Got questions on IGEM/UP/1B?
Tech Talk 11 from Gas Safe Register’s Technical Team discusses the background to the updates to IGEM /UP/1B and how to make sure you’re applying its requirements correctly.
The requirements of IGEM/UP/1B Edition 4 have now come in effect after six-month lead-in period. Engineers are expected to be working in line with the requirements of this updated edition.
Gas Safe Register and Registered Gas Engineer magazine have been receiving queries about why the changes have come about, along with questions about its application. Tech Talk 11 addresses many of these queries.
The video is co-hosted by the Register’s Standards and Training Manager Jonathan Palmer and chair of the UP/1B Review Committee Andy Durber. It sets out what the changes are, the reasons for them and walks through the processes of testing for leakage as well as purging.
Background
The permissible leakage rates had been based on an average pipework installation, historically a maximum rate of 19 ml/min. The new guidance now bases the 19ml/min calculation to volume of gas within the system as a whole.
The changes
IGEM says the main changes to the tightness testing procedures are:
- The movement from the ‘maximum permissible pressure drops during a tightness test on an existing installation’ being based on meter designation and pipework diameter to the actual estimated installation volume (IV); and
- The requirement to confirm that any perceptible movement (fall) on a pressure gauge during a tightness test on an existing installation is not attributable to gas installation pipework or meter, where fitted.
The first change ensures that the maximum permissible leak rates (MPLRs) that had previously been determined by the industry for existing installations typically covered by the procedures in IGEM/UP/1B are not exceeded, for example, for natural gas installations an MPLR of 19 ml/min.
The second requires that, where a perceptible movement on a pressure gauge is identified, but within the new limits shown within the table, that any appliances are isolated from the installation and another tightness test is undertaken. This test is to ensure that the installation pipework and any meter are gas-tight to the criteria ‘no perceptible movement’.
This proves that any permissible pressure drop can be attributed to appliance(s) not the installation pipework or meter.
In all situations, however, irrespective of any tightness test results, a smell of gas is not acceptable.
Purging
The purging procedure itself remains unchanged. But the estimated installation volume should determine the volume of gas to be purged. The purge volume for all installations covered by the standard is 1.5 x the installation volume.
Summary of key changes
- Maximum permissible pressure drop based on estimated installation volume rather than meter designation and pipework diameter.
- For existing installations, confirm any perceptible movement on a pressure gauge is NOT attributed to any installation pipework with or without a gas meter installed.
- All purge volume to be based on installation volume rather than meter designation and pipework diameter.
Industry Standard Update 133 provides an overview of the key areas of change arising from the revision. You can read and download ISU 133 by logging into your Gas Safe Register online account and at registeredgasengineer.co.uk
Tech Talk is a regular video series designed to help you keep up to date with seasonal topics and technical updates relevant to you and your work. You can find Episode 11 here