ISO 10400:1993
(Main)Petroleum and natural gas industries — Formulae and calculation for casing, tubing, drill pipe and line pipe properties
Petroleum and natural gas industries — Formulae and calculation for casing, tubing, drill pipe and line pipe properties
Establishes the formulae. Requirements are specified in the fifth edition of API BULLETIN 5C3 (Bul 5C3), Juli 1989, which is adopted as ISO 10400. For the purposes of international standardization, modifications have been made that are outlined.
Industries du pétrole et du gaz naturel — Formules et calculs relatifs aux propriétés des cuvelage, tubes de production, tiges de forage et tubes de conduites
General Information
Relations
Standards Content (Sample)
INTERNATIONAL IS0
STANDARD
10400
First edition
1993l 2l 5
Petroleum and natural gas industries 
Formulae and calculation for casing,
tubing, drill pipe and line pipe properties
Industries du p&role et du gaz na turel  Formules et calculs rela tifs aux
propriMs des cuvelages, tubes de production, tiges de forage et tubes
de conduites
Reference number
IS0 10400:1993(E)
 Page: 1 
IS0 10400:1993(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be re
presented on that committee. International organizations, governmental
and nongovernmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 10400 was prepared by the American Petro
leum Institute (API) (as Bul 5C3, 5th edition) and was adopted, under a
by Technical Committee ISO/TC 67, Mate
special “fasttrack procedure”,
rials, equipment and offshore structures for petroleum and natural gas in
dustries, in parallel with its approval by the IS0 member bodies.
63 IS0 1993
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH1211 Geneve 20 l Switzerland
Printed in Switzerland
II
 Page: 2 
0 IS0
IS0 10400:1993(E)
Introduction
International Standard IS0 10400:1993 reproduces the content of
API Bul 5C3, 5th edition, 1989. ISO, in endorsing this API document, re
cognizes that in certain respects the latter does not comply with all current
IS0 rules on the presentation and content of an International Standard.
Therefore, the relevant technical body, within lSO/TC 67, will review
IS0 10400:1993 and reissue it, when practicable, in a form complying with
the IS0 directives.
This standard is not intended to obviate the need for sound engineering
judgement as to when and where this standard should be utilized and
users of this standard should be aware thad additional or differing re
quirements may be needed to meet the needs for the particular service
intended.
Standards referenced herein may be replaced by other international or
national standards that can be shown to meet or exceed the requirements
of the referenced standards.
. . .
III
 Page: 3 
This page intentionally Jeff blank
 Page: 4 
INTERNATIONAL STANDARD 0 IS0 IS0 10400:1993(E)
Petroleum and natural gas industries  Formulae and
calculation for casing, tubing, drill pipe and line pipe
properties
1 Scope
This International Standard establishes the formulae used in the calculation of the various casing, tubing, drill pipe
and line pipe properties for the oil and natural gas industries.
2 Requirements
Requirements are specified in
“API BULLETIN 5C3 (Bul 5C3), Fifth Edition, July 1989  Bulletin on Formulas and Calculations for Casing,
Tubing, Drill Pipe, and Line Pipe Properties”,
which is adopted as IS0 10400.
For the purposes of international standardization, however, modifications shall apply to specific clauses and para
graphs of publication API Bul 5C3. These modifications are outlined below.
Throughout publication API Bul 5C3, the conversion of English units shall be made in accordance wtih IS0 31. The
content of section 11, Metrication shall read as given below.
Page 8
Information given in the POLICY is relevant to the API publication only.
1
 Page: 5 
IS0 10400:1993(E)
METRICATION
METRIC CONVERSIONS AND CALCULATIONS
Metric units in API Bul5C3 are shown in italic type and in the text and most tables in parentheses. Outside diam
eters and wall thicknesses are converted from inch dimensions. The converted values are rounded to the nearest
0,l mm for diameters less than 18 in, and to the nearest I,0 mm for diameters 18 in and larger. Wall thicknesses
are rounded to the nearest 0,l mm.
Metric inside diameters and drift diameters are calculated from the metric outside diameters and wall thicknesses
and rounded to the nearest 0,lmm.
Metric plainend masses are calculated from the metric outside diameters and wall thicknesses by the following
formula and rounded to the nearest 0,Ol kg/m.
W pe = 0,024 66(D  t)t
Metric hydrostatic test pressures are calculated from the metric outside diameters and wall thicknesses and metric
fiber stresses as shown in clause 8.
The factors used where conversions are appropriate are as follows:
1 inch (in) = 25,4 mm exactly
1 square inch (in2 ) = 645,16 mm2 exactly
1 foot (ft) = 0,03048 m exactly
1 pound (lb) = 0,453 59 kg
1 pound per foot (Ib/ft) = I,4882 kg/m
1 pound per square inch (lbf/in2 ) = 6,895 kPa for pressure
= 0,006 895 MPa for stress
1 footpoundforce (ftbf) = I,3558 J for impact energy
= 1,355 8 Nm for torque
The following formula was used to convert degrees Farenheit (OF) to degrees Celsius (“C): “C = 5/9 (“F  32).
ROUNDING OF METRIC UNITS
Metric units are converted or calculated in accordance with factors given above and the number of digits shown
in the table.
Table  Number of decimals to be shown in metric units
3
1 2
PROPERTY METRIC UNITS NUMBER OF DECIMALS
Diameter mm 1
Thickness and imperfections mm 1
Upset and coupling length mm 1
Length m 2
Mass 2
kg
Mass per foot 2
kg/m
Stress and tensile strength MPa 0
Pressure kPa x 100 0
Guided bend A mm 1
Thread elements
Major diameter mm 1
Pitch diameter mm 3
Thread length mm 2
Thread height mm 3
Recess depth mm 1
4 (distance from end of pipe to centre of coupling mm 1
2
 Page: 6 
IS0 10400:1993(E)
Bulletin on
Formulas and Calculations for
Casing, Tubing, Drill Pipe
and Line Pipe Properties
API BULLETIN 5C3 (Bul5C3)
FIFTH EDITION, JULY 1989
American Petroleum Institute
1220 L Street, Northwest
Washington, DC 20005
 Page: 7 
This page intentionally left blank
 Page: 8 
IS0 10400:1993(E)
Issued by
AMERICAN PETROLEUM INSTITUTE
Production Department
FOR INFORMATION CONCERNING THE TECHNICAL CONTENTS OF
THIS PUBLICATION CONTACT THE API PRODUCTION DEPARTMENT,
2535 ONE MAIN PLACE, DALLAS, TX 75202  (214) 7483841.
SEE BACK COVER FOR INFORMATION CONCERNING HOW TO OBTAIN
ADDITIONAL COPIES OF THIS PUBLICATION.
Users of this publication should become familiar with its scope and content.
This document is intended to supplement rather than
replace individual engineering judgment.
OFFICIAL PUBLICATION
REG. U.S. PATENT OFFICE
Copyright @ 1989 American Petroleum Institute
 Page: 9 
I§0 10400:1993(E)
2 American Petroleum Institute
TABLE OF CONTENTS
Section Page
1 COLLAPSEPRESSURE .
5
1.1 Collapse Pressure Formulas
........................................................ 5
1.1.1 Yield Strength Collapse Pressure Formula
..................................... 5
1.1.2 Plastic Collapse Pressure Formula 6
............................................
1.1.3 Transition Collapse Pressure Formula
......................................... 7
1.1.4 Elastic Collapse Pressure Formula
............................................ 8
1.1.5 Collapse Pressure Under Axial Tension Stress 8
.................................
1.1.6 Effect of Internal Pressure on Collapse 9
........................................
1.1.7 Collapse Pressure Formula Symbols
........................................... 9
1.2 Derivation of Collapse Pressure Formulas
........................................... 9
1.2.1 Yield Strength Collapse Pressure Formula Derivation IO
...........................
1.2.2 Plastic Collapse Pressure Formula Derivation
.................................. 10
1.2.3 Transition Collapse Pressure Formula Derivation
............................... 12
1.2.4 Elastic Collapse Pressure Formula Derivation . 14
1.3 Collapse Testing Procedure 14
........................................................
1.3.1 Test Specimen 14
...............................................................
1.3.2 Test Apparatus 14
...............................................................
1.3.3 Test Procedure
.............................................................. 14
1.3.4 Data Reporting
............................................................... 14
2 PIPEBODYYIELDSTRENGTH .
16
3 INTERNAL PRESSURE RESISTANCE
.................................................. 16
3.1 Internal Yield Pressure
....................................... ...................... 16
3.1.1 Internal Yield Pressure for Pipe
............................................... 16
3.1.2 Internal Yield Pressure for Couplings
.......................................... 17
3.2 Internal Pressure Leak Resistance at E, or E7 Plane 18
..................................
4 JOINTSTRENGTH .
19
4.1 Round Thread Casing Joint Strength
19
...............................................
4.2 Buttress Thread Casing Joint Strength 20
..............................................
4.3 ExtremeLine Casing Joint Strength 20
................................................
4.4 Tubing Joint Strength 21
..............................................................
4.5 Joint Strength of Round Thread Casing with Combined Bending and Internal
Pressure. . 21
4.6 Line Pipe Joint Strength 22
...........................................................
5 WEIGHTS . 23
5.1 Nominal Weight . 23
5.2 Calculated Plain End Weight 23
.......................................................
5.3 Calculated Threaded and Coupled Weight
........................................... 23
5.4 Calculated Upset and Threaded Weight for Integral Joint Tubing and Extreme
LineCasing .
24
5.5 Calculated Upset Weight
........................................................... 24
5.6 Weight Gain Due to End Finishing
.................................................. 25
5.7 Calculated Coupling Weight
........................................................ 26
5.7.1 Calculated Coupling Weight for Line Pipe and Round Thread Casing and
Tubing . 26
............ ...............................
5.7.2 Calculated Coupling Weight for Buttress Thread Casing
........................ 27
5.8 Calculated Weight Removed in Threading 28
.......... .................................
5.8.1 Calculated Weight Removed in Threading Pipe or Pin Ends 28
.....................
5.812 Calculated Weight Removed in Threading Integral Joint
Tubing Box Ends 30
.............................................................
 Page: 10 
IS0 10400:1993(E)
3
Bulletin 5C3: Formulas and Calculations for Pipe Properties
5.9 Calculated Weight of External Upsets . 31
5.10 Calculated Weight of Internal Upsets . .;. . 31
5.11 Calculated Weight of ExternalInternal Upsets . 31
5.12 Calculated Weight of Extremeline Upsets . 32
6 ELONGATION. . 33
7 FLATTENINGTESTS .
33
7.1 Flattening Tests for Casing and Tubing . 33
7.2 Flattening Tests for Line Pipe . 34
8 HYDROSTATIC TEST PRESSURES . 34
8.1 Hydrostatic Test Pressure for PlainEnd Pipe, ExtremeLine Casing and Integral
Joint Tubing 34
....................................................................
8.2 Hydrostatic Test Pressure for Threaded and Coupled Pipe . 35
8.2.1 Internal Yield Pressure for Couplings . 35
8.2.2 Internal Pressure Leak Resistance at E, or E7 Plane . 37
9 MAKEUPTORQUE. 37
10 GUIDED BENDTESTS . . .~. 38
11 METRICATION .
39
11.1 Metric Conversions and Calculations . 39
Il.2 Rounding of Metric Units . 40
12 CALCULATION ACCURACY AND ROUNDING . 40
12.1 Accuracy . 40
.........................................................
12.2 Intermediate Rounding 40
12.3 Final Rounding . 40
FOREWORD
a. This bulletin is under the jurisdiction of the Committee on Standardization of Tubular Goods.
b. The purpose of this bulletin is to show the formulas used in the calculation of the various pipe properties given in
API standards, including background information regarding their development and use.
c. American Petroleum Institute (API) Bulletins are published to provide information for which there is a broad
industry need but which does not constitute either Specifications or Recommended Practices.
d. Any Bulletin may be used by anyone desiring to do so, and a diligent effort has been made by API to assure the
accuracy and reliability of the data contained herein. However, the Institute makes no representation, warranty or
guarantee in connection with the publication of any Bulletin and hereby expressly disclaims any liability or
responsibility for loss or damage resulting from its use, for any violation of any federal, state, or municipal regula
tion with which an API recommendation may conflict, or for the infringement of any patent resulting from the use
of this publication.
e. This Standard (supplement) shall become effective on the date printed on the cover but may be used voluntarily
from the date of distribution.
Attention Users: Portions of this publication have been changed from the previous edition. The locations of
changes have been marked with a bar in the margin, as shown to the left of this paragraph. In some cases the
changes are significant, while in other cases the changes reflect minor editorial adjustments. The bar notations in
the margins are provided as an aid to users as to those parts of this publication that have been changed from the
previous edition, but API makes no warranty as to the accuracy of such bar notations.
Requests for permission to reproduce or translate
Note: This is the fifth edition of this bulletin. The
all or any part of the material published herein
first edition was authorized for publication at the
should be addressed to the Director, American
1970 Standardization Conference as detailed in
Petroleum Institute, Production Department, 2535
Circ PS7398 and issued in 1971. Subsequent edi
One Main P/ace, Dallas TX 75202.
tions were issued in 1974, 1980, and 1985.
7
 Page: 11 
IS0 10400:1993(E)
4 American Petroleum Institute
POLICY
1. API PUBLICATIONS NECESSARILY ADDRESS FOR THE MANUFACTURE, SALE, OR USE OF
PROBLEMS OF A GENERAL NATURE. WITH
ANY METHOD, APPARATUS, OR PRODUCT
RESPECT TO PARTICULAR CIRCUMSTANCES, COVERED BY LETTERS PATENT. NEITHER
LOCAL, STATE, AND FEDERAL LAWS AND SHOULD ANYTHING CONTAINED IN THE PUB
REGULATIONS SHOULD BE REVIEWED. LICATION BE CONSTRUED AS INSURING ANY
ONE AGAINST LIABILITY FOR INFRINGEMENT
2. API IS NOT UNDERTAKING TO MEET THE
OF LETTERS PATENT.
DUTIES OF EMPLOYERS, MANUFACTURERS, OR
SUPPLIERS TO WARN AND PROPERLY TRAIN
5. GENERALLY, API STANDARDS ARE RE
AND EQUIP THEIR EMPLOYEES, AND OTHERS
VIEWED AND REVISED, REAFFIRMED, 0~
EXPOSED, CONCERNING HEALTH AND SAFETY
WITHDRAWN AT LEAST EVERY FIVE YEARS.
RISKS AND PRECAUTIONS, NOR UNDERTAKING
SOMETIMES A ONETIME EXTENSION OF UP
THEIR OBLIGATIONS UNDER LOCAL, STATE, OR
TO TWO YEARS WILL BE ADDED TO THIS
FEDERAL LAWS.
REVIEW CYCLE. THIS PUBLICATION WILL NO
LONGER BE IN EFFECT FIVE YEARS AFTER
3. INFORMATION CONCERNING SAFETY AND
ITS PUBLICATION DATE AS AN OPERATIVE API
HEALTH RISKS AND PROPER PRECAUTIONS
STANDARD OR, WHERE AN EXTENSION HAS
WITH RESPECT TO PARTICULAR MATERIALS
BEEN GRANTED, UPON REPUBLICATION. STA
AND CONDITIONS SHOULD BE OBTAINED FROM
TUS OF THE PUBLICATION CAN BE ASCER
THE EMPLOYER, THE MANUFACTURER OR
TAINED FROM THE API AUTHORING DEPART
SUPPLIER OF THAT MATERIAL, OR THE MATE
MENT [TELEPHONE (214) 74838411. A CATALOG
RIAL SAFETY DATA SHEET.
OF API PUBLICATIONS AND MATERIALS IS
4. NOTHING CONTAINED IN ANY API PUBLI PUBLISHED ANNUALLY AND UPDATED QUAR
CATION IS TO BE CONSTRUED AS GRANTING TERLY BY API, 1220 L STREET, N.W., WASH
ANY RIGHT, BY IMPLICATION OR OTHERWISE, INGTON, D.C. 20005.
i
.’ 4
 Page: 12 
IS0 10400:1993(E)
Bulletin 5C3: Formulas and Calculations for Pipe Properties 5
SEc?IQN 1
COLLAPSE PRESSURE
1.1 COLLAPSE PRESSURE FORMULAS
The minimum collapse pressures given in API Bul 5C2 are calculated by means of formulas 1.1.1.1, 1.1.2.1,
1.1.3.1 and 1.1.4.1, adopted at the 1968 Standardization Conference and reported in Circular PS1360 dated
September 1968.
Formulas 1.1.1.2, 1.1.2.2 and 1.1.3.2 for the intersections between the four collapse pressure formulas have
been determined algebraically and used for calculating the applicable D/t range for each collapse pressure
formula. Factors A, B, C, F and G have been calculated using formulas l2.2.12, l2.2.13, 1.2.2.14, 1.2.3.2 and
1.2.3.3. Grades with alphabetic prefixes are API grades. Those without alphabetic prefixes are non API grades.
When determining the appropriate formula to be used for calculating collapse resistance for a particular D/t
ratio and minimum yield strength, the D/t ranges determined by formulas 1.1.1.2, 1.1.2.2 and 1.1.3.2 govern,
rather than the collapse formula that gives the lowest collapse pressure. The D/t ranges for API and some non
API grades are given in Tables 1.1.1.1, 1.1.2.1, l1.3.1 and 1.1.4.1.
The collapse pressures for Bul 5C2 are calculated using the specified values for D and t rounding D/t to two
decimals carrying eight digits in all intermediate calculations and rounding the collapse pressure to the nearest
10 psi.
1.1.1 YIELD STRENGTH COLLAPSE PRESSURE FORMULA
The yield strength collapse pressure is not a true collapse pressure, but rather the external pressure, P
yP’
that generates minimum yield stress, Y p , on the inside wall of a tube as calculated by formula 1.1.1.1
pyp = ,,,[ ‘;;;t,’ l. 1.1.1.1
The formula for yield strength collapse pressure formula 1.1.1.1 is applicable for D/t values up to the value of
D/t corresponding to the intersection with the plastic collapse formula 1.1.2.1. This intersection is calculated
by formula 1.1.1.2 as follows:
(A  2)2 + 8 (B + C/Y,jl + (A  2)
. . . . . . 1.1.1.2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..a.
(D/t),, = ‘?!
2(B + C/Y,)
The applicable D/t ratios for yield strength collapse are shown in table 1 .I.1 .I.
TABLE 1.1.1.1
YIELD COLLAPSE PRESSURE
FORMULA RANGE

2
1
Grade? D/t Range*
H40 16.40 and less
50 15.24 ” ”
JK55 14.81 ” ”
60 14.44 ” ”
70 13.85 ” ”
C75 & E 13.60 ” ”
LN80 13.38 ” ”
c90 13.01 ” ”
CT95 & X 12.85 ” ”
100 12.70 ” ”
P105 & G 12.57 ” ”
P110 12.44 ” ”
120 12.21 ” ”
Q125 12.11 ” ”
130 12.02
” ”
11.92 ” ”
s135
140 11.84
” ”
11.67
150 ” ”
11.59
155 ” ”
160 11.52 ” ”
170 11.37 ” ”
11.23
180 ” ”
jGrades indicated without letter designation are not API grades but are grades in use or grades being considered for
use and are shown for information purposes.
*The D/t range values were calculated from formulas 1.1.1.2, 1.2.2.12, 1.2.2.13 and 1.2.2.14 to eight or more digits.
9
 Page: 13 
IS0 10400:1993(E)
6 American Petroleum Institute
1.1.2 PLASTIC COLLAPSE PRESSURE FORMULA
The minimum collapse pressure for the plastic range of collapse is calculated by formula 1.1.2.1.
A
  B  c . . . . . .~.,.,.1.1.2.1
‘, = ‘P D/t
[ 1
The formula for minimum plastic collapse pressure is applicable for D/t values ranging from (D/t) PT , formula
III.2 for yield point collapse pressure, to the intersection with the formula 1.1.3.1 for transition collapse
pressure (D/t) PT . Values for (D/t) PT are calculated by means of formula 1.1.2.2.
YP (A  F)
1.1.2.2
(D/t) PT = 
 * *  *  * *  * * * * * *      *   .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c + yp (B _ G)
The factors and applicable D/t range for the plastic collapse formula are shown in table 1.1.2l.
TABLE 1 .I .2.1
FORMULA FACTORS AND D/t RANGES
FOR PLASTIC COLLAPSE
2 3 4 5
1
Formula Factor*
A B C D/t Range*
Gradet
H40 0.0465 16.40 to 27.01
2.950 754
0.0515 15.24 to 25.63
50 2.976 1056
JK55 2.991 0.0541 1206 14.81 to 25.01
14.44 to 24.42
60 3.005 0.0566 1356
70 0.0617 13.85 to 23.38
3.037 1656
C75 & E 3.054 0.0642 13.60 to 22.91
1806
13.38 to 22.47
LN80 3.071 0.0667 1955
0.071 a ‘3.01 to 21.69
c90 3.106 2254
CT95 & X 3.124 0.0743 2404 12.85 to 21.33
12.70 to 21.00
100 3.143 0.0768 2553
12.57 to 20.70
P105 & G 3.162 0.0794 2702
P110 12.44 to 20.41
3.181 0.0819 2852
12.21 to 19.88
120 3.219 0.0870 3151
Ql 25 12.11 to 19.63
3.239 0.0895 3301
130 12.02 to 19.40
3.258 0.0920 3451
11.92 to 19.18
Sl 35 3.278 0.0946 3601
11.84 to 18.97
140 3.297 0.0971 3751
11.67 to 18.57
150 3.336 0.1021 4053
11.59 to 18.37
155 3.356 0.1047 4204
11.52 to 18.19
160 3.375 0.1072 4356
‘1.37 to 17.82
170 3.412 0.1123 4660
11.23 to 17.47
180 3.449 0.1173 4966
tGrades indicated without letter designation are not API grades but are grades in use or grades being considered for
use and are shown for information purposes.
*The D/t range values and formula factors were calculated from formulas 1.1 .I .2, 1.1.2.2, 1.2.2.12, 1.2.2.13, 1.2.2.14,
1.2.3.2 and 1.2.3.3 to eight or more digits.
10
 Page: 14 
IS0 10400:1993(E)

Bulletin 5C3: Formulas and Calculations for Pipe Properties
7
1.1.3 TRANSITION COLLAPSE PRESSURE FORMULA
The minimum collapse pressure for the plastic to elastic transition zone P, is calculated by formula 1.1.3.1.
P, =Yp[ + G] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.3.1
The formula for PT is applicable for D/t values from (D/t)PT , formula 1.1.2.2 for plastic collapse pressure to
the intersection (D/t TE with the formula 1.1.4.1 for elastic collapse. Values for (D/t),, are calculated by fof
mula 1 .I .3.2.
2 + B/A
3B,A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.3.2
(D/t),E =
The factors and applicable D/t range for the transition collapse pressure formula are shown in table 1.1.3.1.
TABLE 1 .I .3.1
FORMULA FACTORS AND D/t RANGE
FOR TRANSITION COLLAPSE
1 2 3 4
Formula Factors*
Gradet F G D/t Range*
H40 2.063 0.0325 27.01 to 42.64
2.003 0.0347 25.63 to 38.83
50
I .989 0.0360 25.01 to 37.21
JK55
I .983 0.0373 24.42 to 35.73
60
1.984 0.0403 23.38 t0 33.17
70
1.990 0.041 a 22.91 to 32.05
C75 & E
LN80 I .998 0.0434 22.47 to 31.02
2.017 0.0466 21.69 to 29.18
c90
2.029 0.0482 21.33 to 28.36
CT95 & X
2.040 21.00 to 27.60
100 0.0499
2.053 0.0515 20.70 to 26.89
P105 & G
20.41 to 26.22
Pl 10 2.066 0.0532
19.88 to 25.01
120 2.092 0.0565
19.63 to 24.46
Q125 2.106 0.0582
19.40
130 2.119 0.0599 to 23.94
‘9.18
Sl 35 2.133 0.0615 to 23.44
18.97
140 2.146 0.0632 t0 22.98
2.174 0.0666 1 a.57 t0 22.11
150
2.188 0.0683 I a.37 t0 21.70
155
160 2.202 0.0700 ‘8.19 to 21.32
2.231 0.0734 17.82 to 20.60
170
2.261 0.0769 17.47 to 19.93
180
tGrades indicated without letter designation are not API grades but are grades in use or grades being considered for
use and are shown for information purposes.
*The D/t values and formula factors were calculated from formulas 1.1.2.2, 1.1.3.2, 1.2.2.12, 1.2.2.13, 1.2.2.14,
range
1.2.3.2 and 1.2.3.3 to eight or more digits.
11
 Page: 15 
IS0 10400:1993(E)
American Petroleum institute
8
l.Y.4 ELASTIC COLLAPSE PRESSURE FORMULA
The minimum collapse pressure for the elastic range of collapse is calculated by formula 1.1.4.1
46.95 x 106
1.1.4.1
P, =
(D,t) ((D,t) _ 1)2 *.**** . . . . . . . . .*.
The applicable D/t range for elastic collapse is shown in table 1.1.4.1
TABLE 1 .I .4.1
D/t RANGE FOR ELASTIC COLLAPSE
1
2
Grade? D/t Range*
H40 42.64 and greater
11
50 38.83 ”
‘I
JK55 37.21 ”
‘9
60 35.73 ”
19
70 33.17 ”
11
C75 & E 32.05 ”
‘,
LN80
31.02 ”
‘1
c90 29.18 ”
11
CT95 & X 28.36 ”
19
100 27.60 ”
‘1
P105 81 G 26.89 ”
9’
P110 26.22 ”
9’
120 25.01 ”
9’
Ql 25 24.46 ”
11
130 23.94 ”
19
Sl 35 23.44 ”
I’
140 22.98 ”
‘1
150 22.11 ”
‘I
155 21.70 ”
‘1
160 21.32 ”
9I
170 20.60 ”
11
180 19.93 ”
tGrades indicated without letter designation are not API grades but are grades in use or grades being considered for
use and are shown for information purposes.
*The D/t range values were calculated from formulas 1 .1.3.2, 1.2.2l 2, and 1.2.2.13 to eight or more digits.
1.1.5 COLLAPSE PRESSURE UNDER AXIAL TENSION STRESS
The collapse resistance of casing in the presence of an axial stress is calculated by modifying the yield stress to an
axial stress equivalent grade according to Formula 1.1.5.1
Y
pa = [ d 1 O75( S,/Yp)2O5Sa/Yp] Yp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1.5.1
Where:
= 4xial Stress, psi (tension is positive)
Sa
= Minimum yield strength of the pipe, psi
YP
Y pa = Yield strength of axial stress equivalent grade, psi
Collapse resistance formula factors and D/t ranges for the axial stress equivalent grade are then calculated by means
of Formulas 1.2.2.12, 1.2.2.13, 1.2.2.14,1.1.1.2, 1.1.2.2, 1.1.3.2, 1.2.3.2 and 1.2.3.3. Using formula factors for the axial
stress equivalent grade, collapse resistance under axial stress is calculated by means of Formulas 1 .l .l .l, 1 .1.2l,
1.1.3.1 and 1.1.4.1.
The reduced collapse pressures are calculated using D/t rounded to two decimals and carrying eight digits in att
intermediate calculations and rounding the reduced collapse pressure to the nearest 10 psi.
I
API collapse resistance formulas are not valid for the yield strength of axial stress equivalent grade (Y,,) less
than 24,000 psi.
I
12
 Page: 16 
IS0 10400:1993(E)
Bulletin 5C3: Formulas and Calculations for Pipe Properties
9
Formula 1 .1.5.1 is based on the Henckyvon Mises maximum strain energy of distortion theory of yielding.
Example:
Calculate collapse pressure of 7” 26# PllO with axial stress of 11,000 psi. Wall thickness is 0.362”.
= 11,000 psi
Sa
= 110,000 psi
yP
Substituting in Formula 1 .1.5.1:
Y = 104,087 psi
pa
Substituting Ypa for Y in formulas 1.2.2.12, 1.2.2.13, 1.2.2.14, 1.1.1.2, 1.1.2.2, 1.1.3.2, 1.2.3.2 and 1.2.3.3:
A = 3.158, B = 0.0789, C = 2675, F= 2.051, G = 0.0512
= 20.75,
= 12.59, (D& = 27.02
(D/f)pt
( wyp
D/t Range for Yield Collapse = 12.59 and less
D/t Range for Plastic Collapse = 12.59 to 20.75
D/t Range for Transition Collapse = 20.75 to 27.02
D/t Range for Elastic Collapse = 27.02 and greater
D/t = 7/0X2 = 19.34 which indicates that collapse is in the plastic range. Substituting A = 3.158, B =0.0789 and C = 2675
into Formula 1 .1.2.1 for plastic collapse:
P = Ypa (A/ (D/t)B)  C = 104,087 (3.158/l 9.340.0789)  2675
P = 6110psi
1.1.6 EFFECT OF INTERNAL PRESSURE ON COLLAPSE
The external pressure equivalent of external pressure and internal pressure is determined by means of formula
1.1.6.1. The formula is based on the internal pressure
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.