Gas Pipework - Installation & Inspection

Are you replacing your gas appliances or installing new appliances into a new property?
Do you know the up-to-date regulations?
Does the existing pipework comply with the latest directives, are they the correct size and is the correct gas meter is installed?

You may be surprised to know that a significant number of existing gas supply systems are installed with undersized gas meters and pipework. This may be due to the pipework and meter not being correctly sized in the first place or because additional equipment has been added over time. Nearly all new appliances require the correct volume of gas at the designed pressure to operate correctly, so under-sizing the gas meter or gas pipework can cause significant problems in their operation and life expectancy.

For existing systems that are being upgraded the meter and pipework must be fully inspected, not just for size but the length of the pipe run and the number and types of fittings.

These are the questions you should be asking to ensure your pipework is compliant and providing the suitable volume of gas:

  • Do all the fittings meet the current regulations, is it threaded, flanged, copper etc?
  • What will be the pressure drop over the system including the gas meter, is it under the required 1mbar?
  • Is the pipework correctly marked?
  • Is there a solenoid valve correctly installed just inside the plant room?
  • Is there a schematic of the gas pipe system in the gas meter room and the plant room?
  • Does the gas pipe run through void spaces; are the spaces correctly ventilated?
  • Is all the pipework correctly sleeved as it passes through walls and floors?

We are here to inspect the system to ensure that the gas pipework and gas meter is suitable for the new appliances and that the supply pressure is adequate for all the appliances connected running to the system running at 100% output.

All gas meters will have a maximum flow rating, but it is important to check the pressure drop at the required maximum gas flow rate. Most domestic and small commercial properties that require gas meters up to 100m³/h are fitted with diaphragm meters. These will have an inherent pressure drop depending on the flow. The pressure drop can be between 2 and 4mbars when the gas meter is operating at 100% flow rate.

For these gas meters, it is prudent to match the maximum gas requirement to about 70% of the gas meter rating, this is likely to ensure the pressure drop over the gas meter to below 1 mbar.

All gas pipes 100mm and over must now be welded and connected with flanged joint. In the past, it was common to thread pipework up to systems as large as 150mm and on LPG all pipework 50mm and over must be welded with flanged joints.

All pipework and fittings used must be suitable for transporting natural gas and LPG.

We carry out design, installation and commissioning of large domestic and all commercial gas pipework for both natural gas and LPG. The installations comply with all relevant regulations including the Institute of Gas Engineers UP2 Edition 3, BS6644:2011, Safety in the installation and use of gas systems and appliances Gas Safety (Installation and Use) Regulations 1998 as amended Edition 5 (2018) and the Health and Safety document; L56 (Fifth edition) Published 2018.

Other regulations that may cover Gas Supplies passing through communal areas or other properties are covered in the British Standard BS6891-1, IGEM/UP/7 Edition 2 and where necessary, manufacturer’s installation instructions must also be adhered to. Guidance for gas in flats and other multi-occupancy dwelling buildings can be found in IGEM/G/5(3).

Before any commercial (and large domestic) gas pipework is taken out of service or put into service the pipework must be correctly purged by a suitably qualified engineer. This may be using nitrogen as an innate gas to ensure that there is never an explosive air/gas mix in the pipeline, and the procedure is set down in IGE/UP/1 (or1A)