MeasuringAPITubing,Casing&LinePipeCouplingswithPlug

Gages

PMCLoneStarTechnicalBriefDoc.103Rev.C

DavidR.MaischDirectorofEngineering&IndustrialAffairs

PMCLoneStarAugust7,2013

Itiscommontofindtwogagedesignsthroughouttheindustry.Oneisknownas“Shoulder

Design”,andoneisknownas“RemovableKeysDesign”.Bothdesignshavetheirbenefits,

andbothgetthejobdone,whichoneyouuseispurelyamatterofpreference.Bothdesigns

provideBasic,MinimumandMaximumscribelinesforvisualverificationofstandoff;

physicalmeasurementsmayalsobetakenwhennecessary.APISpecification5Bstatesthat

therequiredstandoffbetweenthepluggageandacouplingis:

8TPITubing&Casing=A±1P

10TPITubing=A±1‐1/2P

LinePipe(AllPitches)=A±1P

APISpecification5Bdefines“A”bythenumberofturns.Sinceeachturnis1P,wecanbreak

“A”downtoadecimalvaluethatismoreusefulwhengaging.Forexample,a4”‐8External

UpsetTubinghasan“A”valueof2Turns.Sinceeachturnis1P,and1Pfor8TPIis0.125”

(1/8),thedecimalequivalentof“A“is2x0.125”=0.250”.Sincethishasatoleranceof±1P,

weknowthatthestandofffora4”‐8ExternalUpsetTubingis0.250”±0.125”

Whengagingthecoupling,thepluggageshouldscrewintothecouplinguntilhandtight;at

thatpointthefaceofthecouplingmustfallinbetweentheMinimumandMaximumscribe

linesinordertopassasagoodpart.Ifrequired,adirectmeasurementcanalsobetaken.

Usingthe“ShoulderDesign”plug,thestandoffcanbemeasuredbetweenthefaceofthe

couplingandtheshoulder,thisdimensionshouldbe“A”withatoleranceof±1P(8TPI

TubingandCasingandAllLinePipe)or±1‐1/2P(10TPITubing).Usingthe“Removable

KeysDesign”,thestandoffcanbemeasuredfromthebackfaceofthepluggagetothefaceof

thecoupling.Whenusingthismethod,itisimportanttonotethedimensionscribedonto

thebackfaceofthepluggage“DistancefrombackfacetoV.P.”.Therequiredstandofffrom

thebackfaceofthepluggagetothefaceofthecouplingshouldbe“A”+“DistancefromBack

FacetoV.P.”withatoleranceof±1P(8TPITubingandCasingandAllLinePipe)or±1‐1/2P

(10TPITubing).

PMC Lone Star

Technical Brief

Non‐Upset Tubing  External‐Upset Tubing 

Size  Threads  Standoff  Standoff  Size  Threads  Standoff  Standoff Designation  per in.  Turns  Decimal  Designation  per in.  Turns  Decimal 

D  TPI  A (Turns)  A (Decimal)  D  TPI  A (Turns)  A (Decimal) 

1.050  10  2  0.2000  1.050  10  2  0.2000 1.315  10  2  0.2000  1.315  10  2  0.2000 1.660  10  2  0.2000  1.660  10  2  0.2000 1.900  10  2  0.2000  1.900  10  2  0.2000 2‐3/8  10  2  0.2000  2‐3/8  8  2  0.2500 2‐7/8  10  2  0.2000  2‐7/8  8  2  0.2500 3‐1/2  10  2  0.2000  3‐1/2  8  2  0.2500 4  8  2  0.2500  4  8  2  0.2500 

4‐1/2  8  2  0.2500  4‐1/2  8  2  0.2500 

Casing  Line Pipe 

Size  Threads  Standoff  Standoff  Size  Threads  Standoff  Standoff Designation  per in.  Turns  Decimal  Designation  per in.  Turns  Decimal 

D  TPI  A (Turns)  A (Decimal)  D  TPI  A (Turns)  A (Decimal) 

4‐1/2  8  3  0.3750  1/8  27  3  0.1111 5  8  3  0.3750  1/4  18  3  0.1667 

5‐1/2  8  3  0.3750  3/8  18  3  0.1667 6‐5/8  8  3  0.3750  1/2  14  3  0.2143 7  8  3  0.3750  3/4  14  3  0.2143 

7‐5/8  8  3.5  0.4375  1  11.5  3  0.2609 8‐5/8  8  3.5  0.4375  1‐1/4  11.5  3  0.2609 9‐5/8  8  3.5  0.4375  1‐1/2  11.5  3  0.2609 10‐3/4  8  3.5  0.4375  2  11.5  3  0.2609 11‐3/4  8  3.5  0.4375  2‐1/2  8  2  0.2500 13‐3/8  8  3.5  0.4375  3  8  2  0.2500 16  8  3.5  0.4375  3‐1/2  8  2  0.2500 

18‐5/8  8  3.5  0.4375  4  8  2  0.2500 20  8  3.5  0.4375  5  8  2  0.2500 

6  8  2  0.2500 8  8  2  0.2500 10  8  2  0.2500 12  8  2  0.2500 14  8  2  0.2500 16  8  2  0.2500 18  8  2  0.2500 20  8  2  0.2500 

PMC Lone Star

Technical Brief

Note:requirusingSisthworkthega

StandoffinforresthatstandtheformulaAherequiredstaplugtomasteagestandoffin

rmationproviofftothecoupA+(S1–S).Thandofflistedfoerring.Whennordertomai

dedisbasedoplingiscalculahesevaluescaortheworkpavailable,thentaincomplia

onnominalcoatedusingactanbelocatedolugtomastersevaluesshouancetoAPI5B

onditionandistualsizeofwoonthecertificaring,andS1isuldbeusedinB.

sforreferenceorkingandmaationreceivedstheactualstanordertoprop

eonly.API5Bastergages;dforeachgagandofffortheperlyadjust

B

e,

PMC Lone Star

Technical Brief

Note:requirusingSisthworkthega

StandoffinforresthatstandtheformulaAherequiredstaplugtomasteagestandoffin

rmationproviofftothecoupA+(S1–S).Thandofflistedfoerring.Whennordertomai

dedisbasedoplingiscalculahesevaluescaortheworkpavailable,thentaincomplia

onnominalcoatedusingactanbelocatedolugtomastersevaluesshouancetoAPI5B

onditionandistualsizeofwoonthecertificaring,andS1isuldbeusedinB.

sforreferenceorkingandmaationreceivedstheactualstanordertoprop

eonly.API5Bastergages;dforeachgagandofffortheperlyadjust

B

e,

PMC Lone Star

Technical Brief

Note:requirusingSisthworkthega

StandoffinforresthatstandtheformulaAherequiredstaplugtomasteagestandoffin

rmationproviofftothecoupA+(S1–S).Thandofflistedfoerring.Whennordertomai

dedisbasedoplingiscalculahesevaluescaortheworkpavailable,thentaincomplia

onnominalcoatedusingactanbelocatedolugtomastersevaluesshouancetoAPI5B

onditionandistualsizeofwoonthecertificaring,andS1isuldbeusedinB.

sforreferenceorkingandmaationreceivedstheactualstanordertoprop

eonly.API5Bastergages;dforeachgagandofffortheperlyadjust

B

e,

PMC Lone Star

Technical Brief