I'm Christa Larson, and we're on site today with Utility Construction Company.

They're doing sewer main and sewer service installation.

We'll be demonstrating survey equipment and pipe lasers and how to install sewer on grade and at the right elevation.

[lo-fi music] The sewer pipe on this street is being replaced because it is undersized for the kind of use that it gets nowadays.

This pipe was put in back in the 1950s.

So now we're upgrading the size with 8-inch pipe and the latest material, which is PVC.

As an engineer, my tools for surveying.

I need my book, my calculator, my scale, pencil, my tape measure, and of course my plans.

We'll be demonstrating using a level with grade rod and the receiver, and we'll also take a look at a pipe laser.

First things first, we need our PPE.

Hard hat, safety glasses, safety vest, and our steel-toed boots.

The first step of doing a project is to get a set of plans.

Surveyor goes out and collects all the existing conditions information, and then that goes back to an engineer.

The engineer will take that information and then lay out a plan for, in this instance, replacing old sewer with new sewer pipe.

Then I take this set out to the field, and we construct it.

In this plan, we're seeing old 6-inch sewer being replaced with new, 8-inch PVC sewer.

So this is the plan view where you see the manholes, and then the pipe running in between.

Then we go down to the profile view, and you can see the manholes actually in profile with the pipe running in between them.

The pipe needs to get under the existing utilities, such as water and drain, that you see here.

It also can't be more than 0.1 slope.

And the reason for that is that if the pipe is pitched too high up, that you can actually have solids settle out, and the water runs underneath the solids, which will cause a backup in the pipe.

In the plan view, you can see that we've come in from a side street and we're changing direction.

So the manhole is placed so that we can make that turn around the corner.

So normally when you're driving down the road, all you see of a manhole is the cover on the road.

But this is actually what's underneath.

This is the manhole.

Manholes are used when you want to change direction with the sewer, as in going around a corner, or if you want to change elevation.

If you're coming in steep and you're flattening out, the manhole is used to change elevation.

Or if you're going around a corner, the manhole is used to make a turn.

Manholes are points where the sewer can be cleaned out and inspected.

So right now, the crew is digging and removing the old sewer and installing new sewer.

In order to do that and maintain sewer flow in the existing main, they need to bypass pump from an upstream manhole to a downstream manhole around their work site.

So this hose on the ground is the bypass.

So they're pumping from a manhole upstream into this downstream manhole.

At the next manhole, we've actually changed elevation and slope of the pipe.

So here we are at our maximum 0.1.

We don't need to be as deep.

Here's your existing pipe.

So now we're going to jump up and change elevation with a manhole.

Now we follow, essentially, where the existing pipe is and replace the manhole, and then continue down the street.

So we use the set of plans to locate our manholes and to set our slopes.

We use survey equipment to check the slopes and make sure that we're running the pipe at the right grade.

And we use pipe lasers also to set the slope that's been shown on the plan.

[lo-fi music] So one of the first things we do when we get on the job site is to set up our level.

There's an internal mechanism to make sure that it's self-leveling and it levels to the ground.

Then, once this is set up and turned on, we can get elevation on a known point where we know the elevation.

And we use that information to get the exact elevation of this laser.

And then we use that as our known elevation to get elevations on pipes and road grades throughout the job site.

You can see up top where the mechanism is spinning.

And that's actually sending out the laser, which will be picked up by a receiver that's attached to the grade rod.

So now that I know my level is set up and ready to be used, I can go to a known elevation, and I use the grade rod and the receiver to get the elevation of the instrument.

So I've got the great rod here on top of the catch basin cover.

And I know that the elevation on top of this catch basin cover is 520.

I have a solid tone, so I know that I have the exact elevation of where my instrument is in relation to this catch basin.

If I'm up, it'll beep at me and give me a little signal that I need to move it down with that arrow.

And then, if I'm too low, it'll give me a signal and an arrow to move it up.

And as I get closer, than I get the solid.

So when I read the grade rod now, I'm reading the line right here.

And I'm at four feet, and it's a tenth for every hash mark.

This is the top of the two.

So since my instrument here is at the bottom of the two, I know that I'm at 4.19 feet.

So then I know that the elevation on my temporary benchmark on the catch basin cover is 520.

And I've just read 4.19 as my back site.

So now, this symbol here is the symbol for the level.

And I know that my elevation on the level is 524.19.

520 plus 4.19.

Now I can use this elevation to capture an elevation on the pipe, or on another catch basin cover, or anywhere I need a grade shot or an elevation throughout the job site.

Now I'm going to use my known elevation of my level to get an elevation on this new sewer pipe.

So I attached my receiver, and I'm getting a symbol that's telling me to move it up.

So I'm going to slowly move it up.

And now I have a solid bar and a solid tone, so I'll tighten it there.

So let me show it to you without the receiver on.

My shot that I got was 7.91.

So I'm in seven, and I was up here at nine.

And I was right at the bottom of this hash mark, which tells me I'm 7.91.

The bottom is my 1, 2, 3, 4, and then this longer hash mark is the 5.

So I was at elevation or depth seven, nine, one right here at the bottom.

So, to review, I had my known elevation on the catch basin cover of 520.

I shot the cover and got 4.19.

I add those two, so I know that my instrument is an elevation 524.19.

Then I just took a shot on the pipe, and I got 7.91.

So I'll write that here.

And as a little cheat for myself, I put a plus and a minus so I know what needs to be added.

And what needs to be subtracted.

So I take now my elevation of my instrument in my calculator, and I'll do 524.19.

That's the height of my instrument.

And I'll subtract that foresight.

Minus 7.91.

Equals 516.28.

So now I know that the elevation on the top of my pipe is 516.28 feet above sea level.

Now I can use that information to take a shot on another piece of pipe in the same run.

And I can subtract those to get the difference in height and the distance to get my slope to make sure that the pipe is at the proper slope.

So we set up our level.

We made sure that that was on and working and level.

Then we took a shot on a known elevation at the catch basin cover.

We use that elevation to determine the exact elevation of our instrument.

We then took a shot on the pipe and got an elevation on the pipe using the known elevation, and then the depth of the pipe.

So now we an elevation on a certain point of a pipe.

We're going to then take a second grade shot on the pipe at a 10-foot distance.

So then we can determine what the difference in height is from point A to point B, and determine the slope, and make sure that our pipe is set at the accurate slope.

I'm going to take my second shot at 10 feet from where I took the first shot.

I have my elevation up there.

I'll get my elevation up here.

And we'll do some math and make sure that the slope is good.

[beeping] OK.

So my receiver elevation is set right here on top of this hash mark.

So I'm going to move this out of the way so you can see what the elevation is.

So I'm at seven feet.

6.6, where this is 6.1, 6.2, 6.3, 6.4, 6.5, and 6.6 on the top.

This different looking hash mark on the bottom is the five.

So 7.66 right here on top.

Now I take the elevation of the level, which I calculated at 524.19, and I'm going to subtract the 7.66 that we just got on the grade rod.

I know that at the first point, my elevation was 516.53.

The second point, my elevation was 516.41.

I subtract those two and I get a difference of 0.12.

My two shots were 10 feet apart.

So I'm going to divide that by 10 to get my slope.

Rise over run.

Change in elevation divided by your distance equals your slope.

And now I know that my pipe is pitched in the right direction.

[lo-fi music] The crew that we were looking at down there, they were doing the service pipe.

So the smaller pipe from the house to the main line sewer.

And now this crew is the one that are actually replacing the mainline sewer.

What you're seeing now is a trench box.

A trench box is put in the trench to protect the guys when they're working in the trench to make sure that nothing falls on them.

[lo-fi music] This is an excavator.

It's a tract excavator.

And the attachment that's on it right now is a hammer, or something called a hoe ram.

While they were installing the sewer, they hit rock ledge.

So they're using this hammer to break out the ledge so they can dig it out and put the pipe in.

The green light that you see at the end of the trench, that's the new sewer main that's being put in.

So they hammered out all the sludge in order to put it in the sewer main.

This pipe here comes off the water main and runs over to this house and serves water to this house.

The beam that we saw in the trench and what they're using to set the right slope in the right grade and elevation for the pipe, that's coming from the pipe laser that's down in this manhole.

They set the beam to the slope that they want, and then that beam shoots all the way up the pipe.

And that's how they set every pipe.

This is the next piece of pipe that they're going to put in.

They'll put the spigot end into the bell end at that end.

And then you see here on the end is a Y-connection for a service.

So from this Y-connection, they'll run a lateral pipe out to the house to connect the service pipe, which is what we were looking at down the street.

He is taking what we call pipe soap, or lubricant.

He puts it around the spigot end of the pipe.

Then he'll put that spigot end into the bell end, all the way up to that black line.

[playful music] Whenever you're ready [inaudible].. We need to put a good stone bedding around the pipe to make sure that it doesn't settle, and that it doesn't get crushed.

You want the pipe to be-- gun barrel is what we like to call it.

That's my favorite?

Did you get all that?

[laughs] I did, actually.

[electronic music] Major funding for I Build New Hampshire is provided by-- With additional funding from-- [electronic music]