23 September 2021
Sign up to our newsletterWant more news like this? Sign up to our newsletter.

Flame off

In a construction market still reeling from the tragic Grenfell Tower fire in 2017, Speedpanel 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. The company worked in close liaison with Henkel to identify the optimum flame-retardant bonding product for the panels

Spandrel panels span the vertical distance from the top of a window and the lower sill of the window in the next storey above.

“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 panel manufacturer 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 – which the company has now achieved for both aluminium and glass -- is challenging, it says, as many adhesives feature solvents, isocyanates or PVC, all of which are highly flammable.

Those materials have been outlawed since the November 2018 changes to Regulation 7 of the Building Regulations in order to ban the use of combustible material in the external walls of certain high-rise buildings in England. The newly introduced Regulation 7(2) requires materials certified to A2-s1 d0 or Class A1. In addition, materials need to be certified to A2-s1 d0 if a building falls within the ‘relevant building’ class, which includes residential and institutional buildings that are more than 18m high.

PRODUCT STRUCTURE

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. 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 re-certification 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 Brown. “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 strong 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.

Brown continues: “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.”

Describing the R&D approach of Henkel (01442 278000), he adds: “The research was two-fold, in terms of identifying which adhesive from the Henkel portfolio would best suit our needs for both fire classification and grab strength. It succeeded on both counts.”

In fact, Henkel supplies Speedpanel with two types of adhesive for different bonding tasks within the Speedpanel A2 Glass and Aluminium products. Henkel has also made proposals in terms of suitable application methods that would optimise adhesive quantity and delivery speed: everything from automated spraying to simple pour-and-spread.

Author
FAST magazine

Related Companies

Henkel Ltd

Similar Articles

UK's first FRP lock gates

The UK’s first-ever set of moulded fibre reinforced polymer (FRP) lock gates have been installed on the River Thames at Sunbury Dry Dock. The new gates, fitted on behalf of the ...

Spotlight on Sikaflex 545

Sikaflex-545 is a one-component elastic assembly adhesive based on Sika silane terminated polymer (STP) technology. It is said to be a high initial-grab adhesive that produces low ...

Chemique's garden room help

A small-volume domestic construction firm needed adhesive advice when it brought panel manufacture in-house.

VMI in offsite construction

Building prefabricated modules off-site can speed up the construction process by as much as 50% and cut costs by up to 20%, according to a 2019 report by McKinsey & Company. Mark ...

‘Hyper glue’

With many of the products we use every day held together by adhesives, Canadian researchers hope to make everything from protective clothing to medical implants and residential ...

Specifying fasteners

Fasteners and fixings are very often forgotten about in the build chain and are either a last-minute consideration or left to the contractor’s discretion. However, when fasteners ...

Dispensing Made Easy with the

Fisnar, leading manufacturer of fluid dispensing equipment, is pleased to announce the launch of its DC50 Digital Dispense Controller. A new addition to their popular DC series ...

TOP TIPS FOR DESIGNING WITH FL

Due to improvements in production capacities, Rotor Clip is now offering reduced minimum ordering quantities on all of its flat wire products including flat wire snap rings. Here ...

bigHead invests in innovation

bigHead Bonding Fasteners is continuing its investment in innovation with the appointment of Dr Lawrence Cook.