This question is asked a lot: ” Why is the passive side of building works so expensive? ” To answer this there are a number of items that need to be discussed and understood more importantly. In order for a passive system installed to be certified, the following needs to be understood: Firstly, it must be installed to the manufacturer’s specifications and tested installations method. Secondly, the product being used must pass for use by a NATA test facility and the strict test methods required by AS 1530.4- 2005: Method for fire tests on building materials, components and structures. Fire –.