To lay underground pipes. High-Density Polyethylene (HDPE) pipe is the material of choice in trenchless technology due to the pipe's high minimum required strength, stress and crack resistance, and high fatigue loading capacity.
Trenchless installation, replacement, and rehabilitation of pipes utilize a wide variety of methods. Here are the most common techniques.
New Pipe Installation Methods
Installation of new pipes is usually done using two methods - horizontal directional drilling or pilot tube micro-tunneling.
Horizontal Directional Drilling
Horizontal directional drilling is suitable for laying pipes in congested areas to avoid impeding traffic and daily activities.
This method entails boring a pilot hole using a drilling head and then pulling back the new pipe. As the pipe is pulled back, contractors use slurry to minimize friction and to reinforce the pilot hole.
Also known as pilot pipe jacking or guided auger boring, micro-tunneling is used to install small diameter HDPE pipes. This method is suitable for pipe laying in both soft and rough terrains as well as in underwater installations.
Micro-tunneling entails the use of a remotely controlled boring machine and application of the jack and bore method to install underground pipes. This process allows contractors to lay pipe without the need to dig long open trenches in areas where utility lines already exist.
Pipe Replacement Methods
Pipe bursting and pipe splitting are used to replace HDPE pipes without disrupting the existing piping infrastructure. Both methods can be used to increase the pipe's size and its flow capacity.
Pipe bursting involves pulling a dynamic or static bursting head through the existing pipe to break the pipe. At the same time, a new pipe attached to the tail end of the bursting head is installed to replace the original pipe.
Pipe bursting can be performed using three methods including static, pneumatic, and hydraulic pulling techniques, which use different power sources and different approaches for breaking the host pipes.
This process involves using an internal bursting head with blades to cut the host pipe longitudinally. An expansion head works to open up the host pipe and a new HDPE pipe attached to the back of the cutting head is installed within the existing pipeline to replace the old pipe.
Pipe Rehabilitation Methods
Contractors use numerous methods to rehabilitate and repair broken pipes.
Slip lining is the oldest trenchless rehabilitation method. The process entails inserting a new small pipe inside the faulty host pipe and plastering the region between the two pipes. While the method is simple and inexpensive, pipes face the risk of losing hydraulic capacity.
Advanced slip lining methods such as die drawing and rolldown control the properties of HDPE to allow the pipe to change shape or reduce in diameter before being inserted into the faulty pipe.
This technique entails placing a sturdy fiber or polyester liner inside the host pipe. The liner, which is filled with resin, is inserted into the host pipe using water or air pressure. Heat is then applied to completely attach the liner to the pipe. Compared to slip lining, cured-in-place lining does not shrink flow rate.
Thermoformed liners come in the form of reshaped liners that are inserted into the host HDPE pipe. Upon insertion, steam is pushed through the pipe, causing the liner to change its shape to match the host pipe through a thermo-formation process.
The use of trenchless technology in your piping project can help save costs, protect the environment, and minimize surface disruptions.
A trusted polyethylene pipe laying company can ensure proper installation, repair, and rehabilitation of your piping infrastructure. Whether you are installing municipal or industrial lines, you can trust Fast Flow Pipe & Supply, Inc., to get the job done. Call us today to discuss your project.