Underground Utilities Toolbox Talk

The talk, read this out

Before that machine moves, somebody show me the locate marks and tell me how old they are. If nobody can, we are not digging this morning.

The rule starts before the excavation is opened. The estimated location of every sewer, telephone, fuel, electric and water line that could reasonably be in the way has to be worked out first.

Then the utility owners get contacted within the local response time, told what is being done, and asked to come and mark it. That is the 811 call in most of the country and it is a requirement, not a courtesy.

If they cannot respond within twenty four hours, or cannot pin down the exact position, you may proceed, but only with caution and only using detection equipment or another acceptable means of locating. Proceeding because the phone did not get answered is not that.

Marks are estimates. They tell you a line is somewhere near, not that it is exactly there. As the dig approaches the marked location, the exact position has to be found by safe means, which in practice means hand digging or vacuum excavation in the tolerance zone.

Once a line is exposed and the trench is open, it does not just sit there. It has to be supported, protected or removed while the excavation is open, because an unsupported pipe sagging across a trench is a pipe about to break over somebody's head.

And know the smell test is worthless for some of these. A struck fiber is expensive. A struck electric service can kill the operator through the machine. A struck gas line can take out the street, and by then it is not a jobsite problem any more.

Point at these before anybody starts

A talk delivered in a trailer is a meeting. Stand where the work is and put a hand on each of these.

• The locate marks on the ground, and the date on them.
• The colors, and what each one means on this site.
• Where the marks stop, and whether that is because nothing is there.
• The tolerance zone around each mark that has to be hand dug.
• Any line already exposed in the trench, and what is holding it up.
• The gas meter or riser, and where the service runs from it.

The rules that apply

• The estimated location of all underground installations is determined before the excavation is opened.
• Utility owners are contacted within the local response time, told about the work, and asked to establish the location of their lines before digging starts.
• If they cannot respond within 24 hours, or cannot establish exact locations, work may proceed only with caution and with detection equipment or other acceptable means in use.
• As the excavation approaches an estimated location, the exact location is determined by safe and acceptable means, which means hand digging or vacuum excavation, not the bucket.
• While the excavation is open, exposed installations are protected, supported or removed as needed to keep people safe.
• A struck line stops the job. Nobody re-enters the excavation until the owner of that utility has been called and has said it is safe.

Ask the crew

Three questions, answered out loud by name. This is the part that tells you whether anybody was listening.

• What do the marks on this ground say is under us?
• How wide is the hand dig zone either side of a mark?
• If the bucket clips a gas line, what is the first thing you do?

Close with this

One phone call, made days ago, is what stands between this bucket and the evening news.

Questions people ask

How long are locate marks good for?

That is set by state law and it is typically days to a couple of weeks, not months. Paint gets walked off, rain takes it, and grading removes it entirely. If the marks are stale or gone, the ticket gets refreshed before digging continues.

Does the locate service mark private lines?

Usually not. The one call system covers member utilities up to the meter. Anything past it, the yard lighting, the irrigation, the propane run to the shop, the feed to the detached garage, belongs to the property owner and has to be located privately.

What is the tolerance zone?

The margin either side of the mark inside which mechanical digging is not allowed and the line has to be found by hand. The exact width is set by state law, commonly 18 or 24 inches either side, so check the number your state uses before digging.

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