Open state cavity barrier

PAS 9980:2022, Fire risk appraisal of external wall construction and cladding of existing blocks of flats – Code of practice, published by bsi in January 2022, defines an open state cavity barrier as a: ‘nonloadbearing element designed to provide fire separation in a concealed space (cavity), which is open to allow ventilation and drainage in the cold state, but which closes when exposed to a developing fire.’

It defines a closed state cavity barrier as a: ‘nonloadbearing element designed to provide fire separation within or at the edges of a concealed space (cavity) by forming a tight seal (possibly under compression) between the inner and outer surfaces of the cavity.’

[edit] Related articles on Designing Buildings

• Cavity barrier.
• Cladding for buildings.
• Fire collar.
• Fire compartmentation.
• Fire.
• Fire-barrier.
• Fire-stopping in buildings.
• Flats.
• Grenfell tower.
• PAS 9980:2022.