Tools

Tightness test

Tightness test, live supply

Which gas?

IGEM/UP/1B Edition 4

About this tool

Draft: not yet checked

Walk through a tightness test to IGEM/UP/1B for natural gas, LPG or LPG/air on a live supply, or an air test of a new installation: the let-by test, raising and stabilising the pressure, and the two-minute test, with a timer for each part and a pass or fail at the end.

A training and checking aid

This tool doesn't replace the current standards, the manufacturer's instructions or your own competence. Always check the result against them before you rely on it.

Sources

  • IGEM/UP/1B, Tightness testing and direct purging of small installations, Edition 4, Communication 1903 (5.3.1.1, 5.3.2.1 and 5.3.3.1 (a) to (k), 5.4, 5.5, Tables 1 to 6, 4.1, 4.2, 5.2, Appendices 3, 4 and 6). The let-by test (7 to 10 mbar, 1 minute), the test pressure for each gas (natural gas 20 to 21 mbar with 18 mbar the lowest; LPG/air by operating pressure, Table 1; LPG by fuel, operating pressure and whether the regulator is in the section, Table 4), 1 minute to stabilise, the 2 minute test, what counts as perceptible movement, the permitted drop for an installation with appliances connected (Tables 2, 3 and 5), and the steps after a pass or a fail.

Learn how it works: Lesson 6.3: Stabilisation and tightness testing

Add it to your home screen

On an iPhone or iPad, tap Share, then Add to Home Screen. On Android, open the browser menu and choose Install app or Add to Home screen. It then opens like an app.

This tool follows IGEM/UP/1B Edition 4: natural gas, LPG (propane or butane) and LPG/air on a live supply; older natural gas installations above 75 mbar with no meter inlet valve (guidance in Appendix 4, not a formal procedure); suspected gas escapes; and the air test of a new installation before the gas is connected (Appendix 3). It doesn't do strength testing (5.1), which is done separately where it is needed. The gauge on screen is for entering what your real gauge shows.

Notes from the standard

Your equipment (4.1)
  • A gauge must be suitably ranged and suitable for the gas and the place. If it is electronic it should be zeroed at atmospheric pressure at the start of each test.
  • An electronic gauge must be calibrated at least every 12 months, or as the manufacturer says, and settled at the ambient temperature before the test. Water gauges need no calibration but must be kept well maintained.
  • A water gauge must be readable to 0.5 mbar and an electronic gauge to 0.1 mbar.
  • Electronic equipment must be certified for a hazardous area when you are using a gas detector to find a known or suspected escape, when there may be a flammable atmosphere, when the area is a designated hazardous zone, when the test area will be left unattended, or when a risk assessment says so. Use a water gauge if in doubt.
  • Check the equipment, including the sample line, for integrity just before you measure. Use only proprietary leak detection fluid to BS EN 14291: none with more than 30 parts per million of halogens on stainless steel, none with ammonia on copper or brass, never washing-up liquid, and wash it off afterwards.
Before you start (5.1, 5.2)
  • Work out the supply pressure (MOPu). Above 75 mbar, the parts upstream of the meter inlet valve (or the final-stage regulator where there is no meter) must be pre-assembled and strength tested by the manufacturer, or strength tested to IGE/UP/1. Strength testing on site isn't needed for a part of 75 mbar or less that can be isolated from higher pressure.
  • Before testing, look at every new joint where you can. Don't put a protective coating on site joints until after the test.
  • With a supply above 75 mbar, make sure the safety device on the regulator at the inlet of the MIV is in the open position before the let-by test.
  • A new installation that includes existing appliances: the new parts must show no perceptible fall and no smell of gas, but a permissible drop may be allowed on an existing appliance (the table for appliances connected).
  • Several dwellings, each with its own ECV or AECV (flats, for example): test the whole installation downstream of the valve at the inlet to the primary meter where you can.
  • Where you reduce the pressure at any stage, gas has to be let out to a safe area. Take the safety precautions in the purging section (6.3 (b)) first.
  • If the supply is above 75 mbar and the work involves a new meter installation, a new regulator or anything between the ECV and the MIV, test every connection between them with leak detection fluid as soon as you open the ECV.
Extensions and alterations (5.4)
  • Before you start the new work, test the existing installation and note any drop over the 2 minutes. This finds problems that were already there.
  • When the work is finished, test it again, to show the meter and pipework are gas tight and any drop from the appliances is within the permitted limit. The installation volume may need working out again.

Settings

Your gauge

Kept on this device, so you aren't asked at every test.

Countdown beeps

A beep each second for the last 10 seconds, and a long beep at the end.

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Next steps

Test record