Experimental Investigation on Thermal Degradation …
561
step by step layers of materials are added and tested inside the cone calorimeter. In
total, the evaluation of the fire characteristics of three different assemblies and their
interaction with each other during the fire is attempted. First, assembly of paint and
laminate is made and its thermal decomposition is evaluated under a cone calorimeter.
After that, in the second assembly, honeycomb structure is added to the first assembly
(i.e. P.L) and studied at the same incident flux. In the end, one more laminate sheet
is added at the back of the P.L.H assembly and various decomposition parameters
are evaluated.
It can be seen from the ignition time data (cf. Table 3) that the flame in time
(time at which ignition occurs) in case of all the three different assemblies is the
same (i.e. 15 s) which means that the addition of any number of materials to P.L
assembly does not impact the time to ignition. Similarly, there is no big difference
in PHRR value. In the case of the composite, the extra layer of laminate present at
the back of the honeycomb structure disallows the honeycomb from decomposing
completely (as observed in the honeycomb test case) and gives rigidity to the structure
(see Fig. 5). Therefore, the mass loss percentage and THR are lower in case of the
composite compared to the P.L.H assembly. Addition of layers results in an increase
in mass (i.e. solid fuel) of the assembly which should cause an increase in CO 2 yield.
However, CO 2 yield decreases with the increase of layers.
In order to further understand the thermal decomposition process of these three
assemblies, heat release rate curves are plotted with respect to time (see Fig. 6). It
can be seen that in all three cases, the primary HRR peak is composed of two simultaneous peaks. In which the 1st peak corresponds to paint and the 2nd corresponds
to the laminate decomposition. In order to confirm the above statement in inset (see
Fig. 6), HRR curves of paint and laminate are superimposed on the HRR curve of
Table 3 Experimentally determined thermal decomposition parameters of three different
assemblies
Materials
Mass
PHRR
THR
CO 2
I.T
PBT
M.L
g
kW/m 2
kJ/m 2
g/g
s
°C
%
P.L
10.3
155.3
6046.9
2.9
15–55
649.1
33.0
P.L.H
17.4
146.7
11946.8
1.2
15–150
732.5
59.3
Composite
26.1
148.6
11618.8
1.1
15–234
714.2
45.8
Fig. 5 Residue left after the cone calorimeter test, a Paint + Laminate + Honeycomb (P.L.H) and
b Composite
561
step by step layers of materials are added and tested inside the cone calorimeter. In
total, the evaluation of the fire characteristics of three different assemblies and their
interaction with each other during the fire is attempted. First, assembly of paint and
laminate is made and its thermal decomposition is evaluated under a cone calorimeter.
After that, in the second assembly, honeycomb structure is added to the first assembly
(i.e. P.L) and studied at the same incident flux. In the end, one more laminate sheet
is added at the back of the P.L.H assembly and various decomposition parameters
are evaluated.
It can be seen from the ignition time data (cf. Table 3) that the flame in time
(time at which ignition occurs) in case of all the three different assemblies is the
same (i.e. 15 s) which means that the addition of any number of materials to P.L
assembly does not impact the time to ignition. Similarly, there is no big difference
in PHRR value. In the case of the composite, the extra layer of laminate present at
the back of the honeycomb structure disallows the honeycomb from decomposing
completely (as observed in the honeycomb test case) and gives rigidity to the structure
(see Fig. 5). Therefore, the mass loss percentage and THR are lower in case of the
composite compared to the P.L.H assembly. Addition of layers results in an increase
in mass (i.e. solid fuel) of the assembly which should cause an increase in CO 2 yield.
However, CO 2 yield decreases with the increase of layers.
In order to further understand the thermal decomposition process of these three
assemblies, heat release rate curves are plotted with respect to time (see Fig. 6). It
can be seen that in all three cases, the primary HRR peak is composed of two simultaneous peaks. In which the 1st peak corresponds to paint and the 2nd corresponds
to the laminate decomposition. In order to confirm the above statement in inset (see
Fig. 6), HRR curves of paint and laminate are superimposed on the HRR curve of
Table 3 Experimentally determined thermal decomposition parameters of three different
assemblies
Materials
Mass
PHRR
THR
CO 2
I.T
PBT
M.L
g
kW/m 2
kJ/m 2
g/g
s
°C
%
P.L
10.3
155.3
6046.9
2.9
15–55
649.1
33.0
P.L.H
17.4
146.7
11946.8
1.2
15–150
732.5
59.3
Composite
26.1
148.6
11618.8
1.1
15–234
714.2
45.8
Fig. 5 Residue left after the cone calorimeter test, a Paint + Laminate + Honeycomb (P.L.H) and
b Composite