Plant Engineering Infobase · Chapter 08 of 14
Piping specs
A piping spec defines which components are permitted for a line. This ensures that process requirements are met consistently, and the designer does not have to worry about the detailed definition of each component. The basis is DIN 21057-1:2023-08, based on DIN EN 13480.
Overview
Calculate a piping spec › Piping Spec Calculator: preliminary sizing of wall thickness based on DIN EN 13480-3, AD 2000, ASME B31.3 and for plastic pipes, branch table and spec sheet
Material groups and facings correspond to ISO 15608:2025 (formerly ISO/TR 15608:2017) and DIN EN 1092-1:2018. Check the naming scheme and gasket groups against DIN 21057-1:2023 before adopting them in project standards.
Naming
The piping spec designation consists of pressure rating, material group, material, sequential number, facing or end type, and gasket. Sequential numbers 01–19 are reserved for standard piping specs, 20–99 for project- or plant-specific definitions, such as different manufacturing methods.
Materials
The material designation is governed by the pipe material. The first letter denotes the group, the second the material; X as the second letter stands for other materials in the group. Material groups according to ISO 15608:2025 (formerly ISO/TR 15608:2017).
| Code | Material | Mat. no. | ISO 15608 group |
|---|---|---|---|
| B – Non-alloy steels with specified properties at room temperature | |||
| BA | P235TR2 | 1.0255 | 1.1 |
| C – Non-alloy and alloy steels with specified properties at elevated temperatures | |||
| CA | P235GH | 1.0345 | 1.1 |
| CB | P265GH | 1.0425 | 1.1 |
| CC | 16Mo3 | 1.5415 | 1.2 |
| CD | 13CrMo4-5 | 1.7335 | 5.1 |
| CE | 10CrMo9-10 | 1.7380 | 5.2 |
| F – Fine-grain structural steels and steels with specified properties at low temperatures | |||
| FA | P215NL | 1.0451 | 1.1 |
| FB | P255QL | 1.0452 | 1.1 |
| FC | P355NH | 1.0565 | 1.2 |
| FD | P355NL1 | 1.0566 | 1.2 |
| FE | P355NL2 | 1.1106 | 1.2 |
| FF | 12Ni14 | 1.5637 | 9.2 |
| H – Stainless steels | |||
| HA | X5CrNi18-10 | 1.4301 | 8.1 |
| HB | X2CrNi19-11 | 1.4306 | 8.1 |
| HC | X6CrNiTi18-10 | 1.4541 | 8.1 |
| HD | X6CrNiMoTi17-12-2 | 1.4571 | 8.1 |
| HE | X5CrNiMo17-12-2 | 1.4401 | 8.1 |
| HF | X2CrNiMo17-12-2 | 1.4404 | 8.1 |
| HG | X2CrNiMoN22-5-3 (duplex) | 1.4462 | 10.1 |
| X – Other materials | |||
Facings and connection types
Facings according to DIN EN 1092-1:2018, supplemented by other end types. Rz = mean roughness depth in µm.
| Code | Facing according to EN 1092-1 | Rz max |
|---|---|---|
| A | without sealing ridge (smooth) | 50 |
| B1 | with sealing ridge | 50 |
| B2 | with sealing ridge, finer | 12.5 |
| C | Tongue | 12.5 |
| D | Groove | 12.5 |
| E | Spigot | 50 |
| F | Recess | 50 |
| G | O-ring spigot | 12.5 |
| H | O-ring groove | 12.5 |
| Code | Other end types |
|---|---|
| J | Ring joint |
| L | Lens gasket |
| M | Membrane weld gasket |
| S | Butt-weld end |
| W | Cutting or compression ring |
| Y | Female thread |
| Z | Male thread |
Gaskets
| Code | Gasket group |
|---|---|
| F | Fiber gaskets, also with inner eyelet |
| G | Graphite gaskets, also with inner eyelet |
| K | Kammprofile gaskets |
| M | Metal gaskets (e.g. lens gasket, ring joint) |
| R | Elastomer gaskets |
| S | Spiral wound gaskets |
| T | PTFE gaskets, also enveloped |
| X | Other gaskets |
Materials and combinations, for example in spiral wound gaskets, are distinguished by sequence numbers and documented in the piping spec. A gasket is uniquely described by DN, pressure rating, gasket group, sequential number and facing type.
If the gasket material changes, the flange and bolt assignment may also be affected (facing type, surface pressure). Flange joints are calculated according to DIN EN 1591-1; gasket parameters are provided by DIN CEN/TR 1591-2:2023-12 (successor to DIN EN 1591-2) or the gasket manufacturer's database.
Color coding of pipes
Piping components are color-coded on site by material to avoid mix-ups with remnants that have no stamping. Colors and stripe sequence according to DIN 21057-1 or the operator's plant standard; the paint must not damage the material (e.g. no chlorides on austenitic steels), and weld bevels are kept free.
Example: piping spec 10CA01B1
| Scope | Pressure Equipment Directive 2014/68/EU | Pressure rating | PN 10 |
| Design basis | DIN EN 13480, DIN 21057 | Nominal sizes | DN 15 – DN 1200 |
| Base materials | P235GH (pipe, fittings), P245GH (flanges) | Corrosion allowance | 1.0 mm |
| Facing | B1 according to DIN EN 1092-1:2018 | Gaskets | for PN flanges according to DIN EN 1514; define material and type according to fluid and application range |
Pressure-temperature rating: according to DIN EN 1092-1:2018, Annex G, for flange material group 3E0 (P245GH, 1.0352). The allowable pressures decrease with increasing temperature; for PN 10, the nominal pressure of 10 bar applies only up to the reference temperature. Take the values from the standard.
Components
| Component | Design | Remark |
|---|---|---|
| Pipe | seamless DIN EN 10216-2 or welded DIN EN 10217-2, P235GH | Wall thicknesses: see dimension table |
| Elbow 45° / 90° | Pipe elbow DIN EN 10253-2 (radius according to project specification); 5D machine-made bend from pipe | |
| Reducer | DIN EN 10253-2, concentric and eccentric | max. 3 nominal size steps |
| Branch | Tee DIN EN 10253-2 or reinforced branch outlet DIN 21057-5 | Assignment via the piping spec's branch table |
| Heads | Cap DIN EN 10253-2, torispherical head | |
| Weld neck flange | DIN EN 1092-1 Type 11 / B1, P245GH | PN 40: DN 15–40 · PN 16: DN 50–150 · PN 10: DN 200–1200 |
| Blind flange | DIN EN 1092-1 Type 05 / B1, P265GH | Pressure ratings as for weld neck flange |
| Bolts, nuts | Hexagon, 25CrMo4, selection according to DIN EN 1515 | |
| Washers | 200 HV | salt-bath nitrided |
Dimension table (wall thicknesses in mm)
| DN | OD | Pipe | Elbow | Reducer | Cap | Torispherical head |
|---|---|---|---|---|---|---|
| 15 | 21.3 | 2,0* | 2.0 | 2.0 | – | – |
| 20 | 26.9 | 2,3* | 2.3 | 2.3 | 2.3 | 2.3 |
| 25 | 33.7 | 2,6* | 2.6 | 2.6 | 2.6 | 2.6 |
| (32) | 42.4 | 2,6* | 2.6 | 2.6 | 2.6 | 2.6 |
| 40 | 48.3 | 2,6* | 2.6 | 2.6 | 2.6 | 2.6 |
| 50 | 60.3 | 2,9* | 2.9 | 2.9 | 2.9 | 2.9 |
| (65) | 76.1 | 2,9* | 2.9 | 2.9 | 2.9 | 2.9 |
| 80 | 88.9 | 3,2* | 3.2 | 3.2 | 3.2 | 3.2 |
| 100 | 114.3 | 3,6* | 3.6 | 3.6 | 3.6 | 3.6 |
| (125) | 139.7 | 4,0* | 4.0 | 4.0 | 4.0 | 4.0 |
| 150 | 168.3 | 4,5* | 4.5 | 4.5 | 4.5 | 4.5 |
| 200 | 219.1 | 4.5 | 4.5 | 4.5 | 4.5 | 4.5 |
| 250 | 273.0 | 4.5 | 5.0 | 5.0 | 5.0 | 5.0 |
| 300 | 323.9 | 4.5 | 5.6 | 5.6 | 4.5 | 4.5 |
| (350) | 355.6 | 4.5 | 5.6 | 5.6 | 4.5 | 4.5 |
| 400 | 406.4 | 5.0 | 6.3 | 6.3 | 5.0 | 5.0 |
| (450) | 457.0 | 5.6 | 6.3 | 6.3 | 5.0 | 5.0 |
| 500 | 508.0 | 5.6 | 6.3 | 6.3 | 5.0 | 5.0 |
| 600 | 610.0 | 6.3 | 6.3 | 6.3 | 6.3 | 6.3 |
| 700 | 711.0 | 7.1 | 7.1 | 7.1 | 7.1 | 7.1 |
| 800 | 813.0 | 8.0 | 8.0 | 8.0 | 8.0 | 8.0 |
| 900 | 914.0 | 10.0 | 10.0 | 10.0 | 10.0 | 10.0 |
| 1000 | 1016.0 | 10.0 | 10.0 | 10.0 | 10.0 | 10.0 |
| 1200 | 1219.0 | 12.5 | 12.5 | 12.5 | 12.5 | 12.5 |
Related offering
ASEING piping catalogs – based on standards
49 checked catalogs for AutoCAD Plant 3D: steel, stainless steel, enamel, plastic, ventilation, valves and instruments – with weights and order texts according to DIN 21057. Individual catalogs from €350 net, complete package €9,990 net. Use the Piping Spec Calculator for preliminary sizing of your own spec – it also shows the matching catalogs right away.
Overall concept · Piping construction
Software and training for this discipline
Which Autodesk software fits – and where you can learn it. Overview of all disciplines in the overall concept, all dates in the training calendar.
Software
Training dates
Converter for piping specs
DN and NPS with outside diameters per standard, schedule and wall thickness, PN and Class with pressure-temperature rating, material number and ASTM equivalent – for reading third-party piping specs and specifications.
Also available as a separate page: Converter DN · Class · material
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Standards status for this page 16 standards · researched September 2026
| Standard | Contents | Current edition | Replaced / successor |
|---|---|---|---|
| DIN 21057-1 | Piping classes for process plants – Part 1: General | DIN 21057-1:2023-08 | replaces DIN 21057-1:2016-12 |
| DIN EN 13480 | Metallic industrial piping | DIN EN 13480-1 to -6 and -8:2024-12; Part 7 as DIN CEN/TR 13480-7:2022-08 | replaces the 2017-12 editions with amendments A1 ff. |
| DIN EN 13480-3 | Metallic industrial piping – Part 3: Design and calculation | DIN EN 13480-3:2024-12 | replaces DIN EN 13480-3:2017-12; DIN EN 13480-3/A1:2021-05; DIN EN 13480-3/A2:2020-12 |
| ASME B31.3 | Process Piping | ASME B31.3-2024 | replaces ASME B31.3-2022 |
| ISO/TR 15608 | Welding – Guidelines for a metallic materials grouping system | withdrawn | today: ISO 15608:2025 (published 16 October 2025) |
| DIN EN 1092-1 | Flanges and their joints – Circular flanges for pipes, valves, fittings and accessories, PN designated – Part 1: Steel flanges | DIN EN 1092-1:2018-12 | replaces DIN EN 1092-1:2013-04; DIN EN 1092-1 Corrigendum 1:2014-08 |
| DIN EN 1591-1 | Flanges and their joints – Design rules for gasketed circular flange connections – Part 1: Calculation | DIN EN 1591-1:2026-02 | replaces DIN EN 1591-1:2014-04 |
| DIN EN 1591-2 | Flanges and their joints – Part 2: Gasket parameters | withdrawn | now: DIN CEN/TR 1591-2:2023-12 (technical report) |
| Directive 2014/68/EU (PED) | Pressure Equipment Directive (recast) | Directive 2014/68/EU of 15 May 2014 (OJ L 189 of 27 June 2014) | replaces Directive 97/23/EC (superseded on 19 July 2016) |
| DIN 21057 | Piping specs | DIN 21057-1:2023-08; Parts 5/6:2016-12; Parts 10–12:2026-04/-05 | replaces PAS 1057; DIN 21057-1:2016-12; DIN 21057-10 to -12:2017-04 |
| DIN EN 1514-1 | Flanges and their joints – Dimensions of gaskets for PN-designated flanges – Part 1: Non-metallic flat gaskets | DIN EN 1514-1:2024-10 | replaces DIN EN 1514-1:1997-08 |
| DIN EN 10216-2 | Seamless steel tubes – Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties | DIN EN 10216-2:2025-02 | replaces DIN EN 10216-2:2020-04 |
| DIN EN 10217-2 | Welded steel tubes – Part 2: Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties | DIN EN 10217-2:2019-08 | replaces DIN EN 10217-2:2005-04 |
| DIN EN 10253-2 | Butt-welding pipe fittings – Part 2: Non-alloy and ferritic alloy steels with specific inspection requirements | DIN EN 10253-2:2026-07 | replaces DIN EN 10253-2:2021-11 |
| DIN 21057-5 | Piping classes – Part 5: Technical delivery conditions – Reinforced branch outlets | DIN 21057-5:2016-12 | – |
| DIN EN 1515-1 | Flanges and their joints – Bolting – Part 1: Selection of bolting | DIN EN 1515-1:2000-01 | replaces DIN 2507:1986-02 |
Researched at DIN Media, ISO, IEC and ASME, as of September 2026. Before binding use, please check the current edition with the standards publisher. Overview of all standards: Plant Engineering Infobase · Standards status.