Polyethylene piping systems represent a common feature in the world today. These underground systems convey water or other liquids intended for a wide variety of applications from agricultural to industrial. To those outside the pipe industry, the idea of installing underground pipe seems elementary: you simply dig a hole and put the pipe in it.
Yet the actual process is more complex. If you would like to improve your knowledge of underground piping systems, read on. This article will present a clear yet comprehensive overview of the process for installing underground polyethylene piping.
Step 1: Trenching
Trenching refers to the practice of physically removing soil and rocks from the installation area. This may involve removing several inches of soil - or several feet. Should the trench be more than 5 feet in depth, a protective system will need to be erected to protect workers from the threat of collapse. Likewise, ladders or some other form of access and egress must exist for trenches deeper than 4 feet so workers can maneuver the area easily.
The size of the pipe being installed is the primary consideration when determining the necessary depth. Yet other factors will also come into play. The desired grade of the pipe - in other words, whether the pipe will sit on a slope - will also affect trench depth. So will the presence of any bedding material used to protect the underside of the pipe.
Step 2: Dewatering
The second step involves the removal of any groundwater that may have accumulated at the bottom of the trench during excavation. This represents a natural - and fairly common - phenomenon in areas with a high water table. Because polyethylene pipe possesses a density less than water, it will float on top of any water that happens to be in the trench.
This can make it difficult for workers to ensure that the pipe sits in exactly the desired place. Therefore, if such water is present, a dewatering phase must occur. Sump pumps, deep wells, or other water removal systems may be installed to help remove such water.
Step 3: Bedding
Bedding refers to materials such as crushed gravel or sand placed at the bottom of the trench before the pipe is installed. This material creates a smooth surface against which the pipe can rest. If the soil does not contain an excessive amount of rocks, bedding may not be necessary at all. Instead, the soil can simply be graded to the desired slope and the pipe laid in.
Step 4: Embedment
Once the trench has been dug, dewatered, and bedded, the pipe may be laid in place. Depending on the size and weight of the pipe, this may be accomplished by hand or through the use of construction machinery. With the pipe in place, the trench can then be filled in - a process referred to as embedment.
The material used for embedment varies from project to project. Engineers must determine the necessary amount of support to protect the pipe from becoming bent or crushed by excessive pressure. In the simplest case, the soil that was excavated to make room for the pipe may be used for embedment.
In other cases, crushed gravel or other types of stone may be used. The relatively stiffer nature of such materials will act to provide a high degree of support to the pipe. In cases where the naturally occurring soil has been used for embedment, it must be tamped down by means of a mechanical tamper. This will increase its density and ensure that the pipe remains securely in place.
For more information about what it takes to install underground polyethylene pipe the right way, please contact the industrial pipe supply experts at Fast Flow Pipe & Supply, Inc.