Many utilities run underneath streets, sidewalks, and public soil to keep above-ground communities looking tidy. The sewer system is one such utility that runs under the street, accessible by manholes. Over time, the main sewer line needs cleaning; debris of all kinds, including tree roots, can clog the pipe. Actual men do not have to go into the manholes to perform the cleaning anymore. Water jet blasting is here to the rescue! One must beware of blowback in sewer cleaning, though; let’s take a closer look at what that is.
How Sewer Cleaning Works
While various methods exist, water jet blasting is the most effective. A metal nozzle connected to a hose from the water blasting truck enters the main sewer line through the manhole. A central nozzle powers through debris while back nozzles propel the head forward, going upstream. The nozzle is then pulled back downstream to the truck again. It is then that blowback can occur.
What Is Blowback in Sewer Cleaning?
The water that enters the sewer line from the water blasting machine creates a difference in air pressure between the main pipe and the connected homes’ pipes’ air pressure. There is a positive pressure zone behind the nozzle head and a negative pressure zone in front of it.
The air displaced by the cleaning water must go somewhere; normally, it will go through a drainage vent. If there is insufficient ventilation, it could blow through floor drains or, more commonly, toilets.
Causes of Blowback
As mentioned, blowback in sewer cleaning can happen because of a lack of ventilation. The rapid change in air pressure can cause the air to shoot through someone’s plumbing fixture rather than a blocked drainage vent.
Other potential causes include the following:
- Distance between the main sewer line and the lateral
- Water buildup upstream of the main sewer line
Blowback happens very rarely. Even so, it behooves the responsible authorities to tell applicable residents to keep their toilet seats closed during sewer maintenance cleaning, just in case. Using a lower water pressure setting and opening a manhole upstream can also help alleviate pressure.
Contact Jet Blast Inc. Today!
Jet Blast® Industrial Services strives every day in an effort to provide our customers with the best service and equipment possible. Providing a safe and stable workplace has allowed us to keep a team of quality people, with most having a tenure of 15 – 25 years with Jet Blast®. With all that experience under one roof, we have been able to provide reliable 24-hour service since 1979. I believe this helps to set us apart from the competition.
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