An Experimental Study on Combustion Characteristics of Printers Depending on Geometrical Type and Kind of Plastics Used

Abstract

To estimate the fire load of a room, data pertaining to the combustion behavior and other aspects are required. In this study, the fire behavior of diverse printers was observed by conducting a series of combustion experiments. Twelve units of printers were used for the experiments. The weight of the printers ranged between 6.7 and 54.5 kg. The bulk volume was 0.026–0.147 m³. The projected area was between 0.49 and 1.33 m². The ignition source was a propane gas burner using a 10-mm-diameter copper pipe. The supply flow rate of the gas was set to 1 L/min using a mass flow controller. In the burning test, the heat release rate was measured by using the oxygen consumption method, and the weight change was measured by using a set of load cells. The results of the burning test showed that the combustion behavior and the heat of combustion differed significantly according to the type of printers. The heat of combustion of the inkjet printer was 31.7 MJ/kg and that of the laser printer was 24.7 MJ/kg. The fire load was estimated using the measured HRR and the residual weight after the burning test. The relationship between the initial weight or bulk volume and the fire load is shown. Additionally, the relationships between the surface area and the maximum heat release rate and that between the bulk density and the fire growth rate α are shown. The results of this study revealed that the maximum heat release rate is proportional to the nominal ventilation factor and that the fire growth rate is decreased as the bulk density is increased.

Appendices

Appendix 1: Properties of Plastics

Table 3 shows the physical properties of high-impact polystyrene (PS-HI) and ABS related to the combustion experiment [15, 16].

Table 3 Measurement items

Appendix 2: Method for Finding the Projected Area and the Bulk Volume of Printer by Image Analysis

Five surfaces of specimens except the bottom surface were recorded as shown in Fig. 9. During the recording, a sticker of 75 × 75 mm size was attached on the surface of a printer. The number of pixels of the sticker and a printer was calculated by using an image analysis software, and the projected area of each face was calculated by using Eq. (6). The sum of the projected area of five surfaces was set as a bulk surface area A_s. Bulk volume V_bulk was calculated by Eq. (7) by using the projected surface area of a specimen A_side and the width of the measured specimen. Bulk density ρ_bulk was calculated by Eq. (7).

Fig. 9

a Take a picture of five surfaces. b Using the image analysis software (Image J), obtain the pixel number, respectively

$$ A_{\text{s}} = A_{\text{Tag}} /{\text{pixel}}_{\text{Tag}} \times {\text{pixel}}_{\text{ALL}} $$

(6)

$$ V_{\text{bulk}} = A_{\text{side}} \times W,\quad \rho_{\text{bulk}} = W_{0} \times V_{\text{bulk}} $$

(7)