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SYSTEM OPERATION AND MAINTENANCE
Part 6: Locating Utilities
Setting up the Jobsite
Before you start the utility location work, you should get to know your jobsite. Is the job in a city
setting? What traffic control devices will you need? Will you need to close a lane? Do you need to
obtain a state or local permit? Is the jobsite "off-road" easement work, or limited access highway?
Knowing the answers to these questions ahead of time may save you a headache later. Knowing
your jobsite needs early will help save you time in setup and help provide a safe work area for you
and your crews. Be sure to notify the local utilities to mark their lines in advance of your work.
(Figure 21)
Setting up the Test Hole (Spot Hole)
The Ultilivac® system can excavate very rapidly. The operator must resist the temptation to dig blindly until the target utility is uncovered. Pinpoint the location of the target utility to insure that you are not wasting time by digging in the wrong spot. Utiliscope recommends using and sells electronic utility locating equipment. Remember: the smaller the spot hole, the faster it can be dug and filled in. Because the Ultilivac® is capable of digging to depths of over twenty feet, a one foot horizontal error may result in hours of time wasted. (Figure 22)
Setting up the Equipment Once you have determined the exact point to dig, bring your truck and compressor into the work area. If you will be working in a travel lane, we recommend placing your truck between you and oncoming traffic. Remember, when working around a vehicle, make sure the wheels are always chocked. Next, bring out the hopper and set it at the opposite side of the hole away from the truck, about 3-6 feet from the hole works well. By placing the hopper there you will not have to walk around it if you need to go back to the truck for equipment and may prove helpful when working in traffic or close quarters. Next bring out your vacuum generator. Set the generator on the hopper making sure the compressed air connection on the generator faces the same direction as the pickup hose. This will point the exhaust away from you. Attach the pickup hose to the material inlet. Note: REMEMBER TO USE SAFETY PINS IN ALL OF THE AIR FITTINGS. Next connect the hand operated valve assembly to the vacuum generator HAND TIGHT ONLY. Now, connect the air supply hose from your compressor to the other Chicago fitting on the hand operated valve assembly. Connect a separate air supply line to the air lance if desired. If cutting asphalt or concrete is required, you will need a paving breaker and bits. Also, don't forget the asphalt or concrete patch.
Starting the Spot Hole Although it is not necessary, you may want to start the test hole with a shovel, digging bar or other
hand tool. This will reduce the amount of blowing dust and dirt once the air lance is inserted. If
working around fiber optic cables, gas lines or PVC piping, extreme care must be taken when using
hand tools. Keep the opening in the ground as small as possible. We recommend an initial cut of 8"x
8". After the hole has been started, use the air lance to pinpoint the utility by "pre-locating". "Prelocating"
means using the air lance to "bore" a hole through the soil until you can feel the utility on the
tip of the lance. Excessive downward force is not necessary. A steady "twisting" or 90 to 180 degree
rotation is normally all that is needed. By "pre-locating" the utility in this manner you can save
countless hours of digging, and will let you know right away how deep the line is. Even though you
may feel the utility through the pilot hole, it is imperative that you visually verify. As the soil becomes
aerated and breaks up, use the vacuum to remove the loose soil. When you reach the top of the
utility, start working on the soil to the side of the pipe. It is a good practice to expose the top (crown)
and the side (spring line) of the utility. This will help give you a clearer picture of the utility. Size,
material and condition are more easily obtained in this manner. (Figure 23)
Recording the Data If there are specific details about the utility that need to be recorded, we recommend you create a
standard form to write them on. Recording the data should be done while the hole is open. If you are
digging several holes a day, recalling the details of one from another is tough. Some of the things
you may want to write down are: size, depth, material, color, condition of utility, soil condition (type of
fill, wet or dry), trend of utility, fittings, joints or bends if found. A typical data sheet is illustrated in
Appendix 1. Appendix II shows a data sheet with information recorded. (Figure 24)
Backfill and Site Restoration Proper backfilling of the test hole is very important. If the hole is not backfille properly the utility may be damaged. Insure that select backfill goes in the hole first. The Ultilivac®
tends to keep the soils stratified in the hopper, so the last soil removed from the hole (from around the
utility), will be on the top layer in the hopper. Dumping the hopper away from the hole will allow you to
shovel or sweep the select material back into the hole first. When working under pavement, backfill
only 12" - 18" at a time then tamp thoroughly. If it is available to you, we recommend using a
pneumatic tamper (Figure 26). This will insure that your test hole will not cave in and cause a pothole.
A pneumatic tamper will also help tamp the asphalt patch. If you use cold patch asphalt, make sure
the area is dust free to insure a good patch. Broom the border of the pavement cut before applying
the cold patch. Dusting the patch after it is done with road dust will help prevent it from sticking to
tires and shoes. (Figure 25)
Tear Down and Clean Up Equipment tear down is basically opposite of the setup procedure. Just remember to shut off the air supply at the compressor first and then relieve the pressure from the hoses. Squeeze the trigger on the air lance and open the hand operated valve (or foot operated valve) on the vacuum generator. This will drain the lines. When all the air hoses are completely unpressurized, it will be safe to remove the safety clips and disconnect hoses. Inspect the vacuum generator. Remove any debris that has accumulated inside the vacuum chambers.
