Everything you Need to Know About Pipe Jetting
One of the common maintenance activities required to keep sewer and stormwater pipes flowing at full capacity is pipe jetting. Pipe networks are periodically inspected using CCTV cameras to understand the condition of pipes. Operational & Maintenance (or service) defects identified are an indicator that jetting may be required. The most common problems that jetters are used to fix are:
- Sediment build-up
- Fat, oil, and grease
- Tree root removal
- Object blockages
There are a wide range of jetting units available that are designed to suit specific tasks or pipe sizes.
Figure 1 – Pipe jetter in action
The major components that form a jetting rig are:
- Water tank
- Hose & reel
Depending on the size and power of a jetting unit, it may be: fitted to a truck/van/pick-up, trailer mounted, or be a small portable unit capable of accessing difficult locations.
Figure 2 – Jetting Truck
How do jetters work?
Jetters are commonly powered by a diesel engine, although there are also electric and gas-powered options available. The delivery of water to the nozzle is measured in pressure and flow. It is important to understand how these differ and can affect the success of the work at hand. In general, pressure provides the cutting power, and flow will provide the flushing power. The larger the pipe, the more powerful the engine required, and more water required to carry on-board.
An example range of pressure and flow is listed below; you should contact your local distributor for advice on best options for your typical projects.
Smaller pipe jetting jobs.
Typical all-rounder specification.
High pressure output for more powerful cutting.
Capable of clearing sediment build-up in larger pipes.
Jetting is often completed in the upstream direction so that debris can flow back to the operator’s location, as well as minimising the risk of overflow behind blockages. The jetter nozzle uses the powerful spray of water to move along the pipe and completing the cutting/cleaning/flushing task required. There are hundreds of different nozzle designs on the market with the angle of spray from the nozzle defining if it is better suited to thrust/flushing or cutting/descaling.
Figure 3– The angle of jet stream to suit different performance criteria
Nozzle Types and Accessories
There are standard nozzles designed to cover most circumstances, as well as specific nozzles and jetting accessories available.
Switching Nozzle: The angle of spray can be adjusted while in the pipe from thrust (flushing) to cutting (descaling).
Rotating Nozzle: Cleans full pipe surface. You may have seen stripes after cleaning where a fixed nozzle has not hit all parts of the pipe wall
Sled Nozzles: Designed for heavy duty bottom sediment. Also called bottom cleaners, sledge, or sleigh nozzles.
Camera Nozzle: Provides the ability to collect imagery from within the pipe while cleaning to collect condition data at the same time
Debris Basket: Fitted at downstream point to collect debris and avoid secondary blockages after jetting. Also called drain traps, drain catchers.
Learn more about Sewer Network
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