I need to cut into a pipe that had diesel 10

[kabron1]

I need to cut into a pipe that had deisel in it, What can I flush the pipe with in order to make it safer. I know that diesel has a higher flash point but none the less I want to reduce the risk. The pipe is old and I will also need to tie back in to it with newer pipe. So obviously I will be welding on it. Any help, I would be grateful. I may purge with nitrogen when welding but the concern will be cutting on the pipe. Thanks

 

[pennpiper]

You did not say what size this pipe line is or what kind of environment it is located in.

If you give us a little more details we might be able to be of more help.

One other thing you may want to consider, Contact a local "Hot-Tap" contractor and have them visit your site and advise you.

 

[IFRs]

Cold cut it?

 

[pennpiper]

IFR,
Cold cutting does not help for the welding part of the original question.

 

[IFRs]

Once you have cold cut it, you can use a plug a few feet back into the pipe, clean and gas free the exposed pipe, weld flanges on the cut ends and then install a flanged fitting tie in. Winds up with extra flanges but it's one way of doing it.

 

[Latexman]

Drain or blow back the diesel depending on the layout and elevations.
Circulate or flush with soapy water. Some folks use steam to clean the pipe.
Drain and treat the contaminated water according to local environmental requirements.
Purge with an inert gas until O2 is depleted sufficiently.
Suited up and with breathing air, cut the pipe.

This is just a brief summary. A complete, fully reviewed procedure considering Lock Out/Tag Out could be 10X as long.

Good luck,
Latexman

 

[unclesyd]

It would be nice to know the sizes involved as some of these approaches might have limitations.

All of the above is good advice. One approach not mentioned is cold cut and thread the pipe to use a threaded flange or flange and nipple.

I like to steam for at least 8 hrs if I use this approach.

Here are two approaches using plugs mentioned above.

The best is the EST Isolation Plug with the other being the bolt type medium pressure test plug.

http://estgroup.cwfc.com/productsServices/spokes/01a_HTplugs.htm

 

[kabron1]

Thanks!!! the pipe is 3" diameter and 30' long,there are 4 of them side by side. I am thiking water flush and cutting with a portaband. I was also thinking in lines of a detergent just didn't know what type and if I would harm anything down the line as far a the decompostion or contamination to the diesel but I am checking on that with the client to make sure they have some type of seperator or filter. All of the advise is useful, Thanks a bunch!!!The client requested no flanges, by the way, they want straight pipe i will probably have a tig weld and nitro purge just for insurance... will work right?

 

[unclesyd]

You might want to look at 3" socket weld coupling.

 

[Latexman]

At that scale use a cheap, non-corrosive surfactant, like a dishwashing liquid from a supermarket or WallyWorld. Just don't use too much or you'll have foam everywhere and it's take forever to rinse.

Good luck,
Latexman

 

[donf]

Another option is to use a Lokring(r) tee. Google Lokring.

Regards,

Donf

 

[BigInch]

3" 30 feet long. Wash with water, cut & weld.

**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[Latexman]

I would defer to BigInch on diesel. My advice is tainted by dealing with more hazardous chemicals.

Good luck,
Latexman

 

[BigInch]

I saw a stick of dynamite blow up a diesel tank and it just got everything wet. But ... don't try that at home.

**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[kabron1]

yeah, but the more ... the safer, in reality don't think I need a nitro purge but just to be onthe safer side and eliminate the what if's,Just as long as it doesn't get too extreme in either dirrection , Thank you guys! By the way keep the miners in your thoughts!!! bad thing

 

[11echo]

I worked in a small refinery where the major product was diesel. We would cold cut the lines and steam them out with low pressure steam for 24 hr.s before welding on them.

 

[nino55]

We did a similar job on bigger lines, using a cold cut. The drained diesel can be collected with pumps or a vactor truck. After that, you put a plug made of bentonite, so there is no gases at the welding point.
Then you can weld and flush with diesel.

 

[europipe]

donf, another star for you,
I'm not from that firm, but its works very good(lockrings)

 

[miningman]

Big inch, I thought I was the only one with experience using explosives in old fuel tanks. In my case, we detonated explosives inside old fuel tanks ( still with a couple of inches of fuel at the bottom, in an attempt to burn it off and hopefully blow the tanks wide open.

Diesel burnt off OK but the amount of tank deterioration was less than hoped for.

But as previosly stated, dont try this... especially in a built up area.... unless you know what your doing

 

[BigInch]

If it was up to us we wouldn't have done it, but operating a pipeline system in an area controlled by guerrillas tends to expose a few security issues from time to time. They were out there testing our pipeline integrity at least once a week using similar methods, not to mention our patience.

You can light up liquid diesel, but via the vapor alone, its not quite as easy as one might think.

**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch

http://virtualpipeline.spaces.live.com/