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pig launcher
5

pig launcher

pig launcher

(OP)
we build a tank farm (API 650)with on- and off shore pipeline with pig launcher / receiver. Code for CH-transportation systems is 31.4 and it is written that 31.4 cannot be used for pressure vessels (chapter I, 400.1.2b. My understanding is a pig launcher is a pressure vessel (manufacturing acc. to ASME VIII-I but what about the design and materials (ASME VIII / II)? I want avoid of mixing up standards. Our pig launcher(shell) is made of X42.
Thanks

RE: pig launcher

Why do you think that a pig launcher is an ASME Code vessel?  I've built dozens and every one has met the definition of a "pipeline accessory" in B31.8 (Gas transmission).

David

RE: pig launcher

(OP)
Hi David,
thanks for clarification. In our client's spec is written "manufactured acc to ASME VIII, that's I wasn't sure about the applic. standards. Indeed in 31.4 chapter V and VI (construction, assembly, welding / testing), so why ASME VIII? Thanks

RE: pig launcher

hkjoe

Typically pig launchers are designed to B31.8 or 31.4.  You need to look at where the spec break is, again, typically it is at the side valve going into the facility.  That will determine where the "plant" piping spec will take over.  

In any case I have never seen a pig trap designed to ASME VIII.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: www.oil-gas-consulting.com

RE: pig launcher

We had some ASME coded pig launchers which were a pain to maintain seperately from the B31.8 lines.  They had to have their own PSV's because we didn't use PSV's on the pipeline. Those PSV's had to be test twice per year because the line was DOT jurisdictional.

Stay with B31.8.

RE: pig launcher

Greg,
Frequently the pipeline code covers the pig traps, but the traps are designed to ASME vessel code.
Cheers,
Shiv

RE: pig launcher

c1defence,
Where and in what industry?  In Oil & Gas, and pretty much around the world every operation I've looked at has called them pipeline accessories.  I've only seen PSV's on about 3 launchers, and never seen a code stamp on one.

David

RE: pig launcher

zdas04

Re PSV's what about PSV for fie protection? I have mostly seen pig launcers/traps on off-shore platforms and here they tend to include PSV (and deluge). Yes they will be part of the pipelien but you could put a PSV on it anyway couldnt you?

Best regards

Morten

RE: pig launcher

For reference: The North sea - danish section.

Best regards

Morten

RE: pig launcher

It's probably because owners specify that the end closures have to comply with ASME VIII and it just gets extended (erroneously) to cover the whole trap.

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/

RE: pig launcher

But Steve

On a platform the pig trap may very well be in a fire zone. Just because its allowed by code not to - wouldnt it still be a good idear to install a PSV for fire protection?

Best egards

Morten

RE: pig launcher

Morten,
That is an operational decision on gas pipelines.  I specify (in operting proceedures) that idle launchers and receivers are always in connection with the pipeline (by keeping the kicker/bypass open).  I used to specify that they be isolated and a vent left open until I had a vent line freeze (small leak-through in the barrel-isolation valve, candle-wax freeze in the vent pipe followed by a pressurized barrel that we thought was vented, really scary), now I call for the barrel to be left pressurized and ask people to pay attention to how long it takes to blowdown.

I think that I would put a thermal relief on a pig trap in a liquids line because of the pesky 100psi/degreeF pressure response to temperature.  But I just don't do much with liquids lines.

David

RE: pig launcher

But couldnt you scenari be that there is a fire - and somebody by mistake left the isolation valve closed?

Best regards

Morten

RE: pig launcher

Morten,

PRVs absolutely agree with you - put them on when deemed necessary.  I was theorising about why ASME VIII gets applied to pig traps in response to David's posts and your two posts beat me to it!

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/

RE: pig launcher

The way I design traps, if the kicker/bypass is open then the trap can't become liquid full.  If you do the Thermal Expansion calcs on a trap that is half full of liquid and half full of gas, you'll find that the metal will flow from the temperature in a pooliing-liquid fire before pressure will increase enough to overpressure the trap.  That would not be true on a liquid-full trap.  The important scenario is to make certain that there is no credible way for the trap to become liquid-full.  

If you can come up with a credible scenario that results in a trap being isolated liquid full then you have to have a PSV (probably sized for thermal)

David

RE: pig launcher

Our traps had ASME code stamps on them.  These were in the US, BUT, the design standards were a combination or US, British, and Belgium companies.  

The contractual settlement between the 3 owners were that the most stringent design standards, as put together by the general contractor,  would be used.  We ended up with quite a pipeline.  We had 48 volt controls, no threaded fittings, flanged thermalwells, In station piping had ESDV every 25,000 pounds.

RE: pig launcher

Just a little update - DNV OS-F101 calls pig traps 'pressure vessels' and requires them to be designed in accordance with ASME VIII or PD5500

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/

RE: pig launcher

Steve,
It's interesting that Det Norske Veritas has changed the the status of two of the pipeliner's sacred cows--pig traps and slug catchers for submarine pipelines (http://exchange.dnv.com/OGPI/OffshorePubs/ViewArea/OS-F101.pdf).

I've never known if DNV standards had the force of law anywhere or if their standards were more around ISO certifications.  Do you know?

David  

David Simpson, PE
MuleShoe Engineering
www.muleshoe-eng.com
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.

The harder I work, the luckier I seem

RE: pig launcher

As far as I know OS-F101 is used in the north sea by many companies- but if its a law I don't know.

My company Ramboll designs a lot of pipelines in the Danish and Norwegian sector of the north sea and as far as I know they follow OS-F101.

Maybe that's why I have only seen traps with PSV's?

Best regards

Morten

RE: pig launcher

Steve Jones is correct.
I checked what we designed a few years ago for onshore pipelines.
The data sheet says: Scraper Design Code, (To be suitable for Scraper and Intelligent Tooling.): ASME B31.8 with a design factor of 0.6 for all aspects of the launcher/ receiver design except quick opening closure which shall be to ASME VIII, Div 1,
The spec states: The code ASME B31.8 / B31.4 for an ASME Class 600 / 900 pressure rating shall be used for all aspects of the VENDOR’S design of the launchers / receivers except for the quick opening
end closure which shall be designed to ASME Section VIII,
Division I.
For offshore an operator states: The end closure shall conform to the general requirements of ASME VIII, Division 1, Section.
Typical sizes for the major barrel (limited to common
standard ISO 3183-1 pipe sizes)
A thermal relief valve shall be installed where shut-in pressure of trapped fluid could exceed the design pressure as a result of thermal expansion of the static fluid.

RE: pig launcher

Shiv's got it right as far as I'm concerned.

http://virtualpipeline.spaces.msn.com

"We can't solve problems by using the same kind of thinking we used when we created them." -Albert Einstein

RE: pig launcher

(OP)
I would say the DNV “Standard” is more a guideline or might be a local standard only.
It is not clear that this is an internationally recognised standard because if you see an official EN, you always find a foreword of CEN (European Committee of Standardization) similar in ASME codes. However the problem is the pig launcher and my interpretation is:
The quick opening/closure shall be in accordance to ASME VIII. The rest could be designed acc. to B 31.4 (our case, we have A1 – aviation fuel). If you have a mix of standards you have to make sure that design – operation – and test data in compliance with the strictest code. Of course it will have cost impacts, if you design and manufacture the whole pig launcher acc. ASMW VIII. So, it’s a question of interpretation and what the client / operator really want. It always shall be the cheapest solution but is this always the best solution?
Joerg

RE: pig launcher

DNV OS-F101 is an industry standard as opposed to an international standard (ISO/IEC/IMO), a regional standard (EN), or a national standard ( such as BS, DIN, ANSI etc). Since it is an industry standard that puts it on the same playing field as API, for example.  How it is used is, of course, a matter between the pipeline owner and any regulatory authority with jurisdiction over the pipeline.  I do know that DNV is big in Australia if you'll excuse the terminology.

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/

RE: pig launcher

(OP)
Steve, thanks for your answer and indeed DNV is not recognised here (Asia-Pacific region)I prefer the "well known" standards like ASME, API, ANSI, JIS or EN standards.
All these standards issued by DNV, TUV, ABS, etc. are creating sometimes more confusion instead to be helpful.

RE: pig launcher

DNV is a private organization, of which one of their divisions is engaged in hazard evaluations and sufficiency ratings.  Their standards simply define their requirements.  Some owners of facilities ask for design to DNV standards for insurance purposes.

http://virtualpipeline.spaces.msn.com

"We can't solve problems by using the same kind of thinking we used when we created them." -Albert Einstein

RE: pig launcher

We're now diverging from the original query, and this could be a new topic.  Codes and standards.
My observation is that it is the country law/regulation that determines which code or standard to be followed.
In US it is really Code of Federal regulations, which are similar to ASME.  In other western countries, ISO/EN maybe the regulatory(?) codes usually, replacing BS/DIN,etc.
In Saudi Arabia there is HCIS(?).  Norway offshore may well use DNV and Norsok.
[The NORSOK standards are developed by the Norwegian petroleum industry as a part of the NORSOK initiative and are jointly issued by OLF (The Norwegian Oil Industry Association) and TBL (Federation of Norwegian Engineering Industries). NORSOK standards are administered by NTS (Norwegian Technology Standards Institution).]
Where countries do no have any national codes, or perhaps even a regulatory code, it may be stated that the system shall be in accordance with an approved recognised standard.  The oil companies/operators then specify their preferred standard.
In Nigeria, XOM use ASME for example.
In Qatar, QP joint venture with Shell/CoP specify DNV. Shell (the Netherlands) still specify ASME VIII for the trap door.  There are probably Euro standards equivalent to ASME VIII, but this is one of the more internationally known codes.
And the Russians have GOST, VSN, SN and SNIP!

RE: pig launcher

Quote:

hkjoe (Petroleum) 30 Jan 08 21:05  
we build a tank farm (API 650)with on- and off shore pipeline with pig launcher / receiver. Code for CH-transportation systems is 31.4 and it is written that 31.4 cannot be used for pressure vessels (chapter I, 400.1.2b. My understanding is a pig launcher is a pressure vessel (manufacturing acc. to ASME VIII-I but what about the design and materials (ASME VIII / II)? I want avoid of mixing up standards. Our pig launcher(shell) is made of X42.

hkjoe,
A pig launcher is basically a pipeline component. It can be designed to ASME B31.4 or to ASME Section VIII, Division 1.

If you want to use X42 for the shell, it should be designed in accordance to ASME B31.4. But if your Client wants the pig launcher designed and manufactured in accordance to ASME VIII-1, then the material should be among those covered in ASME Section II. (Note that API 5L Grade X42 is not one of them.) If the pig launcher meets all the requirements of ASME VIII-1, it MAY be stamped with the Code U Symbol. If stamped with a Code U Symbol, then it is mandatory to provide PSV's that are also stamped (Code UV).
The bottomline is that you will end up with an expensive piece of pipeline component if you design it to ASME VIII-1.

RE: pig launcher

hkhoe,

I suggest you clarify everything with your client. Your client has the final say on this matter. They are the ones paying for that pig launcher, and if your client is also the owner, then they are also the ones responsible for that pig launcher.

RE: pig launcher

we are building some right now to go offshore in Brazil

All is considered pipe except quick opening closure is ASME Design with Keyed Interlock to prevent opening while under pressure.

RE: pig launcher

Quoting 15 year old Shell standards that the Iranians should not be putting on the web is probably not the best way of enforcing a point.

Steve Jones
Materials & Corrosion Engineer
http://www.pdo.co.om/pdoweb/

RE: pig launcher

(OP)
Thanks guys for the last info (sorry was abroad for a time) exactly here is the point: As I explained to the client ASMME II (material, X 42 not covered, etc.) U-stamp when designed acc. to ASME VIII, etc. - no clue. what you said: the barrel 31.4 and only the pig launcher closure (door) acc to ASME VIII guess it's the best way. Thanks!

RE: pig launcher

Although I have seen designs both ways, the most common is to use the pipeline code.  The pressure vessel code is a pain in the neck when used to size the minor barrel wall thickness, as ASME VIII reequires thicker walls than the pipeline codes, creating a mismatch.

RE: pig launcher

Currently, under Alberta (Canadian code), we are required to construct the receiver/sender under the applicable pipeline code CSA Z662.  However, the closure is expected to be ASME certified with a CRN registration #.  hkjoe - you're on the right track.

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