Roofs
Fakro roof
windows set
new design
standards
Roof windows are now being used as an intrinsic
element of interior design, even in Passivhaus and
EnerPhit homes. This might seem impractical given the
trend for using windows in combination as the minimum
Passivhaus requirement is for triple-glazed windows
with a U-value of 0.85W/m2K. In terms of building
airtightness too, the requirement is similarly stringent,
with 0.6 air changes per hour at 50 Pascals (positive
and negative pressure) being needed.
The demand for improved roof window performance
has, therefore, prompted products of increasing
sophistication. For some manufacturers, achieving
the standard for passive construction is unachievable
using standard products. FAKRO, by contrast offers
a choice of either triple or quadruple-glazed products,
the quadruple glazed FTT U8 Thermo providing an
installed value of 0.58W/m2K and the FTT U6 0.81.
These products are matched by the recently launched
range of stylish flat roof windows which have truly
raised the bar, particularly for those specifying green
roofs. In terms of airtightness, site tests for EnerPhit
certification revealed no detachable air flow through the
seals of the FTT U8.
Despite such demands on roof window performance,
the gap in performance between manufacturers is
growing with some, for example, quoting U-values for
the glazing unit rather than for the installed window.
Improved performance is, however, far from easy to
achieve as it relies on a number of factors. Most are
not immediately obvious. The seals that Fakro uses
are of thermoplastic elastomer (TPE) which retains its
elasticity and has a proven track record in the medical,
industrial and automotive sectors.
The suggestion that roof windows might provide an
easy point of entry for burglars was, until recently,
considered almost fanciful. It would certainly not have
prompted specification of particular performance
criteria but the trend towards multi-occupancy
FAKRO GB
buildings brought with it easier access to the
roof. Intruders found that the roof window sash
invariably presented an easy target as, under
light foot pressure many can be forced without
breaking the glass. It is perhaps not surprising
that some have been so slow to acknowledge
this problem but the absence of a Standard by
which to measure safety and security didn’t help.
While EN13049 put that right, there is still a
marked absence of performance data from some
manufacturers. By contrast, Fakro’s topSafe®
system of hinge and lock reinforcement took
a completely fresh design approach and
provided a benchmark for performance. All of
the company’s products meet a minimum Class
3, the system not only preventing the sash from
being forced and the timber from being split but
enabling the window to withstand the weight of
an individual jumping on the glass.
The concept of a roof window’s hardware having
an impact on the visual aesthetic might also
seem unusual. However, by positioning the
vent in the top of the frame, Fakro was able to
pioneer the approach in which the operating
handle was placed in the base of the sash. Not
only has this lent greater practicality to window
usage it enabled the window to be installed
higher in the roof. Frames also have a sleeker,
more contemporary style.
Electronically operated windows equipped
with ‘Z-Wave’ are a new development, Z-Wave
utilises a wireless protocol for communication
between appliances, enabling a range of devices
to be operated from a single remote - lighting,
alarm, computer, air conditioning and blinds to
name just a few. Z-Wave has been adopted by
over 200 leading manufacturers including Apple,
Intel, Panasonic and Danfoss.
TEL: 01283 554755
WWW.FAKRO.CO.UK
As a consequence of the increasing demand for high
performance, many architects now specify particular
aspects of performance. This may involve features as
diverse as windows being fixed closed, for example
above a covered walkway, or acoustic value. In many
respects this offers the ultimate test of quality - does
the manufacturer encourage the architect to specify
performance or does it suggest that other facets of the
building design should be used to offset the poorer
performance of the roof window? This is certainly a
question we can expect to be asked more and more.
READER ENQUIRY NO: 35
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