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Completed thermal research projects
New facade technology - removing cold bridges
Thermal performance of a window insert in stick system curtain
walling
Detailing modern non-domestic building envelopes to comply with the
new Approved Document Part L of the Building Regulations
Assessing the heat loss at the insulating glass sealed unit edge
New facade technology - removing cold bridges
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Status
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Completed (2003 - 2005)
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Partners
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Centre for Window and Cladding Technology (lead)
Permasteelisa
Sandberg
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Objectives
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The aim of this project was to study existing common construction
details and products and to develop potential solutions to improve
their thermal performance without affecting other aspects of performance.
This will amount to a guidance of production trends in ten years time.
The guidance covers appropriate calculation methods for assessing the
overall energy loss and condensation risk of different modern cladding
systems and gives potential best practice advice to remove cold bridges.
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The construction types to be considered included:
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• Curtain walling;
• Rainscreen;
• Punched windows;
• Insulated panels.
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The solutions to be considered included:
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• Thicker insulation materials;
• Alternative materials;
• Removal/reduction of metal components;
• Cladding and thermal shielding of components.
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Issues to be studied included:
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• Structural integrity;
• Thermal and acoustic performance;
• Durability;
• Buildability.
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Thermal performance of a window insert in stick system curtain
walling
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Status
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Completed (2004 - 2005)
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Partners
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Centre for Window and Cladding Technology
Council for Aluminium in Building
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Objectives
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This project aimed to specify the methods for
calculating U-values of different types of cladding system. Both
simplified and detailed methods are specified. The project also
calculated default values for the linear thermal transmittance of stick
system curtain walls. These values were found by investigating
the most commonly used systems in the UK and included the
Ψ
-value:
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• At a glass edge;
• At a panel edge;
• Where an opening light is at one side
of a transom/mullion;
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Where an opening light is at both sides of a transom/mullion
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Full details are given in the
CWCT guide
‘The thermal assessment of window assemblies, curtain walling and
non-traditional building envelopes’ described earlier.
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Detailing modern non-domestic building envelopes to comply with the
new Approved Document Part L of the Building Regulations |
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Status
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Completed (2002 - 2004)
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Partners
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Centre for Window and Cladding Technology (lead)
Permasteelisa
Sandberg
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Objectives
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The aim of this project was to develop and publish advice on detailing
non-domestic building envelopes to comply with the new (2002) Approved
Document Part L of the Building Regulations. This amounts to a 'robust
detailing' guide that could in future be annexed to Part L. The guidance
covers appropriate calculation methods for assessing the overall energy
loss and condensation risk of different modern cladding systems and gives
best practice advice on avoiding cold bridging.
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The project considered junctions and interfaces, fixings and penetrations
associated with:
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• Stick system curtain walling;
• Insulated panel walls;
• Unitised walls;
• Slope glazing;
• Rainscreen overcladding;
• Integral rainscreen.
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Assessing the heat loss at the insulating glass sealed unit edge
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Status
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Completed (2001 - 2003)
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Partners
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Azon
Bostik Findley
British Plastics Federation Windows Group
British Woodworking Federation
Centre for Window and Cladding Technology
Chemetall
Council for Aluminium in Building
Glass and Glazing Federation (lead)
Interpane
National Physical Laboratory
Pilkington
Steel Window Association
Tremco |
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Objectives
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In recent years glazing technology has made significant progress
in improving energy efficiency, by the introduction of low-E coating of
the glass and the filling of the space between the glass with heavy inert
gas. These technologies are approaching maturity,
and are well documented and understood. Warm
edge technology, a range of techniques for replacing the aluminium spacer
frame with less conductive metals, metal composites or other materials,
is a more recent development, which has not been thoroughly researched,
or authoritatively appraised. Current warm edge data resembles inspired
market promotion, rather than factual comparisons of performance, when
combined with other technologies, as required for future fenestration.
The combination of technologies should enable the construction industry
to identify routes to better windows, and therefore a significant contribution
to energy conservation. The information developed
by this project will enable all sections of industry to make informed selection
of advanced performance fenestration. In order to meet the national
targets for CO2 reduction, it will be necessary to make energy savings in
both new construction and existing property stock. The adoption of
high performance glazing will contribute to proposed and future targets for
pollution control.
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This project involved both physical testing and calculation.
NPL tested the thermal conductivities of the various systems available
and carried out a series of hot-box tests, and made comparison between
the test data and numerical modelling.
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CWCT carried out thermal analyses of various combinations of materials
and technologies. These included:
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• Six types of window frame
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• Six types of glazing spacer;
• Three different glazing units.
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