Fire resistance parameters (EC3)

Use this option to define the fire resistance parameters for steel member verification with the Eurocode 3 code.

Access

• Select Fire analysis parameters in the Member Definition - Parameters dialog, and then click Fire.

Basic parameters

Time resistance

Specifies the required time of fire resistance in minutes.

The maximum fire resistance time is 120 min.

Temperature curve

Evaluates the temperature of gases resulting from the fire according to the select curve:

• Standard ISO 834
• External fire
• Hydrocarbon fire
• Smoldering fire

Steel member protection

Select if the member is Protected or Unprotected.

Note: The diagram showing the temperature variability curve varies depending on whether the selected steel member is protected or not.

Section exposition

Specify how the section is exposed:

• On all sides
• On three sides
• Only the lower flange is exposed.

Properties of fire protection material (Protected element)

Encasement type

Select a type of encasement: Hollow or Contour.

Group of materials

Select the group of base materials to which the protection material belongs.

Name of material

Contains the list of materials available for the selected group.

Protection thickness

Specifies the thickness of the insulating layer protecting a column.

The default protection thickness depends on the selected type of material.

Unit mass / Specific heat / Thermal conductivity

These parameters give additional information on the selected material.

New material

Opens the New insulating materials dialog which allows you to create, edit, or delete fire protection materials.

Thermal properties (Unprotected element)

Unprotected element

• The Thermal properties of steel field is used to determine:

Unit mass - a default value roa = 7850 kg/m3

Coefficient of heat transfer by convection - a coefficient depending on a selected temperature curve

Configuration factor - a factor which allows accounting for an element shape and position in a structure (more about definition of this factor can be found in recommendations of the ECCS Technical Committee, point III.3); the interval of the parameter variability: <0.01,1>

Member surface emissivity - the interval of the parameter variability: <0.01,1>

Fire emissivity - the interval of the parameter variability: <0.01,1>

Ignore the 'shadow' effect - if this option is selected, then calculations of the k_sh factor, used for evaluating the critical temperature of steel, are not performed - in such a situation, the factor will equal 1.0 (it refers only to calculations according to the EN 1993-1-2 code)

• The Additional parameters field is used to determine:

Safety factor for radiation - a default value = 1.0

Safety factor for convection - a default value = 1.0

Safety factor for fire situation - a default value = 1.0

Adaptation factor - a value that accounts for non-uniform heat flow through the section of a beam in bending in fire conditions; a default value = 0.7

• The Member maximal temperature test field evaluates through testing the maximal temperature on the surface of a selected structure member; using sectional parameters of a member and values defined in the above dialog, the maximal temperature that an element will reach after a determined time resistance is calculated; selecting the Member temperature - user-defined option allows the user to omit the automatic evaluation of the element temperature and to define user's own temperature
• The Temperature Variability Curve diagram presents the way the maximal temperature on the member surface changes in time (the red curve); the blue curve illustrates variability of the temperature of gases resulting from fire in time.