Single random length and double random length 1

[Moh.Ibra]

Can anyone please explain the following paragraph related to SRL & DRL OF ASTM A106 pipes:

If definite lengths are not required, pipe may be ordered in single random lengths of 16 to 22 ft [4.8 to 6.7 m] with 5 % 12 to 16 ft [3.7 to 4.8 m], or in double random lengths with a minimum average of 35 ft [10.7 m] and a minimum length of 22 ft [6.7 m] with 5 % 16 to 22 ft [4.8 to 6.7 m].

 

[canadapipe]

Pipe from the mills is often ordered in pre-determined lengths

SRL - Single Random Length ~6m
DRL - Double Random Length ~12m
RTL - Triple Random Length ~18m
QRL - Qaud Random Length ~24m

Basically the option as to which to have supplied or purchase is down to the end use, on very long pipeline projects TRLs and QRL are quite common as you get more installed pipe per weld but there are additional handling requirements.

For fabrication work SRLs may be more advantageous as the fab shop may not be able to move long joints around before cutting to length.

The use and selection is typically dependent on project requirements

 

[racookpe1978]

I assume also that the individual pipe lengths will be within 5% of the "expected" lengths.

Though that's a very, very broad potential "loss" if you're ordering a lot of pipe. 8 inches short in a 12 foot length of pipe is just over 5%.

 

[LittleInch]

This is the base definition of random lengths which as you might expect are, well, random

Single random lengths as described need to be mainly between 16 to 22 feet and no more than 5% of the total between 12 and 16 feet.

Double randoms need to be an average length greater than 35 feet and no shorter than 22 feet. That last sentence doesn't seem to make sense.

Normally people make the smallest length much closer to the average in their spec so something like average length of no less than 5.5m , min 5m max 7 or something like that.

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

 

[miningman]

In my experience, there is no potential "loss" due to reduced pipe lengths. I've often encountered pipes that exceeded the nominal 20 foot length by 6 , 8 or 10 inches. Plus . I suspect we are invoiced as per the total delivered length. A few 12 foot lengths seem to occur occasionally and my procurement people had no concerns.

 

[pennpiper]

Moh.Ibra,
The answer to your original question, "If definite lengths are not required, pipe may be ordered in single random lengths or in double random lengths" is Cost.

(A) - a pipe mill can be set up to spit out all pipe to a specific consistent length.
(B) - a pipe Mill can be set to spit out all (Standard) single or double random lengths

Option "A" will be more costly than option "B"

What would be your choice?

Sometimes its possible to do all the right things and still get bad results

 

[LittleInch]

but if the pipes are shorter than you expect there's a lot more welding to be done....

And sometimes if they are longer they stick out the end of the trailer. Especially if you transport via container then they can't be longer than the inside of the container.

Most specs I see say something like average 12.2m and no more than 0.5m plus or minus.

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

 

[EdStainless]

Your words are straight from A106.
It is straightforward, if you order SLR you will get pipe ranging in length from 12' to 22', with only 5% of the total (footage or weight) in the range of 12'-16'.
With DLRs it allows much more variation. The inferred max length is 44' even though it does not say that. We would aim to make 42' in our mill usually, but you will see pieces as short as 16' in the lot.

We do see a lot of special requirements.
It is common to see customer requirements with SRL as 20'-22', or if it is going into a container then 16'-19.5'. Most customer do not want anything shorter than 16'.
With longer lengths what we see from customers is all over the place. People often use a 40' or 42' max length to facilitate shipping. It is also common to see 22' min length required.
Anything more restrictive than A106 will incur additional costs, but modest restrictions only have a small premium.
When ordered as cut lengths the tol is +0.25"/-0.0" per A530 (the general spec).

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P.E. Metallurgy, Plymouth Tube