Gas Connection Trench & Ducting Requirements

6th January 2013 written by Richard Hearne in the category Gas Articles

Mini DiggerIf you are ordering a new gas connection pipe and meter for your business or domestic gas supply, it is likely the nearest gas mains will be situated in a local road, footpath or on your own land.


There are rules set by OFGEM and the Health and Safety Executive Executive (HSE) which state the materials which can be used for gas connection, depth of trenches and proximity to other services such as electric, water or phone cables.


If your gas connection service pipe will cross both public land and private land, you  have the option to arrange the digging in private land if you so wish.


This may provide a cost benefit over having engineers doing it for you, especially over longer distances. This is also known as a ‘contestable cost’.


Although, we are providing this information, we must stress it is a guide and therefore, before carrying out any excavation works or laying ducting (especially over distances of 50 metres or more, you should always, check with us before carrying out the works to check it meets the requirements.


Digging in public land must always be carried out by companies who hold a GIRS licence. GIRS stands for Gas Industry Registration Scheme.


If you do wish to pre-excavate a trench on your own land, referring to Healthy and Safety Executive guidance, should ensure the relevant requirements are met. The route of the trench should follow the map provided on 1Gas’ quotation.


Depth and Width

The depth of a service pipe depends on the type of land which it is below. Under a garden the gas pipe service should be 375mm deep and under a footway 450mm. The trench should usually be 200-300mm wide.

Utilities Infrastructure Layout

Trench Requirements

The trench should be safe and secure and not likely to cave in. The route of the trench should avoid obstructions such as drains or manhole covers and should be laid in straight lines.


If a change of direction is needed, it must be at a right angle.


The base should be level, compacted and free or sharp items such as glass, metal, or brick.


If you locate sharp stones at the required depth, you may need to dig 75mm deeper and put in a layer of fine material. You should lay stone dust or sand in the base for the gas pipe to sit on.


Ideally the gas pipe connection will run down in a gentle gradient away from the building requiring gas towards the main. Usually fine sand and a depth of 10cm is required on top of the gas pipe once it is laid in the trench.


When you are backfilling the trench, you should place warning tape advising there is a gas pipe below at least 75mm above the pipe. A minimum clearance of other pipes or utilities services connections should be usually 250mm.


No scaffolding or debris should be an obstruction at site when our engineers arrive to carry out works or this could cause a delay.


Where you are excavating a trench in private land and wish to cover over the trench to carry on with site works such as tarmac, it’s important to remember you can only provide a duct through which the gas pipe will be inserted by the suitably qualified engineers.Warning Gas Pipe Below Tape


This means that the duct should be yellow in colour, perforated, and usually include a drawstring through the duct.


The duct should also confirm to British Standards, currently BS 4962 (specification for plastics pipes and fittings for use as subsoil field drains).


Over longer distances or where there is a change in direction of duct pipework, at the elbows there must not be ducted at these points to allow access for engineers.


The duct size will depend on the size of the gas pipes. For example if a 63mm gas service pipe will be laid the duct may need to be 100mm or more.


It is very important you check with 1Gas before proceeding so we can ensure you will not face expensive or time-consuming remedial action later.


Click here for a free no obligation quote from 1Gas


Mr Bruce cook says:

I had new service installed by British gas and would like the supply and meter box moved to rear of building.
There is an area of concrete down side of building over which the pipe will be laid which will be covered in concert a depth of 300mm cover would this be acceptable.

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