The use of high-pressure jet/vac equipment for cleaning sewers can be dangerous unless operators are well trained and fully understand the potential hazards.

Here are 10 safety tips that address the most common errors I’ve observed during my time in the industry.

No. 1: Properly set up the area around the vacuum truck to ensure operator safety in street traffic.

When you park the vacuum truck in the middle of the road, you need to block off traffic so that it can pass in a safe manner. Set safety cones in front and behind the work zone and make sure the hazard flasher lights are functioning correctly.

No. 2: Keep equipment noise levels low enough to hear traffic.

Revving the truck engine and running its vacuum pump can be noisy. Keep RPMs low enough so that operators can hear and avoid approaching vehicles and converse with co-workers as needed. 

One way to lower vacuum truck RPMs during engine operation is by only using the vacuum when needed. You can put the nozzle in the bottom of the sewer pipe and let the water run around it. The remaining solids can be vacuumed as needed. You do not need to continuously run high RPMs.

Another method is using more efficient nozzles. That enables sewer cleaning with lower-pressure water, reducing engine RPMs.

No. 3: Understand how your specific truck boom operates.

There are differences in how every truck manufacturer configures, deploys, and extends the booms that control the vacuum hose. Some deploy rapidly, some articulate, some telescope. Operators must understand these differences before operating a boom in the field around their co-workers.

You may go out in different vehicles from day to day with different crew members, so it is important that you understand your boom equipment. Do not rush the job because the boom can cause injuries if it is not used with full understanding and control.

No. 4: Use PPE and practice good hygiene.

Protect your hands and feet with waterproof gloves and work boots. Protect your eyes with goggles or a face shield. Of course, protect your head with a hard hat to avoid injury from a swinging boom or a falling object.

Being exposed to sewage or human waste may increase the risk of becoming ill from waterborne diseases. To reduce this risk and protect against illness, operators should wash hands with soap and water immediately after cleaning sewers before eating or drinking. Avoid touching the face, mouth, eyes, and nose while handling sewage, and cover any open cuts, sores, or wounds with clean, dry bandages.

The CDC advises vaccination against Hepatitis A and B and other contagious diseases that could put operators at risk when exposed to sewage or human waste. The CDC, in fact, also recommends vaccinations for tetanus, polio, and typhoid fever in these environments.

No. 5: Open the upstream sewer manhole first.

High concentrations of methane in enclosed areas can lead to hazards as large amounts of methane decrease the amount of oxygen in the air. Oxygen deficiency can cause headache, nausea, dizziness and even unconsciousness. 

With that in mind, one of the first things that operators must do is open the upstream manhole. That will allow the system to draw in fresh air. On the other hand, if the air were to be drawn directly from the homes, it could fill them with sewer gas, which is unsafe and unpleasant for homeowners.

No. 6: Do not start jetting outside a pipe.

With jetting, sewer cleaning nozzles are designed to direct water at exceedingly high rates of pressure. For typical cleaning, 1,000 to 1,500 psi is normal. To remove a blockage, pressures as high as 5,000 psi may be reached.

Cleaning nozzles at extremely high pressures should only be used in a pipe. If a nozzle is used outside of a pipe, it can whip around like a fire hose. I have seen sewer nozzles and hose go up and wrap around telephone wires. I have seen nozzles over 60 feet in the air.

No. 7: Use a hose with a robust safety factor to prevent bursting.

Since hose and nozzle pressures can be so high, it is important to utilize only robust hose of sufficient strength to ensure safe use over time.

Many operators overlook the possibility of burst hoses. However, hose is gradually cut going in and out of sewer pipe. The braided nylon weave remains, but every layer that is cut reduces hose strength and the corresponding psi that can be run.

No. 8: Properly size the nozzle-to-hose connection to prevent nozzle “ricochet.”

If the nozzle-to-hose connection is not sized properly, it can lead to a dangerous, high-pressure “ricochet,” where the nozzle and hose can suddenly turn around and come back at the operator.

One way to prevent nozzle ricochet is to size the nozzle-to-hose connection properly. As a rule of thumb, the distance from the tip of the nozzle to where the hose connects needs to be approximately one-and-a-half times the size of the pipe diameter you are cleaning. Sizing it in this way can help to prevent the nozzle from turning around and coming back at you.

Also, don’t “free spool” a nozzle up the sewer line. Any time you do this, you lose control of the nozzle and it can ricochet back at you. To prevent this, use a nozzle skid and hold the nozzle back.

No. 9: Choose the right nozzle for the job to reduce turbulence and wear.

As is known throughout the industry, there are several tiers of nozzles rated for water efficiency — Tier 1 (about 30% efficient), Tier 2 (50-60% efficient), and Tier 3 (75-98% efficient). 

What sets the most efficient Tier 3 nozzles apart from others in the category is fluid mechanics engineering on par with the aerodynamics of race cars or fighter jets. In the case of our Tier 3 nozzles at KEG Technologies, the high-performance fluid mechanics design leaves little room for power losses and excessive turbulence. 

By more effectively containing, controlling, and directing high-pressure water with less turbulence, a Tier 3 nozzle can deliver more cleaning power at lower psi. This eliminates the need for operators to compensate for the lack of power from Tier 1 or 2 nozzles by increasing the pressure to higher psi on the way back through the line. Ultimately, less psi (with a better, faster result) makes for safer sewer cleaning.

No. 10: Slow and steady wins the race — and is safer for operators.

The top mistake by operators that puts them at risk is rushing through the process.

Many operators run their nozzles way too fast. Rushing to clean more footage of sewer pipe is dangerous. To clean safely, keep the nozzle slow and steady and let it do its job. Never outrun your water or you risk losing control of the process and will eventually run into a blockage. A blockage of roots, grease, mineral deposits, or cave-ins will plug up the front jets. Then you no longer have a penetrating tool but a battering ram — a nozzle with no forward jets trying to feed its way through the blockage.

The reason we put forward jets on the nozzles is to safely open the blockage before the nozzle arrives. Slow down and the water will open the blockage before the nozzle ever gets there.

About the Author

Dan Story is operations manager at KEG Technologies, a Spartanburg, South Carolina-based manufacturer of sewer and storm line products including Tier 1 to Tier 3 nozzles, chain cutters, floor cleaners and camera nozzle systems. As a national trainer of best-practice techniques, the company is a member of NASSCO and its Tier 3 high-efficiency nozzles, such as the Torpedo, Royal and OMG, provide up to 98% efficiency. For more information, call 866-595-0515 or visit www.kegtechnologies.net.