Linear and point thermal bridges

Product	InstalSystem 5
Type of article	FUNCTION AND TOOL
Source for translation	2025-04-22

DESCRIPTION

This article describes methods of accounting linear and point thermal bridges in thermal calculations of partitions and building structures.

LOCATION IN THE PROGRAM

The selection of the Thermal bridges calculation method is available in the General data window, Calculation standards and options tab.

1. Thermal bridges calculation method.

EXAMPLE OF USE

Scenario I - Simplified method of accounting linear thermal bridges

1. Editing the default data:
   • In the General data window, Thermal calculations of building, Calculation standards and options tab choose Simplified for the Thermal bridges calculation method. Note: this method is available for the EN standards;
   • (Optionally) Set auto mode for the Manner of making allowance for thermal bridges. This causes the auto mode status to be set for all fields of the ΔUtb (Allowance for thermal bridges) column, available on the form Building structure / Building (rooms view), with the following default values:
     • ΔUtb = 0.05 W/(m²·K) - for the external partitions (EW, EWi, ED, EF, RO) and for thr partitions in contact with the ground (WG, FL);
     • ΔUtb = 0.00 W/(m²·K) - for the internal partitions (IW, IF, ID, IWi).
       

       

       2. ΔUtb column with "auto mode" status.

       
       
   • (Optionally) Introducing ΔU - available for the DIN standards.
2. Editing the Room data:
   • Select the method of determine ΔUtb (Allowance for thermal bridges) in the form Building structure / Building (rooms view):
     

     

     3. Allowance for thermal bridges.

     
     
     • User's - allows to set the value of the allowance by yourself;
     • Automaticaly - initialises the default values according to the auto mode;
     • Without accounting for thermal bridges in construction terms - ΔUtb = 0.05 W/(m²·K);
     • Accounting for thermal bridges in construction terms - ΔUtb = 0.1 W/(m²·K).

Scenario II - Acc. to EN 12831 method of accounting linear thermal bridges

1. Editing the default data:
   • In the General data window, Thermal calculations of building, Calculation standards and options tab choose Acc. to EN 12831 for the Thermal bridges calculation method. Note: this method is available for the EN standards.
2. Editing the Room data:
   • Select the method of determine ΔUtb (Allowance for thermal bridges) in the form Building structure / Building (rooms view), just like in Scenario I - Simplified method of accounting linear thermal bridges.

Scenario III - Automatic - based on the thermal model method of accounting linear thermal bridges

1. Editing the default data:
   • In the General data window, Thermal calculations of building, Calculation standards and options tab choose Automatic - based on the thermal model for the Thermal bridges calculation method. Note: this method is available for the EN standards.
2. Definition of default types of the linear thermal bridges:
   • After making Calculations the 3D view of linear thermal bridges will be available in the H&E(TB) (Thermal bridges in heat transfer calculations) scope. Open Project browser, Thermal calculations of building and define the default types in Definitions of thermal bridges for each field choosing from the offered list. Note: One definition per bridge type is available by default.

2. Editing the Room data:
   • Select the method of determine ΔUtb (Allowance for thermal bridges) in the form Building structure / Building (rooms view), just like in Scenario I - Simplified method of accounting linear thermal bridges.