VESTAMID® NRG For GAS Applications
Competitor to STEEL
The year 2004 saw the market launch of a new PA12 grade, VESTAMID® NRG, that satisfies the requirements on large gas pipes with external diameter up to 300 mm: The material withstands pressures up to 18 bar and is therefore suitable for distribution lines and industrial connections. Since December 2015 it has been included in the test specifications of the DVWG (the German Technical and Scientific Association for Gas and Water) with the title “Plastic piping systems in gas and water supply; GW335-A6: PA-U 160 and PA-U 180 pipes and their joints and jointing.”
All-plastic PA 12 pipes have many advantages over steel. Plastic piping can be wound so that about 150 to 200 meters fit on a roll; steel pipes, on the other hand, have a maximum length of 18 meters because they cannot otherwise be transported by truck. Plastic pipes therefore require far fewer weld seams when being laid, which reduces installation time and costs.
Maintenance is also less costly because no cathodic corrosion protection (permanent current or sacrificial anode) is needed. Due to simpler assembly, easier handling, and lower maintenance costs, system costs are significantly lower with PA 12 than with steel.
The VESTAMID® NRG piping systems allow general working pressures to be increased by 25 % compared to similar high-pressure plastic materials. They are
Resistant and durable
Resists heavy hydrocarbons
High resistance to both Slow Crack Growth (SCG) as well as Rapid Crack Propagation (RCP)
Improved installation effiiciency
A number of VESTAMID® NRG commercial supply lines are now in regular operation. Pipe producers and installation firms are benefiting from this experience. The first installation in Germany (160 mm SDR 11, 16 bar) was in Beckum, North-Rhine Westphalia, in July 2017. Since 2005 global projects have led to installations in Brazil, Colombia, the US, and Indonesia with pipe diameters between 90 and 160 mm SDR 11 and SDR 13.6 and pressures of 14 to 16 bar.
A GAS LINE GOES UNDERGROUND
Since late 2016, a 4.6 km underwater VESTAMID® NRG pipeline has been supplying the inhabitants of Tierra Bomba, an island off Colombia’s Caribbean coast, with natural gas. The video describes the entire project.
VESTAMID® NRG piping systems have been laid worldwide in many different soils and climate zones, using a variety of welding techniques and laying methods. Trenchless installation is also possible. The advantages are:
Conventional joining methods (heating element butt welding and electrofusion welding) can be used
The network can be expanded while in operation, with the use of appropriate fittings
Squeeze-off is possible
Laying is possible under roads carrying traffic or under watercourses
Alternative laying methods without a sand bed are available
ALTERNATIVE Pipe laying
Horizontal directional drilling method
This laying technique is particularly environmentally friendly, since it causes minimal ecological damage, which is restricted to areas in close proximity to the system. Various factors also highlight the need for this directional drilling technology even in urban areas: The technique is superior for laying in open trenches in terms of construction times and costs, approval procedures, earth displacement, surface reclamation and traffic disruptions.
Earth displacement methods with non-steered impact moles
Earth displacement methods have proven their worth for three decades as a technique for underground pipe laying. Using a pneumatically driven displacement hammer, an underground cavity is created, in which long plastic or metal pipes of up to DN 200 can be inserted, preferably without joint ends. The pipes are inserted in lengths of up to 40 m and depending on the soil, this can be done either simultaneously or in a second individual operation. This technique allows trenchless crossing of transport routes, building connections, preparation of anchorages, circumvention of obstacles and other measures.
Dynamic ramming method with non-steered rams
The ramming method involves pneumatically actuated pipe hammering machines deployed for dynamic pipe jacking. This method allows open steel pipes as casing or product pipes up to 4000 mm in diameter to be installed over lengths of up to 80 m in soil classes 1-5 (partly even soil class 6 – easily soluble rock) particularly economically without jacking abutments under track systems, highways and rivers.
The plow method
The plow technique has been successfully used since the 1970s for laying power and telephone lines. It is particularly suitable for large, open sections in rural areas where long lengths of pipeline are required.
However, the plow method can also be employed over shorter distances and for pipes in less accessible locations. Laying such pipes on steep slopes and traversing areas of water (up to 1.20 m deep) is no problem from a technical perspective thanks to the blade shape with four jibs adjustable in all directions.
The burst lining method is a tried and tested technique, which is used in accordance with the latest generally recognized technical standards. The bursting machine proceeds through the old pipe, shatters it with dynamic impact energy and pushes out the fragments into the surrounding soil. At the same time, a new pipe of equivalent or larger diameter is threaded. The old drilling path must be usable for the new pipeline. To ensure safe, leak-proof and professional joints, side ports or curves must be open. The soil around the old pipeline must be displaceable and the distance to the existing lines should be > 0.5 m.