendix 8

Pressure testing has been added plus sections covering safety precautions, testing, combined strength and tightness testing and final leak checks. Figure 21 shows a typical layout for testing ECVS pressure transducer.

Bibliography
(1) IGEM/GM/5 Edition 3 Electronic gas volume conversion systems (Communication 1730)
(2) IGEM/GM/5 Edition 4 Electronic gas volume conversion systems (Communication 1817)
(3) IGEM/GM/7A Electrical connections for gas metering equipment (Communication 1731)
(4) IGEM/GM/7B Hazardous area classification for gas metering equipment (Communication 1732)
(5) BS EN 12405-1:2021 Gas meters. Conversion devices Volume conversion

Summary
As previously stated, this Industry Standard Update is only a brief overview of the information contained in the amended standard. Registered businesses should be aware that they have a responsibility to ensure that they are fully apprised of all the requirements of the whole published standard and their practical application.