Why select Spiral Welded Linepipe?

Easy to manufacture and saving in manyfacturing / processing cost. This is the only advantage that comes to mind.

Thanks sb.

Good reply. Cheapness is usually the governing factor.

Stewie

As SB pointed out. It is less expensive.

milo

Hi Stewie,

here's a lift from a vendor's page:

"Spiral Pipe is smooth on the inside and is used successfully in conveying wood dust, paper trim, plastic trim, and air with particulate matter. Available in 3-inch to 42-inch diameter and five and ten foot lengths. Spiral Welded Pipe is considerably stronger than longitudinal pipe of the equivalent gauge. All 22 gauge Spiral Pipe measures 1/16" less than the noted diameter on the inside (I.D.). Example 6" diameter is 5-15/16" I.D."

this is why they are produced in shorter lengths (5 ft up to 12" in dia.) than longitudinally-welded pipes.

here's another one from GE.

other uses for such pipes are in:

• transmission mains,
• treatment plant piping,
• pump station piping,
• Power Plant Circulating Lines,
• Penstocks,
• Force Mains,
• Intakes and Outfalls,
• Aerial Crossings,
• Aqueducts,
• Trenchless Applications - HDD.

HTH!

Thanks Langyaw,

Great website too!!!

Stewie (Sharjah)

Instead of the Spiral Welded Linepipe is a cheaper, and even it recommended by such a code, I don't recommend to use it in transmitting any fluids, because of its higher risk due to leakage (especially with flammable fluids) expected from its long spiral weldment which will damage at long run. Only, I recommend that type of spiral welded pipes to be used in fabrication of columns used for lightning of public streets/roads and similar jobs for fences, ... etc.

Hi Abdel,

thanks for your kind comments. on the other hand, I believe users' inclination for other types of pipes was based on past experience with spiral pipes which were not acceptable.

GE has a comment on that, too:

"...The defects that occur in spiral welded pipe are mainly those associated with the SAW weld, and are similar in nature to those for longitudinally welded SAW pipe. An additional problem with early spiral welded pipe was poor dimensional accuracy, particularly out of roundness at the pipe ends. This led to problems of poor fit-up during field girth welding. Spiral linepipe gained a poor reputation in some companies as a result of these early experiences, and it was considered suitable only for low pressure applications such as water pipe. However, modern spiral linepipe from a premium quality supplier is of a quality equivalent to straight seam welded pipe, and it has been used extensively in Canada and Europe for high pressure gas pipelines in grades up to API X70."

in short, spiral pipes have, or should have better internal qualities, which is why they are used in conducting fluids, and do it more efficiently than others.

kind regards!

Thanks Abdel,

With the E value of 0.8 you immediately devalue the remaining WT by 25%.

My proposed use is for Gas and Oil on long distance Xcountry pipeline. I will take your recommendation as (obviously) the fluids are highly flammable.

TQ vm

Stewie

Dear Stewie,

That is right, and you are welcome.

well, now that you've stated the application (long-distance linepipe), OCTG ERW would be good for you.

but, then again, as Steamerst (post # 12) has pointed out, make sure the material grade used in this pipe is compatible with the medium.

If I remember correctly API 5L permits spiral welds for transporting Gas and Crude. In fact the spiral welds are being used for this purpose (maybe restriction are still there in some regions )

Thanks Sb,

Very good references too.

Stewie

I use spiral wound welded pipe for non critical and a few low pressure applications. Stuff like water, effluent, smoke stacks, air ducting and so on. I do this because it is cheaper and does just as good as other types.

I also use what is called mill grade stainless steel pipe for allot of low pressure systems where stainless is needed for corrosion prevention. Mill grade is basically rolled plate welded together to make a piece of pipe and does not have any particular finish as does the other grades so it is allot cheaper. The fittings and ells are made from rolling and welding pie sections together instead of forging from a single piece of pipe. The tees are made by welding a branch onto a header piece instead of forging. If you do not mind the extra seams and a little different appearance from piece to piece then mill grade is the way to go IMO.

Be careful the fluids you are considering are not sour (H2S). Spiral wound pipe has a much greater area of weld heat affected zone than seamless or ERW pipe due to the spiral length. The location of the seam cannot be controlled for bending of the pipe, so the HAZ will be located at the areas of highest stress concentration when forming bends. This is unlike seamless or ERW line pipe, where you can locate the seam on the lower stress side of the bend.

The heat affected zone is much more suseptical to corrosion pitting from even trace amounts of H2S, especially if fluid pockets can build up (at road, river crossings) in gas pipes or water pockets in oil lines. With the combination of pitting and seam located on the high stress side of a bend, spiral wound pipe has a nasty habit of exploding at bends. For this reason it is banned from sour service in my home province of Alberta, Canada.

Cheers,

Steamer Stan

Thanks Stan,

Very valid point for the bends.

Keep on Steamin'

Stewie

The "Big Rocky Express" pipeline, here in the states, is almost all spiral wound pipe, shipped over here from Germany.

Thank you pipeit, but why?????

As pointed out its cheaper.