Did you know that epoxy pipe liners can be used to line vent and drain stacks? The process of installing new pipe liners in drain and vent stacks is very similar to how we install epoxy coatings into potable water pipes. We still have to isolate, clean and inspect the pipe before we install your Chicago building’s new liner.

1. Pipe Preparation and Isolation

The first step in the pipelining process is the isolation and preparation of the riser. The pipe isolation process involves disconnecting the specific riser or plumbing pipe from the rest of the system. The goal is to allow water service to the rest of the building while the specific riser, vent stack or drain line is being rehabilitated. If existing water shutoff valves are available, we use those. If they are not available, our certified plumbers will install new shutoff valves and access panels to those valves so that they can be utilized in the future, if needed. Once all the shutoff valves are off, our pipelining technicians will clean the plumbing pipe in preparation for pipelining.

2. Cleaning the Existing Drain or Vent Stack

In order to ensure the epoxy coating or pipe liner adheres properly to the existing plumbing pipe, the pipe must be thoroughly cleaned in order to remove any corrosion and debris. For pipes with diameters of four inches or larger, we can use milling machines to clean the pipe instead of compressed air. The milling machines used for pipe cleaning are basically drills on 100-foot cables, which may remind you of a commercial plumbing snake or auger. The difference is that the drill head automatically rotates in order to scrape away all the debris on the inside of the pipe.

Our milling machines can be fitted with different types of heads, including chain knockers and carbide tips. This may seem like a brutal way to clean the pipe, and we receive a lot of questions pertaining to the risk of potential pipe damage from the chains whipping around at 1300rpm and hitting the pipe wall. Our milling machines are safe to operate and safe for your vertical stacks and drain lines. This is because the heads are sized, depending on the pipe diameter. For example, if you have a four-inch pipe, we use a cleaning head that is designed for four-inch pipes. As the milling machine is inserted into the pipe, it is centered down the middle of the pipe, and the rotating head only cleans the specific diameter. For a four-inch pipe, the head would only clean and scrape four inches, which means the pipe walls aren’t at a high risk for damage.

3. Camera Inspection

Once the cleaning is complete, we perform a pipe inspection in order to make sure the pipe walls are clean and smooth and that all of the corrosion and debris have been removed. We perform this inspection with a special digital plumbing camera that shows images on a screen and also records those images.  Our plumbing pipe camera pans and tilts in order to make sure that we see every inch of the internal pipe diameter.  If there is still evidence of filth in the pipe, we will clean it again until we have the desired results.

4. Lining the Pipe

For smaller diameter pipes, we use an epoxy coating to seal and rehabilitate the pipe in order to extend their useful lives. Most vent and drain lines are at least four inches in diameter, which means we can use a pipe liner that is soaked in epoxy to repair and rehabilitate the pipe.

Our pipe liners for vent and drain stacks are constructed out of white felt and come in 150-foot rolls. When we line pipes with pipe liners, we choose the correct diameter liner and cut it to the desired length, even as small as six inches. Once the pipe liner is cut to length, we insert a deflated air bladder, which will be needed in order to press the pipe against the pipe walls. Next, we mix a two-part epoxy solution. The epoxy solution we use for drain and vent stacks is blue, and when we pour the blue epoxy into the white liner and wet it out, which is the process of laying the pipe liner on a protective pad and rolling a weighted roller down the liner to ensure the pipe liner is saturated, the liner turns blue. This is how our pipelining technicians know that the liner has been fully saturated with epoxy.

After the liner has been fully saturated with epoxy it is rolled up and carried to the entrance of the pipe to be lined. For vertical vent stacks, the liner is simply unrolled and dropped down the pipe. Once the liner is in the proper position, we inflate an air bladder, which expands and presses the epoxy soaked liner against the host pipe’s walls.

5. Pipe Curing

After the bladder has been inserted into the host pipe and inflated, we leave the liner in place to cure between four and six hours. At the end of that time, we deflate and remove the air bladder. Once the air bladder has been removed, we perform another camera inspection to ensure that the epoxy liner is inserted correctly and that it is smooth and free of and defects, line wrinkles and bulges. Once we’ve inspected the pipe and determined that the liner is inserted correctly, the pipe is returned to service.

6. New Pipe within a Pipe

At the end of the process, your building is left with a plumbing pipe that is as good as a new pipe. We call this rehabilitation technique a pipe within a pipe because the host pipe still exists, but all the wastewater now flows down the hardened liner instead of the original pipe. This eliminates future corrosion of the host pipe and extends the pipe’s useful life. This new pipe within a pipe also seals leaks and cracks and has some structural stability.

In fact, once the curing process is complete, the pipe within a pipe is considered to be as durable as a brand new pipe. In short, once your new pipe within a pipe is installed, it’s not going anywhere. It will remain in place and operate as you would expect a new pipe to operate. Your new pipe within a pipe is also expected to last between 30 and 50 years, and in some instances, the hardened liner can last longer

7. Installation Guarantee

Here at Nu Flow, when we line your vent and drain stacks, you can expect to get a 10-year installation guarantee. This means that if something goes wrong with your lined pipe due to an installation error or problems with the products, we will correct the issue with no additional charges.

To see if pipelining would be right for your Chicago building’s plumbing pipes, call us at 815-790-9000.

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