uPVC has inherent flame retardancy properties.
uPVC window profiles do not support combustion and are in fact self-extinguishing once a flame source is removed.
One of the few homes to have survived the 2009 Marysville bushfire in Victoria, had uPVC windows, and PVC was extensively used in other parts of the home. The vinyl weatherboards and window frames escaped any significant damage and protected the house from ember attack to the interior.
uPVC window frames have been developed and tested specifically to meet construction requirements for designated Bushfire Attack Levels (BAL) within Australian Standards for Construction in Bushfire Prone Areas (AS 3959:2009).
uPVC windows with metal reinforcing are permitted in zones classified as up to BAL-29 (where the number represents the heat flux in kW m2) risk. Some uPVC window systems have been independently tested and comply with AS 1530.8.1 which permits their use in zones BAL-40 and above.