Steel Buildings in Europe

Part 7: Fire Engineering 7 - 19 Table 5.1 Temperature of unprotected steel members after 15 and 30 minutes of standard ISO fire exposure Steel temperature (°C) Steel temperature (°C) Section factor ( A m / V ) sh 15 min 30 min Section factor ( A m / V ) sh 15 min 30 min 10 113 257 130 621 802 20 194 431 140 634 809 30 265 554 150 646 815 40 328 636 160 655 819 50 383 690 170 664 822 60 432 721 180 671 825 70 473 734 190 677 827 80 509 741 200 682 828 90 539 753 250 699 833 100 565 767 300 708 835 110 586 781 400 716 837 120 605 792 500 720 838 5.2.2 Protected steel member EN 1993-1-2 also provides a simple design approach for insulated members with passive fire protection materials. In such cases, the temperature rise depends on the section factor A p / V for the steel member insulated by fire protection material ( A p is the appropriate area of fire protection material per unit length and V is volume of the steel member per unit length) and the insulation characteristics. The insulating materials can be in form of profiled or boxed systems, but this simple approach does not cover intumescent coatings. Assuming uniform temperature distribution, the temperature increase   a,t in an insulated steel member during a time interval  t may be determined from:     g,t /10 a,t g,t p a a p p a,t e 1 1 / 3 1 /                       t V A c d (8) with V A d c c p p a a p p     (9) where: p d is the thickness of fire protection material [m] p C is the specific heat of fire protection material [J/kgK] p  is the thermal conductivity of the fire protection material [W/mK] p  is the unit mass of the fire protection material [kg/m 3 ]