How to Conduct a Hydrostatic Test on Ductile Iron Pipe

Welcome to Iron Strong.

In this edition we're discussing hydrostatic testing.

The biggest misconceptions we find though in the field,

folks don't understand the difference between water and air.

Hi I'm Jerry Regula, Product Engineer for McWane Ductile.

Today we're gonna walk you through a hydro testing process.

This is all documented in the ANSI/AWWA C-600 installation guide

for ductile iron pipe and fittings.

We've taken this section of 12 inch pipe and slow filled it,

ensuring that we remove all the air.

We have here our pump and our gauge,

which is located at the low spot and our air release at which is at a high spot.

The test pressure should be the ultimate pressure that that line will see in its lifetime.

That's different from the working pressure.

Tests are usually conducted for two hours with a plus or minus 5 PSI on the gauge.

This again is where people get a little confused about the process,

they focus too much on the pressure and not on the make up water.

Hydrostatic testing the main thing again is air.

Next thing is pipe movement. Pipelines move underground.

Think of it as a big accordion under the ground.

As you pressurize it and if that pipe moves just a little bit,

the pressure will go down.

For the purposes of this video,

and safety concerns we're only going to 50 PSI.

But what we want to show you,

is what happens when we go over here and loosen this come-a-long

and allow the joint to separate a little bit.

As I loosen this,

you can see the joints start to separate

you can see the spigot stripe starting to come out.

That's good enough there.

And we've dropped down quite a bit on the pressure gauge.

We're not losing any water

the volume of the pipe has just gotten bigger.

So the pressure drops.

Measuring the make up water is the key to success.

We can see here we started with a full bucket of water.

We used a little bit of makeup water to get back to our original pressure.

So now we have two quarts in this pitcher.

So I can measure and refill,

and I still have just a little bit of water.

So I know it took less than two quarts of water

to fill that pipe back up.

Is that a leak? No. We did not lose any water.

we just used our make up water

to get the pressure back up to the original pressure.

It's all about the makeup water, not about the pressure.

Today we've discussed the process

of doing a hydrostatic test in the field.

If you'd like a more detailed checklist,

click the link in the video description below.

And as always, work hard, work smart, and work safe.