In the case of fire rating walls, no polystyrene blocks can be fire rated where polystyrene bridges secure one side of the block to the other.
To achieve a fire rating for Thermacell systems in a situation such as a party wall between units, solutions could involve either the removal of the ‘bridges’ and filling of the gaps with concrete to produce a solid core, or the fixing of 6mm ‘fire rated’ plasterboard to both sides of the wall.
An assessment on how to fire rate your Thermacell walls is available upon request; this has been provided by the Warrington Fire Research Consultancy and CSR, and approved by the CSIRO.
The use of a fire-rated system called ‘Magboard’ will also achieve a similar result. Information regarding this board is also available from Thermacell.