Construction of pipelines, Pipe waste. 3

[hfpolo]

Engineers
Morning.


How much is pipe lost in the construccion of pipelines to estimate waste of pipe?

We are estimating 1.5 % for prefabrication and 1 % for pipeline construccion.

Thanks

hfpolo

 

[pennpiper]

hfpolo,
You need to give us more information, such as the length of the pipeline, the size of the pipe and the material.
- There is a big difference between 2.5% of 500 feet and 2.5% of 500 miles when considering the amount of stock needed for welder qualification, damage during installation, etc.
- There is a big difference between the potential for wastage between the short pipeline and the very long pipeline.
- There is a big difference in damage and pilferage depending on where the project is located.



prognosis: Lead or Lag

 

[zdas04]

It really depends on so many things. If I'm building a 50 mile pipeline I need something like 880 joints of pipe. I'll generally buy 885 (0.5% for waste, losses, and pilferage). If I'm doing a 500 ft lateral I need about 17 joints and I'll buy 20 (18%) which often gets me a different price. On cross country jobs there isn't much waste at all since you can generally move risers to the end of a pipe (or cut a joint and use both pieces on the tee).

Fabrications tend to be a bit fussier about lengths and stuff. I did a job last year to build 4 launchers/receivers. The throat section needed to be about 1/4 the length of a joint of pipe, more or less. So I called out 1/4 joint on the drawings. I had a great fabricator the took that to mean that he needed to cut the double random joint into 4 equal pieces--zero waste. By not being very fussy about things that don't matter, my waste on that project was much less than your 1%. I've worked for companies that act like they are building a precision instrument on pipeline fabrications and specified everything to the 1/8 inch, and had their inspector verify every measurement. Waste on those sorts of projects is probably closer to 5%.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[hfpolo]

Thank for reply.

I deliver more information about project:

Pipe of pipeline, 16 inches, sch - std carbon stell, 12 miles. In cross country

pipe of prefabricaction 16 inches, sch - std, carbon stell, 2.81 miles. in cluster.

what standard or rule of thumb should be applied?

hfpolo

 

[zdas04]

If your alignment sheet stations out to 63,336 ft (12 miles), I'd probably call it 64,000 ft (around 1%) of coated pipe.

For the fabrication you really have to ask how fussy you are going to be in the design. Are you going to pay welders to build up pups into useful lengths? How close are you going to hold the fabricator to his labor estimate (if you had doing this as hard dollar, then he's not going to want to waste time looking for the right length pup)? Is the fabricator going to acquire the materials as part of his bit? Are your dimensions exact or "more or less"? All of those things have a big impact on waste.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[dcasto]

here here zdas, street smart versus book smart.....

 

[bimr]

Here is an estimate from the SCPX (BP) Pipeline Project, a 450km cross-country pipeline through Azerbaijan.

The 48”-diameter pipeline will comprise line pipe formed of continuously welded, high-grade API 5L Grade X70 carbon steel with an outside diameter of 48 inches (1219mm) and a nominal 16.7mm wall thickness where the route crosses agricultural land.

The wall thickness of the pipe is determined by operating pressure considerations while applying the specified 0.72 design factor. In areas of particular environmental or social risk, where an increase safety factor applies, the wall thickness will increase from 16.7mm for a design factor of 0.72 to 20.1mm for a design factor of 0.6, and increasing up to a maximum of 24.1mm for a design factor of 0.5.

20 tonnes waste metal from construction is estimated.

http://www.bpgeorgia.ge/external/content/document/1339/2127282/1/05 Project description_web.pdf

Pipe weight 509.15kg/m. Total pipe weight = 450km * 509.15kg/m = 229,119 tonnes of pipe.

For this example, the amount of waste metal is nil, substantially less than .01%.

The answer to your question depends on the length of pipeline, diameter, contractor quality, weather, speed of project construction, availability of materials, project location, etc.

 

[LittleInch]

That's more or less my working - for pipelines under about 10km, go with a fixed number of spare pipes - 5 is about right. After that start at 1% and go to 0.5% above about 50km. As ever it is all risk - not enough and it costs a fortune to get it in a hurry, too much and you've got a lot of scrap metal on your hands. Equally welding lots of shorter pieces in line can end up costing more than the pipe - it's a fine balance.

Bimr - if you think the 20 tonnes is pipe I think you're incorrect. Extra pipe becomes "spare pipe" stored for future repairs and replacements, not "waste"....

zdas04 - I hate to be picky, but there's something wrong with your maths on the 50 mile pipe example - it's a lot more than 880 joints. My estimate is about 6400. I totally agree with the theory though

As for fabrications - harder to judge without seeing the total lengths and what lengths they are cut in - however you say pre-fabrication? do you mean river crossings etc? Should be no waste on those as you tie-into them when they're installed

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[zdas04]

Damn calculator. My old eyes can't see the decimal point so good any more. With 30 ft joints it is 8800. Good catch.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[LittleInch]

No problem - Do you buy 30 foot joints? Standard for me is 40 foot / 12m. A number of people now talk about 18m joints especially when you don't have to navigate small country roads

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Standard lengths are SRL, or DRL

SRL, single random lengths, 18' to 25', 5% of order can be supplied at 16-18' lengths seldom exceed 22'

DRL, double random lengths, usually 38'-40', but can go to 44'

Learn from the mistakes of others. You don't have time to make them all yourself.

 

[zdas04]

OK, I've been working with well tubulars too long. Need to get back to horizontal pipe.

David Simpson, PE
MuleShoe Engineering

Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat

 

[bimr]

LittleInch - I don't think there will be any "pipe" wasted. For the example used, the amount of waste metal on the construction project in comparison with the length of the pipeline is only 0.009%.