Henkel adhesives used on A2 spandrel panels 06 July 2021

Speedpanel, part of the Speedclad group of businesses, has developed a range of insulated composite spandrel panels that provide both extremely quick building encapsulation and fire retardant properties in accordance with the latest regulations. Notably, the company worked in close liaison with adhesive expert Henkel to identify the optimum flame retardant bonding product for the panels.

In a construction market still reeling from the tragic Grenfell Tower fire in 2017, the resulting Speedpanel A2 Glass and Speedpanel A2 Aluminium carry an independently certified fire rating of A2-s1 d0, creating a huge USP for the company and opening up vast market potential in both new build and replacement façade projects.

“Unfortunately, many spandrel panel manufacturers still state that their products are fire-rated to A1 as they make their products from A1-rated materials,” says Fraser Brown, regional director at Speedclad. “In truth, however, once these materials combine to form a composite panel, any individual material fire rating doesn’t mean the A1 rating still stands.”

Speedpanel insulated composite panels use adhesives to bond various materials together. However, achieving the required A2-s1 d0 fire rating for the panel is challenging as many adhesives feature solvents, isocyanates or PVC, all of which are highly flammable.

“For this reason, we opted to partner with Henkel, to develop a panel construction using a flame retardant adhesive,” states Fraser. “As a result of our collaboration we now have a suite of industry first aluminium and glass faced spandrel panels that have been independently tested by Warrington Fire to achieve A2-s1 d0, in accordance with BS EN 13501-1 2018, thus giving specifiers, clients and contractors complete peace-of-mind. Moreover, compared to fitting a conventional double-glazed unit - with its supplementary insulation and associated framework - Speedpanel is far quicker.”

In terms of composition, Speedpanel A2 Glass features a steel rear tray, an insulated (mineral wool) core, a proprietary interlayer and a glass front face that is available in the full grey scale from white to black. The same composition applies to Speedpanel A2 Aluminium - powder coated or anodised in a wide range of colours - minus the specialist interlayer. Any composite panel built of several materials and sold as a single panel - even if the materials are individually A1 fire certified, as is the case with Speedpanel, will require recertification as the complete panel.

“We initially considered mechanically fixing the front and back trays using non-combustible fasteners, although this was dismissed due to the negative impact on thermal bridging and the potential for condensation issues,” explains Fraser. “As a result, we chose adhesives to bond the components together, but there were many challenges to overcome beyond just being flame retardant.”

Although heat-soak-tested toughened glass is up to five times stronger than normal glass, a particularly heavy impact can force it to shatter into thousands of tiny ‘pebbles’. It is the cracks between these pebbles that create stress on the adhesive, which means the glass could potentially fall from the building.

“We wanted to create a product where this outcome could not occur; where the glass would remain in place even in the unlikely event of a heavy impact,” says Fraser. “I’m pleased to say that our partnership with Henkel and the extensive adhesive trials helped us to meet this objective. A2-s1 d0 classification is really important, but so is glass retention.”

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.

Claire prides herself on keeping readers well informed and up to date with the latest industry news.