FOREWORD

(This Foreword is not part of ANSI.ASME B36.10M-1985)

In March 1927, the American Standards Association authorized the organization of a Sectional Committee on Standardization of Dimensions and Material of Wrought Steel and Wrought Iron Pipe and Tubing for the purpose of unifying the standards of these commodities in force in this country. The American Society for Testing and Materials and the American Society of Mechanical Engineers were designated as sponsors, and the first meeting of the Sectional Committee was held in Pittsburgh, Pennsylvania, on May 18, 1928.

The dimensions of commercial pipe in general use in the United States at the time conformed rather generally to those recommended by the ASME Committee on Standard Pipe and Pipe Threaads published in 1886 (ASME Transactions, Vol. VIII, p. 29). On these standards an enormous industry has been built and the satisfactory use of this product proves the soundness of the original design and specification.

Increasingly severs service demands at the time of the Committee's organization had been met by using the nearest available pipe or tubing for heavier sections such as casing, mechanical tubing, etc., with resulting uneconomical multiplicity of wall thciknesses.

Subsequently the Committee, with the cooperation of the industry, made a survey of existing practice as the logical starting point for the development of an American Standard.

From this survey, a table was designed to provide a selection of wall thicknesses of pipe to cover the power piping requirements of industry where strength to resist internal pressure governs selection and was later expanded to include pipe diameters and thicknesses used in other industries.

The original intent of the Committee was to establish a system of Schedule Numbers for pipe size/wall thickness combinations which would have an approximately uniform relationship equal to 1000 times the P/S expression contained in the modified Barlow formula for pipe wall thickness as defined in the Appendix to this Standard. The resulting Numbers departed so far from existing wall thicknesses in common use that the original intent could not be accomplished. The Schedule Numbers were then adopted strictly as a convenient designation system for use in ordering.

In all cases, the designer must base his selection on the rules and allowable stresses set by the code which governs his particular construction. The table is dimensionally complete for all sizes and wall thicknesses within its scope, but some of the larger, heavier wall sections are beyond the capability of seamless mill production and must be obtained from forged and bored billets or other sources.

The first issue of this standard was approved by letter ballot of the Sectional Committee in October 1934, by the American Society of Mechanical Engineers in November 1934, and by the American Society for Testing and Materials in February 1935. Formal approval was given with the designation American Standard "tentative" by the American Standards Association in November 1935.

Subsequent slight revisions to Table 1 and the footnotes of the dimensional tables were approved, in order, by the Sectional Committee, the Sponsors, and the American Standards Association. The latter changed the designation to American Standard; the date of ASA approval was April 28, 1939.

Further revisions have been made by the Sectional Committee and approved by the Sponsors and the American Standards Association. The list of specifications in Table 1 has been revised where necessary and slight revisons in wall thicknesses of some of the large sizes of the heavy schedules have been made where P/S values were out of line.

It was the hope iin 1939 that the designations of pipe used commercially by all industry as Standard weight, Extra-Strong, and Double Extra-Strong would gradually be replaced by Schedule Number designation. However, owing to customs of over 50 years' stading, demand and production of pipe to these traditional dimensions is undiminished. Consequently, in response to a demand from users, accepted practice for dimensions and weights of commercial wrought steel and welded wrought iron pipe were added.

These changes in the stadard were approved by the Sectional Committee, the Sponsors, and the American Standards Association, and it was designated an American Standard on February 23,1950.

Subcommittee No. 1 was reorganized in 1957 to revise and bring the standard up to date. In addition to the necessary editiorial changes, a simplified format was selected for the tables of weights and dimensions so as to include and identify the sizes and weights of API Standards 5L and 5LX. The decimal wall thicknesses and plain end weights were established by a uniform procedure recognized by the tubular industry, and for some sizes the decimal wall thicknesses and plain end weights shown may vary slightly fro those shown in the tables of previous issues of this standard. These changes to the standard were approved by the Sectional Committee, the Sponsors, and the American Standards Association, and it was designated an American Standards on December 21, 1959.

This standards was revised in 1969 to bring it up to date. A uniform method to calculate the plain end weight of steel pipe was included, and minor adjustments were made in the tabulated weights of steel pipe in Table 2 to conform to this new method. Additional sizes and thicknesses of steel pipe which have come into common use were also added to Table 2. Inasmuch a API Standard 5L no longer included wrought iron pipe, reference to this API Standards Committee, the Sponsors, and the American National Stnadrads Institute, and it was designated an American National Standard on February 3, 1970.

Further revisions were made to this standard in 1975. Additional sizes and thicknesses of steel pipe which had been added to API Specifications were added to Table 2. Table 3, Dimensions and Weights of Welded Wrought Iron Pipe, was deleted in its entirety, since wrought iron pipe is no longer produced. These changes in the standard were approved by the Standards Committee, the Secretariat, and the American National Standards Institute, and it was designated an American National Standard on June 5, 1975.

This standard was revised in 1978 to include SI metric dimensions. The outside diameter and wall thicknesses were converted to millimeters by multiplying the inch dimensions by 25.4 Outside diameters larger than 16 in. were rounded to the nearest millimeter, and outside diameters 16 in. and smaller were rounded to the nearest 0.1 mm. Wall thicknesses were rounded to the nearest 0.01mm. These converted and rounded SI metric dimensions were rounded to the nearest 0.01 mm. These converted and rounded SI meteric plain end mass, in kilograms per meter, using SI metric diameters and thicknesses was added to Section 5. The SI metric plain end mass was calcuated for each size and thickness, and was added to Table2. These changes in the standard were approved by the Standards Committee, the Secretariat, and the American National Standards Institute, and it was designated an American National Standard on July 18, 1979.

This standard was revised in 1984 to bring it up to date. The ANSI designations, which are no longer in use, have been deleted from Table 1, and the list of specifications has been revised to agree with current ASTM and API Specifications. Addoitional sizes and thicknesses which have been added to API Specifications were added to Table 2.

The present edition was approved as an American National Standard on August 19, 1985.

-----------------------------------------------
1Reprinted by permission of the American Society of Mechanical Engineers, 345 East 47th St., New York, NY 10017.

1. Scope

This Standard covers the standardization of dimensions of welded and seamless wrought steel pipe for high or low temperatures and pressures.

The word pipe is used as distinguished from tube to apply to tubular products of dimensions commonly used for pipeline and piping systems. Pipe dimensions of sizes 12 in. and smaller have outside diameters numberically larger than corresponding sizes. In contrast, the outside diameters of tubes are numerically identical to the size number for all sizes.

2. Size

The size of all pipe is identified by the nominal pipe size.

The manufacture of pipe in the nominal sizes of 1/7 in. to 12 in. inclusive is based on a standardized outside diameter (O.D). ThisO.D.was originally selected so that pipe with a standard O.D. and having a wall thickness which was typical of the period would have an inside diameter (I.D). approximately equal to the nominal size. Although there is no such relation between the existing standard thickness - O.D. and nominal size - these nominal sizes and standard O.D.'s continue in use as "standard".

The manufacture of pipe in nominal sizes of 14 in. O.D. and larger proceeds on the basis of an O.D. corresponding to the nominal size.

3. Materials

The dimensional standards for pipe described here are for products covered in the ASTM and API Specifications listed in Table 1.

4. Wall thickness

The nominal wall thicknesses are given in Table 2. Table 2 also indicates wall thicknesses listed in API Standard 5l.

5. Weights

The nominal weights of steel pipe are calculated values and are tabulated in Table 2. The nominal plain end weight, in pounds per foot, is calculated using the following formula :

Wpe = 10.68(D - t)t

where
W = nominal plain end weight rounded to the nearest 0.01 lb/ft
D = outside diameter to the nearest 0.001 in. (The symbol D is to be used for O.D. only in mathematical equations or formulas).
t = specified wall thickness rounded to the nearest 0.001 in.
The nominal plain end mass, in kiilograms per meter, is calculated using the following formula :

Wpe = 0.02466 (D - t)t

where
Wpe = nominal plain end weight rounded to the nearest 0.01 kg.m
D = outside diameter to the nearest 0.1 mm for outside diameters which are 16 in. and smaller and to the nearest 1.0 mm for outside diameters larger than 16 in. (The symbol D is to be used for O.D. only in mathematical equations or formulas).
t = specified wall thickness rounded to the nearest 0.01 mm

6. Permissible variations

Variations in dimensions differ depending upon the method of manufacture employed in making the pipe to the various specifications listed in Table 1. Permissible variations for dimensions are indicated in each specification.

7. Pipe threads

Unless otherwise specified, the threads of threadded pipe shall conform to ANSI/ASME B1.20.1, Pipe Threads, General Purpose (Incj).

8. Wall thickness designations

The wall thickness designations Stnadard, ExtraStrong, and Double Extra-Strong have been commercially used designations for many years. As explained in theForeword, the Schedule Numbers were subsequently added as a convenient designation for used in ordering pipe. Standard and Schedule 40 are identical for nominal pipe sizes up to 10 in. inclusive. All larger sizes of Standard have 3/8 in. wall thicknesses. Extra -Strong and Schedule 80 are identical for nominal pipe sizes up to 8 in. inclusive. All larger sizes of Standard have 3/8 in. wall thicknesses. Extra-Strong and Schedule 80 are identical for nominal pipe sizes up to 8 in. inclusive. All larger sizes of Extra-Strong have 1/2 in. wall thicknesses.

Pipe of sizes and wall thicknesses other than those of Standard, Extra-Strong, Double Extra-Standard 5L. It was not considered practical to establish Schedule Numbers or nwe designations for them.

9. Wall thickness selection

When the selection of wall thickness depends primarily upon capacity to resist internal pressuree under given conditions, the designer shall compute the exact value of wall thickness suitable for conditions for which the pipe is reguired, as prescribed in detail in the ASME Boiler and Pressure Vessel Code, ANSI/ASME B31 Code for Pressure Piping, or other similar codes, whichever govems the construction. A thickness shall be selected from Table 2 to suit the value computed to fulfull the conditions for which the pipe is desired.