Work site and stringing area: how much space is needed to install a hydrogen pipeline?

The stringing area forms part of the work site. Individual pipes are delivered here, laid out in a row, welded together and inspected. In this way, pipeline sections are assembled above ground one step at a time before being installed underground. Together, these sections ultimately form one continuous hydrogen pipeline.

The amount of space required varies by location. It depends on factors including the surrounding area and the method used to install the pipeline.
 

What is a stringing area?

A hydrogen pipeline consists of individual pipes. In the stringing area, these pipes are welded together to form pipeline sections. Welding, inspection and the application of protective coatings to the welded joints all take place above ground. This is safer and more practical than carrying out this work in the trench excavated for the pipeline, for example.

As a result, long sections of pipeline may temporarily be visible above ground. Once construction has been completed and the pipeline has been installed underground, we clear and restore the work site.
 

Why does the space required vary by location?

The amount of space needed to install a pipeline varies by location. This is because every surrounding area is different and the same installation method cannot be used everywhere. The amount of space required depends on factors such as:

• The size of the pipeline
• Ground conditions
• Roads, railway lines and waterways, such as canals, rivers and ditches
• Cables and other pipelines in the surrounding area
• The space available
• Nearby natural areas, agricultural land, homes and businesses
   

A work site may therefore look different at one location than at another.

Different activities require different work sites

A hydrogen pipeline is not installed in the same way everywhere. In many locations, a trench is excavated and the pipeline is laid inside it. Elsewhere, drilling is required, for example beneath a road, railway line, waterway or natural area.

The installation method determines both the amount of space required and the layout of the work site. Different methods have different spatial requirements. As a result, the layout of one work site may differ considerably from that of another.

Open-cut installation

For open-cut installation, the pipes are first laid out in the stringing area. Here, we weld them together and inspect them. The pipeline is then lowered into the trench excavated for this purpose.

Horizontal directional drilling

For horizontal directional drilling, or HDD, individual pipes are first welded together in the stringing area to form a single pipeline section. This entire section is then pulled through the drilled hole in one operation.

The longer the drilling route, the longer the pipeline section and the more space is required in the stringing area.

Arc drilling

We use arc drilling to install a pipeline beneath a road, railway line or waterway. The drilling route follows a curved path through the ground, which is where this technique gets its name.

Working space is required on both sides of the crossing for machinery and construction activities. As with other drilling techniques, arc drilling requires space for both a work site and a stringing area.

The amount of space required depends on the length of the drill route and the pipeline section being installed. Pipes are delivered to the stringing area and welded together to form a single pipeline section. The spatial requirements vary by location.

Closed-face drilling

When a pipeline needs to pass beneath a road, railway line or waterway, we also often use closed-face drilling, known in Dutch as GFT drilling.

The pipes are delivered to the stringing area and welded together to form a single pipeline section. This section is then connected to the drilled crossing.

The amount of space required depends on the length of the drill route, the space available and the conditions at the location. The layout of the work site and stringing area may therefore vary for each crossing.

Ploughing

With ploughing, a specialised machine installs the pipeline directly into the ground. This means that a trench does not need to be excavated beforehand.

The pipes are delivered to the stringing area and welded together to form a single pipeline section. The ploughing machine then installs this section in the ground.

The amount of space required depends on the length of the pipeline, the ground conditions and the situation at the location. The layout of the work site and stringing area may therefore vary by location.

The type and size of work site required depends on the installation method and the conditions at the location. Would you like to find out how the different installation methods work? Visit our page about the construction of new hydrogen pipelines.