Let's have a look at the whole external wall system
Why A2-s1,dO are preferred over a straight A1 when specifying facade membranes?
Learning from Grenfell
Since the Grenfell Tower fire, there has been a great deal of time and effort spent understanding fire and smoke control that is needed in times of an unfortunate building fire. The use of combustible cladding highlighted what a high-rise building fire can create through intense fire, dense smoke and hot burning droplets.
Euroclass A1 or A2 should be the norm now.
For architects and façade engineers Euroclass A1 or A2 products should be the norm for non-combustibility or limited combustibility of an outer wall system particularly for high-rise buildings.
Installing an A2-s1,d0 vertical wall system is recommended within the ADB part 4 guide.
Which functionality is essential for the lifetime and safety of a building?
Architects when specifying a vertical wall membrane as part of the façade system, should consider a membrane that is A2-s1,d0 for limited fire, limited smoke and no hot droplets, that is also breathable, water proof to W1with high UV protection.
Whilst an A1 membrane gives us the fire, smoke and hot droplets control we seek, it does not offer the other attributes of breathability to remove moisture from the building, offer the rain coat or water proofness to the outer wall and give the UV protection that an open façade will need.
Doing the right thing for the occupants of the building
When it comes to a building's cost and safety, then all the above attributes should be considered.
An Euroclass A2-s1,d0 membrane, breathable, water proof, with UV protection has to be better than the current ADB guide of having membranes “exempt” from being Euroclass A2, this by definition allows a Class B-s3 membrane to be acceptable within a A2 wall system.
When membranes were made exempt from an outer wall system it took into account damp course and roof membranes, these are not considered as part of the outer wall system. Vertical wall membranes should no longer be part of the “exempt” list as Class A2-s1,d0 membranes are now available. Do not wait for ADB changes. Do the right thing now by selecting an A2-s1,d0 water proof and breathable membrane for your façade system.
Learn more about maximum fire safety and creativity for your full façade system with Stamisol Safe One façade breather membrane Class A2-s1,d0
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