pipe thickness in metallic buried piping 1

[energeng]

Hello all,

I would like to know if there is some restricction to select the minimun wall tickness in metallic buried pipes?
In the european code EN-13480, the part 6 (Requirements for buried piping) there is a table with the following restricctions for the wall thickness:

DN Mininum Thick.
mm
DN <=80 3,2
80<DN<=150 4,7
150<DN<=450 6,35
450<DN<=600 7,9
600<DN<=950 9,5

I would like to know if can I use less thickness than shown in the table. Could anyone let me know if in others codes exist a restrictions like that?

Thanks you in advance.

 

[Frank1344]

Hi,

Canadian Code CSA-Z662 does have a similar minimum thicknesses.

 

[BigInch]

D/wt is often limited to around 100 to help ensure that you can handle it without kid gloves and get it into the ground without too dinging it up too much.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[energeng]

BigInch,

What do you mean when you said "limited to around 100"? 100?

Thanks in advance.

 

[TD2K]

Big Inch's "limited to 100" refers to the diameter divided by the wall thickness. For example, 6" sch 40 pipe has a ratio of about 24. Take std wall 36" pipe and the ratio is 96.

 

[EnergyMix]

Is there a reason you want to go with something less than the standard? In my opinion, that will just lead to problems. Hard to justify up front, and if there ever is a failure, your neck is on the chopping block.

 

[BigInch]

There are quite a number of walls that are less than "standard" wall thicknesses, ie. sch40 in most cases, and using them is quite alright as long as the pressure and stress levels remain lower than allowables and you don't need a corrosion allowance.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[energeng]

EnergyMix,

The reason is that the pipe is stainless steel (each mm of material increase the cost) and the fluid is not dangerous. This is the reason because I would like to select less thickness.

 

[BigInch]

As long as the stress is OK and the pipe is not damaged during handling and installation, we would suppose that you can do it. Only you can ensure that.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[stanier]

Burying stainless steel is likely to give you pitting corrosion problems donw the track. Are you wrapping the ss ?

The pipe has to be designed for external and soil loadings. many culverts are built wihtt a very ow wall thickness as the loads are carried by the soil.

To design a thin wall buried pipe you need to investigate, stress, strain, deflection, strain, buckling and combined loading. Check out AS 2566

Books inlude Buried Pipelines Moser
Structural Design Of Buried Pipelines Watkins

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