Standards guide · Fittings
Dished ends and caps: torispherical heads to DIN 28011 and caps to DIN 2617
Where a vessel or a pipeline ends, there sits a dished end: the torispherical head to DIN 28011 in apparatus and vessel construction, the cap to DIN 2617 as a welded-in pipe closure. This page explains the geometry of crown, knuckle and straight flange, the difference between head, cap and blind flange, the details an order needs – and why a fire bowl, despite its similar form, is something entirely different.
Choose the type – dimension table and dimensional drawing per type
Torispherical head or cap? – the same pipe diameter compared
Both parts for a 168.3 × 4 mm pipe, side by side at the same scale: on the left the cap to EN 10253-2, on the right the torispherical head to DIN 28011. The cap is considerably taller, the torispherical head is shallower.
Height outside: cap 89 mm · torispherical head 54.7 mm (inside height h3 50.7 mm). All dimensions: Caps in steel · Torispherical heads DIN 28011
- Standards
- DIN 28011 (heads) · DIN 2617/EN 10253 (caps) · EN 1092-1 (blind flanges)
- Materials
- steel (e.g. P235GH, S235JR) · stainless steel 1.4571
- Use
- vessel construction, pipe and vessel closure
- Availability
- available (from stock or sourced)
Closing a pipe end: which of the six ways fits?
A pipe end can be closed in six ways, and none of them is “the right one” – each answers a different question. The comparison of all six with standards, size range, height, pressure and typical use is on a page of its own: Closing a pipe end – cap, dished end, blind flange, plug or spectacle blind.
This page stays with the form: what distinguishes a torispherical head from a semi-ellipsoidal head, how the cap relates to them and where the fire bowl ends.
The torispherical head to DIN 28011
The torispherical head – Klöpperboden in German – is the most widespread form of dished end in the German-speaking countries. Its contour is made up of three zones: the crown (spherical segment with crown radius R = Da), the knuckle (transition radius r = 0.1 × Da) and the cylindrical straight flange, at which the head is welded to the vessel shell or pipe. Typical uses: vessel and apparatus heads, covers, end heads on silos and storage tanks – from the small vessel to the large apparatus.
All dimensions per size – with capacity, surface areas, weight, limit deviations, dimensional drawing and 3D model – are on the page Torispherical heads DIN 28011 – dimension table and dimensional drawing.
For higher pressures there is the deeper dished Korbbogen head (semi-ellipsoidal) to DIN 28013 (R = 0.8 × Da, r = 0.154 × Da) – larger knuckle, more favourable stress distribution, more height. We supply both forms in steel (e.g. P235GH, S235JR) and stainless steel (e.g. 1.4571), on request with an inspection certificate to EN 10204 – as a pressure-bearing component, the certificate belongs to the documentation.
Caps to DIN 2617: the welded-in pipe closure
The cap (also called welding cap or head) closes a pipe end permanently: it is butt-welded in like a fitting and ordered by pipe dimension – outside diameter and wall thickness to match the pipe. Historically standardised in DIN 2617, it belongs today to the fittings series EN 10253 – just like elbows (formerly DIN 2605), tees (DIN 2615) and reducers (DIN 2616); in trade the designation “cap DIN 2617” is still common.
Cap or blind flange? The cap is the permanent, tight and inexpensive solution – it is opened only by cutting. If the line is to be opened occasionally (inspection, cleaning, later extension), the removable blind flange is the right choice – more on our page flange standards. All six closures side by side: closing a pipe end.
Dimension table and dimensional drawing · steel
Caps of steel – EN 10253-2
Dimensional drawing for every size, type A and type B switchable, with full dimension tables, overall height K, pressure factor and tolerances.
Dimension table and dimensional drawing · stainless steel
Caps and dished ends of stainless steel – EN 10253-4
The same drawing for stainless steel – and in addition the dished end, which part 4 lists as a design of its own: lower, with a larger crown radius.
How caps and dished heads are made
Caps and dished heads are pressed from a plate blank. This is almost always done cold in a die; only very thick-walled single pieces are heated in a furnace before pressing. The material is therefore a plate material, for example P265GH to EN 10028-2 – and that is what the certificate shows.
Distinction: a fire bowl is not a dished end
Confusingly similar in form, technically two different worlds: fire bowls (also used as planters or decorative bowls) are non-standardised formed parts of markedly thinner sheet. They are subject neither to the dimensional and material requirements of DIN 28011 nor to any certificate requirement – and are therefore noticeably cheaper. Just right for the garden, not permissible as a pressure-bearing component in vessel or piping construction. The reverse also holds: whoever only needs a fire bowl need not pay for a certified torispherical head.
These details make your inquiry unambiguous
- Outside diameter Da and wall thickness s – for caps to match the pipe dimension.
- Material: e.g. P235GH or S235JR (steel), 1.4571 (stainless steel) – if in doubt, our overview materials compared helps.
- Standard or form: torispherical form DIN 28011, semi-ellipsoidal form DIN 28013 or cap DIN 2617 / EN 10253.
- Inspection certificate to EN 10204 (e.g. 3.1) if the part is used under pressure.
- Quantity and, if required, machining (holes, nozzles, coating).
Can this be 3D printed? Elbows, tees and reducers to EN 10253 are made from pipe or plate – a printed one is not a standard fitting and, as a pressure part, needs its own appraisal. Printing pays only for geometries no fitting offers: manifolds with internal channels, combined parts to drawing. What works, what does not – and what the rules say
Measuring the part yourself? Diameter and wall thickness at the welding end, not on the dome – plus overall height and straight flange height. How to measure correctly
Frequently asked questions about dished ends and caps
What is the difference between a dished end and a cap, and where are the dimensions?
Choose the dimension table and drawing at the top – cap in steel, cap in stainless steel, cap ASME B16.9 or torispherical head DIN 28011 – and you reach the dimension table with dimensional drawing, for the torispherical head also with capacity and weight; what distinguishes torispherical and semi-ellipsoidal heads to DIN 28011 and DIN 28013 from the cap is in the basics below.
What is the difference between a torispherical and a semi-ellipsoidal head?
Both are dished ends; they differ in geometry: the torispherical head to DIN 28011 has the crown radius R = Da and the knuckle radius r = 0.1 × Da. The semi-ellipsoidal head to DIN 28013 is dished more deeply, with R = 0.8 × Da and r = 0.154 × Da and a larger knuckle – it is higher and distributes stresses more favourably, which makes it interesting for higher pressures. The torispherical head is the most widespread form in vessel construction; semi-ellipsoidal heads we source on request.
Cap or blind flange – how do I close a pipe end?
The cap is butt-welded in and closes the pipe end permanently – tight, compact and inexpensive, but reopenable only by cutting. The blind flange closes a flanged joint removably: for cleaning and inspection openings or later extensions it is the right choice. Rule of thumb: permanently closed = cap, opened occasionally = blind flange. The decision table of all six closures is on the page closing a pipe end.
Is a fire bowl a torispherical head?
Similar in form, technically no: fire bowls are non-standardised formed parts of markedly thinner sheet – without the dimensional and material requirements of DIN 28011, without an inspection document and therefore noticeably cheaper. Just right for a fire bowl, planter or decoration, not permissible as a pressure-bearing component in vessel or piping construction. We supply both – what matters is only that the application fits the part.
What details does an inquiry for dished ends or caps need?
Outside diameter Da, wall thickness s, material (e.g. P235GH, S235JR or 1.4571), standard or form (DIN 28011 torispherical, DIN 28013 semi-ellipsoidal, cap DIN 2617/EN 10253), the required inspection certificate to EN 10204 (e.g. 3.1) and the quantity. For heads it also helps to know the planned use (pressure-bearing or not) and whether machining such as holes or nozzles is needed.
Order dished ends and caps directly
Steel and stainless steel versions are in the shop – special dimensions, semi-ellipsoidal heads and machined versions simply on inquiry; our export team will reply.
To the shop
Torispherical heads, steel
DIN 28011 in steel – category fittings → steel.
To the shop
Torispherical heads 1.4571
DIN 28011 in stainless steel 1.4571 – category fittings → stainless steel.
To the shop
Caps, steel
Caps DIN 2617 for butt welding – category fittings → steel.
Your inquiry to Zickwolff
Send us what you have – designation, standard, quantity, date. We will clarify the rest with you.
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Tell us by when you need the material – we will tell you what is possible.
Technical basis: DIN 28011, DIN 28013, DIN 2617 and EN 10253, EN 10204; range and distinction information from Zickwolff’s own trading practice (as of July 2026). All information without guarantee – the current standard texts and the manufacturers’ technical data sheets always prevail.
We supply this material – availability, delivery options and inquiry on the supply page →
