Pipe Material for Inspections: Pros vs. Cons
When conducting sewer pipe installation and/or inspections, a large deciding factor for contractors is what type of pipe material to use.
What Type of Pipe Material Should You Use for Your Next Project?
The most frequently used pipe material are concrete, steel, clay and plastic (HDPE and PVC). Below, we’ve outlined the details of each so that you are educated on the most appropriate material for your next project.
Materials of Pipe: Pros vs. Cons
High-density polyethylene (HDPE) and polyvinyl chloride (PVC) are two different materials, yet they contain many similarities when discussing sewer pipe applications. For that reason, we’ll refer to both as just “plastic.”
Plastic is a preferred piping material given its lightweight, long lifespan (50-100 years) and ability to be procured in different lengths. Best of all, it is a practical material for earthquake-prone areas, such as the Pacific Northwest.
They are slightly difficult to maintain, though, as they require frequent performance checks. Also, neither can withstand high heat, which can make them susceptible to bending or warping.
During inspections, it can be more difficult for traditional inspection methods such as CCTV to see defects due to darker colors. When there is slime or debris in the pipe and it hasn’t been recently cleaned, pipe crawlers with regular wheel materials such as rubber or pneumatic tires will slip, so having a high traction material tire such as carbide is important, particularly in the flat surface PVC pipe.
Clay is more common with older installations than with new projects. It isn’t used too often today.
It does have its pros – it resists chemicals and erosion, a natural by-product. It is also more cost effective than steel or iron and has the longest lifespan in comparison to other materials. However, similar to plastic, traction can be an issue, so it is important to have heavier material with grit such as carbide. CCTV is a great way to inspect clay since it is much easier to evaluate tree roots infiltrating.
Steel is a more popular material for water piping, but can also be used for sewer pipes. Its main benefit is its strength, durability, and resistance to buildup and corrosion.
The drawback is its lifespan, which is the shortest of what we’ve listed here. It’s also the most expensive of materials.
Corrugated steel is a bumpy surface, meaning that it is important to have a level tracked vehicle to traverse without having a bumpy video. Also, corrosion is typically difficult to monitor from a CCTV vehicle, as it cannot see the extent of the corrosion and usually corrosion occurs from the outside of the pipe. Though steel is listed as being resistant to corrosion, it still faces the challenge of corrosion regardless being a metal interacting with water.
Concrete is the go-to choice for many contractors, as it stands well for both lifespan and durability. It can withstand high-pressure conditions without compromising integrity or allowing intrusion.
Concrete does require regular maintenance, to limit buildup that occurs from sewage material. This can be done with regular inspections. It is also susceptible to breaking when handled, so it must be installed with care and the proper equipment.
Concrete is ideal for CCTV inspection, since issues in concrete are much more easily determined with a camera. Traction is also not an issue even with regular build up.
Read WinCan Series 2: Coding Software for Pipe Inspections
What Tires Do I Need on my Crawler for which Pipe Material?
When looking at a pipe crawler, it is important to understand different pipe materials require different tires in order to maximize performance and travel through a pipe. A car acts the same way, if you are driving on ice or snow, you need tread to work with and to gain traction. However, on asphalt in the summer, a car loses efficiency and burns through the tread much quicker.
Within a pipe, size is also a big consideration. Pipe crawlers are designed to remain the center of the pipe. Therefore, it is important in larger diameters to widen the base of the crawler to maintain stability and increase maneuverability.
Concrete is a friend to rubber tires. Large tread rubber can grip on concrete even when there is slime or debris. When looking at Deep Trekker crawlers, diameter plays a factor in what tire selection to make.
6” – DT320, 6” Rubber Wheel Kit
8-12” – DT320, 6”/8” Rubber Wheel Kit – DT340 S – 8”/10”/12”
14” and larger – DT340 X – 12” Rubber Wheel Kit
Corrugated Steel pipe is “wavy” in shape, so when you drive a regular wheeled vehicle down a pipe it will bounce with the waves. This isn’t harmful to the vehicle, but can make for a bumpier video. Tracks are the answer for this since they allow for a smooth ride across the grooves, but tracks are best suited for larger diameter pipe (over 24”). Rubber wheels will have no issues with traction, so if a little bump in the video is okay, you can use these as well.
6” – DT320, Base Tracks, 6” Rubber Wheels
8-24” – DT340 8”- 12” Rubber Wheel Kits
24”+ – DT340 Tracks
HDPE has grooves similar to corrugated steel, however it is usually spaced closer together so the “bump” effect in the video is limited. PVC, when wet and slimy, as sewers get, will cause a rubber or pneumatic tired vehicle to slip particularly at longer distances. Having weighted tires with extra “grit” such as a carbide tire set is important for getting traction. HDPE is less prone to slipping due to the grooves.
8-24” – DT340 – 8-12” Rubber, 8-10” Carbide
6-12” – DT320 – 6-8” Rubber, 6-8” Carbide
24”+ – DT340 Tracks
6-12” – DT320 – 6-8” Carbides
8”-12” – DT340 – 8” Carbides
10”+ – DT340 10” Carbides
Clay is also susceptible to slipping with a crawler vehicle, so the same wheel recommendations apply as Plastic/PVC.
There are other materials used for pipes, such as Brick, Cast Iron or even Wood. Standard Rubber tires have no trouble in these materials.