The Rooflight Association is recommending the first choice for the inner pane of a rooflight should always be a laminated glass, unless a stringent risk assessment shows that a toughened inner pane does not pose any additional risk to those below the rooflights.
This recommendation follows examples of rooflights with a double glazed unit using a toughened inner pane shattering, spontaneously. This can happen when small inclusions (invisible flaws) cause the pane to shatter, usually into small dice, but it may also fall in clumps which may cause injury or damage to people, pets and property, below.
The use of a laminated inner pane minimises the risk of any glass falling into the room beneath and potentially causing injury, if the inner pane should break.
This recommendation is outlined in The Rooflight Association’s technical guidance: Document NTD14 Glass Rooflights – Specification Guide, which is free to download via www.rooflightassociation.org.
To raise awareness of this safety guidance, relevant Rooflight Association members are encouraged to use the campaign logo in all related communications and promotional activities. The aim is for this message to reach builders, installers and ultimately, homeowners, and member use of the campaign logo will help achieve that.
The Rooflight Association’s Technical Chair, Paul Smith, explains more: “Statistically, the likelihood of a spontaneous explosion is low for heat soak tested toughened glass, but it is a risk. We have seen footage of these incidents and witnessed the aftermath, and it’s scary. Fortunately, we are not aware of any serious damage or injury, but there have been near misses. As the voice of the UK’s rooflight industry, we must educate the supply chain to minimise this risk and promote good practice.
“Until a laminated inner pane is made a requirement in Building Regulations guidance – ideally, within Approved Document K, we are encouraging builders, roofing contractors, rooflight installers and home improvement companies to study the guidance, understand the risk and share this information with homeowners. Only then can they make an informed decision.”
British Standards
The association recognises that this recommendation is currently beyond British Standards which state that inner panes must always be laminated wherever rooflights are more than 5 metres above floor level or are located over water (e.g., swimming pools). Toughened inner panes can be used in certain circumstances and locations, subject to satisfactory risk assessment.
The Rooflight Association is in favour of British Standards being updated to remove the option for monolithic toughened glass to be used for the inner pane of any overhead glazing, irrespective of height or location (except for over restricted spaces that are only accessed for maintenance and where additional safety precautions are in place to mitigate the risk).
To drive positive change, The Rooflight Association is lobbying Government regarding overhead glazing safety and safety for building users and is in communication with the Health & Safety Executive.
Until the option for toughened inner panes in overhead glazing is removed from British Standards and/or prohibited via Approved Document K, Rooflight Association members that offer glass rooflights without a laminated inner pane will always make the associated risks and responsibilities clear in their literature and quotations and will request that customers, including builders and rooflight installers acknowledge those risks and responsibilities before supplying such products.
