What Is Dewatering in Construction?

What Is Dewatering in Construction?

Water and construction generally don’t mix. Just like a rainy day can halt work on your site, so can the standing water it leaves behind once the sun is shining — along with other surface and groundwater in areas slated for construction or excavation. If this is a problem for your construction project, your site may need dewatering. But what exactly does that entail?

What is Dewatering? What Is Dewatering in Construction?

Dewatering is removing water from an area. In construction, this means removing water from a construction site — whether it’s removing ponded water from the surface or removing unwanted or excessive groundwater. 

Water can be an impediment to most construction activities, particularly anything involving concrete, which needs time to cure before it can tolerate moisture. Therefore, dewatering is a must for particularly wet sites, such as those with poor surface water drainage or high water tables.

4 Common Dewatering Methods

There are several methods for dewatering; the best method is dependent on a variety of factors specific to the application. Some of the most common dewatering methods are

  • Pumping (open sumping)
  • Channeling
  • Well points
  • Deep wells

1. Pumping

One of the methods for dewatering a site is to place a sump pump into wet, ponded areas and pump the water to another location. This method works specifically for surface water; for moving groundwater, more sophisticated pumping solutions are needed.

2. Channeling 

Channeling is one of the oldest, and lowest-tech, methods of dewatering surface water. It involves digging channels or ditches, into which water will drain. These channels harness the power of gravity to move water away from the worksite. 

To prevent this water from draining into the channel soil and prevent soil washout, some kind of geosynthetic liner or erosion control system may be used to line the channel.

3. Well points

For dewatering groundwater, one method is to drill a series of small, shallow wells around the work area, known as well points. From these wells, groundwater can be pumped out of the soil.

4. Deep wells

For applications where well points are insufficient, such as construction sites that are large or that require deep excavation, large, deep wells can be installed to draw up groundwater.

How is Excess Water Managed After Dewatering?

In all of the methods mentioned above, the water that is being removed from the construction area is generally redirected to another area of the site, where ponding will not be an issue for construction activities. Water may be diverted to densely vegetated areas of the property, which can absorb the excess water without risking extreme soil erosion or runoff. In some cases, detention ponds, tanks, or other infrastructure are needed to contain the excess water after it has been removed from the dewatered areas of the site. 

Regardless of where it is diverted, except when using the channeling method of dewatering, water is pumped and transported through pipes to the designated release or containment area. Water, as a fluid, is heavy and difficult to transport via other means. Temporary or permanent piping networks are established to divert water removed from the surface and soil. 

HDPE piping is often used for this purpose, as it is light and flexible, and can be installed using any of a variety of methods, depending on the application. Unlike other types of pipe, the sections of which are joined together with additional pipe components and adhesives, HDPE pipe is connected via plastic fusion: pipes are essentially melted together at high heat. This creates truly seamless piping, meaning that there are no opportunities for leaks. 

Need Dewatering Solutions? US FUSION Can Help

HDPE pipe is the natural choice for specialty construction dewatering needs, as it’s durable, flexible, affordable, and corrosion-resistant, with leak-free performance. To discuss how US Fusion’s HDPE offerings can meet the dewatering needs of your site and application, contact us today.

Hydro Testing: What Is It, and Why Is It Important?

Hydro Testing: What Is It, and Why Is It Important?

Once a plastic pipe system is installed, you may think a pipe specialist’s job is done. It’s not. 

Before plastic pipes can be considered safe and ready for use, hydro testing must be completed. Below, we’ll define what hydro testing is, why it’s important, and how it’s carried out. 

What is Hydro Testing? 

Hydro testing, short for hydrostatic testing, is a pressure-based process where piping systems are tested for performance and leaks. It’s most often completed right after a plastic pipe system has been installed, but can also be done later on for routine inspection and maintenance checks. 

what is hydro testing US Fusion

Hydro Testing Process

Here are five steps for what the general hydro testing process looks like for plastic pipe or HDPE pipe applications:

  1. Fill up the pipe system completely with water. 
  2. Remove all air within the system (this is done by filling completely with water). 
  3. Pressurize the system up to 1 ½ times its design pressure limit. 
  4. Hold this pressure for a specified amount of time. 
  5. Inspect the pipe system for leaks. Sometimes pipe specialists use dyes to find the exact location of any leaks.

Why Is Hydro Testing Important? 

Hydro testing isn’t just a recommendation. In most cases, it’s a post-installation requirement. 

Hydro testing is so important because it helps to ensure that the system passes inspection and safety standards for plastic piping. It’s a proactive approach that reduces the chance of an emergency and ensures the safety of your people, facilities, and environment. It also helps you save resources and money because you can catch leaks before they become a larger issue.

3 Hydro Testing Methods for Plastic Pipe Systems

There are three common hydro testing methods used for plastic pipe systems and other vessels/cylinders. There are certainly other methods that specialists use, but these popular ones will help give you a better understanding of what any test typically involves. 

Water Jacket Method

The pipe system is filled with water and loaded into a sealed chamber called a test jacket. The test jacket is also filled with water. The pipe is then pressurized inside the test jacket for a specific amount of time, causing it to expand within the test jacket. This results in water being forced out into a glass tube that measures total expansion. That expansion is recorded, then the pipe is depressurized, and then it shrinks to its original size.

Direct Expansion Method

The pipe system is filled with a certain amount of water, then pressurized. Then the amount of water that’s expelled upon pressure release is measured. The permanent expansion and total expansion values are calculated using the amount of water forced into the pipe, the test pressure, and the amount of water expelled.

Proof Pressure Method

Internal pressure is applied to the pipe to see if it has any leaks or weaknesses in the wall lining. In the United States, the proof pressure method is only permitted when the Code of Federal Regulations (CFR) doesn’t require permanent and total expansion values to be recorded. 

Trust US FUSION For Your Plastic Pipe & Hydro Testing Needs

Hydro testing is an important practice to ensure plastic pipes are installed and working properly on your site. If you need help completing this specialized process, contact the experts at US FUSION. With decades of industry experience, we have the knowledge and mastery it takes to get quick, accurate results.