Abstract: [Objective] Cone calorimeter sample shape and size affect its experimental results. In order to clarify whether the powder samples are appropriate for CONE tests or not, seven different forms of wood samples were investigated by cone calorimeter. Study on the influence of sample shape and size on cone heat release parameters have important significance on selecting heat release parameters, evaluating combustion process and researching flame retardant mechanism.[Method] Seven different processing methods and forms of wood samples were investigated by cone calorimeter under a heat flux of 50 kW·m^-2. The PHRR(peak of heat release rate), HRR(heat release rate), THR(total heat release), EHC(effective heat combustion) results were measured. [Result] Through analyzing the arithmetical mean error(ΔX), relative error(E_r)and standard deviation(S)of the cone calorimeter results from seven types of wood samples, it was found that the error estimate of MEHC(mean of effective heat combustion)was the minimum and the error estimate of PHRR was the maximum in PHRR, MHRR, THR, MEHC four thermal parameters determination results. And the above-mentioned four heat release parameters of powder samples had low error estimates, far less than those of the plate samples. Such as two powdery samples of PP and FPP, their S_MHRR respectively are 1.2 and 1.1 kW·m^-2 respectively, which was about 1/8 of PPB and far lower than values of five plate samples.[Conclusion] The experimental results show that MEHC is mainly influenced by the combustion process, while the PHRR is influenced by the combustion state, sample itself and the external factors. Furthermore, the precision of the powdery samples is better than that of the plate samples, being with good reproducibility and high reliability. Therefore, powdery samples is suitable to be used in laboratory test and materials selection in scientific research, which can save the materials and time prepare the standard samples, and provide scientific basis to simplify the experimental sample of cone processing technology.

Key words: cone calorimeter, sample form, heat release parameter, standard deviation, precision