Fire Tests on Wood Products Subjected To Different Heat Fluxes

The paper analyses three different wood products used for research exposing them to the surface heat flow density of 30 kW/m², 50 kW/m² and 70 kW/m² and applying the test method described in ISO 5660–1 Reaction‐to‐fire tests – Heat release, smoke production and mass loss rate – Part 1: Heat release rate (Cone calorimeter method). Research was performed applying 18 mm and 29 mm thick laminated wood chipboards and 24 mm thick medium density fibreboard. The paper provides an overview of the fire properties of wood products and discusses testing methods and the percentage composition of the tested wood products. Mean time to their ignition was determined. The mean values of the maximum heat release rate and time required to achieve them were investigated. Furthermore, the measurements of the released heat and efficient heat of combustion were taken. Further research covers the performance of statistic analysis, deriving empiric equations, correlation and determination coefficients, standard errors and Student criterion. The results of research are summarized. Conclusions are provided at the end of the paper. Santrauka Straipsnyje nagrinejami trys skirtingi medienos gaminiai, su kuriais atlikti tyrimai veikiant 30 kW/m², 50 kW/m²bei 70 kW/m² paviršiniais šilumos srautais taikant ISO 5660–1 “Reaction‐to‐fire tests – Heat release, smoke production and mass loss rate – Part 1: Heat release rate (Cone calorimeter method)” bandymo metoda. Tyrimai atlikti su 18 mm ir 29 mm storio laminuotomis medžio drožliu plokštemis bei 24 mm storio vidutinio tankio plaušo plokšte. Darbe apžvel‐giamos medienos gaminiu gaisrines savybes. Aptariama bandymo metodika ir tirtu medienos gaminiu procentine sudetis. Nustatytas vidutinis laikas iki ju užsidegimo. Ištirti vidutiniai maksimalios šilumos išsiskyrimo greičio ir laiko iki ju pasiekimo dydžiai, taip pat išmatuota visa išskirta šiluma ir efektyvi degimo šiluma. Atlikta statistine analize, gautos em‐pirines lygtys, koreliacijos bei determinacijos koeficientai, standartines paklaidos bei Stjudento kriterijai. Apibendrinami tyrimo rezultatai. Darbo pabaigoje suformuluojamos išvados.