This study was performed the combustion characteristics of cypress specimen for the constructional interiors, especially focusing on smoke generation characteristics. Smoke production properties were measured using a cone calorimeter (ISO 5660-2). The external heat flux was maintained at 50 kW/m2. 4 wt% boric acid and ammonium pentaborate were used as flame retardants. Combination of the two compounds was used to observe the smoke behavior according to the concentration. The total smoke release of 4 wt% boric acid and ammonium pentaborate was 426.47 m2/m2 and 395.40 m2/m2, respectively. However, the total smoke release rate of the combined specimens was 557.09 m2/m2, which was 22.8% higher than 453.5 m2/m2 of the base panel. The total smoke production of the combined specimens was 4.93 m2, which was 22.7% higher than that of 4.01 m2 of cypress. The flame retardant combined with 4 wt% was found to increase smoke generation.
