The Seven Major Hazards in Drain and Sewer Cleaning
Editor's note: This is the third and final part on drain and sewer cleaning safety. The text is from Chapter 1 of The Professional Handbook-Drain and Sewer Cleaners, Second Edition. It is reprinted with permission of Spartan Tool's International Institute of Sewer and Pipe Cleaning. The handbook was authored by Ernest L. Weber.
The third major hazard in drain and sewer cleaning concerns exposure to CHEMICAL DRAIN OPENERS. I tell every one of my students to be prepared to deal with chemical drain openers on every service call. Assume the customer has already used them. This way you will help avoid the risk of injury from chemical drain openers. For many years, there were two types of chemical drain openers available in the marketplace-acids and caustics. Both are extremely dangerous. 1 am happy to report that, recently, less dangerous products are becoming available to the consumer. The new drain cleaners are enzymatic. These drain cleaners work with biological and digestive type reactions. They are much safer to use than acids and caustics. For safety's sake I hope that someday the enzymes are the primary chemicals used for drain and sewer cleaning.
Since the market hasn't completely changed and will not for some time let's talk about the most common types of chemical drain openers-acids and caustics. (I will not discuss oxidizing agents because they are often added to caustic drain cleaners to enhance performance. I want to keep the topic as simple as possible.) The most common acids used in chemical drain openers are sulfuric acid and hydrochloric acid. The most common caustics are sodium hydroxide caustic soda and Iye.
Whether a substance is an acid or a caustic depends upon something called the PH. PH stands for "power of hydrogen." A PH Scale ranges from 0 through 14. Water has a PH of 7. Water is neither an acid nor a caustic. It is neutral. Acidic values have a PH below 7 and caustic values have a PH above 7. Every change of whole numbers represents a tenfold change in strength. I do not want to make the subject too complicated so I will stop here.
Both acids and caustics (bases) are dangerous and can cause injury or death. Acids are usually more dangerous and life threatening than caustics. Acids are powerful enough to produce violently explosive reactions. Acids release heat when mixed with water. If water is added to an acid while it is still in the container an explosion is possible. If an acid is poured into a drain containing a caustic a violent reaction can be created repelling the acid. The reaction is called a splashback.
If you read the label on most chemical drain openers you will notice the instructions always mention putting the chemical "in the pipe." I have yet to read an instruction, which mentions placing the chemical in a toilet for a stoppage. I know of times, however, when a homeowner has placed four or more ounces of an acid in the toilet bowl and caused the bowl to crack. The instructions typically say to use only two ounces in the pipe. Sometimes the instructions are not followed. Remember most chemical reactions release heat. If there are chemicals in the toilet or in the sink and you put in your hands or if the chemicals splash in your face or on your arms, you can be severely burned. Blindness is also a possibility. Be prepared to deal safely with chemicals.
Sometimes the smell will tell you chemical drain openers have been used. If chemical drain openers (acids/caustics) are mixed with ammonia or a cleaner with ammonia, chlorine gas may be created. Chlorine gas can be fatal.
If the chemical drain opener does not remove the obstruction, it may remain in the pipe. It may also damage the pipe. If a drain and sewer cleaner attempts to clean the blockage where chemicals have been used, he will be exposed to the chemical and injury may result.
Whenever I teach professional drain and sewer cleaners, I'm always amazed with the number of students who do not realize that some chemical drain openers may cause breakage or damage to drain or sewer cable. Let me assure you that some chemical drain openers may destroy your cables!
A drain or sewer cable is a steel wire, which has been tightly wound. Most quality cables are made of music wire-a high grade of steel-and heat treated to release the stress placed on the wire after coiling. The wound steel wire becomes a spring or coil to be used to clean the pipe. The coiling gives the flexibility to the steel and allows turns to be executed by the cable.
When steel cable is tightly wound, microscopic cracks result on the inside of the wire. The cracks do not affect the life of the cable under normal conditions; however, if the cable is exposed to chemicals in the pipe, damage or breakage may result. Acids can enter through microscopic cracks in the cable and can cause cable failure. Crystallization of the wire is also possible. The flexing of the cable allows the acids to work their way into the steel. In sufficient strength, acids can break the cable in minutes.
Caustics can also cause cable damage but in a different manner. Caustics can cause severe pitting of the wire. The pitting can cause wire fatigue and the strength of the cable will be reduced, so breakage may occur. You as a service technician may not care how it technically works. You do know, however, that you are now out the price of a cable. Some service technicians charge the customer for the price of a cable when it has been exposed to chemical drain openers to minimize the cost of the service call.
To help minimize cable breakage caused by some chemical drain openers, a lightweight oil or lubricant may be put on all cables. The cable should be cleaned each time a service call is completed. Rinsing the cable with water before it is put away is always a good idea. Some professionals are even disinfecting their cables and machines after each usage to kill the microorganisms, which were picked up while the sewer was being cleaned.
To prevent injury due to chemical drain openers, I suggest drain and sewer cleaners always wear safety goggles for eye protection. Rubber gloves should be used. Some technicians use a heavy duty waterproof rubber glove. Others use a rubber glove beneath their sewer cleaning glove or mitt. Either is acceptable as long as the rubber glove will help protect the skin against chemicals. The skin should be covered at all times. Coveralls help cover the skin. If the chemicals soak through the coveralls, the coveralls should immediately be removed and the exposed area rinsed for at least 15 minutes.
When working around chemicals, splashing must also be held to a minimum because exposure may result in injury. Proper ventilation is also required in the work area. Remember, as mentioned earlier, chlorine gas is a possibility. It may be necessary to vacate the premises until it is safe to return.
Beware of the dangers of some chemical drain openers and be prepared to deal with them on every service call.
The fourth of the Seven Hazards in Drain and Sewer Cleaning is the ROTATING CABLE AND ATTACHMENT UNDER TORQUE. If a sewer cleaner uses a cable machine, he must be concerned with the proper management of the cable and attachment. If not, serious injury and possibly death may result. There are four major dangers when dealing with a continuous cable machine and a rotating cable and attachment:
Danger No.1- Excessive Distance Between the Pipe Opening and the Machine. A continuous cable drain or sewer cleaning machine should always be located within 3 feet of the pipe opening. If the machine isn't located within 3 feet of the opening and precautions are not taken, a cable under torque can loop or form a "figure 8." When it loops, a finger may be severed, tendons torn or even the wrist or arm broken.
Let's examine the operation of a rotating cable more carefully. When torque builds in a rotating cable, it transfers to the point of least resistance. The point of least resistance is usually the space between the machine and the pipe opening. If the space is less than 3 feet, the cable doesn't normally loop. A cable safety guide should be used whenever possible to minimize the chance of cable looping and/or becoming entangled in the cable during operation.
If the space between the machine and the pipe opening exceeds 3 feet, chances are the looping or "figure 8" may take place in the unrestrained area. If it is not possible to locate a continuous cable machine within 3 feet of the pipe opening, a piece of plastic pipe, Schedule 40 (PVC or ABS) 1 1/2-2" in diameter, should be placed between the machine and the opening of the pipe to be cleaned. The plastic pipe will help keep the cable from looping and causing injury. Keep in mind that if the front of the cable is free to turn at all times, there will be minimal torque buildup. If the front of the cable is not free to rotate, however, torque builds. The cable must be properly managed at all times to maintain control. The 3 feet distance will vary with sectional machines. (Note: See manufacturers recommendations when using a sectional cable machine.)
Danger No. 2-Lightweight Cloth Gloves,Long Hair, Loose Fitting Clothing and Lack of Safety Gear. When a cable rotates and torque builds and releases, many things are happening to the cable. The cable expands and contracts. It gets larger and smaller-smaller when it goes under torque and larger when the torque is released. What many technicians fail to realize is the loops of the cable (helixes) also open and close. The opening and closing of the helixes of the cable create a pinch space. If the technician wears cloth gloves or any type of thin, lightweight glove or allows his long hair to come in contact with the cable as it opens and closes, the cable will grab the glove or the hair and severe injury may result.
People wearing thin, lightweight cloth gloves have lost fingers, torn tendons and even broken the wrist or arm while on the job. People with long hair have had major chunks of it pulled out by the roots from a rotating cable. It is a very serious matter. A heavy duty glove too thick to become pinched by the cable should be used at all times. Some sewer cleaning gloves have staples in the palm to help insure the glove will not become entangled in the cable. If you have long hair, make sure it is tied up and cannot come in contact with the cable or the moving parts of the machine. A properly dressed service technician wears coveralls, which are not baggy or loose fitting. He has hair short enough to help avoid cable entanglement and injury. He wears rubber boots with metatarsal guards, sewer cleaning gloves and safety goggles. Remember also, if the technician chooses not to wear gloves, he runs the risk of cutting his hands on the burrs which occur occasionally on the cable and exposes himself to the risk of infection and disease.
Danger No 3-The Rotating Cable Shooting Out of the Drum Causing Personal Injury and/or Property Damage. Drain and sewer cleaning machines are designed to operate with the electrical switch in the "forward" position. Forward position is a clockwise rotation of the cable when viewed from behind the machine. The only time a drain or sewer cleaning machine is ever to be put in "reverse" position and the cable rotated is when the cable is caught on an obstruction in the pipe and cannot be removed in any other manner. A misconception takes place by technicians who think a machine is to be used in the "forward" position when the cable is entering the pipe and "reverse" position when the cable is coming out of the pipe. Nothing can be further from the truth. Let me repeat, nothing can be further from the truth. When I say "forward" or "reverse" I am talking about the position of the electrical switch on the machine. I am not talking about the position of the automatic feed (if your machine has such an option).
When the electrical switch on a sewer and drain cleaning machine is in the "forward" position and the cable rotates, a left hand wound cable tightens down, torque builds, and the obstruction is removed. When the electrical switch is in the "reverse" position and the cable rotates, a left hand wound cable begins opening up instead of torquing down. In other words, the cable is being twisted in the opposite direction from which it is wound. When enough torque is developed, the cable will release the tension. There may be enough space in the drum (or between the inner and outer drum) for the cable to flip completely around. When this happens, up to 4 feet or more of cable can exit the drum in an instant. Injury and property damage may result.
Some continuous cable (drum) machines even have a warning label on them saying not to use the electrical switch in "reverse" unless the cable is caught and cannot be released in any other way. The reason is because the cable may shoot out of the drum. Never continue to operate a drum machine in the "reverse" position for more than a few seconds. (Note: If you own a sectional machine, you do not have a drum and need not worry about the cable shooting out.)
Danger No. 4 -Turning the Machine On Before the Attachment is Placed Inside the Pipe. Before a cable is rotated, the attachment needs to be placed in the pipe. Placing the end of the cable in the pipe before rotation lowers the possibility of injury from the attachment. Never grab the end of the cable while it is rotating to avoid injury by the attachment. At trade shows, most companies manufacturing sewer and drain cleaning machines have stopped putting attachments on the end of a cable because an inadvertent brush against the attachment may cause injury or damage to clothing. The same problem exists when operating the machine.
The key to successful drain and sewer cleaning includes the proper use and management of a rotating cable. The danger is very real and accidents can occur much too often.
The fifth major hazard in drain and sewer cleaning is CONFINED SPACE ENTRY. Too many drain and sewer cleaners fail to understand the environment in which they operate. They forget about enclosed areas. The National Institute for Occupational Safety and Health says that a confined space meets any one of the following characteristics:
- Limited openings for entry or exit.
- Unfavorable natural ventilation.
- Not designed for continuous worker occupancy.
The most obvious confined space areas for drain and sewer cleaners are sewer manholes and septic tanks; however, any area which meets the criteria above qualifies as a confined space. There is a lack of natural air movement in a confined space. Confined spaces may also have oxygen-deficient atmospheres, oxygen-enriched atmospheres, flammable atmospheres or even toxic atmospheres.
The atmosphere normally contains 21% oxygen. If the oxygen level drops below 19.5%, it becomes an oxygen-deficient atmosphere. If the oxygen level rises above 23.5% it becomes an oxygen-enriched atmosphere. Both are dangerous. An oxygen-enriched atmosphere is also a flammable atmosphere. If a source of ignition is introduced, fire and explosion may result. Always ventilate a confined space with normal air. Never use pure oxygen to ventilate a confined space so as to avoid an oxygen-enriched atmosphere. Toxic atmospheres contain liquids, vapors, dusts, or gases and should always be considered hazardous. Confined spaces should not be entered without proper safety equipment and an approved self-contained breathing apparatus (SCBA). All applicable OSHA guidelines must also be followed.
Confined spaces involving human waste are especially dangerous. When human waste putrefies, dangerous gases are generated. To drain and sewer cleaners working in a confined space, there are four major gases of concern from putrefying waste. The first gas of concern is Hydrogen Sulfide. Hydrogen Sulfide is heavier than air. It normally rests in the bottom of a confined space. At low concentrations it smells like rotten eggs but at higher concentrations it is odorless. If you have ever stopped at a wastewater treatment plant and smelled what you thought was rotten eggs, you were, most likely, smelling Hydrogen Sulfide. Hydrogen Sulfide paralyzes the respiratory center and causes death at .2%. It is explosive at concentrations of 4.3% in the air. It will oxidize to sulfuric acid under given conditions. If you have ever seen sewer pipe with the top of the pipe (crown) eaten away, chances are sulfuric acid did the job.
The second gas of concern to drain and sewer cleaners produced by putrefying matter is Methane. I'm sure everyone, at one time or another, has heard of methane explosions. Methane will not support life. It is flammable, colorless, odorless and is also produced by the decomposition of organic matter.
Concentration at 9% will cause nausea. Methane is lighter than air and is more than likely to be found in the top of a confined space.
The third gas we need to deal with as drain and sewer cleaners in a confined space is Ammonia. Urine is high in ammonia. Ammonia has a sharp pungent smell. It is toxic at .O l % and colorless. It is also a by-product of the decomposition of organic manner.
Finally, Carbon Dioxide is a concern when waste putrefies in a confined space. Carbon Dioxide is colorless and odorless, and can cause suffocation at a 10% concentration. Carbon Dioxide is not to be taken lightly. It can cause death.
Remember that some industrial sites and some municipal sites can also be explosive. Companies which manufacture industrial gases and gasoline refineries are two examples of these types of environments. If you are ever called to operate an electromechanical machine or even an electric high velocity water jet at such facilities, make sure your machine has an explosion proof motor. Always consult with the safety director before beginning work in any potentially explosive environment at a factory or municipality. It may save your life.
Be aware of confined-space entry in drain and sewer cleaning. It can be a silent killer. About half the deaths in confined-space entry involve one worker trying to save another who entered a confined space without proper safety precautions and safety gear. Don't let a confined space take your life or the life of a friend. Follow all applicable OSHA Guidelines for Confined Space Entry.
Hazard No. 6 in drain and sewer cleaning involves HEAVY LIFTING and the possibility of back or leg injury on the job from not lifting properly. The National Safety Council has rules and regulations designed to prevent injury from lifting. You have probably seen many of them on posters in factories and warehouses. I would like to summarize some of the basic rules of lifting:
- When you lift, keep the back straight and let the legs do the work. When you use your back for lifting, you increase the possibility of injury.
- Stand close to what you lift with your feet firmly on the ground. The farther away you are from what you lift the more likely you are to injure your back.
- If you must squat to lift, keep the back straight, knees bent and stomach muscles tight. Lift with you legs. By bending over to lift an object you have increased the risk of back injury.
- When putting the load down, let your legs do the work. Avoid using the back.
- Push and do not pull heavy objects. When pushing, you use your legs. When pulling, you use your back. Avoid using the back whenever possible.
- Use mechanical help if the load is too heavy. Everyone needs to know his limitations and not exceed them.
- Keep your knees bent when working on your back. Get up and stretch frequently. When your knees are bent, much of the strain is taken off the back.
- Use a ladder instead of jumping from short heights. Consider putting another step on your service vehicle so the distance between the vehicle and the ground is minimized.
- Use exercise to help relax tense muscles. Exercise will lower risk of on-the job injury.
Some sewer cleaning machines weigh in excess of 200 pounds. While loading or unloading a machine of this size, the service vehicle needs a ramp, a hoist or a liftgate. If your sewer machine can be disassembled, take it apart and load it separately on the service vehicle. Minimize the weight whenever possible. Drain and sewer cleaning can be a difficult way to earn a living. Every step taken to minimize weight will make the job easier.
The final major hazard in drain and sewer cleaning applies to those drain and sewer cleaners who own a high velocity water jet. It is becoming difficult to find a drain and sewer cleaner who doesn't own a high velocity water jet these days. It is the growth product in drain and sewer cleaning. If you don't own one yet you are missing an opportunity to increase revenue.
Yes, you guessed it, the seventh and final hazard in drain and sewer cleaning is HIGH PRESSURE WATER. High velocity water jets operate normally in the 1,000-4,000 psi range. That's 1,000 to 4,000 pounds per square inch of pressure! Pressure at this level can remove an eye from the socket. It can cause blinding and scarring. Cuts or abrasions to the skin are quite possible. The water can even be injected into the skin. Hand and foot injuries can occur. If the water jet noise level exceeds 90 decibels, hearing damage may occur unless proper car protection is worn. With water jets, of course, there is always concern with confined space entry because water jetting municipal sewers and septic tank pipes is so common.
I recommend, for your own safety, when you are water jetting to use safety goggles or a full face shield if water pressure exceeds 2,000 psi. Protective covering is an absolute necessity. Coveralls and a raincoat are recommended. A hard hat is ideal. Rubber boots with steel toes or metatarsal guards are necessary. Heavy duty, waterproof protective gloves are required. Ear protection should be implemented when necessary.
High velocity water jetting is a dangerous business. Make sure you have taken all the precautions necessary to protect yourself. Act like a professional. Dress like a professional. It won't take long before you are a professional.
We have now discussed the seven major hazards in drain and sewer cleaning. It is your responsibility to take the recommended steps to avoid injury or death caused by these hazards. No longer can you say that you aren't aware of the major dangers in drain and sewer cleaning.
"This article was originally posted on ww.reevesjournal.com."