Shadowing Effect in Fire Resistance Design According to EN 1993-1-2

Tips & Tricks

For unprotected I‑sections, the standard provides the correction factor ksh according to Equation 4.26a in Chapter (2) to consider the shadowing effect. A term [Am/V]b is used there. This section factor includes Am, which represents the box enclosing the cross‑section (Index b = boxed). In the case of a three-sided fire exposure (a girder with massive ceiling), the flange surface unexposed to fire is not taken into account when determining [Am/V]b.

Three-sided: [Am/V]b = (h + h + b)/V
Four-sided: [Am/V]b = (h + h + b + b)/V
h and b are outer dimensions of the cross-section.

There is no information in the standard regarding the determination of the correction factor ksh for three-sided fire exposure. In the RF‑/STEEL EC3 add‑on module, the correction factor ksh is always considered.


Shadowing effect Correction factor Three-sided


Contact us

Contact Dlubal Software

Do you have questions or need advice?
Contact our free e-mail, chat, or forum support or find various suggested solutions and useful tips on our FAQ page.

(267) 702-2815

RFEM Steel and Aluminum Structures

Add-on Module

Design of steel members according to Eurocode 3

Price of First License
1,480.00 USD