HYDROSTATIC TEST PRESSURE FOR PIPING 2

[Dawoon]

I'm looking for the code about hydrostatic test pressure for piping. As I've found, the latest version is "ASME B31.3 PIPING GUIDE (2004)". And according to this code, the hydrostatic test pressure for piping is "1.5 x DESIGN PRESSURE x St/Sd".

But my team manager told me there's a new standard which hydrostatic test pressure for piping is "1.2 x DESIGN PRESSURE".

Have you ever heard about this latest standard?
I can't find about this anywhere.

I'll wait your kind answer, Thx~!

 

[Dawoon]

P.S : Pipings for the petroleum refinery.

 

[BigInch]

If its a B31.3 code refinery, you've already found out everything you need to know about test pressures.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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

 

[zdas04]

If the pipe is outside of a plant then look at B31.8.

David

 

[C2it]

You should be looking at the 2006 edition of B31.3. Don't worry, testing is the same in both.

 

[gerhardl]

'Someone' is always trying to do tests the simplest way, with lowest possible test criteria.

'Someone else' is always responsible for the the safety and risk of the total finished installation (including economical risk if anything goes wrong) and is also the decision maker for wich standards and test limits to utilize.

Advice: Try to identify 'someone else' and ask.

 

[Dawoon]

Thanks for everyone.

And I have one more question to zdas04.

I already read ASME B31.8 but it's about pressure vessels.

Not for pipings.

Isn't it?

Is there something I misunderstand?

 

[zdas04]

I've got it right here and the title is "Gas Transmission and Distribution Piping Systems" The copy I have is ASME B31.8-2003.

We've had many discussions over the years about whether Gas Gathering comes under B31.8 or under some other code. Section 802.11 (Scope) says "This Code covers the design, fabrication, installation, inspection, and testing of pipeline facilities used for the transportation of gas." Section 802.12 (exclusiong) (f) "Wellhead assemblies, including control valves, flow lines between wellhead and trap or separator ..." Which seems to imply that B31.8 covers upstream piping after the wellsite separator. The big question is what code applies between a wellhead and a separator? No one knows, but some companies say it is B31.3, some say "we've got to use something, so we'll apply B31.8 even though it is explicitly excluded". Bottom line is that you need to make a decision about design standards and document it.

David

 

[BigInch]

CFR 30 Part 250 ss 803 regulates flowlines when they fall under the control of the Department of Interior (Minerals Management Service, i.e. offshore GOM.

http://edocket.access.gpo.gov/cfr_2001/julqtr/pdf/30cfr250.803.pdf

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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

 

[SeanB]

Just as a lesson learned - don't hydrotest to the minimum, go to the max allowable at the flange rating. At our refinery in the newer units all piping was only tested to the minimum. Now, everytime we upgrade a pump impeller for more flow/head we end up having to re-hydrotest the entire pump circuit. It has become a major headache.

 

[StressGuy]

Just make sure all your components are capable of handling being tested to the flange rating. Not all components are, which is one reason "design pressure" isn't just set to the rating of the flanges in the class by default.

There's just no avoiding having to put some thought into decisions when there's oil, gas, steam, and chemicals involved.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[BigInch]

StressGuy, I have to take a little opposing view. Designing all components to flange rating is not an economic design concept (esp. for pipelines) no matter how convenient it can be for establishing uniform operation pressure rating and test pressures. Why design 1500 miles of pipe to 1460 psig, if you only need 750 psig? You can save millions by not doing that.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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

 

[zdas04]

I've got to agree with BigInch here--you design the system for the expected operating pressure plus some fudge factor. 3-inch Sched 40 pipe is rated for 1600 psi at 100F, does that mean that you always have to use ANSI 600 flanges? How about connecting two atmospheric tanks with 3-inch Sched 40 pipe? Can I use Victalic fittings or (since the pipe is good to 1600 psi) to I have to use ANSI 600 flanges?

I find that standardization is almost never worth much. I once built 8 miles of 20-inch with yard-sale pipe (6 different wall thickness and 4 different coating systems in 8 miles), and got gas flowing a year sooner than waiting for a mill run for half the cost. If I had been locked into a "standard" then we would have had to forgo the benefit ($60k/day) for a year. Every plant I've ever visited was built based on best available technology at the time the plant was designed--should industry forgo advances in technology for the sake of "standards"? I say that any business that does that (e.g., builds a gas plant based on 1900 technology in 2009) does not have a chance in hell of competing and should quietly just go out of business.

David

 

[BigInch]

Being that gas pipelines use different design factors through different area classifications and have many types of external loading and installation stresses thwart any effort to standardization on one internal pressure anyway. You can have up to 4 wall thicknesses on DF criteria alone on gas lines. Oil lines use one design factor, but still have different external load types. A few road/railroad crossings, fault crossings, landslide areas, river crossings, extra burial depth, aerial crossings(?), offshore platform risers with wave loads, different water depths and external pressures, installation stresses, etc. and you can see the number of wall thicknesses required to meet just one internal design pressure, with many different external load catagories and combinations, is many.

The BTC (1750 miles of 42") pipeline has 9 different wall thicknesses.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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

 

[Sachinkathe]

Yes what u have taken is correct one. St/Sd is generally one
As Hydrotest is generally room temperature only but chk this with ur boss may be he is suggesting you for difference in test temperature and design temperature.

Sachin

 

[StressGuy]

BigInch - actually, we are in agreement. At the company I work for, we usually resist a client urge to "test everything to the flange limit" for many of the reasons you indicate.

My warning was for SeanB - if you do intend to test a system to the flange rating, you'd better make sure all the components in the spec can handle it.

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

 

[BigInch]

Yes, reading more carefully, I now see that you wern't recommending to test to flange limits. Sorry, my mistake.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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

 

[BigInch]

I should have directed my comment to Sean as well. Whoops. Collateral damage.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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