Plywood with phosphorus-nitrogen flame retardants showed very low toxic fire gases and achieved IMO fire performance. The plywood was vacuum impregnated with water soluble PIN FR consisting mainly of ammonium polyphosphate (APP) (pinfa comment: probably short-chain to enable solubility), guanyl urea phosphate (GUP) and phosphonic acid. Toxic fire gases were tested according to IMO (International Marine Organization) Res. MSC. 307(88):2010/ANNEX 1/Part 2[8]. All toxic gases tested were non detectable for the PIN FR plywood, whereas they were significant for polyurethane and PVC, except carbon monoxide which was considerably lower for the PIN FR plywood and below IMO specifications. Smoke emission was also below IMO requirements. Fire performance (CF Critical Flux at Extinguishment, Total and Peak Heat Release THR and PHR) were also below IMO specifications.
“Evaluation of Toxic Gas Generation, Smoke Generation, and Flammability in Flame-Retardant Plywood Combustion Tests”, H-J. Park & S-U. Jo, Prepints 2022 https://doi.org/10.20944/preprints202209.0003.v1