API Tension and Burst - Work

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Tubular Tension and Burst Strengths, release 5, issued 6 March 2008. Work version.

This worksheet exists in two versions. They are identical apart from the way they are formatted. The Work version hides intermediate calculations and allows the user to see the results just below the inputs. This is useful for quick “what-if” games, changing various inputs to see what works best. The JIT version displays all intermediate calculations, plus adds tutorial text to explain the methodology.


This worksheet takes a set of inputs to calculate the burst and tensile strengths of a tubular. It uses the formulae defined in the referenced documents to calculate the tubing design parameters and will account for the effects of temperature, internal pressure and tension.

API monogrammed pipe is manufactured to tolerances specified in API Specification 5CT. The tolerance for wall thickness t is wide – the actual wall thickness can be 12.5% less than the nominal size and still be within API limits. Modern steel mills are capable of making tubings to much less than this tolerance and what usually happens in practice is that the tube is manufactured to use the least amount of steel, to maximise profit. The effects of these tolerances are documented in the JIT version of this worksheet.

User input


4.5″  9.5 ppf4.5″  10.5 ppf4.5″  11.6 ppf4.5″  13.5 ppf4.5″  15.1 ppf5″  11.5 ppf5″  13 ppf5″  15 ppf5″  18 ppf5″  21.4 ppf5″  23.2 ppf5″  24.1 ppf5.5″  14 ppf5.5″  15.5 ppf5.5″  17 ppf5.5″  20 ppf5.5″  23 ppf5.5″  26.8 ppf5.5″  29.7 ppf5.5″  32.6 ppf5.5″  35.3 ppf5.5″  38 ppf5.5″  40.5 ppf5.5″  43.1 ppf6.625″  20 ppf6.625″  24 ppf6.625″  28 ppf6.625″  32 ppf7″  17 ppf7″  20 ppf7″  23 ppf7″  26 ppf7″  29 ppf7″  32 ppf7″  35 ppf7″  38 ppf7″  42.7 ppf7″  46.4 ppf7″  50.1 ppf7″  53.6 ppf7″  57.1 ppf7.625″  24 ppf7.625″  26.4 ppf7.625″  29.7 ppf7.625″  33.7 ppf7.625″  39 ppf7.625″  42.8 ppf7.625″  45.3 ppf7.625″  47.1 ppf7.625″  51.2 ppf7.625″  55.3 ppf7.75″  46.1 ppf8.625″  24 ppf8.625″  28 ppf8.625″  32 ppf8.625″  36 ppf8.625″  40 ppf8.625″  49 ppf9.625″  32 ppf9.625″  36 ppf9.625″  40 ppf9.625″  43.5 ppf9.625″  47 ppf9.625″  53.5 ppf9.625″  58.4 ppf9.625″  59.4 ppf9.625″  64.9 ppf9.625″  70.3 ppf9.625″  75.6 ppf10.75″  32.75 ppf10.75″  40.5 ppf10.75″  45.5 ppf10.75″  51 ppf10.75″  55.5 ppf10.75″  60.7 ppf10.75″  65.7 ppf10.75″  73.2 ppf10.75″  79.2 ppf10.75″  85.3 ppf11.75″  42 ppf11.75″  47 ppf11.75″  54 ppf11.75″  60 ppf11.75″  65 ppf11.75″  71 ppf13.375″  48 ppf13.375″  54.5 ppf13.375″  61 ppf13.375″  68 ppf13.375″  72 ppf16″  65 ppf16″  75 ppf16″  84 ppf16″  109 ppf18.625″  87.5 ppf20″  94 ppf20″  106.5 ppf20″  133 ppf

Select a casing





Enter the temperature at the depth of interest. Temp =



Enter the number part of the steel grade eg for L80, enter 80 (units are kpsi). Gr =



Enter the design factor for burst. DFb =



Enter the design factor for tension. DFt =


Click here when any values are modified to update the result.


Maximum possible pipe OD within API tolerances

Minimum possible pipe OD within API tolerances

API nominal wall thickness

Minimum possible wall thickness within API tolerances

API nominal ID

ID for minimum CSA within API tolerances

API Drift Dia

Nominal cross sectional area

Temperature Correction Factor

API Minimum Yield Strength, nominal, ambient

API Minimum Yield Strength, with TCF and DF

Pipe body API Minimum Internal Yield, ambient

Pipe body API Minimum Internal Yield, with TCF and DF


Worksheet references

API Specification 5CT, 5th Edition, April 1 1995 “Specification for Casing and Tubing (U.S. Customary Units)”.

API Bulletin 5C3, 6th Edition, October 1 1994 “Bulletin on Formulas and Calculations for Casing, Tubing, Drill Pipe, and Line Pipe Properties”, also ISO/TR10400:2007 which is expected to replace API 5C3 during 2008.

API Bulletin 5C2, 21st Edition, October 1999 “Bulletin on Performance Properties of Casing, Tubing and Drill Pipe”.

Formulae for Temperature Correction Factor taken from the Exxon Casing Design Manual.

SG of steel from http://www.simetric.co.uk/si_metals.htm taken as 7.85.

Version 1 of this worksheet released on 11 January 2008.

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