Pile Driving Near Chlorine Pipeline minimum distance 2

[iangineer]

Hi everyone,

I'm not familiar with pile driving or what specifications are used with the design of a procedure to do so. A contractor is planning on driving piles about 5 feet from an underground chlorine line. I don't have much other information on it, but mainly wanted to see if there was any guidance from those of you with experience. Does 5 feet seem like an ok distance?

Thanks,

 

[LittleInch]

What type of pile driving?

5 feet is a bit close for me.

What is size and material of the pipeline?

But it should be ok so long as it is welded steel. Just quite difficult to prove a negative.

Any calculation on soil movement over a distance from the pile?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[EireChch]

he should at least pre drill to below the pipe bottom then drive. 5ft is pretty close. I would be concerned if its old infrastructure.

 

[iangineer]

5 feet is uncomfortably close for me, too. As I said, I don't have much information. I did find out that the piles are expected to be mostly pushed. So that may help alleviate some of the vibration concerns from impact driving. My company is meeting with a geotechnical consultant to determine the best path forward. I was just trying to provide some value to the email chain.

 

[LittleInch]

The people with skin in the game are the owners / operators of the chlorine line.

It's what they say, but usually pipelines have an easement / zone where you can't do anything without their permission of at least 3m / 10ft from the edge of the pipeline.

Unless this is within a facility, but even then the part of the company operating the Chlorine line will have something to say about it. Like NO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SlideRuleEra]

During pile driving, find out if the chlorine can be shut off and the pipeline pressurized with an inert gas, such as nitrogen. (Probably wishful thinking)
If not, see if the flow of chlorine can be halted, but static pressure maintained in the pipeline.

Even if nothing can be changed, what is happening in the pipeline (pressure, flow rate, etc.) needs to be known.

 

[TigerGuy]

How deep is the pipeline buried? I would want the pipeline potholed for location confirmation before ever considering driving piles that close, driven or vibratory.

 

[1503-44]

You absolutely do not want any leaks. Appropriate PPE is a must.

Don't do it with a pipeline guy sitting in a lawn chair above it. If he's not worried, then I'm not worried.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[dik]

Great thread and post... the engineer in the lawnchair cannot be wearing PPE, just to be sure...

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[LittleWheels]

Pipeline owner will give you chapter and verse on what you can do near their pipeline, in my experience.

Piling can have surprisingly little effect on buried objects, depending on technique. Historic England publishes a guidance note regarding exactly that subject.

https://historicengland.org.uk/imag...d-archaeology/heag270-piling-and-archaeology/

 

[iangineer]

I appreciate all of the responses to this thread begun with little information.

The work was to replace an old rail scale that is situated above a 4" chlorine line that is ~15ft below ground. Piles were originally going to be pushed into the ground, but after the old rails were removed, the soil was tested and shown to exceed the required compaction of 4000psf which allows for acceptable support without piles. New reinforced concrete slabs will reach 5ish feet below grade, leaving 10 feet above the chlorine line.

That's the basic plan, which sounds much better to me than the one originally conveyed to me.

 

[dik]

If on rail property, a whole new level of complexity may have been added...

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JedClampett]

I'm still waiting for some call backs from railroads from 1977.

 

[1503-44]

It sounds like there isn't much of a problem if you are not going to use piles, as the 10ft clear should be very forgiving. Still chlorine is exceedingly dangerous. This is your only chance to reduce risk. How careful you need to be depends on the condition of that pipeline material. I would try to get some verification of its condition, keeping in mind that it could have been subject to both internal and external corrosion. Is there a water table depth, what pipe material specification was used and its wall thickness, what external coating was applied, if cathodic protection is being used, has it been inspected recently, how was it inspected, inspection results, etc. Even if it all looks good, I would feel better if the pipeline was at least depressured during the work. Chlorine doesn't give second chances.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Oh, did you mean 5 ft ABOVE a chlorine line??

I think I thought you meant 5 ft horizontally away.

Doing anyhting ABOVE a buried line - no idea why its buried 5m (15ft) down - is never really a great idea, especially if it involves a 5 ft thick piece of concrete?? how do ypou know where the line is? Never ever trust as laid drawings for buried lines. Always dig to discover.

A decent sketch would help a LOT.

This plan sounds a lot worse to me than I initally thought.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

It's "10 feet above the chlorine line."

A slab or footing 10ft above, even loaded to max soil bearing of 4000psf, will only be a few psi at the pipeline level. Not all that much, if the pipe is in good condition. At this point it's more important to verify the pipe's condition. Once that and pipe properties are known, he can do some pipe stress calculations.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Since when did you start trusting as built drawings??

And good luck trying to repair that line if you ever needed to.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[iangineer]

Some follow-up notes:

The chlorine line was placed in 2000.
I'm not directly involved with the planning of this project; I was just added to an email string to see if I had any concerns. I did, but piles are no longer being driven, and I believe a geotechnical expert was involved, so my concerns are alleviated. The consulting firm designing the project is expected to have the final plan tomorrow. I'll try to remember to respond to this thread if anything is much different than the basic plan I've already shared here.

Again, I appreciate all of your discussion and recommendations. My initial desire for this thread was to figure out if there was some U.S. standard that laid out does, don'ts, and other restrictions.

 

[1503-44]

As built or not, FIELD VERIFY"

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Yes there is. Don't put a hole in a Chlorine pipeline.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.