This study shows that PFRs acts very specifically depending on their chemical structures and on the type of polymers they are used in. It is important to know the chemical structure and composition of PFRs. Unfortunately, for most of the commercially available PFRs detailed specifications on the chemical structure and composition are not available. Therefore, for our developmental research, it was important for us to benchmark the chemical composition of the PFR s that were effective as HFFR additive in correlation to the UL-94V tests.