An Evaluation of the Fire Safety of Waste Paper-Based Internal Finishing Materials Combined with Expandable Graphite According to Changes in Magnesium Hydroxide Content

Abstract

Inflammable building finishing materials act as a major cause of fire propagation, and they, therefore, pose significant risks to life and can lead to property damage. To replace such flammable building finishing materials, many countries have established regulations limiting their use, which has led to extensive research on the development of flame-retardant building finishing materials. Such methods have included adding flame retardants to construction materials to reduce the heat release rate and total heat release. The present study aimed to enhance the fire performance of cellulose-based architectural finishing materials by creating a dual flame-retardant mixture using expandable graphite and magnesium hydroxide added to recycled paper waste. Specimen fabrication involves using a pressing method to apply uniform pressure to compress the mixture in a mold. The total heat release (THR), CO, and CO₂ production of the produced specimens were measured using a cone calorimeter while varying the magnesium hydroxide additive ratio. The combustion gases were measured through NES 713 experiments to determine any changes in the Toxic Index corresponding to variations in the magnesium hydroxide content. The experiment results established a correlation between the magnesium hydroxide additive ratio and the total heat release, as well as the existence of variations in CO and CO₂ production for the dual flame-retardant recycled paper material. A database for combustion gases was also obtained. It was confirmed that the fire performance was improved by confirming that the total heat release decreased by 52% from the previous one in the magnesium hydroxide content of 30 g, and it was confirmed that the inflection points of the Toxic Index value due to the change in CO and CO₂ gas production occurred in the magnesium hydroxide content of 20 g due to the improvement of the fire performance. Through the ISO 5660-1 experiment data, we have secured data that can be used as foundational information for performance-oriented fire risk assessments, thereby ensuring the fire safety of cellulose materials that are vulnerable to fire.

1. Introduction

To replace combustible building finishes that contribute to the spread of fire [1,2,3,4,5], countries around the world stipulate the fire performance of building finishes in attempts to secure the appropriate fire performance of all finishing materials used in buildings. For example, in the United States, NFPA 255 standards are applied to interior architectural finishes, which are classified into Classes A to C based on their flame spread index and smoke development criteria [6]. As another example, Germany’s DIN 4102-1-1998 standard classifies building materials into non-combustible materials (Class A) and flame-resistant materials (Class B) [7,8]. Meanwhile, in Korea and Japan, the fire performance of buildings is classified into non-combustible, semi-non-combustible, and flame-resistant categories using ISO 1182, ISO 5660-1, and ISO 2271 test standards [9,10]. As various countries around the world enact regulations to ensure the fire performance of architectural finishing materials, it has become essential to secure the fire performance of these materials. In this context, various studies have developed flame-resistant finishing materials by adding flame retardants to existing building materials. For example, Hwang et al. manufactured cellulose architectural finishing materials with ceramic binders using a 3D printer. Through an ISO 11925-2 experiment, they confirmed that cellulose finishing materials with 20 wt% added ceramic binder satisfied the criterion of vertical charring length within 150 mm at 30 s ignition, according to EN 13501-1. Moreover, cellulose finishing materials with 40 wt% added ceramic binder showed no residual combustion after the ISO 11925-2 experiment [11]. In another study, Ahn et al. confirmed that cellulose architectural finishing materials produced using an LWC 3D printer exhibited the same mass, density, and fire performance, thus verifying the production efficiency of the LWC 3D printer. They also added ceramic binder to cellulose architectural finishing materials and accordingly conducted the ISO 5660-1 test. The results showed that cellulose finishing materials with 50 wt% added ceramic binder could successfully be utilized as fire-resistant architectural finishing materials [12]. Kim et al. measured the thermal conductivity and specific heat of the flame-resistant cellulose architectural finishing material that was prepared using the LFA 1000 experiment. They also confirmed the generation of toxic gases through a NES 713 experiment. Using the measured data, they conducted FDS simulations that considered medical facilities. By comparing the data between the produced cellulose architectural finishing material and polyurethane, they concluded that cellulose architectural finishing material was appropriate for use as a building finish material in medical facilities [13]. Similarly, Kim et al. conducted FDS simulations using fire data from cellulose architectural finishing materials with varying sizes of expandable graphite particles. The results of those simulations confirmed that cellulose architectural finishing materials with varied particle sizes were efficient in providing safe evacuation times for evacuees [14]. This study aimed to enhance the fire performance of cellulose architectural finishing materials by creating a dual flame-retardant mixture using expandable graphite and magnesium hydroxide added into recycled paper waste. Specimen fabrication involved using a pressing method and applying uniform pressure to compress the mixture in a mold. The cone calorimeter was used to measure the total heat release (THR) as well as variations in CO and CO₂ emissions in response to changes in the magnesium hydroxide additive ratio in the produced specimens. Moreover, NES 713 experiments were conducted to assess alterations in the Toxic Index values associated with fluctuations in magnesium hydroxide content. Figure 1 shows the flow chart for this study.

2. Description of Specimens and Test

2.1. Description of Process to Make Specimens

The manufactured architectural finishing material specimens were produced using a small press designed for the preparation of cone calorimeter specimens. The specimen was made by stirring flame retardants in the cellulose slurry used in the Large Wet Cellulose 3D Printer study [11]. To ensure uniform pressure across the specimen, the sample was placed in the mold, and a constant pressure was applied through compression. The mold size was designed to be 100 mm × 100 mm, following the specifications of the cone calorimeter, with a height of 50 mm to prevent the sample from escaping outside the mold due to pressure. Figure 2 depicts the configuration of the small press used to create architectural finishing material specimens.

The specific flame retardants of expandable graphite and magnesium hydroxide were added to improve the fire performance of cellulose in this study for the following reasons:

• Expandable graphite has been utilized as a flame retardant based on its physical mechanism in various architectural materials research studies [15,16,17,18]. Expandable graphite expands into a carbon layer upon heating, thus protecting the bottom of the specimen and simultaneously inhibiting the external spread of fire [18,19,20]. An 80-mesh expandable graphite was chosen in this study due to its significant reduction in total heat release compared to expandable graphite of other particle sizes [21];
• Magnesium hydroxide has been utilized as a flame retardant with a chemical mechanism in various studies [22,23,24,25,26]. Magnesium hydroxide was added to enhance the fire performance through an endothermic reaction during the heat reaction. The endothermic reaction of magnesium hydroxide is expressed in Equation (1) [27,28,29].

  $${Mg\left(OH\right)}_2\to MgO+H_{2}O 1244~1450J/g$$

  (1)

In this study, a cellulose slurry of a constant mass was prepared by adding the same expandable graphite (30 g) to evaluate the fire performance and analysis of toxicity gas emissions based on variations in the content of added magnesium hydroxide. The mixture of cellulose architectural finishing material was created by increasing the magnesium hydroxide content in 10 g increments, thus resulting in mixtures with 0 g, 10 g, 20 g, and 30 g.

Table 1. Composition of specimens (g).

Specimens Name	Basic Material	Flame Retardant		After Drying Mass (g)
	Waste Paper	Expandable Graphite (EG)	Magnesium Hydroxide (Mg(OH)2)
A	100	30	0	56
				55.9
				56.6
B	100		10	69
				69.8
				69.4
C	100		20	79.7
				79.3
				79.5
D	100		30	85.1
				86.2
				87.5

presents the compositions of the specimens.

2.2. Description of Heat Release Rate Test

Construction finishing materials must go through a performance certification procedure for the heat emission rate to ensure safety in case of fire. The cone calorimeter test is often used in small-scale experiments to test the fire behavior of building materials, and the International Organization for Standardization has adopted a cone calorimeter tester as a standard for measuring the heat release rate (HRR) of a test material [30]. In this study, the heat emission rate of the specimen was measured by applying the ISO 5660-1 cone calorimeter test method. This test involves the continuous application of radiant heat to the specimen, positioned at a distance of 22.5 mm from the heater, with a heat flux of 50 kW/m². The calculation of the heat release rate emitted by the test specimen is based on the principle that approximately 13.1 MJ of heat is generated when 1 kg of oxygen is consumed during combustion. The theoretical equation is represented by Equation (2)

$$\dot{q}\left(t\right)=\left(\frac{∆h_c}{r_0}\right)\left(1.10\right)C\sqrt{\frac{∆P}{T_e}}\frac{X_{O_2}^0-X_{O_2}}{1.105-1.5X_{O_2}}$$

(2)

where

$∆h_c/r_0$ represents the heat released when 1 kg of oxygen is consumed, which is 13.1 MJ.

$C$ represents the orifice constant of the cone calorimeter.

$∆P$ denotes the pressure difference measured at the orifice.

$T_e$ denotes the absolute temperature measured at the orifice.

$X_{O_2}^0$ denotes the molar fraction of oxygen measured by the oxygen analyzer during the initial 60 s before the experiment.

$X_{O_2}$ denotes the molar fraction of oxygen measured by the oxygen analyzer during the experiment.

The consumed oxygen quantity was measured using the oxygen analyzer of the cone calorimeter [30,31,32,33]. Figure 3 shows a schematic diagram of the ISO 5660-1 test equipment.

Table 2. The detailed conditions of the ISO 5660-1 test.

Case	Details
Heat flux of cone heater	50 kW
Specimen distance of cone heater	22.5 mm
C-factor	0.0411
Duct flow rate	24 ± 0.1 L/s
Specimens size	100 mm × 100 mm × 20 mm
Number of tests per specimen type	3
Test time	600 s

presents the detailed conditions of the ISO 5660-1 test.

Table 3. Performance standard using the ISO 5660-1 test method.

Standard	Class	Evaluation Criteria
ISO 5660-1 (Cone Calorimeter Method)	Semi- non-combustible Material	- Total radiant heat 10 min after heating is 8 MJ/m2. Within 10 min, max. heat radiant rate does not exceed 200 kW/m2 for longer than 10 consecutive seconds. - There shall be no cracks that penetrate the sample, holes, or melting (for mixed content materials, this includes melting and dissipation of all core materials) after heating for 10 min.
ISO 5660-1 (Cone Calorimeter Method)	Fire Retardant Material	- Total radiant heat 5 min after heating is 8 MJ/m2. Within 5 min, max. heat radiant rate does not exceed 200 kW/m2 for longer than 10 consecutive seconds. - There shall be no cracks that penetrate the sample, holes, or melting (for mixed content materials, this includes melting and dissipation of all core materials) after heating for 5 min.

lists the fire and intermediate fire performance criteria for the ISO 5660-1 test, as specified by the International Organization for Standardization. The criteria were applied here to evaluate the fire and intermediate fire test performances of the specimens of interest [30].

2.3. Description of NES 713 Test

The NES 713 test is conducted to verify the composition and release of toxic gases in building materials. The NES 713 toxicity test method is based on the Naval Engineering Standard Code [34]. The toxicity analysis test for the combustion gases emitted by the produced architectural finishing material specimens was conducted using the Toxicity Test Apparatus from UK FTT, which complies with the UK NES 713 standard [35]. The conditions of the NES 713 toxicity test used in this study are detailed in

Table 4. Detailed conditions of NES 713 toxicity test.

Specimens
Mass	1 ± 0.05 g
Sample type	A, B, C, D
Number per sample type	3
Mechanical
Chamber volume	800 × 800 × 1000 (W × D × H) mm 0.7 m3
Exhaust	50 L/s
Calibration Test
Calibration gas	CO, CO2, NOx
Calibration test time	2 min
Test
Flame temperature	1150 ± 50 °C
Flame height	100 ± 10 mm
Test time	2 min
Stirring time	30 s
Ventilation time	at least 5 min

. A schematic representation of the apparatus is provided in Figure 4.

This test specification detects 13 types of toxic gases that are generated during the combustion process following the complete combustion of the material using detection tubes. The types of toxic gases detected and their lethal concentrations are presented in

Table 5. Toxicity concentration fatal to humans with NES 713.

Toxic Gas	Cf (ppm)
Carbon Dioxide (CO2)	100,000
Carbon Monoxide (CO)	4000
Hydrogen Sulfide (H2S)	750
Ammonia (NH3)	750
Formaldehyde (HCHO)	500
Hydrogen Chloride (HCl)	500
Sulfur Dioxide (SO2)	400
Acrylonitrile (CH2CHCN)	400
Nitrogen Oxides (NOx)	250
Phenol (C6H5OH)	250
Hydrogen Cyanide (HCN)	150
Hydrogen Bromide (HBr)	150
Hydrogen Fluoride (HF)	100

[35,36,37,38,39].

The NES 713 standard extracts gases generated after the complete combustion of the material. By applying the chamber volume and the weight of the sample used, the amount of gas emitted when 100 g of the specimen is burned can be calculated. The equation used to calculate the gas generation concentration (C_θ) is given in Equation (3) [35]:

$$C_{\theta }=\frac{C_i\times 100\times V}{m}$$

(3)

where

C_θ = gas generation concentration.

C_i = concentration of each gas measured in the combustion results (ppm).

m = mass of the test specimen (g).

V = volume of the chamber (m³).

The concentration and Toxicity Index for each detected gas are calculated using Equation (4),

$$\mathrm{T}\mathrm{o}\mathrm{x}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{t}\mathrm{y} \mathrm{I}\mathrm{n}\mathrm{d}\mathrm{e}\mathrm{x}= \frac{C_{\theta 1}}{C_{f1}}+\frac{C_{\theta 2}}{C_{f2}}+\dots +\frac{C_{\theta n}}{C_{fn}}$$

(4)

where

C_θ = the average value of the gas concentration calculated in Equation (3) (ppm).

C_f = the lethal dose for a person exposed to the gas for 30 min (ppm).

In the NES 713 experiment, we used the Toxicity Index and detected gas concentrations to examine variations in the production of toxic gases with changes in the amount of magnesium hydroxide added.

3. Test Results

3.1. Result of ISO 5660-1

To investigate the impact of the addition of varying amounts of magnesium hydroxide on the fire performance of expanded graphite–cellulose composite finishing material, ISO 5660-1 tests were conducted three times for each magnesium hydroxide addition level. The parameters assessed include HRR, THR, CO, and CO₂ production, as well as mass loss.

Figure 5 shows the variations in HRR with changes in magnesium hydroxide content, showing the measured values obtained from three tests for each specimen.

Figure 6 shows the difference in THR and fire performance with respect to changes in magnesium hydroxide content. The values presented are obtained from three tests for each specimen.

Figure 7 and Figure 8, respectively, depict the changes in the measured values of CO production and CO₂ production over time during the ISO 5660-1 testing process with respect to variations in magnesium hydroxide content. The values presented are obtained from three tests for each specimen.

Figure 9 shows the changes in the measured values of mass over time during the ISO 5660-1 testing process with respect to variations in magnesium hydroxide content. The values presented are obtained from three tests for each specimen.

Table 6. ISO 5660-1 test results.

Sample Type	No.	Ignition Time	Peak Heat Release Rate (kW/m2)	THR (MJ/m2)		Toxic Gas Generated		Mass Loss (g)
				at 300 s	at 600 s	CO (%)	CO2 (%)
A	1	12 s	87.259	9.854	30.31	0.0069	0.204	25.76
	2	16 s	48.999	9.05	21.217	0.0065	0.137	21.93
	3	11 s	90.972	8.853	24.842	0.0070	0.202	21.15
B	1	21 s	41.262	7.293	15.678	0.0076	0.111	19.52
	2	14 s	47.873	7.052	16.581	0.0084	0.122	21.54
	3	14 s	48.554	7.691	17.973	0.0086	0.119	20.94
C	1	16 s	38.64	7.123	15.958	0.0097	0.106	21.81
	2	16 s	39.713	7.028	16.138	0.0093	0.103	23.35
	3	11 s	39.245	7.307	15.918	0.0096	0.098	21.22
D	1	17 s	38.535	6.34	12.183	0.0114	0.077	21.04
	2	16 s	33.795	6.078	11.575	0.0112	0.068	18.48
	3	15 s	34.495	6.171	12.594	0.0113	0.071	15.59

presents the fire performance data obtained from ISO 5660-1 testing, which showcases variations in fire performance with changes in magnesium hydroxide content.

3.2. Result of NES 713

To investigate whether varying the amount of magnesium hydroxide addition affects the production of toxic gases during the combustion process of cellulose material, we conducted NES 713 tests with magnesium hydroxide addition as the variable.

Table 7. NES 713 test results.

Sample Type	Toxic Gas
	CO2	CO	H2S	NH3	HCHO	HCl	SO2	CH2CHCN	NOx	C6H5OH	HCN	HBr	HF
A-1	3300	80	0	0	0	0	0	0	0.1	0	0.2	0	0
A-2	3700	60	0	0	0	0	0	0	0.1	0	0.2	0	0
A-3	3500	70	0	0	0	0	0	0	0.1	0	0.2	0	0
B-1	2950	110	0	0	0	0	0	0	0.1	0	0.2	0	0
B-2	3150	120	0	0	0	0	0	0	0.1	0	0.2	0	0
B-3	2900	130	0	0	0	0	0	0	0.1	0	0.2	0	0
C-1	2350	220	0	0	0	0	0	0	0	0	0.5	0	0
C-2	2500	185	0	0	0	0	0	0	0	0	0.5	0	0
C-3	2650	180	0	0	0	0	0	0	0	0	0.5	0	0
D-1	800	240	0	0	0	0	0	0	0	0	0.5	0	0
D-2	1300	190	0	0	0	0	0	0	0	0	0.5	0	0
D-3	900	200	0	0	0	0	0	0	0	0	0.5	0	0

summarizes the concentrations of toxic gases detected during the NES 713 testing process, along with variations in magnesium hydroxide addition. Figure 10 shows the changes in the generation of toxic gases with variations in magnesium hydroxide addition in the specimens.

4. Discussion

4.1. ISO 5660-1 Test

Through ISO 5660-1 testing, we investigated the impact of variations in the particle size of magnesium hydroxide on the fire performance and combustion by-products of cellulose-based building finishing materials.

Figure 11 shows the THR at 600 s as well as the trendline with respect to varying magnesium hydroxide addition amounts. It can be seen that the flame-retardant magnesium hydroxide addition and THR results are inversely proportional to each other. As the amount of magnesium hydroxide addition increases, a more consistent fire performance is observed.

The variation in THR results with respect to magnesium hydroxide addition is expressed by Equation (5):

$$y = 0.0121x^2 - 0.7693x + 24.9$$

(5)

where

y = THR at 600 s.

x = magnesium hydroxide addition amount.

Figure 12 and Figure 13, respectively, compare the quantified measurements of CO and CO₂ gases over time in ISO 5660-1 experiments conducted with varying magnesium hydroxide addition amounts as the variable. The quantification equations for the gases generated in the ISO 5660-1 experiment were organized and calculated as expressed in Equations (6) and (7).

$$CO \mathrm{P}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n} \mathrm{I}\mathrm{n}\mathrm{d}\mathrm{e}\mathrm{x}= {\int }_0^{600}COProduction$$

(6)

$${CO}_2 \mathrm{P}\mathrm{r}\mathrm{o}\mathrm{d}\mathrm{u}\mathrm{c}\mathrm{t}\mathrm{i}\mathrm{o}\mathrm{n} \mathrm{I}\mathrm{n}\mathrm{d}\mathrm{e}\mathrm{x}= {\int }_0^{600}{CO}_{2}Production$$

(7)

The correlation between changes in magnesium hydroxide addition and the generation of each of CO and CO₂ in cellulose specimens was examined. It was observed that an increase in magnesium hydroxide led to incomplete combustion, thus resulting in a decrease in carbon dioxide generation and an increase in carbon monoxide generation.

The variation in the CO Index with respect to magnesium hydroxide addition is expressed by Equation (8), while the corresponding variation in the CO₂ Index is represented by Equation (9):

$$y=-0.0001x^2+0.0827x+3.3433$$

(8)

where

y = CO Index.

x = magnesium hydroxide addition amount.

$$y=0.034x^2-2.156x+96.045$$

(9)

where

y = CO₂ Index.

x = magnesium hydroxide addition amount.

Table 8. Initial mass and after ISO 5660-1 test mass and mass loss data.

Sample Type	Test No.	Initial Mass (g)	After Test Mass (g)	Mass Loss (%)	Standard Deviation
A	1	56	30.24	46	3.71
	2	55.9	33.97	39.23
	3	56.6	35.45	37.37
B	1	69	49.48	28.29	1.09
	2	69.8	48.26	30.86
	3	69.4	48.46	30.17
C	1	79.7	57.89	27.37	1.17
	2	79.3	55.95	29.45
	3	79.5	58.28	26.69
D	1	85.1	64.06	24.72	2.82
	2	86.2	67.72	21.44
	3	87.5	71.91	17.82

represents the initial mass and the mass after the ISO 5660-1 experiment. Utilizing the mass data recorded during the ISO 5660-1 experiment, the analysis of the mass loss rate variation with changes in magnesium hydroxide addition was conducted by comparing the initial mass with the mass at the end of the experiment. The equation for calculating the mass loss rate of the specimens during the experiment is given by Equation (9), and Figure 14 illustrates the distribution of mass loss rates along with the trendline with respect to varying magnesium hydroxide addition amounts.

$$\mathrm{M}\mathrm{a}\mathrm{s}\mathrm{s} \mathrm{L}\mathrm{o}\mathrm{s}\mathrm{s} \mathrm{R}\mathrm{a}\mathrm{t}\mathrm{e} \left(\%\right)=\frac{InitialMass-AfterTestMass}{InitialMass}\times 100$$

(10)

The analysis of the mass loss rate revealed that as the magnesium hydroxide addition increased, the mass loss rate decreased.

The variation in the mass loss rate results with respect to magnesium hydroxide addition is expressed by Equation (11),

$$y=0.0095x^2-0.8975x+38.621$$

(11)

where

y = mass loss rate (%).

x = magnesium hydroxide addition amount.

4.2. Toxic Index

To investigate the trend in the measured CO and CO₂ production in the ISO 5660-1 experiments for cellulose with varying magnesium hydroxide additions, NES 713 experiments were conducted on specimens with the same mass but differing amounts of magnesium hydroxide added. This was carried out to verify the differences in the presence and quantity of toxic gas generation. The results of NES 713 experiments indicated that, as the magnesium hydroxide addition increased, the CO production in specimens with the same mass increased, while the CO₂ production decreased.

The NES 713 experiment results revealed a turning point in the Toxic Index in response to the changes in magnesium hydroxide addition, which could be attributed to a decrease in carbon dioxide production and an increase in carbon monoxide production, which are combustion by-products. It could be observed that the Toxic Index values increased up to a magnesium hydroxide addition of 20% in Sample Type C. However, beyond that, with a magnesium hydroxide addition of 30% in Sample Type D, there was a tendency for the Toxic Index to decrease. This decrease was attributed to changes in the reduction in carbon dioxide production as well as the increase in carbon monoxide production. Figure 15 represents the Toxic Index values of cellulose specimens for each magnesium hydroxide content, which are calculated based on the concentrations of toxic gases detected in the NES 713 experiment results.

$$\mathrm{T}\mathrm{o}\mathrm{x}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{t}\mathrm{y} \mathrm{I}\mathrm{n}\mathrm{d}\mathrm{e}\mathrm{x}= \frac{C_{\theta 1}}{C_{f1}}+\frac{C_{\theta 2}}{C_{f2}}+\dots +\frac{C_{\theta n}}{C_{fn}}$$

(12)

5. Conclusions

In this work, ISO 5660-1 (cone calorimeter) heat release experiments and NES 713 Toxicity Index experiments were conducted to investigate the impact of varying magnesium hydroxide addition in cellulose finishing materials manufactured using a small press on fire performance and toxic gas production, and the following conclusions were obtained:

• The cellulose building finishing material manufactured using a small press exhibited uniform total heat release, consistent CO and CO₂ generation, and uniform mass loss;
• ISO 5660-1 tests conducted on specimens produced by varying magnesium hydroxide additions revealed that as the magnesium hydroxide content increased, the total heat release rate of the cellulose building finishing material decreased;
• Based on the results of ISO 5660-1 tests, it was confirmed that cellulose building finishing material, composed of 100 g of cellulose and 20 g of expanded graphite along with the addition of at least 10 g of magnesium hydroxide, did not exceed a THR of 8 MJ/m² at 300 s. This affirms its potential utility as a fire-resistant building finishing material;
• The investigation of CO and CO₂ emissions with varying magnesium hydroxide additions through both ISO 5660-1 tests and NES 713 toxicity tests revealed that, as the magnesium hydroxide content increased in cellulose building finishing material, there was an increase in CO emissions and a decrease in CO₂ emissions during fire conditions;
• The architectural finishing material produced was confirmed not to emit harmful levels of CO to humans by comparing the CO emissions generated over 10 min in the ISO 5660-1 experiment and over 2 min in the NES 713 experiment, with the levels specified in the NES standard for 30 min of exposure;
• Through the analysis of Toxic Index values from the NES 713 toxicity test, it was observed that the Toxic Index was high when the magnesium hydroxide addition was 20 g. The Toxic Index decreased above that due to a reduction in CO₂ generation.

Through the heat emission rate data and toxic gas data obtained through the ISO 5660-1 test and NES 713 test, it was confirmed that fire performance could be improved by adding flame retardants to the abandoned paper-based building finishing material, and basic data necessary for evaluating the fire risk of building finishing materials were obtained.

The ISO 5660-1 experiment and the NES 713 experiment conducted in this study secured basic data on fire performance for small specimen sizes according to specifications. However, data on the application of the manufactured cellulose building finishing materials to actual buildings and the fire performance have not been secured at present. Various studies, such as the size expansion of the current specimen, mass production method, and real fire performance experiment, are needed to determine the applicability of the cellulose building finishing material produced after this study. For future performance-oriented design, it is necessary to conduct a fire simulation based on the ISO 5660-1 experiment and the NES 713 experimental data secured in this study and to compare the applicability of buildings and fire damage reduction by comparing the performance with the building finishing materials currently used in the market.