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Simulation Standards
This pages gives information on the two main
Standards used for simulations. Both have two parts. They
are:
•
BS EN ISO 10211 Part 1
•
BS EN ISO 10211 Part 2
•
BS EN ISO 10077 Part 1
•
BS EN ISO 10077 Part 2
BS EN ISO 10211-1
Content
•
Title;
•
Scope;
•
General principle of
the calculation method;
•
Assumptions;
•
Exclusions;
•
Validation.
Title
Thermal bridges in building construction – Heat
flows and surface temperatures – Part 1: General calculation
methods.
Scope
The Standard sets out the specification of 3D
and 2D geometrical models of thermal bridges for numerical calculation
of:
•
Heat flows in order to assess the overall heat
loss from a building;
•
Minimum surface temperatures in order to assess
the risk of surface condensation.
The
specifications include the geometrical boundaries and subdivisions of
the model, the thermal boundary conditions and the thermal values and
relationships to be used.
The Standard may also be used for the derivation
of the linear and point thermal transmittance and of surface
temperature factors.
General principle of the calculation method
The calculation is carried out using two- or
three-dimensional numerical methods.
Assumptions
The Standard is based upon the following assumptions:
•
Steady-state conditions apply;
•
All physical properties are independent of temperature;
•
There are no heat sources within the building element.
Exclusions
This Standard does not include:
•
The effect of solar radiation;
•
Heat transfer caused by air leakage.
Validation
Annex A gives benchmark examples for validation
of the software used and the capability of the simulator.
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BS EN ISO 10211-2
Content
•
Title;
•
Scope;
•
General principle of
the calculation method;
•
Assumptions;
•
Exclusions;
•
Validation.
Title
Thermal bridges in building construction – Heat
flows and surface temperatures – Part 2: Linear thermal bridges.
Scope
The Standard sets out the specification of 2D
geometrical models of linear thermal bridges for the numerical
calculation of:
•
The linear thermal transmittance of a linear thermal
bridge;
•
The lower limit of the minimum surface temperature.
The specifications include the geometrical boundaries
and subdivisions of the model, the thermal boundary conditions
and the thermal values and relationships to be used.
The Standard may also be used for the derivation
of the linear and point thermal transmittance and of surface
temperature factors.
General principle of the calculation method
The calculation is carried out using a two-dimensional
numerical method.
Assumptions
The Standard is based upon the following assumptions:
•
Steady-state conditions apply;
•
All physical properties are independent of temperature;
•
There are no heat sources within the building element;
•
Only one internal thermal environment applies;
•
One or two external environments apply.
The second external thermal environment only
applies when surface temperatures are calculated and the ground
soil is part of the geometrical model.
Exclusions
This Standard does not include:
•
The effect of solar radiation;
•
Heat transfer caused by air leakage.
Validation
The software and the capability of the simulator
shall be validated using the benchmark example given in Annex
A of BS EN ISO 10211-1 or benchmark examples given in Annex D of
BS EN ISO 10077-2.
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BS EN ISO 10077-1:2000
Content
•
Title;
•
General principle of the calculation method;
•
Scope;
•
Exclusions;
•
Alternative calculation
method;
•
Deviations.
Title
Thermal performance of windows, doors and shutters
– Calculation of thermal transmittance - Part 1: Simplified
method.
Scope
The Standard gives a method for the calculation
of the thermal transmittance of windows (Uw) and doors
(UD) consisting of glazing or opaque panels fitted in
a frame (with or without shutters, Uws) when the transmittance
of the components are known either by calculation or test in accordance
with other Standards. The relevant parameters of the components
considered are:
•
Uf
–
thermal transmittance of the frame excluding the edge effect;
•
Ug
–
thermal transmittance of the central portion of the glazing
unit;
•
Ψ
–
linear thermal transmittance, which represents the extra
heat flow due to the interaction between the frame, the glass panes
and the spacer bar.
The Standard also gives charts or tables from
which the approximation of Uf can be calculated and
default values of Uf, Ug and ψ can be found when
they can not be obtained by other means or are used at the early
design stage. It allows for:
•
Different types of glazing at a vertical orientation;
•
Various types of frame at a vertical orientation;
•
Where appropriate, the additional thermal resistance
induced by different types of shutters depending on their air
permeability.
The U-value of frame obtained from this Standard
is applicable to frames at a vertical orientation. It can also
be used as an approximation to frames at slopes.
General principle of the calculation
method
The thermal transmittances of windows, doors
and shutters are calculated using a simplified area weighted
calculation method.
For different types of window combinations, such
as double windows etc, the calculation is based on the principle
of thermal resistance.
Exclusions
This Standard does not include:
•
The effect of solar radiation;
•
Heat transfer caused by air leakage;
•
Ventilation of the air space in double and
coupled windows;
•
Three dimensional heat transfer;
•
Extra heat transfer induced by thermal bridges
at the rebate or joint between the window or door frame and the
rest of the building envelope.
This Standard is not applicable to:
•
Curtain walls and other structural glazing
which are not fitted in a frame;
•
Roof windows or slope glazing due to the orientation
of the frame and glazing not being vertical;
•
Condensation risk assessment.
Alternative to the calculation method
An alternative to the calculation method is to
test in accordance with BS EN ISO 12567-1:2000, ‘Thermal performance
of windows and doors – Determination of thermal transmittance by
hot box methods – Part 1: Complete windows and doors’.
Deviations
In Germany the calculation of the thermal transmittance
of windows forms part of the national German regulations.
The German regulation specifies that the design thermal transmittance
for glazing and windows and window doors shall be in accordance
with Table 3 of DIN 4108-4:1991-11. Information about
the German deviation due to the regulations is given in BS EN ISO
10077-1:2003 Annex ZA.
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BS EN ISO 10077-2:2003
Content
•
Title;
•
Scope;
•
General principle of the calculation method;
•
Assumptions;
•
Exclusions;
•
Validation of the simulation program;
•
Determination of the thermal transmittance;
•
Boundary conditions;
•
Cavity in frame;
•
Deviations.
Title
Thermal performance of windows, doors and shutters
– Calculation of thermal transmittance - Part 2: Numerical method
for frames.
Scope
The Standard specifies the method for the calculation
of:
•
The thermal transmittance of frames (Uf
) excluding edge effect;
•
The linear thermal transmittance (ψ) at
the junction between the frame and the glazing units/opaque
panels;
•
The heat flow rate of the frame with insulation panel;
•
The surface temperatures of the frame profile;
•
The thermal characteristics of roller shutter boxes.
The Standard gives data for the calculation of:
•
The thermal resistance of a shutter profile.
'Frame' covers frames, sashes, mullions, transoms,
and grid systems for windows and doors.
The method specified in this Standard is applicable
for vertical frames. However, it can also be used to provide
acceptable approximations for horizontal frames and frames in
a sloped position.
General principle of the
calculation method
The calculation is carried out using two-dimensional
numerical method complying with EN ISO 10211 (Part 1 & 2).
Exclusions
This Standard does not include:
•
The effect of solar radiation;
•
Heat transfer caused by air leakage;
•
Three dimensional heat transfer;
•
Extra heat transfer induced by thermal bridges
at the rebate or joint between the window or door frame and the
rest of the building envelope.
Validation of the simulation program
The Standard sets out ten benchmark examples
in Annex D for the purpose of validating the simulation program
and the simulator’s capability. The allowed relative errors
of the calculated values are also given in Annex D.
Alternative to the calculation
method
Alternatively, the frame U-value can be tested
according to BS EN ISO 125412-2:2003 - Thermal performance of
windows, doors and shutters. Determination of thermal transmittance
by hot box method. Frames.
Deviations
In Germany the calculation of the thermal transmittance
of windows forms part of the national German regulations.
The German regulation specifies that the design thermal transmittance
for glazing and windows and window doors shall be in accordance
with Table 3 of DIN 4108-4:1991-11. Information about
the German deviation due to the regulations is given in BS EN ISO
10077-2:2001 Annex ZB.
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