The goal of this experiment is to assess the mass and volume loss of medium size pine wood particles undergoing pyrolysis. Wood samples of different sizes and shapes were pyrolysed at 500 ºC with different residence times. A thermogravimetric analysis was carried out for comparison purposes. Finally, the pyrolysed samples were analysed using radiographic methods. A connection between the different analyses was found. For larger particles, the heating rate is lower, and a time gap between hemicellulose and cellulose thermal decomposition was noticed. Research shows that an important part of the analysis of the process is the rate of biomass heating and sample size. As the sample size increases, the pyrolysis time increases; however, the increase is not linear. The publication also shows the great possibilities of radiographic methods in analysing the pyrolysis process.; Cilj istraživanja bio je procijeniti gubitak mase i volumena čestica borovine srednje veličine podvrgnutih pirolizi. Uzorci drva različitih veličina i oblika pirolizirani su pri 500 °C i pri različitim vremenima trajanja pirolize. Za usporedbu je provedena termogravimetrijska analiza borovih čestica. Nakon toga pirolizirani su uzorci analizirani metodom radiografije. Pronađena je veza između različitih analiza. Brzina zagrijavanja većih čestica je niža, a primijećen je i vremenski jaz između toplinskog raspadanja hemiceluloze i celuloze. Istraživanja su pokazala da su važan dio analize procesa pirolize brzina zagrijavanja biomase i veličina uzorka. Kako se veličina uzorka povećava, tako se povećava i vrijeme pirolize, i to nelinearno. Usto, rad upućuje na velike mogućnosti radiografskih metoda u analizi procesa pirolize.