BS8579 – The New Standard for Balcony Design
The new British Standard for design of balconies and terraces, BS8579, was published in August this year. With the construction industry using so many different interpretations of national standards it was felt there needed to be guidance to clear up some differences in opinion. The aim of the standard is to have a unified set of ideas relating specifically to the design of balconies and terraces.
While the guidance is not mandatory, it goes a long was to clear up many anomalies in the industry, The new standard applies to all nations in Britain although there may still remain some differences with English, Northern Irish, Scottish and Welsh regulations.
Key issues cleared up by BS8579
Written into the standard is a clear definition between balconies and terraces. It is important to distinguish between the two as regulations refer to them separately. This is especially helpful when it comes to insurance and warranties, which are different for balconies and terraces.
A distinction has also been made between open and enclosed balconies. This has been previously stated by BS9991 (relating to fire safety in residential buildings). If the facing enclosure is over 50% of the relevant height it becomes classified as an enclosed balcony. Enclosed balconies are, by definition, an internal room, adding to the distance that any person needs to escape in the event of a fire.
Standards to consider when designing discussed in BS8579
Where enclosed balconies are stacked, this triggers the need for fire-separating floors and walls. The guidance from the standard about the proximity of balconies, fire resistance and reactions to fires has been more clearly determined.
The standard recommends non-combustible material on balconies. This point will be very important in terms of setting a precedent on the issue of laminated glass for balustrades, which whilst combustible may be considered unlikely to contribute significantly to a balcony fire. There has been considerable debate on safety and whether laminate or toughened glass should be used.
Concern over water and dripping from balconies has long been an issue. Drainpipes can be unsightly and prone to blockage, but without them, staining can become a concern.
The document gives clear guidance as to how to overcome these concerns using edge drainage. The advantage of soffits to reduce fire risk, prevent spillages onto balconies or public areas below etc is also emphasized.
The standard also gives guidance on inclusive design to ensure all occupants and guests have ease of access across a door threshold and wheelchair users have the ability to turn and exit the balcony.
Other points to consider
The psychological effects of movement on balconies cannot be underestimated. Designing a rigid balcony with very little bounce feels safer to occupants. The standard gives guidance on limitations on stiffness.
Minimum balustrade heights have also been the subject of a lot of discussions and are clarified in the document. On high-rise building the effect of the wind is significant, so the need for shelter and containment has been laid out.
It will be interesting to see how much the new standard is used as guidance and it is hoped it will set responsible criteria for the industry to adopt.
This article is based on an interview with two of those involved in the compilation of the document;
Mark Tylor, Technical Director at Allies and Morrison Architects
Mark is responsible for technical design and quality at Allies and Morrison. He is Chair of BSI panel for BS8579 and a member of BIBA Regulations and Standards Committee. He sits as a board member of the Society of Façade Engineering.
Andrew Parsons Technical Director, Sapphire Balconies Ltd.
Andrew has been allied to the industry for over 40 years and has for the last three decades focused his attention entirely on balustrades and balconies. His role now as a technical consultant and trusted advisor, together with his contribution to the BSI committee for balconies, gives testament to his technical expertise and specialist industry knowledge.