Fire safety proposals for public buildings still allow combustible cladding

figures from the government's report on buildings with ACM cladding

The Department of Education’s (DoE) new fire safety proposals for school buildings still allow for combustible cladding to be installed on buildings less than 18 metres high. At least 70 schools have had the plastic foam insulation installed since it was banned on taller residential buildings in December 2018. Other installations of the material have taken place on around 25 new hospitals, care homes and sheltered housing complexes.

Some of the buildings even use the same Kingspan insulation that was instrumental in the Grenfell Tower fire. Others have been built using the same type of high-pressure laminate panels used on the Cube student housing block in Bolton that caught fire two years ago.

Over the last five years, nearly 50 school buildings have been destroyed by fire, but at the moment sprinklers are not mandatory in new or refurbished schools.

The May 2021 proposals state that cladding on school buildings “with a storey 18m above ground level should achieve Class A2-s1, or better”. However, only on residential areas of boarding schools or where school buildings are prone to vandalism, identified in a risk assessment at feasibility stage, is this material required to be used on the ground floor walls of buildings.

Consultation on the DoE’s proposals ends on 18th August 2021. Findings from the separate consultation on the possible ban extension on the use of combustible cladding materials on smaller buildings, which closed a year ago, have not yet been announced.

What does A2-s1,d0 mean?

Class A1 ratings are awarded to material that is non-combustible and have no contribution to fire at any stage. Class A1 products are not rated for smoke or burning droplets and particles given off during the test.

Class A2 certification is given to products with no ‘significant’ contribution to fire. Class A2 products also have an ‘s’ and ‘d’ assessment after the rating (i.e A2-s1,d0) which refers to the smoke (s) and burning droplets (d) emitted by the product during testing. Smoke is rated s1-s3, with s1 being the best. Droplets and particles produced during testing is measured d0–d2, with d0 being the best.

Is this good enough?

The RIBA has previously recommended that external wall construction should be restricted to Class A1 insulation and cladding products only. A2 certified products have a higher combustibility rating and can sustain flame for up to 20 seconds. Class A1 products have a lower combustibility rating and produce no sustained flaming when tested.

Surprisingly, a product can be certified A2 even though it produces an unlimited amount of smoke, flaming particles or droplets.