Can glazing take the strain of regulatory change?

Proposed changes to Building Regs will likely have a significant impact on the supply of glass units, according to Angus Herdman, commercial and technical director of Cornwall Glass Manufacturing.

Revisions to Part L of the Building Regulations are already on the cards for this summer, which will affect the U-values of windows and doors going in to both newbuild properties and refurbishments.

But there are also proposed revisions to Part Q (security), Part O (overheating) and Part F (ventilation), which will all, at varying degrees, affect the specification of glass.

“Part L (energy efficiency) is on everyone’s minds at present because it comes into force in June,” Angus Herdman, commercial and technical director of Cornwall Glass Manufacturing, says. “While the focus has been on the reduction of U-values, fabricators will have to consider the wider implications for security, ventilation and overheating, all of which affects the specification for glass.”

Windows and doors with a glazed of >60% going into refurbishments will have to achieve U-values of 1.4W/m²K, while those going into newbuild properties will have to achieve 1.2W/m²K from the summer. These are expected to fall further by 2025.

Specifiers will soon have to acknowledge their responsibilities regarding Part O, which will expect them to mitigate the effects of overheating. Since large expanses of glass often equate to increased solar gain, some in the industry expect to see a shift in demand from large glazed areas to smaller windows.

“I don’t think that needs to be the case,” Angus says. “Increased light improves overall health, and we supply a range of products that can offer those benefits without the negative overheating side effects.

“For example, Saint Gobain’s SKN 176 and 183 were first developed for commercial applications to provide cooler conditions for office workers. They can produce a g value of 0.37 and a U-value of 1.0W/m²K on a 16mm cavity, while achieving a light transmittance of 70%.

“Available in a 4mm outer leaf, SKN176 can also be used to manufacture a very lightweight unit and can be combined with Saint Gobain’s SGG STADIP product range for improved solar or acoustic control.”

Cornwall Manufacturing also offers units made with Saint Gobain’s Planitherm One T. Manufactured using a unique combination of metal oxide layers, Planitherm One T can deliver exceptionally low U-values, regardless of frame material.

“Planitherm One T represents a real step forward in glass technology,” Angus says. “Depending on specification, you can get U-values as low as 1.0 W/m²K. The performance is exceptional even if you’re fitting aluminium bi-folds or large patio doors.”

Cornwall Glass Manufacturing – which sits alongside glass merchanting business Mackenzie Glass and retail-focused Cornwall Glass & Glazing – is fully geared to offer a very diverse range of options in IGUs and single glass, with three manufacturing facilities in St Austell, Highbridge and Plymouth.

The latter provides the foundation for the manufacture of super-sized units in a wide range of solar control, acoustic and Low E monolithic and laminated glass options. The company also has heat soaking and jumbo cutting facilities and has invested in enhanced CNC and waterjet capabilities.

“Part O is still in consultation, but it is expected to include guidance on providing the means for cross-ventilation, which could affect the security and acoustics, something which we already have to mitigate for from a glazing standpoint,” Angus continues.

Part Q currently demands that reasonable provision must be made to resist unauthorised access to new dwellings. This has led to the requirement for laminate panes of glass in frames that could give access to locks and handles from the inside if broken. Updates to Part Q are expected to apply to existing dwellings undergoing refurbishment as well as new dwellings.

“As a result, we expect demand for laminate glass to increase in IGUs, which is already expected from other applications, such as balustrades, balconies, and walk-on roofs,” Angus says. “Therefore, this is in an area we are really focusing on.

“The changes to the Building Regulations over the course of the next few years are going to really push the envelope in terms of both technical capability and the strength of the supply chain,” Angus concludes. “As we discovered with the effects of the pandemic, you can’t have one without the other. Which is why Cornwall Glass Manufacturing is investing in every aspect of its business to make sure those demands are met.”