The Case for Laminate Glass
Under the 2018 ban of laminate glass balustrades were banned in the UK, although it is permitted in doors and windows. The amendment to Approved Document B banned all combustible materials on the whole of the façade of buildings over 18 metres tall (11m in Scotland). The materials must be compliant with fire classification A2-s1 or A1 in accordance with BS EN 13501-1:2007 and A1:2009.
In contrast, monolithic glass is permitted (from a fire perspective, but not with regards to the CDM or regulation 7) but itself carries safety concerns in the event of a breakage. Another source of confusion is due to the use of laminate glass in windows and doors being included in the exemption list which is not the case in balcony balustrades. It is questionable as to whether the ban on laminate is intended, entirely justified or seen as a blanket decision born out of misunderstanding its properties. This has caused much confusion and hesitation to use laminate at any height.
Drivers for choosing laminate glass
The main reason for choosing laminate as opposed to monolithic is that the barrier integrity means it is safer at height and meets Regulation 7.
- Effects of wind at height. Screening the balcony enables a more comfortable environment for users and also provides protection for furniture and plants. One of the largest housing associations has stated that, in a post-Grenfell world, they specified aluminium vertical bars on all their jobs, presuming it would reduce their fire risk. However, when occupied, residents installed makeshift windbreaks using plywood sheets and other materials which were cable tied to the railing. There is now an inherent dilemma about whether the decision to specify railing over laminate mitigates any fire risk.
- Although many balconies choose clear glass, it is easier to achieve privacy with glass than it is with railings. The interlayers can simply be switched for obscure interlayers, avoiding the need for residents to use potentially combustible screens.
- General safety. It is a common problem amongst apartment block residents that items can fall from one balcony to the next, causing a safety risk. Many owners prefer glass balcony balustrades rather than railings to avoid this.
- Light glass offers the ability to allow light into the apartment, many metal systems can detrimentally affect the light into the building.
Although there is no one test for laminate glass’s safety on balconies, Sapphire carried out combustion tests on their own balcony model to show the behaviour of the glass under the extreme heat of a fire. While the tests showed that the common interlayer types do combust in direct flame, the performance of the entire balustrade meant that it remained whole, while the monolithic glass shattered, creating an unsafe void and a hazard to those below. In each area researched, the results appear to show that the likelihood of laminate contributing to the fire load is of a very low probability, even in a potential worst-case furnishing scenario.
From our extensive research with all the UK fire services, no incidents involving laminate have seen it as a primary ignited material and the cause of fire. Instead, laminates have been damaged by the intensity of the fire spread and the heat of furnishings and other materials on fire in immediate proximity to glass balustrades.
The potential safety of laminate glass is in the hands of everyone involved in a building, from designers to end users, by ensuring that all elements that make up a balcony work with the properties of the laminate glass. To lessen the effects of a fire on materials, designers can provide balcony components that are all non-combustible. Adding soffits, for example, helps deflect heat, restricts the flow of oxygen and contains embers should items on a balcony be on fire.
It goes without saying that end users can make sure that they do all they can to prevent fires on their balconies. They can do this in many easy ways, first and foremost by not storing combustible materials or lighting barbeques on balconies – both of which are all too common. Many residents make use of bamboo privacy screens, have combustible furniture and dry laundry on their balconies giving any fire ample sources of fuel.
The future of laminate glass
Although many industry leaders feel the ban on laminate glass was inadvertent, they also feel that the benefits of laminate glass far outweigh the reasons for the ban. Thankfully, the Ministry of Housing, Communities and Local Government has now commissioned a working group and several pieces of research to review the wording of the new regulation and its overall impact on building safety and to look at the best approach for the future. We recommend that clients and all professionals research the current situation and fire safety generally when specifying balconies going forward.