Visibility range in smoke produced during combustion of flame retardants-modified and non-modified corn. epoxy materials was studied in a room-corridor system. Calcns. were performed by using an available computer program. The crit. time of achieving visibility in the system decreased in series of the materials contg. MoO(3) > Rof lam P > Sb(2)O(3)> without additives > Roflam E > Roplast FN-1 > melamine.