Specified Minimum Yield strength of the pipe

[Joli21]

What is the relationship between Specified Minimum Yield strength of the pipe and allowable stress value and which one must be considered in finding maximum allowable working pressure of the pipe?

 

[BigInch]

It depends on what code you are using. Some codes DEFINE an "allowable stress" for particular materials (often a percentage of SMYS combined with safety factors for pipe type, joint factors, etc.) and some codes CALCULATE allowable stresses based on class location design factors times the SMYS. Chemical plant codes tend towards the first method, because of homogenous characteristics found within a chemical plant, as opposed to design of a pipeline. Pipeline codes use the second method, since they cross many different areas where safety factors do not need to be held to one single value, temperatures not as high, tight piping not as common, etc.



**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Joli21]

Tnx for your useful information, in fact i am going to calculate Maximum safe working pressure for a peace of pipe(material is Incoloy alloy 825)I've got specified minimum yield strength and i don't know if i should put it on the formula or must multiply by a design factor?if so , what design factor should i apply to the minimum yield?

 

[BigInch]

Tell me the Design Code.[/]

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Joli21]

API and also i am not sure about formula P=(2*E*t*S)/(D-2*t*y)
do u know the same formula used for API ?

 

[BigInch]

There's hundreds of APIs.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Joli21]

I don't know the particular API, if i knew that i wouldn't ask here.

 

[SJones]

Then how can you perform the design? Would it be RP14E by any chance?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[Joli21]

Ok, let me tell you the story, there is a Test jig for for excavation purpose, it has 3 different pipe materials coupled together, nobody knows about the alloy , all we could measure are Wall thickness, Alloy types (PMI and Replication,hardness) and out side Diameter of pipes.
Now, i am going to Maximum allowable working pressure of each section. I want to know wich part of API can help me to do. and which formula? i couldn't findn any formula like ASME 31.3 in API.
please advise me.
tnx

 

[BigInch]

What do you mean by "test jig" for excavation purposes.

That dosn't sound like its a pipeline, refinery or power plant, so why are you looking for a "API" piping code to design excavation equipment?

Just because it might look like a pipe and have internal pressure does not mean you use a pipe design code. Pipe sections are sometimes used in structural design, but the structural engineers do not use a piping code.

Piping codes can have allowable stress up to 80% of yield strength. Excavation equipment components might be designed to only 25%-50% of yield stress.


**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Joli21]

tnx for reply,i found a API sign on one section of equipment that endorsed by inspection body. so other sections have different materials and no stamps. what formula usually use for calculating MAWP?

 

[BigInch]

I can't help you.
chao.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/