Material type: Glass fibre reinforced aluminium sarking with polypropylene polymer backing.
Polymer: Polypropylene (92%)
Additives (fire retardants, fillers or traces of inorganic elements): Chlorine (3%), Calcium (3%), Titanium (2%), Aluminium (1%), traces of other elements (<1%)
Core thickness: 0.27mm
Table 1. Estimated mass concentration of compounds.
Compound
Mass Concentration (%)
Polypropylene (PP)
92
Chlorine (Cl)
3
Calcium (Ca)
3
Titanium (Ti)
2
Aluminium (Al)
1
Traces of iron (Fe)
<1
Traces of bromine (Br)
<1
Traces of sulfur (S)
<1
Traces of silicon (Si)
<1
A. Material composition identification
A.1 Attenuated total reflection – Fourier transform infrared spectroscopy (ATR-FTIR)
Table 2. FTIR compound identification.
Identified Compounds
Polypropylene (PP)
Figure 1 . FTIR spectra: Absorbance percentage versus wavenumber from the sample.Figure 2. FTIR spectra: Absorbance percentage versus wavenumber from the sample and the identified compounds.
A.2 Energy Dispersive X-Ray Fluorescence (EDXRF)
Table 2. Inorganic elements and their mass concentration identified with EDXRF.
Element
Mass Concentration (%)
Cl
3
Ca
3
Ti
2
Al
1
Fe
<1
Br
<1
S
<1
Si
<1
Figure 3. EDXRF spectra. Counts vs energy. Identified elements are shown as vertical lines.
B. Thermogravimetric analysis
Table 3. Mass fraction of residue after thermal decomposition.
Condition
Fraction of mass residue at 800°C
Non-oxidative (nitrogen)
0.03
Oxidative (air)
0.03
Table 4. Temperature and amplitude of main peaks in non-oxidative conditions.
Peak ID
Temperature peak (°C)
Amplitude of peak (°C-1)
Peak 1
467
2.128 x 10-2
Table 5. Temperature and amplitude of main peaks in oxidative conditions.
Peak ID
Temperature peak (°C)
Amplitude of peak (°C-1)
Peak 1
267
4.74 x 10-3
Peak 2
362
8.15 x 10-3
Figure 4. Normalised mass (solid line) and derivative of the normalised mass (dashed line) in 150 ml min-1 of nitrogen and a heating rate of 20°C min-1.Figure 5. Normalised mass (solid line) and derivative of the normalised mass (dashed line) in 150 ml min-1 of air and a heating rate of 20°C min-1 .
C. Gross Heat of Combustion
Table 7. Gross Heat of Combustion individual results for sample.
Trial
ΔHc [kJ g-1]
Trial 1
42.44
Trial 2
41.39
Trial 3
42.54
Average
42.12
Std dev
0.64
D. Ignition parameters
Table 8. Summary of ignition parameters for sample.
Critical heat flux for ignition
Ignition temperature
Total heat transfer coefficient of losses
Apparent thermal inertia
q̇″cr [kW m−2]
Tig [°C]
hr [W m-2 K-1]
kρc [kW2 m-4 K-2 s]
13
344
36.10
0.127
Figure 6. Time-to-ignition vs incident radiant heat flux for samples.
E. Burning behaviour
Table 9. Summary of key burning behaviour metrics.
Heat flux
Test
Time to ignition
Fraction of mass residue
Peak heat release rate
Total energy released
q̇″inc [kW m-2]
tig [s]
mres [-]
q̇″p [kW m-2]
Qt [MJ m-2]
35 kW m-2
Test 1
50
0.02
131.73
3.22
Test 2
45
0.06
118.10
3.12
Avg
48
0.04
124.91
3.17
50 kW m-2
Test 1
25
0.03
151.69
3.26
Test 2
20
0.02
146.17
3.20
Avg
22
0.02
148.93
3.23
60 kW m-2
Test 1
-
-
-
-
Test 2
-
-
-
-
Avg
-
-
-
-
80 kW m-2
Test 1
2
0.08
210.68
3.18
Test 2
1
0.11
217.90
3.25
Avg
1.50
0.09
214.29
3.21
Figure 7. Normalised mass loss over time for samples tested with 35, 50, 60 and 80 kW m-2.Figure 8. Heat release rate per unit area over time for samples tested with 35, 50, 60 and 80 kW m-2.Table 10. Effective Heat of Combustion individual results for sample.
Test
ΔHc [kJ g-1]
35 kW m-2 (Test 1)
38.76
35 kW m-2 (Test 2)
38.44
50 kW m-2 (Test 1)
38.34
50 kW m-2 (Test 2)
37.89
60 kW m-2 (Test 1)
-
60 kW m-2 (Test 2)
-
80 kW m-2 (Test 1)
40.28
80 kW m-2 (Test 2)
42.24
Average
39.32
Std dev
1.64
F. Flame Spread
Table 11. Minimum heat flux for flame spread rate and minimum flame spread rate for sample.
Orientation
q̇″min.spread [kW m-2]
Vf.min [mm s-1]
Horizontal
9.50
0.20
Vertical
9
0.70
Figure 9. Lateral flame spread rate versus heat flux.Figure 10. Vertical flame spread rate versus heat flux.Table 12. Flame spread parameter results for sample.
Orientation
Trial
(kρcp⁄Φh2)1⁄2 [m3⁄2 s1⁄2 kW-1]
Φ [kW2 m-3]
Horizontal
1
100
-
Horizontal
2
100
-
Vertical
1
100
-
Vertical
2
100
-
Additional information:
1. Excessive shrinkage away from the heat source and pilot ignitor prevented the establishment of a uniform flame front 2. Melting and dripping of material during test forming flaming droplets 3. A wire mesh was placed in front of the sample to prevent curling of the material.
