When designing and constructing buildings today, there are a wide range of demands that need to be considered. These range from aesthetics and energy efficiency to stability and waterproofing. A range of materials must be used and combined in such a way as to limit the spread of smoke and fire.
However, this can be achieved with correct planning. Incorporating smoke control features such as mechanical ventilation systems at the design stage can reduce the risk to occupants and protect the fabric of the building too.
Unfortunately, many buildings are designed with appearance in mind, which has led to many being fitted or retrofitted with façade cladding. In order to ensure these buildings are energy efficient and waterproof, there is a gap between the cladding and the building. This acts as a chimney, both in a positive sense, preventing water egress into dwellings as condensation rises to the top of the building, but also in a negative sense, facilitating the spread of fire. Fire can ignite the combustible material in the insulation adjacent to the cavity and is then funnelled upwards by the cavity and fuelled by the ready access to oxygen. Buildings without a masonry wall (i.e. without brickwork and blockwork forming the wall) must have a barrier in the cavity between each floor to stop the spread of fire up the building. However, if the façade is flammable, the fire can circumvent this, leading to it ascending the outside of the building and nullifying the containment of fire within each flat (known as compartmentation).
Tragically at Grenfell Tower the fire did enter the cavity between the insulation and the external cladding and climbed the outside of the building, with disastrous consequences for its occupants. The tragedy at Grenfell has led the Government to bring in new building regulations to avoid anything similar happening again. This includes the banning of combustible materials on external walls of new buildings over 18 metres high and buildings currently under construction. Buildings being refurbished or renovated are included in the ban too. The ban applies on residential buildings, student accommodation, boarding school dormitories, care homes and any similar residence for all buildings over 18 metres high.
Banned materials include all external cladding panels, insulation and materials in window panels and infill panels which are combustible. The ban also applies to balconies, which are often made from combustible materials, which have facilitated the spread of fires across walls in the past. There are also new rules on the use of timber materials in the external walls of buildings over 18 metres high. This and other materials have been frequently utilised by architects as an attractive, sustainable and cheaper alternative to steel.
Local authorities are being backed by the Government to carry out emergency work on private residential buildings with unsafe cladding. Costs will be recovered from building owners, allowing buildings to be rendered safe more quickly and efficiently. The Government is also funding the replacement of unsafe cladding on social housing buildings above 18 metres.
This ban has been somewhat controversial. Architects, as represented by RIBA, have welcomed the move but are concerned it has not gone far enough. Many in the timber industry are concerned about what this means for their business going forward and there is a concern within the construction industry that this will limit progress in environmentally conscious building design.
Constructing buildings that limit the risk of fire is essential, which is why Vemco Consulting and our expert fire consultancy team are here to help you. With our proportionate and appropriate fire safety solutions, we make achieving those high standards as smooth and as easy as possible.