Watch where you dig

[MotoSook]

Every state or region has a "one call" number. The utilities will respond within 72 hrs. If they screw up, it's their fault. Generally the pipelines are easily located, but I suspect buried telepnone lines and such are more difficult to pin point within a foot. The steel lines are easy. The utilities will locate on private property with flags or markers. If you are working around a marked utility, be careful as you dig close to it. Most companies have requirements that force contractors to hand dig within 1-2 feet of their equipment.

Pipelines are installed below the frost line or at least 36" down to top of pipe. Most property owners know when a pipeline is running through their property as there was some payment when the pipe was installed. If the property was sold, it would have been indicated on the plat of survey.

It's common for property owners or contractors to be careless resulting in line strikes. Some just dent the pipe, some end like the pictures in the OP.

Pipeline companies have dedicated personnel or departments tasked with preventing this type of thing and they take it very seriously as accidents will result in the Feds coming down on them hard. The Feds have in the past several years been very critical and created requirements for pipeline operators to prevent accidents and maintain pipeline integrity. I assure you the operators are not taking safety lightly, but accidents happen when individuals are careless.

Safety is not the sole responsibility of the pipeline owner or utility.

As for pipelines that parallel or cross powerlines, this is safe and the operators monitor the condition of the pipe on a regular basis.

I wasn't able to find whose pipeline was hit in that OP. Anyone know?

[PorscheGAL]

The story says that the blast was actually caused by corrosion of the pipeline, not being dug up. The Utility company noted the corrosion in an earlier inspection. That is more scary.

[MotoSook]

I'm using my iPhone. I can't see any text associated with the link. Where did you find the info regarding the corrosion?

[PorscheGAL]

Snopes.com link that was posted earlier. They quoted the Lynchburg VA newspaper article.

[johnco]

I've hit quite a few lines diging pools. checked with the city before one job and they said it was clear. found a 2" gas line for them. they told me thanks when they come to repair the gas blowin out, they didn't know it was there since it wasn't on the subdivision prints. last summer I dug a pool 2 ft from where they marked the 10 phone trunk lines. 10 pair to a monster 50 pair cables. well.... I found an 11th one. they were there in 5 minutes

[sammyg2]

Originally Posted by PorscheGAL

The story says that the blast was actually caused by corrosion of the pipeline, not being dug up. The Utility company noted the corrosion in an earlier inspection. That is more scary.

They run inspection pigs through the lines periodically. Some have cameras, some have ultrasound or other measurement techniques.

Every single pipe has some amount of corrosion.
Some have a little bit, some have a lot. Pipes have quite a bit of safety factor built in, they are thinker than necessary. Corrosion allowance.
If it has a little corrosion or thinning they keep an eye on it. if it has a lot they take it out of service and repair it. It is trended and predicted.

That one showed a little corrosion in testing. Evidently in one spot it had a whole bunch more than they suspected.

[VaSteve]

Originally Posted by schamp

On another note, does a utility like a pipeline company send you a calender each year? If so, your property is within the explosion zone. Look on the back of the calender- it will have emergency procedures on it. They have to send it out each year by law.

That makes me laugh.


We have something here called "Miss Utility". I have head about this for some 25 years...last year I figured out the pun since I was thinking of a nice lady with a surname Utility. I'd probably dig into a gas line.


They mark my private property, but it's not that big.

[MotoSook]

Sammy - smart pigs, aka MFL Tool.

Magnetic flux leakage

more links:

PHMSA - Regulations

49 CFR Ch. I (10-1-00 Edition)

[speeder]

Originally Posted by 125shifter

These lines should be deeper than that. It wasn't a farmer digging that caused it:

snopes.com: Call Before You Dig! - Gas Main Explosion

But hey, I read it on the internet! On PPOT, no less. And you're saying it's not true?

I'm crushed.

[David]

I hope these companies have electric cathodic protection on these lines. Anyone know if they do?

[A930Rocket]

Here in Charleston, SC we have to hand dig within 5' of the marked lines. That's 10' of hand digging to what ever depth. A 10' estimate is the best they can do?

For cable, we have no problem finding them. They are usually within 6" of the surface.

[MotoSook]

I hope these companies have electric cathodic protection on these lines. Anyone know if they do?

They do.

[cgarr]

So I should let someone know about all the stuff I have buried in my yard?

[schamp]

All of the pipelines I have worked on had cathodic protection. All of the electric transmission lines I have worked on had the towers inspected from time to time. I have seen the legs on many towers eaten by acidic soil. Putting high pressure gas lines in close proximity to high voltage transmission lines is an accident waiting to happen. There was a reason they weren't built that way in years past. Don't think a large explosion but rather a large continous explosion. Sure, there are shut down valves but it takes awhile for the pressure to drop. These things are targets.
As far as call before you dig- a little planning and a phone call and its no charge if you hit something. Take out a large high traffic fiber optic line and you could get a very nasty bill.

[masraum]

Some of these remind me of Lake Peigneur in LA.

Someone was drilling for oil, but got too close to a salt mine.

Lake Peigneur - Wikipedia, the free encyclopedia

The now generally accepted explanation is that a miscalculation by Texaco regarding their location resulted in the drill puncturing the roof of the third level of the mine. This created an opening in the bottom of the lake, similar to removing the drain plug from a bathtub. The lake then drained into the hole, expanding the size of that hole as the soil and salt were washed into the mine by the rushing water, filling the enormous caverns left by the removal of salt over the years. The resultant whirlpool sucked in the drilling platform, eleven barges, many trees and 65 acres (260,000 m2) of the surrounding terrain. So much water drained into those caverns that the flow of the Delcambre Canal that usually empties the lake into Vermilion Bay was reversed, making the canal a temporary inlet. This backflow created, for a few days, the tallest waterfall ever in the state of Louisiana, at 164 feet (50 m), as the lake refilled with salt water from the Delcambre Canal and Vermilion Bay. The water downflowing into the mine caverns displaced air which erupted as compressed air and then later as 400-foot (120 m) geysers up through the mineshafts.

Days after the disaster, once the water pressure equalized, nine of the eleven sunken barges popped out of the whirlpool and refloated on the lake's surface.

[MotoSook]

Let's understand that pipelines may occupy the same area or right of way as power lines, but the pipeline does not run directly under the lines. Pipe may parallel the power lines within a reasonable distance. Where they have to cross each other, the pipeline integrity engineers and techs know what to expect and treat it accordingly. This is not to say everything is perfect.

As for multiple explosions, not as likely as you think. A blowout does not mean there will be a fire ball. And if there is a fireball, the burning gas isn't likely to migrate up or down the line like the movie makers would want the public to expect. The mainline valves do shut in fairly quickly when a rupture is detected. The segment of pipe is then isolated and the fire will die out as the gas flows out the break point until the pressure dissapates.

Natural gas will not ignite itself easily. There has to be a source of ignition and oxygen. NG auto ignition temp is high, over 600 degrees F. So a rupture may just blow a lot of dirt and gas into the air. Static discharge or some other ignition source will ignite the venting gas.

[chocolatelab]

A neighbor of mine has a son who was working for a demo company. They were taking out some concreteand trenching. Apparently the line was called and everything appropriate was marked. The young man ( 20 at the time ) hit a high voltage. That line wasnt marked. 480 maybe. Really high. Blew his arm off and cooked him inside out. Some how he survived. Permanently disabled. Heartbreaking.

After hearing his story i dig with a hand trowel.