Solar Shading Systems - Passivent

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SOLAR SHADING SYSTEMS
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CI/SfB (31.9) Xh4
Uniclass L421
February 2009

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SOLAR SHADING SYSTEMS
Passivent Solar Shading systems provide
external shading for control of solar
heat gain through glazing. Designed as
a complete system which can be installed in
various configurations.
Applications
Suitable for offices, schools and other
commercial and public buildings, both new
and refurbished.
Why use solar shading ?
In sunny weather, solar heat gains through
glazing can represent a substantial input of
heat to a building. Apart from the direct
solar heating, re-radiated heat becomes
trapped inside the building, increasing the
internal temperature even more. Ventilation
rates or cooling loads must then be increased
to maintain comfortable conditions.
Solar heat gain from
direct sunlight and
trapped (re-radiated)
heat
Solar shading cuts
out direct sunlight
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Solar shading benefits
● Properly designed external shading can
reduce solar heat gain through glazing by
up to 85%.
● Solar shading is an effective complementary
strategy to air conditioning or mechanical
ventilation, providing savings in running
costs as well as general energy savings and
reduced CO 2 emissions.
● In naturally ventilated buildings it will
provide lower internal temperatures by
reducing the effects of solar heat gain.
● With the lower sun incidence angles in
winter, it allows solar gains into the
building, providing passive heating and
reducing the energy consumption of the
heating system.
● Can reduce solar heat gain and help to
meet the energy conservation
requirements of Building Regulations.
External shading cuts out solar energy
before it enters the building.
● Reduces building running costs and
increases occupants’ comfort.
● Can reduce direct glare whilst allowing
high levels of diffused (indirect) natural
light, giving a further potential energy
saving by reducing artificial lighting needs.
● Can play a major part in controlling light
levels in sensitive buildings such as
museums and art galleries, for
conservation and climate control.
● Can be used as a striking feature of a
building’s design, and provide greater
design freedom in the use of glazing.
● External shading allows natural
ventilation through opening windows, can
provide privacy by shielding glazing and
an uninterrupted view to the outside.
● Comfort conditions can be achieved using
a combination of solar shading and nighttime
cooling in buildings that suffer from
overheating, eliminating the need to
retro-fit air conditioning.
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TECHNICAL BACKGROUND
Building Regulations
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Approved Document L2A Conservation of
fuel and power in new buildings other than
dwellings, 2006
Section 1 Design Standards: Criterion 3:
Limiting the effects of solar gains in summer
Spaces not served by air conditioning
systems
Provision should be made to limit solar
gains so as to reduce internal temperature
rise in summer. This can be done by an
appropriate combination of window sizing
and orientation, solar protection through
shading and other measures. BR 364 and
CIBSE AM10 offer guidance on strategies to
limit solar gain. Specific guidance is given
on what would be considered reasonable
provision.
Spaces served by air conditioning systems
For spaces served by air conditioning
systems, reasonable provision for the
control of excessive solar gains is
demonstrated by meeting the TER (Target
carbon dioxide Emission Rate).
If solar gains are controlled to the limits for
non air-conditioned spaces, cooling energy
demand can be reduced, and it will be easier
to achieve the TER.
The TER is based on a notional building
with modest amounts of glazing. Building
designs with more glazing will have to
compensate through enhanced energy
efficiency measures in other aspects of
the design.
Running costs
● Calculations based on the Hevacomp
software show that a typical office
building can suffer 5-20% of total heat
gain through glazing.
● Solar shading to the glazed area could
reduce this heat gain by as much as
50-85%.
● Properly designed shading could reduce
building running costs by 3-13%.
BREEAM assessments
BREEAM, the BRE Environmental
Assessment Method, can be used to assess
environmental performance of buildings.
Credits are awarded under a range of
environmental aspects according to
performance, and added together to
produce a score. Passivent Solar Shading
systems can help achieve BREEAM credits
by reducing the overall demand for energy
and increasing the thermal comfort of the
building.
Passivent Solar Shading
A system of continuous fixed blades, normally
installed on support arms projecting
horizontally above areas of glazing.
All main components are aluminium for
long life with good corrosion resistance.
Available in two types of blade; Z blade and
S blade.
Z Blade
140mm pitch max
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1200mm max
Composition
Blades, support arms and clips are extruded
aluminium grade 6063 T6 to BS 1474.
Blades are carried in aluminium clips, which
are factory attached to the support arms. The
outer end of the arm is closed off with a
welded aluminium cap; the inner end slots
over the stainless steel fixing bracket.
Size, shape
Support arms: maximum projection 1200mm,
maximum spacing: 1500mm centres.
Blade pitch must be specified when ordering,
maximum: 140mm. This will give complete
shading for the UK.
Appearance
Standard finish to blades, support arms and
clips: polyester powder coating to BS 6496,
in any RAL colour to order.
Alternative finishes: PVF2, natural or colour
anodised AA25 to BS 3987, natural mill finish.
Installations
Horizontal, underblade
Horizontal, overblade
Aluminium cap
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S Blade
Wall bracket
130mm pitch max
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1500 max centres
Wind loadings
Maximum wind loadings are given in the table for
support arm projection 1200mm (maximum
allowable) with ten equally spaced blades.
For fixing brackets to the structure, the tensile load
resistance of anchors must be 5.0kN minimum, per
bolt.
Indicative installation heights are based on a site wind
speed of 25m/s which covers all of the UK except NW
Scotland and NW Ireland, site altitude approx 60m,
no shelter from surrounding buildings. For sheltered
sites installation heights of up to 50m may be
possible; in more exposed sites lower heights will
apply.
The advice of a structural engineer should be sought
for guidance on the expected loads resulting from
particular building design, location and orientation.
Support arm spacing (mm)
1500 1250 1000
Maximum dynamic wind pressure Pa 1020 1225 1530
Maximum design wind pressure Pa 1225 1470 1835
Indicative installation height (m) 4-5 6-10 10-20
Installation
The fixing bracket base plate has four 12mm diameter
holes for fixing to the main structure of the building
(these fixings are not supplied).
Each support arm slots over a bracket and is fixed to it
using two M10 stainless steel bolts with dome nuts.
Blades are attached to support arms by slotting into
the pre-attached clips.
Maintenance
Periodic cleaning is required to maintain appearance;
this may be carried out when glazing is cleaned.
Blade
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Support arm
Aluminium clip
Specification clause
Provide external solar shading
to glazing as shown on
drawings ……
Shading to be Passivent Solar
shading Z/S* blade system
supplied by Passivent Ltd,
North Frith Oasts, Ashes Lane,
Hadlow, Kent. TN11 9QU.
Tel: 01732 850770
Fax: 01732 850949
email:projects@passivent.com,
comprising blades, support
arms and clips of extruded
aluminium grade 6063 T6 to
BS 1474. Blade pitch
……mm, finish ……, colour
……
*delete as appropriate

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FURTHER INFORMATION
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Services
Installation and commissioning service
through an independent network of
MasterCare Installers.
Extended warranty and maintenance
contracts are available.
Quality assurance
Passivent products are designed, developed
and manufactured under a BS EN IS0 9001
quality management system, giving an
independently audited assurance that the
products will fulfil their intended purpose.
Operational commitment
As part of our commitment to minimising
our impact on the environment, and to
continuous improvement in our methods
of operation, Passivent is accredited to
IS0 14001 Environmental Management,
OHSAS 18001 Health and Safety
Management, and ISO 9001 Quality
Management Systems.
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PASSIVENT LIMITED
North Frith Oasts, Ashes Lane, Hadlow, Kent TN11 9QU Tel: 01732 850770 Fax: 01732 850949
Email: info@passivent.com Web: www.passivent.com
Passivent Limited maintains a policy of continuous development and reserves the
right to amend product specifications without notice.
A member of the Building Product Design Group
Other products
Passivent market a range of other ventilation
and daylighting products for commercial
buildings including:
Aircool ventilators for windows, curtain
walling and walls.
Airstract roof terminals for passive stack and
other natural ventilation systems.
Airscoop wind-driven ventilation terminals.
Ventilation control systems.
Natural ventilation systems for commercial
buildings.
Sunscoop tubular rooflight systems.
Litevent combined ventilator and rooflight.
Metrodome rooflights.
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