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Standards guide · Steel reducers

Steel reducers: dimensions to EN 10253-2

Butt-welding reducers in steel are standardised in EN 10253-2. This page carries the figures: pick the design, the large end, the small end and the wall thickness series, and the dimension finder shows the dimensioned drawing, the dimension table and the limit deviations for exactly that size. The dimensions are the same for both designs – what separates the concentric from the eccentric reducer, and how type A differs from type B, is explained on the reducer basics page.

Standard
EN 10253-2:2026-07
Material
non-alloy and alloy steel
Designs
concentric / eccentric
Dimension
L

Dimension finder: dimensioned drawing for one specific size

Select design, large end, small end and wall thickness series – the drawing and the dimension table then show exactly that size, with the figures in the drawing itself instead of only the dimension letters. What separates the concentric from the eccentric design, and type A from type B, is on the reducer basics page. The dimension tables for the size pairs listed here are further down this page.

Design

EN 10253-2 covers the greyed-out sizes. Our dimension overview lists them as order dimensions – see the table “Further deliverable dimensions” below.

Steel reducer · concentric · 219.1 × 6.3 – 168.3 × 4.5 mm

Dimensioned drawing of a reducer in steel, concentric, 219.1 × 6.3 – 168.3 × 4.5 mm 219.1 (D) 168.3 (D1) 152 (L) 6.3 (T) 4.5 (T1) © zickwolff.de large end small end Steel reducer · concentric · 219.1 × 6.3 – 168.3 × 4.5 mm DIN EN 10253-2:2026-07 · Data as of 2026-08-25 · all dimensions in mm · to scale L is the overall length across both welding ends the transition is drawn as a cone with short cylindrical end sections – the standard dimensions D, D1, T, T1 and L, not the shape in between the two circles are the view onto the welding ends, at the scale of the drawing above – the large end on the left, the small one on the right · drawing calculated from the dimensions of the standard · Otto Zickwolff GmbH · zickwolff.de/wissen
Reducer in steel, concentric, 219.1 × 6.3 – 168.3 × 4.5 mm: section in the axial plane with the overall length L, below it the view onto both welding ends. The transition is drawn as a cone with short cylindrical end sections, the standard dimensions D, D1, T, T1 and L, not the shape in between.

Technical basis: DIN EN 10253-2:2026-07. Zickwolff has prepared this presentation for practical use, with our own structure, our own designations and a statement of what kind of value each figure is. The original standard governs normative requirements.

Dimensions of the reducer in steel, concentric, 219.1 × 6.3 – 168.3 × 4.5 mm
PropertyValueType of information
basic data
Wall thickness seriesSeries 2standard dimension
Availabilityfrom stock or procuredtrade information
nominal size (large end)DN 200assignment
nominal size (small end)DN 150assignment
mass5 kgguide value
connecting dimensions The dimensions at the welding ends that govern the joint with the pipe that follows.
outside diameter (large end) D219.1 mmstandard dimension
wall thickness (large end) T6.3 mmstandard dimension
inside diameter (large end)206.5 mmcalculated
outside diameter (small end) D1168.3 mmstandard dimension
wall thickness (small end) T14.5 mmstandard dimension
inside diameter (small end)159.3 mmcalculated
installation dimensions The dimensions that determine the installation space.
centre-to-end dimension L152 mmstandard dimension

Without an entry in the “Type of information” column: standard dimension. A dimension that EN 10253-2 specifies for this size.

Where exactly it is measured

outside diameter (large end) D
measured across the edge at the welding ends
outside diameter (small end) D1
measured across the edge at the welding ends
inside diameter (large end)
ID = D − 2T
inside diameter (small end)
ID1 = D1 − 2T1
centre-to-end dimension L
overall length across both welding ends
mass
guide value for estimating freight and loads

Not in the dimension finder: ⌀ 21.3 – 17.2 – No dimension row arises for these combinations: for one of the two diameters the standard gives no wall thickness series – without a wall thickness there is neither a scale drawing nor a complete dimension row.

Dimensions are nominal dimensions to EN 10253-2 and do not replace the data sheet of the actual item. No statement about pressure or temperature suitability and no statement about the material. L is the overall length across both welding ends. The design makes no difference to the dimensions. Direct link to this size

The standard names dimensions. What is listed here is deliverable – from stock or procured; how quickly a size is available we clarify on request.

How to measure correctly

A reducer is identified by five measurements: outside diameter and wall thickness at the large end (D, T), the same at the small end (D1, T1), and the overall length L across both welding ends. Measure the diameters across the edge of the welding ends. Whether the part is concentric or eccentric is seen, not measured: on an eccentric reducer one side runs straight through.

outside diameter (large end) D
measured across the edge at the welding ends
outside diameter (small end) D1
measured across the edge at the welding ends
centre-to-end dimension L
overall length across both welding ends

A measured value rarely matches the table exactly. The dimension finder on this page shows the limit deviations of EN 10253-2 for every size.

Design

Concentric and eccentric

On the concentric reducer both welding ends lie on a common centre line – the reduction runs evenly all round. On the eccentric reducer the two axes are offset parallel to each other: one generatrix runs straight through, and on that side the part stays flush with the line.

The standard lists both designs in one dimension table (Table A.3): large end D, small end D1, wall thicknesses T and T1 and the overall length L are identical – even the weight does not differ. That is why the design is, in the dimension finder above, a switch on the drawing and not a size selection of its own. Only the pressure factor depends on the design; the tables for it are given further down.

When which design is installed – straight generatrix at the top or at the bottom – is explained on the basics page on reducers.

Eccentric reducer in steel P235GH to EN 10253-2 with straight generatrix
Eccentric reducer – the straight generatrix is clearly visible. Where which design is installed is explained on the basics page.
Type A and type B

Type A and type B: the pressure factor

At the conical transition a reducer carries the internal pressure differently from the straight pipe. The standard describes this with two versions:

Version

Type A – reduced pressure factor

Wall thickness at the fitting body as at the welding ends. How much internal pressure the part carries compared with the straight pipe is stated by the pressure factor X in per cent – separately for both designs, in the tables below.

Version

Type B – full pressure resistance (standard: “for use at full service pressure”)

Increased wall thickness at the fitting body, designed for the same internal pressure as the straight pipe. The standard verifies the wall thickness needed according to Annex B; it is listed in Annex D.

The pressure factors on this page are calculated by us – via the equations of Annex B, clause B.4.5, with an arithmetical cross-check (reference in the standard: Annex C).

What this page does not show yet. The increased wall thickness of type B is not given here. We have not yet checked the associated verification route (Annex B, B.5.4) against the values of Annex D – and an unverified number would look on this page exactly like a verified one. It will be added as soon as it is substantiated.

Installation dimension

The overall length L

The reducer has exactly one overall dimension: L, the length across both welding ends. It depends only on the large end – all small ends of the same run share the same overall length.

The standard dimensions nothing more at the transition: neither the cone angle nor the length of the cylindrical end sections. The drawing above says so in its footer – drawn is the usual shape, dimensioned is what the standard specifies.

The permissible deviations of L are given in EN 10253-2, Table 13; the drawing above shows them in tolerance mode as a second line at the dimension.

Tolerances and testing

Limit deviations and out-of-roundness – per welding end

The drawing above carries the complete tolerance block – here the points that are particular to the reducer:

  • Each end counts with its own diameter. The standard measures “the corresponding outside diameters (D–D1) … at the welding ends” (clause 11.2.1.1). For the small end, the diameter and wall thickness limit deviations therefore apply with D1 and T1 – not with the values of the large end. For a 711 – 508 the large end can thus lie in a different band from the small end.
  • No out-of-roundness limit at the fitting body. The 4 % at the body applies, according to clause 11.2.2, only “to elbows and 180° elbows”. At the welding ends the general graduation applies – for each end with its own diameter.
  • No form tolerance P. In the overall dimension table it is expressly listed as a form tolerance for elbows.

Above ⌀ 610 mm the wall thickness limit deviations depend on whether the fitting is seamless or welded – again for each end with its own diameter and wall thickness. Below that, the distinction makes no difference to the dimensions.

Limits of this page

Which sizes this page shows – and where they come from

For each run, the dimension table of the standard names a range of possible small ends (“57 × 26.9 to 48.3”) – which sizes lie within it is enumerated one by one by the normative Annex C. That enumeration is the source of the size pairs on this page.

Two groups deserve a note:

  • Five runs are not enumerated individually by Annex C (⌀ 57, 108, 133, 159 and 559 mm), although the dimension table names a range for them. The sizes shown for these runs follow the basic series within the range of the standard – an interpretation, not an express enumeration of the standard. In the dimension tables below they carry footnote a, and the drawing says so in its footer.
  • One pair remains without a drawing: ⌀ 21.3 – 17.2. For 17.2 mm the standard names no wall thickness series, and without a wall thickness there is neither a drawing to scale nor a complete dimension row. Its standard dimensions are listed in the tables below.

We spell out both instead of silently smoothing it over: an interpretation that can be seen is something different from one that passes as a statement of the standard.

Read on

Dimension tables for reducers in steel: 76 size pairs

Zickwolff dimension overview (standard reference EN 10253-2) – one row per size pair of large and small end, the wall thicknesses of each series side by side. They apply to the concentric as well as the eccentric design. If you need a dimensioned drawing for one of these sizes, the dimension finder at the top of this page has it.

Nominal dimensions Pressure factor outside the preferred series Further deliverable dimensions

Nominal dimensions by wall thickness series

T is the wall thickness at the large end, T1 the one at the small end, both belonging to the same series number. L is the overall length across both welding ends.

Show full table · more than 70 rows
Reducers in steel to DIN EN 10253-2:2026-07, from stock or procured – 72 size pairs in 4 wall thickness series, all dimensions in millimetres.
Doutside diameter (large end) in mmDNnominal size (large end)D1outside diameter (small end) in mmDN1nominal size (small end) in DNLcentre-to-end dimension in mmSeries 2Series 3Series 4Series 5
T – large end wall thickness in mm, series 2T1 – small end wall thickness in mm, series 2T – large end wall thickness in mm, series 3T1 – small end wall thickness in mm, series 3T – large end wall thickness in mm, series 4T1 – small end wall thickness in mm, series 4T – large end wall thickness in mm, series 5T1 – small end wall thickness in mm, series 5
26.92021.315382.32we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
33.72521.315512.62we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
33.72526.920512.62.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
42.43221.315512.62we do not show this wall thickness series at presentwe do not show this wall thickness series at present54
42.43226.920512.62.3we do not show this wall thickness series at presentwe do not show this wall thickness series at present54
42.43233.725512.62.63.63.2we do not show this wall thickness series at present54.5
48.34021.315642.62we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
48.34026.920642.62.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
48.34033.725642.62.6we do not show this wall thickness series at present44we do not show this wall thickness series at present
48.34042.432642.62.6we do not show this wall thickness series at present44we do not show this wall thickness series at present
57a (size derived from the base series, see footnote a)26.920762.92.3no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
57a (size derived from the base series, see footnote a)33.725762.92.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
57a (size derived from the base series, see footnote a)42.432762.92.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
57a (size derived from the base series, see footnote a)48.340762.92.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
60.35026.920762.92.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.35033.725762.92.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.35042.432762.92.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.35048.340762.92.6we do not show this wall thickness series at presentwe do not show this wall thickness series at present5.65
76.16533.725892.92.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
76.16542.432892.92.6we do not show this wall thickness series at present5.64we do not show this wall thickness series at present
76.16548.340892.92.6we do not show this wall thickness series at present5.647.15
76.16560.350892.92.9we do not show this wall thickness series at present5.647.15.6
88.98042.432893.22.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
88.98048.340893.22.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
88.98060.350893.22.9we do not show this wall thickness series at present5.6485.6
88.98076.165893.22.9we do not show this wall thickness series at present5.65.687.1
108a (size derived from the base series, see footnote a)48.3401023.62.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
108a (size derived from the base series, see footnote a)60.3501023.62.9no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
108a (size derived from the base series, see footnote a)76.1651023.62.9no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
108a (size derived from the base series, see footnote a)88.9801023.63.2no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
114.310048.3401023.62.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
114.310060.3501023.62.9we do not show this wall thickness series at present6.348.85.6
114.310076.1651023.62.9we do not show this wall thickness series at present6.35.68.87.1
114.310088.9801023.63.2we do not show this wall thickness series at present6.35.68.88
133a (size derived from the base series, see footnote a)60.35012742.9no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
133a (size derived from the base series, see footnote a)76.16512742.9no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
133a (size derived from the base series, see footnote a)88.98012743.2no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
133a (size derived from the base series, see footnote a)114.310012743.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
139.712560.35012742.9we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
139.712576.16512742.9we do not show this wall thickness series at present6.35.6we do not show this wall thickness series at present
139.712588.98012743.2we do not show this wall thickness series at present6.35.6108
139.7125114.310012743.6we do not show this wall thickness series at present6.36.3108.8
159a (size derived from the base series, see footnote a)76.1651404.52.9no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
159a (size derived from the base series, see footnote a)88.9801404.53.2no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
159a (size derived from the base series, see footnote a)114.31001404.53.6no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
159a (size derived from the base series, see footnote a)139.71251404.54no wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
168.315076.1651404.52.9we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
168.315088.9801404.53.2we do not show this wall thickness series at present7.15.6118
168.3150114.31001404.53.6we do not show this wall thickness series at present7.16.3118.8
168.3150139.71251404.54we do not show this wall thickness series at present7.16.31110
219.120088.9801526.33.2we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
219.1200114.31001526.33.6we do not show this wall thickness series at present86.3we do not show this wall thickness series at present
219.1200139.71251526.34we do not show this wall thickness series at present86.312.510
219.1200168.31501526.34.5we do not show this wall thickness series at present87.112.511
273250114.31001786.33.6we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
273250139.71251786.34we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
273250168.31501786.34.5we do not show this wall thickness series at presentwe do not show this wall thickness series at present12.511
273250219.12001786.36.3we do not show this wall thickness series at presentwe do not show this wall thickness series at present12.512.5
323.9300139.71252037.14we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
323.9300168.31502037.14.5we do not show this wall thickness series at present107.112.511
323.9300219.12002037.16.3we do not show this wall thickness series at present10812.512.5
323.93002732502037.16.3we do not show this wall thickness series at presentwe do not show this wall thickness series at present12.512.5
355.6350168.315033084.5we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.6350219.120033086.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.635027325033086.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.6350323.930033087.1we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4400219.12003568.86.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.44002732503568.86.3we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4400323.93003568.87.1we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4400355.63503568.88we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
457450323.9300381107.1we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
457450406.4400381108.8we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present

standard dimension: D, D1, L, T, T1 · assignment: DN, DN1

a For this run the standard does not list the sizes of the small end individually – the sizes shown follow the basic series within the range of the standard. This is an interpretation, not an explicit listing by the standard. Large ends 57, 108, 133, 159

DN: The standard does not assign a nominal size to every size. Where the dash stands there is none – the size is designated by its outside diameter.

Where a series column carries no figure, the digit at the dash says why – mostly the standard, in one case us:

1 EN 10253-2 lists no wall thickness of this series for this large end. 48 cells

5 EN 10253-2 does list a wall thickness of this series for this size pair; our dimension overview does not show it at present. 123 cells

Pressure factor by design and series

The pressure factor X says what proportion of the pipe pressure a reducer of this size carries. The values are those of tables C.3 (concentric) and C.4 (eccentric) of the standard. We additionally recalculated every cell through the equations of Annex B and matched them in full. α is the largest opening angle for which the row applies – that too is how the standard states it.

Show full table · more than 70 rows
Pressure factor in per cent for reducers in steel to DIN EN 10253-2:2026-07, tables C.3 and C.4 – 72 size pairs, the same rows as above.
Doutside diameter (large end) in mmD1outside diameter (small end) in mmα conc.largest opening angle, concentricα ecc.largest opening angle, eccentricSeries 2Series 3Series 4Series 5
conc. – pressure factor concentric in per cent, series 2ecc. – pressure factor eccentric in per cent, series 2conc. – pressure factor concentric in per cent, series 3ecc. – pressure factor eccentric in per cent, series 3conc. – pressure factor concentric in per cent, series 4ecc. – pressure factor eccentric in per cent, series 4conc. – pressure factor concentric in per cent, series 5ecc. – pressure factor eccentric in per cent, series 5
26.921.315°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
33.721.312°24°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
33.726.913°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
42.421.319°42°10097we do not show this wall thickness series at presentwe do not show this wall thickness series at present100100
42.426.915°30°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at present100100
42.433.716°100100100100we do not show this wall thickness series at present100100
48.321.322°37°10099we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
48.326.916°28°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
48.333.710°19°100100we do not show this wall thickness series at present100100we do not show this wall thickness series at present
48.342.4100100we do not show this wall thickness series at present100100we do not show this wall thickness series at present
5726.9size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
5733.7size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
5742.4size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
5748.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
60.326.921°36°10098we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.333.716°29°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.342.411°20°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
60.348.313°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at present100100
76.133.723°42°10090we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
76.142.418°34°10097we do not show this wall thickness series at present100100we do not show this wall thickness series at present
76.148.315°27°100100we do not show this wall thickness series at present100100100100
76.160.315°100100we do not show this wall thickness series at present100100100100
88.942.426°50°10080we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
88.948.322°44°10087we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
88.960.316°30°10099we do not show this wall thickness series at present100100100100
88.976.113°100100we do not show this wall thickness series at present100100100100
10848.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
10860.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
10876.1size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
10888.9size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
114.348.331°60°97(65)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
114.360.326°51°10078we do not show this wall thickness series at present1008610094
114.376.118°37°10093we do not show this wall thickness series at present100100100100
114.388.913°24°100100we do not show this wall thickness series at present100100100100
13360.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
13376.1size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
13388.9size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
133114.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
139.760.330°51°9777we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
139.776.125°43°10086we do not show this wall thickness series at present10091we do not show this wall thickness series at present
139.788.920°35°10093we do not show this wall thickness series at present10098100100
139.7114.310°18°100100we do not show this wall thickness series at present100100100100
15976.1size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
15988.9size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
159114.3size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
159139.7size derived from the base series - the standard gives no pressure factor for itno wall thickness for the large end in this seriesno wall thickness for the large end in this seriesno wall thickness for the large end in this series
168.376.131°52°96(75)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
168.388.927°48°9880we do not show this wall thickness series at present1008510093
168.3114.319°34°10094we do not show this wall thickness series at present10098100100
168.3139.718°100100we do not show this wall thickness series at present100100100100
219.188.939°60°90(64)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
219.1114.333°55°95(71)we do not show this wall thickness series at present9774we do not show this wall thickness series at present
219.1139.727°45°99(74)we do not show this wall thickness series at present100(86)10093
219.1168.318°31°100(90)we do not show this wall thickness series at present10098100100
273114.340°60°87(62)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
273139.736°55°91(69)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
273168.330°48°95(75)we do not show this wall thickness series at presentwe do not show this wall thickness series at present10086
273219.116°28°10097we do not show this wall thickness series at presentwe do not show this wall thickness series at present100100
323.9139.740°60°87(61)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
323.9168.335°55°91(69)we do not show this wall thickness series at present94(72)9675
323.9219.124°44°99(83)we do not show this wall thickness series at present100(86)10088
323.927312°23°100(99)we do not show this wall thickness series at presentwe do not show this wall thickness series at present100100
355.6168.329°47°9679we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.6219.122°37°10090we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.627314°25°100(97)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
355.6323.9100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4219.128°46°9680we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.427321°36°100(83)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4323.913°24°100(96)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
406.4355.615°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
457323.918°31°100(85)we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present
457406.411°100100we do not show this wall thickness series at presentwe do not show this wall thickness series at presentwe do not show this wall thickness series at present

standard dimension: D, D1 · standard value: α, X

( ) Values in brackets apply only if the cylindrical end lengths reach the minimum values to Annex B, or if the reducer sits between pipes of wall thickness T and T1 respectively – that is how the standard states it. 20 cells

Where a series column carries no figure, the digit at the dash says why – mostly the standard, in one case us:

1 EN 10253-2 lists no wall thickness of this series for this large end. 48 cells

4 For this run the standard does not list the sizes of the small end individually – the sizes shown follow the basic series within the range of the standard. This is an interpretation, not an explicit listing by the standard. The standard gives no pressure factor for these sizes. 16 cells

5 EN 10253-2 does list a wall thickness of this series for this size pair; our dimension overview does not show it at present. 123 cells

Dimensions outside the preferred series

EN 10253-2 pairs diameter and wall thickness through a series number. The sizes below we carry with a wall thickness that is in no series for that size – or with two wall thicknesses that are each in the standard, but not in the same series. The dimensions are established in the same way as in the grid above. Where the standard gives its values through the series number, the cell stays empty.

Show full table · more than 40 rows
Dimensions outside the preferred series to EN 10253-2, from stock or procured – 47 rows, all dimensions in millimetres.
Doutside diameter (large end) in mmD1outside diameter (small end) in mmnominal size (large end) in DNnominal size (small end) in DNTwall thickness (large end) in mmT1wall thickness (small end) in mminside diameter (large end) in mminside diameter (small end) in mmLcentre-to-end dimension in mm
33.721.325153.23.227.314.951
33.721.325154425.713.351
33.726.925203.23.227.320.551
33.726.925204425.718.951
42.421.332153.63.235.214.951
42.426.932203.63.235.220.551
48.326.940205538.316.964
48.333.7402543.240.327.364
48.333.740255438.325.764
48.333.740255538.323.764
48.342.4403243.640.335.264
48.342.440325438.334.464
60.326.950205.65.649.115.776
60.333.750254.53.251.327.376
60.333.750255.6449.125.776
60.342.450324.53.651.335.276
60.342.450325.6449.134.476
60.348.350404.5451.340.376
60.348.350405.65.649.137.176
76.142.465325566.132.489
76.148.365405566.138.389
76.160.3655054.566.151.389
88.942.480328872.926.489
88.948.380405.65.677.737.189
88.960.380505.64.577.751.389
114.348.3100406.33.6101.741.1102
114.360.3100506.36.3101.747.7102
114.388.910080101094.368.9102
114.388.9100806.35101.778.9102
114.388.9100808.88.896.771.3102
139.7114.31251001010119.794.3127
139.7114.31251006.35.6127.1103.1127
168.376.1150655.65.6157.164.9140
168.3114.31501001111146.392.3140
168.3114.31501007.17.1154.1100.1140
168.3139.71501251111146.3117.7140
219.188.92008012.512.5194.163.9152
219.1114.320010012.58194.198.3152
219.1139.720012512.512.5194.1114.7152
219.1168.320015088203.1152.3152
273168.32501508.87.1255.4154.1178
273219.12502008.88255.4203.1178
323.9273300250108.8303.9255.4203
508323.9500300117.1486309.7508
508355.6500350118486339.6508
508406.4500400118.8486388.8508
5084575004501110486437508

Further deliverable dimensions (84)

Show full table · more than 80 rows
Further deliverable dimensions – 84 rows, from stock or procured, all dimensions in millimetres.
Doutside diameter (large end) in mmD1outside diameter (small end) in mmTwall thickness (large end) in mmT1wall thickness (small end) in mm
4572736.35
457273106.3
457273118.8
45727312.510
45727317.512.5
45727322.216
4572733222.2
4572734530
457355.66.35.6
457355.6108
457355.61110
457355.612.512.5
457355.617.516
457355.622.220
457355.63228
457355.64536
610406.46.36.3
610406.4108.8
610406.412.510
610406.417.512.5
610406.42517.5
610406.43022.2
610406.44530
610406.46040
6104576.36.3
6104571010
61045712.511
61045717.512.5
6104572517.5
6104573022.2
6104574532
6104576045
6105086.36.3
6105081010
61050812.511
61050817.512.5
6105082517.5
6105083025
6105084536
6105086050
7115087.16.3
7115081010
71150812.511
7115082512.5
7116107.16.3
7116101010
71161012.512.5
7116102517.5
81361086.3
8136101010
81361012.512.5
8136102517.5
81371187.1
8137111010
81371112.512.5
8137112525
914711107.1
91471112.510
9147112012.5
9147112525
914813108
91481312.510
9148132012.5
9148132525
1016813108
101681312.510
10168132012.5
10168132525
10169141010
101691412.512.5
10169142020
10169142525
1219813108
121981312.510
12198132012.5
12198132525
12199141010
121991412.512.5
12199142020
12199142525
121910161010
1219101612.512.5
121910162020
121910162525

Order dimensions and values calculated by us; deliverable from stock or procured, availability on request. Limit deviations and figures from the standard: see the main table and the standard itself.

The dimensions given are nominal dimensions. The text of the standard prevails. The German edition DIN EN 10253-2:2026-07 reproduces the European version EN 10253-2:2021+A1:2025.

What has changed since the earlier edition

For the reducer, the comparison covers the editions from DIN EN 10253-2:2008-09. Not yet recorded: DIN 2616:1964 and 2616-1/-2:1991.

DIN 2616-2:1991-02 → DIN EN 10253-2:2008-09

  • not yet recorded

    For this period the edition is not available to us - no comparison is claimed.

These entries say what the standard has changed. They say nothing about material, pressure rating, scope of testing or the condition of an installed part — and nothing about whether an existing part can continue to be used. That assessment remains with the specific plant.

Reducers by dimension – ask our warehouse

You know both ends? Send us the two outside diameters with their wall thicknesses and the design, together with the material and the inspection document required. Our export team answers in English, with price, availability and certificate.

Send an inquiry
← Back to the English knowledge hub

How this data is compiled. This page does not reproduce a standard. It shows the dimensions you need for an enquiry, an order and installation – for sizes we supply, checked against documents from manufacturing works and suppliers and against our own range. Each value states what kind of value it is: specified by the standard, calculated by us or customary in the trade. The currently valid standard is binding. It is available from DIN Media or from your national standards body. How we select our sources and keep them up to date: About this knowledge.

Technical basis: DIN EN 10253-2:2026-07 (butt-welding fittings of non-alloy and alloy steel), EN 10204. All information without guarantee – the current standard texts and the manufacturers’ technical data sheets always prevail.