Pioneering unglazed R9 window completes technical approvals

Published last month [May], the new R9 Technical Manual includes the for the first time the use of Timberweld® sash-welding technologies as an approved manufacturing process.

The marks the culmination of more than a year-long process of testing, delivered by HWL in partnership with the Residence Collection, to achieve technical approvals.

Mark Haley, Managing Director, HWL Trade Frames, said: “It’s been an involved process, the outcome however, has been worth it because it gives us, our customers and R9 new commercial reach.

“Getting rid of the requirement to glass bond R9 delivers so many savings and efficiencies. We knew how god the window was – but we needed an audit trail of proof.

“Having completed all relevant testing last year, Residence Collection has given Timberweld® sash-welding technologies approved manufacturing status with inclusion in the R9 Technical Manual. It’s a vindication of where we’ve gone and recognition of the work that the entire team has put in.”

The application of Timberweld® sash-welding technologies gives HWL an almost unique capability in the UK to butt weld window sashes inside and out, replicating the aesthetic delivered in a 90° mechanical joint.

This increases sash corner strength, which in most configurations eliminates the requirement to glass bond IGUs, which have historically been used in R9 fabrication to give the system structural strength.

With all of its’ pre-existing customers now buying its non-glass bonded R9 windows, HWL argues installers can cut their installation costs by up to a third by switching from buying in mechanically jointed sashes, to its Timberweld® R9 sash by reducing weight and simplifying handling and installation costs.

Buying in R9 unglazed can cut installation costs by as much as a third

“The advantages that we could deliver to the installer by welding and not glass bonding R9 were obvious. We just had to get there”, continued Haley.

“You can buy your glass in as normal, you reduce handling weight, you don’t have to remove sashes to install it and remedial work is the same as on any other window – buying R9 unglazed saves so much time, money and hassle.”

The HWL window was put through its paces in a series of initial tests by independent testing house, Exova in April last year.

The BS EN 6375 – 1 Weather Test results, completed on a side hung option returning an Exposure Category of 1600, a Class 3 Air Permeability Rating (600pa); a Class 9A (600pa) Water Tightness Rating; and top Class C4 (1600pa), resistance to wind.

These were followed up by PAS24 testing, again by Exova and in partnership with Residence 9, in May for mechanical load and manual intervention testing, also returning a pass. With further tests on top-hung options completed at the end of August.

“R9 is a great product. It’s defined a whole section of the market but there isn’t an installer in the country who would fit a window glass bonded by choice because of the weight and because the install is much more difficult”, Mark said.

“We’ve removed all of those obstacles. Non-glass bonded R9 is the same to fit as any other PVC-U window. The complexity is gone – what you’re left with is the market leading flush casement product and the higher margin opportunities, which go with that.”