Standards · ASME and ASTM

ASME and ASTM standards in piping: the 13 standards we supply to

Whoever holds a flange data sheet from Houston, a pipe list from Rotterdam or a plant with an American pedigree reads standard numbers from a second world: ASME B16.5 instead of EN 1092-1, A106 instead of P265GH, schedule 40 instead of wall 3.6. This page sorts the 13 standards to which we supply flanges, fittings and pipe – one profile per standard with what it covers, the European counterpart and the limits of the comparison.

Choose the standard – profile and dimension page

ASME dimension standards with European counterpart (profiles from the data layer)
Standard	Covers	European counterpart	Profile
ASME B16.5 Pipe flanges and flanged fittings NPS 1/2 through NPS 24	Pressure-temperature ratings, materials, dimensions, tolerances, marking and testing of steel pipe flanges and flanged fittings in the Class system – the US counterpart of the PN flange world.	EN 1092-1 (PN) / EN 1759-1 (Class)	read the profile
ASME B16.9 Factory-made wrought buttwelding fittings	Overall dimensions, tolerances, ratings, testing and marking of buttwelding elbows, tees, reducers, caps and stub ends – the dimension standard – the steel comes from A234, A403 or A420.	EN 10253-2 / EN 10253-4	read the profile
ASME B16.25 Buttwelding ends	Preparation of the welding ends of pipe, fittings, flanges and valves that are joined by butt welding: bevel geometry, transitions of thick walls, internal end preparation, with and without backing rings or consumable inserts.	EN ISO 9692-1 / EN 10253 / EN 1092-1	read the profile
ASME B36.10M Welded and seamless wrought steel pipe	The dimension standard of the inch pipe world: nominal pipe size (NPS), outside diameter and the schedule wall thicknesses for carbon, alloy and ferritic stainless steel pipe. It defines no steel – that is the job of A106, A333, A335 or API 5L.	EN 10220 / EN 10216 / EN 10217	read the profile
ASME B36.19M Stainless steel pipe	Dimension standard for welded and seamless stainless steel pipe: NPS, outside diameter and the thin-wall schedules with the suffix S.	EN ISO 1127 / EN 10216-5 / EN 10217-7	read the profile

The material specifications (ASTM)

ASTM material specifications with European counterpart (profiles from the data layer)
Standard	Covers	European counterpart	Profile
ASTM A105/A105M Carbon steel forgings for piping applications	The standard carbon steel of the ASME flange and forged-fitting world for ambient and elevated temperature: flanges, forged fittings, valve parts up to 4540 kg piece weight, made to B16.5, B16.47, B16.11 or MSS dimensions.	EN 10222-2 (P250GH 1.0460, P280GH 1.0426, P245GH 1.0352)	read the profile
ASTM A106/A106M Seamless carbon steel pipe for high-temperature service	The black seamless pipe of the ASME world for steam, water, gas and air at elevated temperature – killed steel, seamless only, dimensions to B36.10M, suitable for bending, flanging and welding.	EN 10216-2 (P235GH 1.0345, P265GH 1.0425)	read the profile
ASTM A182/A182M Forged or rolled alloy and stainless steel pipe flanges, forged fittings, valves and parts	The forging standard for everything that is not plain carbon steel: low-alloy heat-resistant steels (F1, F11, F22, F91), austenitic stainless steels (F304/L, F316/L, F321, F347) and duplex (F51, F53) for flanges, forged fittings and valve parts up to 4540 kg.	EN 10222-2 / EN 10222-5	read the profile
ASTM A234/A234M Piping fittings of wrought carbon steel and alloy steel for moderate and high temperature service	The material standard of the carbon and alloy steel buttwelding fittings to B16.9 (and forged fittings to B16.11): chemistry, strength, heat treatment and testing of elbows, tees, reducers and caps made from pipe, plate or forgings.	EN 10253-2 (P235GH 1.0345, P265GH 1.0425, 16Mo3, 13CrMo4-5, 10CrMo9-10, X10CrMoVNb9-1)	read the profile
ASTM A333/A333M Seamless and welded steel pipe for low-temperature service	The low-temperature pipe of the ASME world: carbon and nickel steels with guaranteed notch toughness for LNG, cold boxes, refrigeration and any line that runs below −29 °C – the point where A106 stops.	EN 10216-4 (P265NL 1.0453, 12Ni14 1.5637, X10Ni9 1.5682)	read the profile
ASTM A350/A350M Carbon and low-alloy steel forgings requiring notch toughness testing for piping components	The low-temperature sister of A105: forged flanges, fittings and valve parts whose notch toughness is tested at the design temperature – the forging that belongs to A333 pipe and A420 fittings.	EN 10222-4 (P285NH 1.0477, P285QH 1.0478, P355QH1 1.0571) / EN 10222-3 (12Ni14 1.5637)	read the profile
ASTM A403/A403M Wrought austenitic stainless steel piping fittings	The material standard of the stainless buttwelding fittings to B16.9 (and forged fittings to B16.11): austenitic grades with the prefix WP, made seamless or welded from pipe, plate or forgings, with mandatory solution annealing.	EN 10253-4 (1.4301, 1.4307, 1.4401, 1.4404, 1.4541, 1.4550)	read the profile
ASTM A420/A420M Piping fittings of wrought carbon steel and alloy steel for low-temperature service	The low-temperature counterpart of A234: buttwelding and forged fittings whose notch toughness is tested at the design temperature – the fitting that belongs to A333 pipe and A350 flanges.	EN 10253-2 (P265NL 1.0453, 12Ni14 1.5637)	read the profile

ANSI: accredits – writes no piping standards itself
ASME: dimension and design standards: B16 (flanges, fittings), B36 (pipe sizes), B31 (piping)
ASTM: material specifications: A105, A106, A182, A234, A333, A350, A403, A420
Rule: a part needs a dimension standard plus a material specification
Comparison: Class is not PN, NPS not a diameter, schedule not a wall thickness
Zickwolff: deliverable from stock or to order, on request, with certificate 3.1

ANSI, ASME, ASTM: who writes what

In trade much is called an “ANSI flange” – yet the American National Standards Institute writes no piping standards. ANSI accredits the procedures of the standards bodies and declares their standards national standards. The dimension standards come from ASME (American Society of Mechanical Engineers): the B16 series for flanges, fittings and welding ends, B36 for pipe sizes, B31 for the design of whole piping systems. The materials are written by ASTM International (formerly American Society for Testing and Materials): A105, A106, A182 and so on. The ASME Boiler and Pressure Vessel Code adopts the ASTM materials as SA specifications (SA-105 is A105 with the code stamp).

From this follows the basic rule of the second standards world: a part always needs two standards – a dimension standard and a material specification. A flange is “B16.5 in A105”, an elbow “B16.9 in A234 WPB”, a pipe “B36.10M Sch 40 in A106 Gr. B”. The EN world is similar, but the product standard (EN 1092-1, EN 10253-2) carries the material with it.

Three families: flange, fitting, pipe

Flanges: dimensions to B16.5 (up to NPS 24) or B16.47 (from NPS 26), material A105 (carbon steel), A350 (low temperature) or A182 (alloy and stainless). Fittings: dimensions to B16.9, welding ends to B16.25, material A234 (carbon and alloy steel), A420 (low temperature) or A403 (stainless). Pipe: dimensions to B36.10M (steel) or B36.19M (stainless), material A106 (seamless, elevated temperature), A333 (low temperature) or A312 (stainless, only mentioned here).

The families match like their pipes: A106 Gr. B pipe, A234 WPB elbow, A105 flange for the normal case; A333 Gr. 6, A420 WPL6, A350 LF2 for low temperature; A312 TP316L, A403 WP316L, A182 F316L for stainless. Whoever mixes families mixes certificates, toughness proofs and bevels – and has to know it.

“To ASME” means three different things Dimensions to an ASME standard with a European material, dimensions plus an ASTM material, or a whole line designed to ASME B31. Under the Pressure Equipment Directive and the operating law these are not the same case – and the stamp on the part says nothing about the later inspection regime.

ASTM materials in Europe: the Pressure Equipment Directive

Pressure equipment in Europe falls under Directive 2014/68/EU. Materials to harmonised EN standards carry the presumption of conformity – ASTM materials do not. Whoever uses A105 or A234 WPB in pressure equipment of categories I to IV needs a European approval for materials or a particular material appraisal (PMA) by the equipment manufacturer, in categories III and IV assessed by the notified body. For equipment under Article 4(3) (sound engineering practice) and outside the directive this does not apply. That is why every ASTM profile has a section “Use in Europe” – and why all comparisons with EN grades are orientation, not equivalence.

At Zickwolff

We carry the common parts of these 13 standards – flanges in A105, A182 and A350, fittings in A234, A403 and A420, pipe in A106 and A333 – from stock or to order, with inspection certificate 3.1 to EN 10204. The standard names dimensions. What is listed here, we carry – from stock or to order; how quickly a size is available we clarify on request. Dimension tables for the ASME standards we build up step by step from manufacturer catalogues – until then they are available on request.

Frequently asked questions about ASME/ASTM

What do ASME B16.5, B16.9 and B36.10 cover?

Choose the standard's profile at the top – B16.5 covers flanges, B16.9 fittings, B36.10 and B36.19 pipes, the ASTM standards the materials; each standard is explained with scope and editions and leads to the dimension page with values in millimetres.

What is the difference between ANSI and ASME?

ANSI accredits and declares standards national, ASME writes them. An "ANSI flange" is a flange to ASME B16.5 – the old designation ANSI B16.5 lives on in trade.

Can I use ASME parts in an EN plant?

Dimensionally only where outside diameter, wall and bolt pattern match – rarely exactly. Material-wise only with an appraisal under the Pressure Equipment Directive. Our advice: stay in one standards world per line and plan the transitions deliberately.

Must a plant with ASME parts be inspected more often?

No – the inspection interval comes from the operating law of the country (in Germany the Betriebssicherheitsverordnung Annex 2, the operator's risk assessment, the inspector under TRBS 1201 Part 2), not from the code of the part. No legal advice – the legal text is binding.

Which ASME standards does Zickwolff supply?

The 13 standards of this page: flanges B16.5 (and B16.47 on request), fittings B16.9 with welding ends B16.25, pipe B36.10M/B36.19M, materials A105, A106, A182, A234, A333, A350, A403, A420 – from stock or to order.

Parts to ASME and ASTM – from one source

Tell us standard, size (NPS and schedule or Class), material grade, certificate and quantity – we check what is in stock, what we procure and which European part would do the same job.

Send an inquiry

Your inquiry to Zickwolff

Send us what you have – designation, standard, quantity, date. We will clarify the rest with you.

One item or a question

Send inquiry

Not in stock? We procure it – single items too.

Designation, standard and quantity are enough.

Several items

Send bill of materials

200 items? One parts list is enough – we deliver complete.

Attach it as a file.

Helpful if already known: project and country, date needed, certificates, packaging and language of the packing lists. If anything is missing, we will ask.

It is urgent

Request express

When do you need it? Express delivery, to the site if required.

Tell us by when you need the material – we will tell you what is possible.

← Back to the standards guide

Basis: the publicly accessible scopes and abstracts of ASME and ASTM (editions as of 2 October 2026), manufacturer catalogues, a trade reference catalogue DIN/EN/ASME and specialist sources for marking and impact test values – the legal statements follow Directive 2014/68/EU and the German Betriebssicherheitsverordnung. No standard text was reproduced – the current original edition is binding. Comparisons with EN grades are orientation, not equivalence. Information without guarantee, no legal advice, no prices.