API 5L Minimum Temperature

http://www.engineeringtoolbox.com/astm-steel-pipes-pressure-temperature-d_742.html

That's for the process piping code (ASME B31.3).

Lol CR4 wasn't my first stop on the internet.

If you already know the answer, why are you asking the question pmsl?

I don't know the answer. If you read my post then you would know that I'm asking for the minimum temperature according to ASME B31.8.

These pipe codes take different things into account so each has different rules.

Look Cingold the minimun and the max temp (Or pressure). if defined by the process requirements. Then for, desing, Fabrication and Test/Testing you will go to corresponding the Codes.

I think you are going in the oposite secuence. WP

I'm not real sure what you're saying here, so I'll try not to overreact to what feels like a condescending tone.

I have to design to the pipeline code (it's a pipeline). My process temperature is Ambient in Louisiana...so around probably 0F to 120F.

My material is selected, API 5L, but I need to verify that this is the correct material for the application. And I need to verify that we are within the code limits.

Someone told me (the guys that make a pipe stress analysis program) that ASME B31.8 does not allow you to go below 32F with API 5L material. ASME B31.3, however, allows you to go down to -20F.

What I need to know: Is this code difference correct? If so, where can I find the minimum allowable temperature in ASME B31.8?

<...probably...>

Maximum applicable stresses in pipes vary with temperature, hence the pressure rating varies with both the temperature and the wall thickness across a range of diameters. So the correct approach is for the Process Engineer to define the pipe nominal diameter, the maximum and minimum temperatures and pressures to be encountered, and then leave the Piping Designer to sort out the correct solution from the information tabulated in the standard(s) as a next step.

• Is there a colleague nearby who could act as a mentor, perhaps? If not, why not?
• Is "second person sanity check before approval for construction" a part of the facility's established design procedures? If not, why not?

Yes probably!

I've lived in Louisiana long enough to have seen temperatures as low as 0F (maybe even a little lower) and as hot as 115F. If I wanted to get exact ambient design numbers, I could check an ASCE code, but that's getting off topic.

Regardless of the minimum ambient temperature being 0F or -5F, it's still below 32F which is a problem for me.

I know the stresses on metal change with temperature. However, we will not do a stress analysis on this because it doesn't need it, so these stress differences are irrelevant.

1. I don't need a mentor on this. I'm looking for code clarifications.

2. I am the second person check. I'm asking for the minimum permissible temperature.

Has anyone actually read the code ASME B31.8? Or are these just random bits of information?

ASME B31.8 Table 841.1.8-1 Temperature Derating Factor, T, for Steel Pipe

For 250F or less the temperature derating factor is 1!

That means that with a temperature change from 32F to -20F there will be no difference in the wall thickness. Since we are not doing a stress analysis, there will be no change to the system due to this temperature change.

What I'm asking for is: If I design my system with a minimum temperature of 0F with API 5L x52, is that permissible by ASME B31.8?

If this isn't permissble, then I'll need to add insulation and heat tracing to keep it at a minimum temperature of 32F and make it permissble.

Random for Louisiana, maybe yes.

It sounds as though the project is under-resourced. Hire a qualified Piping Designer, and delegate.

<unsubscribes>

The project is not under-resourced. CR4 just has a lack of informed people and an abundance of trolls.

You know what...forget it! I'm going to eng-tips. At least there's intelligent/informed discussions on that website.

I didn't realize that simply seeing a pipe or piece of metal qualified one as an "expert."

Next time someone asks for a code clarification, try picking up the code and reading it before providing input. Simply stating that metal stress changes with temperature or that a process engineer should select the operating temperatures is completely worthless to this discussion.

And by the way, there's 8 different ASME piping codes...not 1. It's called the ASME B31 series, not the ASME B31.3.

I was hoping for an intelligent and informed response to my question, but apparently that's not going to happen here.

Aren't you contradicting yourself? You are asking for a code clarification and seem to believe that somebody else has to read API5L for you.

Is what you ask of us not this what you needed to do in the first place?

Very irritating what you say here.

Anyway you are asking for a consultancy fee for this clearly commercial lucrative question of yours. Its neither News nor a Discussion as such!

If you want my (free) advice: Join the pipeline group in Linkedin. If for some reasons somebody is willing to give free professional help you better get your answers there.

PS What is a pipe?

PSPS I know where Louisiana is!

"PS What is a pipe?"

I'm glad you asked that!

1. All pipe is to be made of a long hole, surrounded by metal or plastic, centered around the hole.

2. All pipe is to be hollow throughout the entire length - do not use holes of different length than the pipe.

3. The ID (Inside Diameter) of all pipes must not exceed their OD (Outside Diameter) - otherwise the hole will be on the outside.

4. The pipe is supplied with nothing in the hole, so that water, steam or other stuff can be put inside at a later date.

5. All pipes is to be supplied without rust; this can be more readily applied at the job site.

NOTE: Some vendors are now able to supply pre-rusted pipes.
If available in your area, this product is recommended, as it will save a great deal of time at the job site.

6. All pipe over 150m in length should have the words "LONG PIPE" clearly painted on each side and end, so the contractor will know it's a long pipe.

7. Pipe over 3000m in length must also have the words "LONG PIPE" painted in the middle so the contractor will not have to walk the entire length of the pipe to determine whether it is a long or short pipe.

8. All pipes over 1.8m in diameter must have the words "LARGE PIPE" painted on it, so the contractor won't mistake it for a small pipe.

9. Flanges can be used on pipes. Flanges must have holes for bolts, quite separate from the big holes in the middle.

10. When ordering 90 or 30 degree elbows, be sure to specify left-hand or right-hand, otherwise you will end up going the wrong way.

11. Be sure to specify to your vendor whether you want level, uphill or downhill pipe. If you use downhill pipe for going uphill, the water will flow the wrong way.

12. All couplings should have either right-hand or left-hand threads, but do not mix the threads, otherwise, as the coupling is being screwed on to one pipe, it is being unscrewed from the other.

13. All pipes shorter than 3mm are very uneconomical in use, requiring many joints. They are generally known as washers.

14. Joints in pipes for water must be watertight.
Those pipes for compressed air, however, need only be airtight.

15. Lengths of pipes may be welded or soldered together.
This method is not recommended for concrete or earthenware pipes.

16. Other commodities are often confused with pipes. These include; Conduit, Tube, Tunnel, and Drain. Use only genuine pipes.

I hope these technical definitions help.

Yes and I knew you know the answer!

Yep, I posted the same question that I did here on eng-tips and I already have an informative answer with code references and background information.

This place is a waste of time and shouldn't be used if you actually want a well-informed answer.

Don't bother reporting this to an admin...I'm cancelling my subscription to CR4!

Cingold,

We have run into this discussion before. CR4 is plagued by folks who consider themselves Engineers. However, as you can see from the above comments, much of what you get is designer level thinking and a fundamental lack of understanding of the topic.

There are some legitimately smart folks on here, but more often then not, they are sleping when you ask a serious question.

If only we had something like an, "Engineer's Place for News and Discussion."

It would be cool if someone were to build a website like that.

-A-

BTW, if you still don't have an answer by this afternoon, I can do some digging for you.

Didn't unsubscribe fast enough...

Yea I got an answer for this. Check eng-tips. I can email you the actual link if you care to see it.

By the way, can I actually delete my profile here or do I just have to unsubscribe from everything?

I vote for deletion of your profile.

This is, "The Engineer's Place for News and Discussion". Not the "Code reference and interpretation place for those unschooled in their supposed occupation".

It's an anonymous forum. You get what you pay for.

"I didn't realize that simply seeing a pipe or piece of metal qualified one as an "expert." You have to actually touch it, or lick, it before being qualified as an expert. Get over yourself.

Goodbye

Do mean minimum temperature in service, or minimum temperature to perform welding on it? Your sources thus far may be referring to different things.

Click HERE and HERE for useful information!

The correlation between low temperature ( Low temperature due to environmental changes or Low temperature due to process fluid) and ferritic steel's properties are well documented in various materials science books.I don't think that ferritic steels are going to melt away in low temperature. Code may restrict the use of certain materials for low temperature application (Eg. White cast Iron ,I am not sure whether this material is restricted by code or not,However, I am sure this material cannot be used for low temperature application). Some ferritic materials can be used up to certain low temperature range without impact testing as per code.However, if you can prove the material's suitability beyond that range by Charpy 'V' notch impact testing or CTOD (Crack Tip Opening Displacement) test to evaluate the fracture toughness of the material,then code has no problem at all

If you read ASME B31.8 carefully, then you can find terms like Fracture toughness,Crack arrest etc.Just take the code book,hit 'ctrl+Shift+F' button, type the key words, the result will provide you extensive information.