Wednesday, March 31, 2010

Hydro Jetting FAQS for sewer and drain cleaning

Hydro jetting is the use of water under high pressure to clean pipes clear of various types of debris. It's an amazing process that got it's start years ago in the oil fields and has found it's way into numerous different industries that need to keep their pipes operating at a high rate of efficiency.

It's extremely effective and in high demand for the simple reason that it is the only process that can actually clean a line of debris. You see when you run a cable in a line to clear a blockage,( ie. rooter a line), you are typically puching a hole in a blockage to allow flow again in the pipe. This can leave debris behind and this debris can act as a starting point for another blockage some time in the future. Now a skilled technician running a cable may be able to get close to the true pipe diameter but only if variables work in his favor. Never the less they will never be able to clean a line like a hydro jetter could. A common situation is a clean/out that is smaller than the mainline. For Example a 4 inch clean out on a 6 inch mainline. Now, if your running a cable your limited by that 4 inch access. If your running a cable, your punching a hole in the blockage because you can't get a full size tool into the line. A hydro jetting nozzle does not work that way. The high velocity streams of water that do the cleaning spread out to impact the pipe wall. On a regular basis we tackle major root intrusion problems, many with multiple intrusion points in a single sewer line and when finished, it was very difficult if not impossible to see with video inspection where the roots were making their way into the pipes because the pipes and joints were that clean. Just yesterday we were called to a school that had a large mainline backed up. Turned out it was an 8 inch. After we poked a hole in the blockage and it drained away a bit, we were able to see a huge root intrusion at the sweep into the line. With careful placement of a Warthog rotating nozzle we were able to polish this completely out and there were roots that were as big around as my thumb. At the other end 150 feet away in a vault was another monster root mass that was spreading out from the opening and holding back the flow. Again careful placement shredded this all out of the way without having to enter the vault and it was a deep one. This rate of success is par for the course and explains why hydro jetting is now an industry standard.

One big misconception is that the pipes might not be able to withstand that pressure. The pipes are not pressurized with water. When the water is in the hose it is under high pressure but when it leaves the nozzle it is no longer under pressure but it is traveling at a high speed. It's this speed of the water hitting the pipe walls that does the actual cleaning of the pipe.

There is a huge difference in the quality of work based on the machine used. Larger trailer towed machines are capable of producing high pressure, 4,000 psi at 18 gallons per minute. That high water flow volume is crucial to flushing the debris out of the line once it has been loosened from the pipe walls. Many many companies, plumbers use small cart type machines that they carry around inside their van. They produce a reasonable pressure but do not produce the high flow volume to flush the debris out of the line. A typical cart type jetter might produce 3,500 psi @ 5gallons per minute. If your working on a smaller line, 3 inches or less, it may be fine but a medium or larger line with any sort of heavy debris, your wasting your money. They'll be there all day on a job that a big machine could do in an hour or two. Be careful, they're probably charging the same rate as the big machine.
Hydro Jetting Grease
There are various reasons to use hydro jetting as opposed to running a cable in a line. The most glaring is grease. If your in a commercial application as in a restaurant, grease is a huge issue. We see it in homes as well but there it happens over a longer period of time. You can't touch that problem with a cable machine. By that I mean, you may cable a line open but it's going to be very difficult and time consuming and it will not last long. Depending on how severe the problem is, it could last a week or a day. Any restaurant manager with more than a few years in the business has figured this one out already and can probably give you an ear full.

One of the heaviest situations I have run into are some of the El Pollo Loco restaurants we service. Think about how many chickens they cook every day with three shifts a day. Now multiply that by a month and now by a year. All that grease drips down from the broiler and into the broiler floor drain. We are able to clear those lines to the extent that some of those customers are jetting once every year or year and a half. That's pretty incredible.
Hydro Jetting Roots
We've already mentioned roots but let me just say that completely cleaning the roots out of a line as opposed to punching a hole with a cable machine will allow longer intervals between services and also help to minimize the amount of damage done by the roots to the pipe itself. We are probably all familiar with that stretch of sidewalk in our neighborhood slowly buckling up over the years. Every year the concrete gets pushed up a bit more and more by the tree roots. Well the same thing is happening under the ground with respect to roots entering sewer and drain lines. If you don't keep these in check, they move the pipe more and more and can and often do cause pipes to crack and collapse. It's going to be expensive to fix and if the pipe is deep, it's going to be very expensive.
Hydro Jetting Debris
The other situation is debris. We had this job a while back where a lady was dumping her cats litter box into her toilet. This had been going on for quite some time till finally, you guessed it, the toilets didn't work anymore. Well you can't cable that type of a blockage. It's completely ineffective. All the cable does is stir the debris. We were able to actually pull a great deal of that material out of the line through the clean/out on the side of the house. Think of a badmitten bird. The little plastic skirted toy that you bat back and forth with a raquet. A hydro jetting nozzle looks similar when the water leaves the nozzle. If you go beyond the debris and slowly pull back, those fingers of high pressure water will pull the debris back with it as they scour the pipe walls. Pretty amazing result. We pulled a huge amount of cat litter out of their lines in just a couple of hours. When we left, everything was working perfectly.
Hydro jetting is more effective at longer distances.
Another neat thing about the hydro jetting process is that it is able to deliver it's full cleaning effectiveness at very great distances. Our machine carries 500 feet of hose. Many of our jobs require that or more. But what is interesting is that the nozzle delivers the same amount of pressure and cleaning quality if we are out 50 feet or 500 feet. This is in direct contrast to a cable machine. The motor on a cable machine produces a fixed amount of torque or power to rip through that clog or roots or whatever it may be. But the more cable that is run out of the machine, the less torque or power is transfered to the cutting head at the blockage. That is because the cable actually starts to absorb some of that energy. The more cable you have out, the more energy or torque is absorbed by the cable. A cable machine is also pretty much at the end of it's limit in the 150 to 200 ft range.
Doing The Impossible
Cast iron drain or sewer pipe that is fairly old tends to blister on the interior. This blistering makes the pipe very rough and it tends to catch debris, grease etc. With time, this can literally change the interior shape of the pipe with large ledges left and right of the flow channel line. These can get almost as hard as a rock. Hydro jetting is unique in that it is a process that is, in many instances, capable of returning that pipe back to a round condition and substantially smoothing out the surface. This may allow a customer to postpone pipe replacement and save them thousands of dollars. That isn't going to happen with a cable machine.

2 comments:

  1. Blocked Drains spread odour and spoil the environment. For this clearence of the drains is very necessary. Our company serves guaranteed and carried out by our fully trained engineers. Thanks! Admin Look for additional posts on this topic soon. I am waiting for next post.

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  2. You made some good points there. I did a search on the topic and found most people will agree with your blog. Thanks
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