Intumescent PIN flame retardant reduces fire risk and smoke in polyurethane seats achieving railway safety standards. The Adeka PIN FR at 0 – 60% loading in resin inserts in foam seat material was compared to magnesium and bromine based flame retardants and to neat resin. For the resin insert, the magnesium and intumescent (both PIN) considerably reduced smoke emission. The intumescent PIN FR offered the best fire performance in the resin, reducing peak heat release rate and smoke emission by nearly 90% at 40% loading. The insertion of the PIN FR resin layer into the seating foam (below 20 mm depth of foam) was effective in suppressing foam combustion because of the intumescent and char forming effect.
“Improvement of Flame Retardancy of Seat Cushion Materials for Railway Vehicles Using Intumescent Flame Retardant”, T. Toyohara, S. Yamanaka, QR of RTRI vol.65, n°2, May 2024 https://www.jstage.jst.go.jp/article/rtriqr/65/2/65_83/_pdf