When our current inner-city infrastructures were initially built, construction sites needed to employ a large number of people to get the work done. Trenches were excavated manually, pipes were lifted into the trenches without lifting equipment, and huge volumes of sand and filler material were placed back into the trenches by hand.
The most commonly used pipe material was cast iron; the pipe joints were tied off with hemp and sealed with lead.
Today, over 100 to 120 years later, the original pipe networks are in dire need of renovation and replacement.
In urban streets that were previously populated only by pedestrians and the odd vehicle belonging to a member of the wealthier classes, multiple lanes of dense traffic now thunder over the road surface; cars park along the sides of the road, forcing delivery vehicles to stop in the flow of traffic and causing further hindrance to road users.
If the essential renovation and replacement work were to be carried out in this kind of environment using a traditional open trench procedure, the transport system would collapse entirely – and the public would have to bear the costs of the resulting delays, exhaust gas and noise emissions and financial losses due to public transport delays.
It was with this kind of situation in mind that the urban centres of industrial nations started – as many as 30 years ago – to develop trenchless pipe installation procedures, initially to replace old drainage channels and to build new drainage systems, which are generally located under the surface on the lowest pipeline level.
These developments soon branched out to the replacement and renovation of drinking water and gas pipelines too. The new technology snowballed, creating a new segment for trenchless construction with its own special machinery, construction processes, technical standards and, of course, pipes that were suitable for this type of trenchless installation procedure.
Pipes are generally installed in an open trench, which is then filled in once the pipe has been laid. The choice of substrate depends on the outside coating selected for the pipes. Lining elements are generally installed to ensure that the trench can be excavated safely. To install and embed pipes in a trench, the working area must be large enough.
Trenchless pipeline construction
In most installation procedures, ductile cast-iron pipes are pulled into position. The only exception to this rule is the push-in pipe relining process. To pull the pipe into position, the joints in the pipe must be able to withstand tension. Generally, the joints should be of a positive locking design. Restrained socket joints can be recognised by the presence of a welding bead on the spigot end of the joint, as is the case with the BLS® joint.
- Prevents construction noise, does not affect traffic and causes no environmental damage
- Reduces CO2 emissions
- Route underneath obstacles
- Replace pipelines of the same size or larger
- High tensile strength
- Quick and easy installation
- Radii from 70 m