IPE vs IPN Beams: Key Differences and Which One to Choose

IPE and IPN look alike on a bill of materials, but they are different sections. This guide compares IPE vs IPN beams on flange shape, weight, stiffness and connection detailing, using figures published by the producers, so that engineers and buyers can specify and order the right one.

What are IPE and IPN beams?

Both are European I-sections, and the number after the name is the section depth in millimetres: IPE 200 and IPN 200 are both 200 mm deep. IPN is also written INP in the trade; it is the same product.

According to ArcelorMittal's product page, the dimensions of both ranges are given in EN 10365: IPE from 80 to 750 and IPN from 80 to 600. In the Ahan Asa catalog both are supplied in grade S235JR in 12 m lengths:

• IPE beams: 18 sizes from IPE 80 to IPE 600 (including 270 and 330);
• IPN / INP beams: 21 sizes from IPN 80 to IPN 600 (including 340 and 380).

The core difference: parallel or tapered flanges

• In an IPE, the inner flange surface is flat and parallel to the outer face. ArcelorMittal describes the range as «steel sections with parallel flanges».
• In an IPN, the inner flange surface slopes. ArcelorMittal's data sheet gives a flange slope of 14%: the flange gets thicker from the tip towards the web.

At equal depth this makes the IPN flange narrower but thicker, and its web thicker. British Steel's data gives IPE 200 a 100 mm flange and a 5.6 mm web; ArcelorMittal's sheet gives IPN 200 a 90 mm flange and a 7.5 mm web.

Side-by-side figures for three common depths

IPE values are from British Steel's IPE data sheet; IPN values are from ArcelorMittal's IPN sheet. Iy is the second moment of area about the strong axis (normal bending under gravity load); Iz is about the weak axis (lateral direction).

Our arithmetic on these figures:

• Weight: at the same depth the IPN is about 17% (200), 18% (240) and 28% (300) heavier.
• Strong-axis stiffness: the IPN's Iy is about 10%, 9% and 17% higher, so stiffness rises less than weight.
• Weak-axis stiffness: thanks to its wider flange, the IPE is stiffer laterally at all three depths (604 vs 451 cm⁴ at 300).
• Weight efficiency: dividing the strong-axis elastic section modulus by mass per metre, the IPE scores higher at all three depths, roughly 8.7 vs 8.2 at size 200 and 13.2 vs 12.0 at size 300. In plain terms, the IPE gives more bending capacity per kilogram of steel.

Nominal weight per 12 m length

Beams are normally sold by weight, so the heavier IPN directly increases shipment weight and freight. Nominal weights from the Ahan Asa catalog:

Actual weight is confirmed on the weighbridge. For a fuller table see our rebar and beam weight tables.

Connections: what the flange slope means on site

When a bolt passes through a sloped flange, a flat washer bears on one edge only. According to fastener supplier PTS, square taper washers for I-sections to DIN 435 compensate for the slope so that the bolt head and nut seat on a square surface, and washers made for channel (U) sections are not interchangeable with them. An IPE's parallel flange needs no such extra part.

Which one should you choose?

The section is the structural engineer's decision, and you should buy what the drawings specify. These points help when coordinating with the designer and the supplier:

• New buildings with ordinary bending members (floor beams, secondary beams): with its better weight efficiency, the IPE is usually the more economical choice for the same capacity.
• Limited depth with a need for more strong-axis stiffness: an IPN of the same depth is slightly stiffer, at the cost of extra weight.
• Repair or extension of an existing IPN structure: matching the existing section keeps dimensions and connections consistent.
• Substitution at purchase: do not swap an IPE for an IPN of the same depth, or the reverse, without the engineer's approval.

Summary

The IPE vs IPN difference starts at the flange: parallel on the IPE, sloped at 14% on the IPN. At equal depth the IPN is heavier, slightly stiffer about the strong axis and less stiff about the weak axis, and needs taper washers in bolted joints; the IPE delivers more bending capacity per kilogram. Order to the drawings, and to request a quote for available IPE and IPN sizes, contact Ahan Asa.