Si – So safe and sustainable

// the building envelope

HA Magazine hears from Mark Robinson, Technical Director for Sapa Building Systems about why the social housing sector is specifying the Dualframe window system for so many different developments.

Abseiling is something most people will only do once in their lives: normally sliding down a rock-face or some skyscraper to raise money for charity.  They certainly wouldn’t view it as a routine way to clean their windows.

Which is probably why, as Sapa Building Systems’ Technical Director, Mark Robinson informed HA Magazine, that many window specifications begin by a consideration of the cleaning regime for the building concerned.

While with corporate properties, where acres of high level glazing might be accessed via special gantries and sliding ladders – or abseiling teams – the designers of social housing developments must plan for fenestration to be readily accessible. And if possible for residents to be able to complete the task quickly and safety from inside.

Referring to the four core designs to the manufacturer’s widely specified Dualframe 75 Si range, Mark Robinson recounted: “While casements are what we are used to in UK properties, and a cost effective solution, due to the evolution of regulations and design to respect health & safety requirements, we are seeing an increasing trend towards windows that are cleanable from inside. Not only does our pivot window feature locks to hold it for cleaning, but has options for the use of the key before it can be fully reversed to, to prevent misuse by children.

“Then the TBT (tilt-before-turn) offers the unique solution of incorporating all the safety features into one bespoke handle: so the tilt position can be operated without the key, but the turn requires two-handed operation with the spring loaded key, so preventing any young child misusing the action.

Once the window is closed again the barrel resets automatically so that only the safe, tilt action is available. Both of these window types have been extensively taken up by the social housing sector. The TBT in particular is safe, secure and offers high level ventilation.”

In terms of physical security, the new Part Q which came into force last year references the requirements of PAS 24 and every window in the Dualframe 75 Si range has been tested to comply with this industry standard; in turn ensuring Secured by Design specifications are no obstacle even including the pivoted window which was only included in PAS24 a matter of a few weeks ago.

Despite the Government’s downgrading of its near to zero carbon ambitions for housebuilding, social housing providers remain committed to a low-energy affordable warmth agenda and will find Dualframe fully facilitates Part L considerations.

In fact Sapa Building System’s Dualframe 75 Si range, with its uniquely designed polyamide thermal break, was not only the first such suite of aluminium windows on the market to achieve the A+ Window Energy Rating (WER) standard across the range of windows with options from Casement, Fully Reversible and TBT, but also offers unparalleled benefits to both the specifier and fabricator.

Mark Robinson continued: “We have created specific profile shapes which offer excellent insulation and reduced heat flow paths, without the uncertainty of foam filling.  We can achieve a U-value of 0.9 W/m2 K - as well as the WER A++ - and can offer a very cost effective alternative to fully PassivHaus certified products.” Indeed, while Sapa can offer a full PassivHaus certified products, the company would urge specifiers to consider the embodied carbon footprint of such products, compared to the carbon emissions savings which are achieved during a window’s service life.  

Mark concluded: “Ultimately, specifiers as well as fabricators are attracted by the fact that Dualframe Si represents a suite of products which enables the construction of frames with any of the optional vents in different combinations: making it very economical to  have either inside or outside glazed and inward or outward opening vents in the same frame. It is just so versatile that it can suit any type of development.”

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