45° | 90° | 180° | EN 10253-2 and EN 10253-4 | DN 15 – DN 1200
A Type B elbow to EN 10253-2 or EN 10253-4 carries the full service pressure of the connecting pipe of the same material and wall. Under internal pressure the inside of an elbow (the intrados) carries the highest stress, so a Type B elbow has extra wall at the intrados while the ends are machined to the wall of your pipe. We make 45°, 90° and 180° Type B elbows in non-alloy, CrMo, stainless and duplex grades, with the intrados thickness measured and reported on the certificate.
| Standard | EN 10253-2 (non-alloy, ferritic), EN 10253-4 (austenitic, duplex) |
| Type | Type B (Type A also available) |
| Angles | 45°, 90°, 180° |
| Size | DN 15 – DN 1200 |
| Intrados | Increased wall, measured and reported |
| Ends | Machined to your pipe wall and bore |
| Documents | EN 10204 3.1 std, 3.2 on request |
In a pressurised elbow the hoop stress is not the same all round. It is highest at the intrados (the inside of the bend) and lowest at the extrados. A Type A elbow with the same nominal wall as the pipe is therefore weaker than the pipe, which is why Type A has a reduced pressure factor.
EN 10253 Type B solves this by requiring extra wall thickness at the intrados, so the elbow carries the same pressure as the pipe. When we hot-form an elbow, metal naturally thickens on the inside of the bend; we select the starting pipe and forming process so the intrados reaches the Type B value, and we measure it on the finished elbow.
If you have been offered Type B elbows and want to check the intrados figure, use our free Type B thickness check.
| Item | Type A elbow | Type B elbow |
|---|---|---|
| Pressure capacity | Reduced pressure factor | Full service pressure of the connecting pipe |
| Intrados wall | About the pipe wall | Increased to the value required by the standard |
| Ends | Pipe wall | Machined or tapered to the pipe wall |
| What to check on delivery | Wall and dimensions | Intrados thickness, end wall, dimensions |
16Mo3, 13CrMo4-5, 10CrMo9-10, P91 (1.4903)
It is a buttweld elbow made to EN 10253-2 or EN 10253-4 that carries the full service pressure of the connecting pipe of the same material and wall. It has extra wall thickness at the intrados (inside of the bend), where pressure stress is highest, and ends matched to the pipe wall.
It is measured by ultrasonic thickness gauge on the inside of the bend and compared with the value required by EN 10253 for that size and wall. We report the measured intrados thickness on the inspection certificate.
45°, 90° and 180° elbows are standard. For other angles, tell us the angle and design basis; we will propose an elbow or an induction bend that meets it.
EN 10253-2 covers non-alloy and ferritic alloy steel fittings, such as P265GH, 13CrMo4-5 and P91. EN 10253-4 covers austenitic and austenitic-ferritic (duplex) stainless steel fittings, such as 1.4404, 1.4571 and 1.4462. Both parts have Type A and Type B.
Yes. EN 10204 3.1 is standard and 3.2 is available with the inspection body you nominate, such as TÜV or another third-party agency.
Reply from our Mumbai sales office, usually within one working day. You can attach drawings by email to marketing@arshyafittings.com.
