About PipeData

What this is

PipeData reproduces the dimension and rating tables from the ASME B16 and B36 series in a form you can read on a phone at a fabrication shop. Every page answers one question directly: the wall thickness of a size, the bolting of a class, the centre-to-end of a fitting. Around the tables it explains what the figures mean and how they are used, in guides and comparisons that work their examples from the same data.

Who publishes it

PipeData is an independent publication. Its pages are written and maintained under the name PipeData Editorial, and the site names no individual author. It is a reference work and not an engineering practice: nobody at PipeData is acting as your engineer, and nothing here has been reviewed or stamped by a licensed professional engineer for your application.

We say this plainly because a site like this one is only as good as its figures, and the honest basis for trusting a figure here is the method described below and the fact that you can check it against the standard, not the standing of whoever typed it.

What it covers

• ASME B36.10M — 30 pipe sizes from NPS 1/8 to NPS 36, all fourteen schedules, with bore, weight and flow area calculated for each.
• ASME B16.5 — 6 flange types across seven pressure classes, NPS 1/2 to NPS 24.
• ASME B16.47 — large-diameter flanges NPS 26 to NPS 60, both series.
• ASME B16.9 — 10 buttweld fitting types with their governing dimensions.
• Reference tables for NPS/DN conversion, schedules, materials, bolting, flange faces and pressure-temperature ratings.

How the figures are checked

The site is generated by a program from a small set of data files, one for each standard. No table on any page is typed by hand, so a figure exists in one place only, and the pipe page, the flange page and the comparison page that quote it cannot disagree with each other.

• Tabulated values such as outside diameter, wall thickness, flange diameter, bolt circle, bolting and pressure rating are entered once in the data files from published tables.
• Derived values such as bore, weight, flow area, water content, bolt hole spacing and end load are calculated from the tabulated ones every time the site is built. The formula is printed beside the table.
• Figures in the text are calculated from the data wherever that is possible, so a sentence cannot go on saying one thing after a table has been corrected to say another.
• The build stops if the data contains a wall so thick it would close the bore, if a stainless pipe size is missing from the carbon steel table it takes its diameter from, if two pages share a title or a description, or if any link on the site leads to a page that does not exist.

These checks catch inconsistency. They cannot catch a figure that was copied wrongly at the start and is wrong everywhere, which is why corrections from readers matter.

Errors found and corrected

Working the examples from the data has so far exposed four statements that read plausibly and were wrong. They are listed here because a reference that hides its corrections gives you no way to judge it.

• The pipe sizing example gave NPS 6 as its answer. Worked from the flow areas, the smallest Schedule 40 size that meets the duty is NPS 5.
• The 45° elbow page said the centre-to-end dimension is always the same fraction of the size. ASME B16.9 publishes rounded figures, so the ratio varies, and the table governs, not the formula.
• The wall of NPS 24 Schedule 40 pipe was written as 0.687 in. The published value is 0.688 in.
• An early page said that the 5S and 10S stainless walls are thinner than anything in B36.10. The correction made then was itself wrong for 10S: see the pipe entries below.

A check of the flange data against published reproductions of the ASME B16.5 tables, completed on 28 September 2026, found larger errors. All have been corrected:

• Pressure-temperature ratings, Group 1.1. Classes 300 to 2500 carried values from an edition of the 1980s and 1990s at 850 °F and above, and in a few cells below. At 900 °F a Class 300 carbon steel flange was shown as 170 psig; the current figure is 230 psig.
• Pressure-temperature ratings, Group 1.2. Both the list of materials and the whole table were wrong and have been replaced.
• Type 316 stainless steel was listed in Group 2.1 with Type 304. It belongs to Group 2.2, which now has its own table. The Group 2.1 table had carried old Type 316 values and now carries the Type 304 values.
• Flange thickness and hub length in Classes 150 and 300 were the older figures that include the 1/16 in raised face, on pages that said the raised face was excluded. Every one was 0.06 in too large and has been reduced.
• Slip-on hub lengths in Class 150, NPS 14 to 24, were those of the lap joint flange.
• Slip-on and socket weld flanges were shown in classes and sizes in which ASME B16.5 does not publish them. There is no Class 2500 slip-on flange, and no socket weld flange in Class 900 or 2500. Those pages have been withdrawn and the remaining tables cut back to the published sizes.
• Pipe specifications such as A312 and A335 were listed among the materials of the rating groups. The groups are defined for forgings, castings and plate, and the pipe specifications have been removed.

A second check on the same date covered every other data file, against publicly hosted copies of the text of ASME B36.10, B36.19, B16.9 and B16.47 and of several ASTM specifications. It found and corrected:

• Pipe, Schedule 10 at NPS 14 to 22 carried the stainless 10S walls of 0.188 and 0.218 in. ASME B36.10 Schedule 10 is 0.250 in in those sizes. Because of this the site had also said, wrongly, that 10S and Schedule 10 are the same wall in every size.
• Schedules that do not exist were listed: Schedule 5 in NPS 1/8, 1/4 and 3/8, and XXS in NPS 3 1/2. Schedule 30 was missing from NPS 1/8 through NPS 4.
• NPS 4 1/2, 7, 9 and 11 were described as ASME B36.10 sizes. They are in none of the 2004, 2015 and 2022 editions. Their pages are now marked as unconfirmed trade sizes and they have been taken out of every table.
• Pipe weights were calculated with a constant of 10.6802. ASME B36.10 uses 10.69, which reproduces its published weights. Every weight on the site was about 0.09% light.
• Stainless 40S and 80S were said to stop at NPS 12. ASME B36.19 publishes them through NPS 24.
• Buttweld elbows in NPS 3/4 were 1.12 in for the 90° and 0.44 in for the 45°. They are 1.50 in and 0.75 in. The 45° elbow in NPS 22 was 13.75 in and is 13.50 in.
• Reducers were listed with a large end of NPS 1/2, which does not exist.
• Caps were shown with one length. ASME B16.9 gives a longer one above a limiting wall thickness, and the page now carries both.
• Large flanges, Series A Class 150: every thickness was between 0.7 and 1.9 in too thin, and the bolts for NPS 50 to 60 were given as 1 1/2 and 1 5/8 in where the standard has 1 3/4 in.
• Series A and Series B large flanges were said never to bolt together. At NPS 38 and larger in Classes 400, 600 and 900 they have the same dimensions.
• Material grades: A350 LF2, A182 F316 and the L grades were placed in the wrong rating groups, and the minimum tensile strength of grade 91 forgings and fittings was given as 85 ksi where it is 90 ksi.

The first check was made against manufacturers' and distributors' reproductions of the tables, and the second mostly against hosted copies of the standards' own text, with two or more independent sources for most values. Neither was made against a purchased copy of a standard. A few items could not be confirmed and are marked on the pages concerned: the Class 400 rows of four rating tables, the size range of threaded flanges in Classes 1500 and 2500, the Class 400 socket weld flange, and the dimensions of the four obsolete pipe sizes.

The same check covered the tables written into the guides. It corrected the pipe marking page, which carried the colour scheme and size bands of an earlier edition of ASME A13.1; the flange face finish, which B16.5 sets at 125 to 250 microinches, not 125 to 500; the statement that the raised face diameter differs in Classes 900 and above, which it does not; and the hydrostatic test guide, which compared a test pressure with the flange rating where it should have compared it with 1.5 times the rating, and described a reduction to design pressure that belongs to the pneumatic test.

Standards and editions

The table lists the standards these pages refer to and the most recent edition of each that we know of. The data on PipeData was compiled from published tables of these standards and cross-checked between sources. It was not transcribed line by line from one particular printed edition, and we do not claim that it was. Pipe and flange dimensions of the kind tabulated here have been stable across many editions, but ratings, notes and the range of sizes covered do change, so the edition your contract invokes is the one that governs.

ASME, ASTM and API publish and sell these standards. PipeData does not reproduce their text, and links to none of it; it tabulates dimensions and explains them in its own words.

Units

Imperial is primary — inches, pounds per foot, psig — because that is how these standards are written and how the material is ordered in North America. The metric equivalent appears alongside in every table: millimetres beneath inches, kilograms per metre beneath pounds per foot, bar beside psig.

Coverage gaps we admit to

ASME B16.47 is published here with the full table for Series A Class 150 only. The other series and class combinations are described but deliberately not tabulated. Large-flange data varies between the two series in ways that make a transcription error expensive, and an incomplete page is better than a confidently wrong one.

How the site is paid for

PipeData is free to use and carries advertising. Advertisers have no say in what the pages contain, and the site sells no products and takes no commission on any. The privacy page lists every third-party service the site loads.

Corrections

If a figure here disagrees with your copy of the standard, the standard is right and we want to know. Email info@pipedata.org with the page and the clause, or see the contact page for what to include.

Independence

PipeData is an independent reference project. It is not affiliated with, endorsed by or sponsored by ASME, ASTM, API, MSS or any manufacturer or distributor.