Fire (PRE-Stress)

Last modified by Fredrik Lagerström on 2022/01/04 16:37

Version 6.4 of PRE-Stress introduces the Fire module. This functionality models the effect of high temperature combustion upon an element. 

Fire settings are made in the Fire tab, which is found by clicking the element node of the project in the project tree dialog. The available settings are detailed below.

Fire settings 001.png

Fire Time

The fire time is a measure, in minutes, of how long the construction is able to withstand a fire.

Fire sides

Fire sides denote the faces of the construction that are exposed to and affected by the fire. The shape of the element determines which sides can be selected. A rectangular element can be affected on one to all four sides, but a circular element can only be affected on the top side (in addition to being affected all around the element). 

Concrete aggregate

Here we can select the type of aggregate to use. There are two types of aggregate, siliceous and calcareous, and two general types, standard and Danish, to choose between. The aggregate is used to calculate the reduced strength of the concrete according to EN 1992-1-2 (DS2426 for Danish).

The type of concrete aggregate is defined under EN 1992-1.2 3.2.21, the reinforcement class and manufacture shown under EN 1992-1.2 3.2.3 (figure 3.3), and the pre-stressed reinforcement in EN 1992-1.2 3.2.4 (2).



Possible options are Class A, Class B and Class C. The options are described in EN 1992-1-2 annex C. 


This is the manufacturing process used for the reinforcement. We may choose between "Hot rolled (Q)", "Brat cooled tempered (AC)" (Quenched), "Cold worked(C)", "Minimum of Q and C " or "Minimum of Q, C and AC". If "Minimum..." is used, the program uses the smallest of the three values for the calculation of the reduced strength, as per EN 1992-1-2 3.2.3. 

Prestressed reinforcement


Possible options are Class A and Class B. These options are described in EN 1992-1-2 3.2.4. 

This field may be closed for editing depending on which national annex is currently selected.


This denotes the manufacturing process used for the PreStressed reinforcement. Possible choices for the calculation of the reduced strength are "Cold worked" and "Quenched and tempered", as per EN 1992-1-2 3.2.4. 

Epsilon values

- Use Epsilon 0,2% values

Epsilon describes the projected strain on the wires upon structural failure. The reduced strength of the reinforcement in EN 1992-1-2 3.2.3 and 3.2.4 is at 2,0 % strain. By selecting the option Use Epsilon 0,2% values, we use alternate epsilon values taken from the Danish National Annex. According to Danish National Annex, use of 2,0 % strain values must be justified.

After the design is complete, effects of fire can be viewed under the Fire design results menu option.