Comparative study on fire retardancy of various wood species treated with PEG 400, phosphorus, and boron compounds for use in cement-bonded wood-based products

Abstract

The aim of this study was to find suitable fire retardants to increase the fire resistance of Scots pine, poplar, and date palm trees. The fire retardants used in this study were disodium-tetra borate (Na2B4O7) (Borax), disodium-hydrogen phosphate (Na2HPO4) (DSHP), diammonium-hydrogen phosphate ((NH2)4HPO4) (DAHP), and polyethylene glycol 400 (PEG 400). The fire retardants were prepared in different concentrations, and the selected wood species were tested in particle form and as solid wood, both with three different surface roughness: sawn, sanded, and planed. Fire tests were completed with a single flame source test, Lindner test, and calorimeter test. Since the fire retardants may affect cement curing, a cement hydration test was conducted by measuring the temperature of the hydration process. Fire retardant concentrations affected the performance of fire retardancy, while surface preparations proved effective only for Scots pine. Nevertheless, much depended on the type of fire retardants used and the wood species upon which they were applied. For the hydration tests, all samples treated with fire retardants were cured normally with the exception of PEG 400, DAHP and DSHP with high concentration. DAHP with 300 g/l and DSHP with 77 g/l concentrations were found to be suitable fire retardants for CBPB production since they increased fire resistance and had small effect on cement curing.