Original Article Journal of Fire Sciences 2017, Vol. 35(6) 565–576 Ó The Author(s) 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734904117737464 journals.sagepub.com/home/jfs Effectiveness of new wood fire retardants using a cone calorimeter Wojciech L Grzes ´kowiak Date received: 12 July 2017; accepted: 25 September 2017 Abstract This article presents results of fire retardants’ tests for wood. Analysis was conducted for two preparations, A1 containing guanidine carbonate and A2 with urea, in accordance with the stan- dard ISO 5660-1 and nonstandard method using Mini Fire Tube. Samples of Scots pine (Pinus syl- vestris L.) wood were protected using the above-mentioned mixtures applied under vacuum. Recorded results for pine wood impregnated with the tested preparations at a concentration of 15% show that they have high fire-retardant effectiveness at the intensity of the radiant heat of 35 kW/m 2 . An increase in the number of nitrogen atoms in the preparation provides greater fire- retardant effectiveness of the agent. Keywords Wood, fire retardant, cone calorimeter, guanidine, urea, synergism Introduction The application of fire retardants as elements of passive fire protection is an extremely important factor for fire safety of buildings. 1 Thanks to the use of fire retardants; we may considerably reduce values of parameters connected with fire performance of materials such as combustion rate, flame spread and heat release rate (HRR). These preparations enhance fire resistance and limit fire spreading through building structures. 2 Wood Protection & Conservation Laboratory, Institute of Chemical Wood Technology, Faculty of Wood Technology, Poznan ´ University of Life Sciences, Poznan ´, Poland Corresponding author: Wojciech L Grzes ´kowiak, Wood Protection & Conservation Laboratory, Institute of Chemical Wood Technology, Faculty of Wood Technology, Poznan ´ University of Life Sciences, 38/42 Wojska Polskiego St., PL 60-637 Poznan ´, Poland. Email: wojblack@up.poznan.pl