RESEARCH
Wall and ceiling linings
reaction to fire
New methods for testing wall and ceiling linings reaction to fire could
provide a good alternative to current techniques.
By Peter Collier, BRANZ Senior Fire Engineer
o regulate the fire properties of wall
and ceiling linings, New Zealand
uses a long-established fire test
method, AS/NZS 1530 Part 3. We
are now the only country in the world to use
this test, which could be a barrier to trade and
goes against the desire to use international
standards wherever possible.
International research into the reactionto-fire behaviour of wall and ceiling linings
has identified new fire test methods that
more accurately represent the early fire
growth hazards associated with ignition and
of Australia (BCA) groups, which are as
follows:
Group 1: no flashover within 20 minutes
Group 2: flashover between 10 and
20 minutes
Group 3: flashover between 2 and
10 minutes
Group 4: flashover within 2 minutes.
The materials tested were distributed over the
four groups, giving a spread of results to enable
an evaluation of the new test methods.
flame spread over room linings. Two of these
ISO 9705 room
methods are the ISO 9705 room, and the
An ISO 9705 test consists of a room
measuring 3.6 x 2.4 x 2.4 m high, where
three walls and the ceiling are lined with the
material being investigated. A gas burner in
one rear corner exposes the test specimen to
100 kW for 10 minutes, followed by 300 kW
for 10 minutes. The exhaust gases exit from
cone calorimeter.
A recently completed project at BRANZ
involved the fire testing of eight examples of
lining materials (see Table 1), using the ISO
9705 room and cone calorimeter, to classify
the materials according to the Building Code
1000
a 2 m high x 0.8 m wide doorway and are
removed by an extraction hood and analysed
to determine oxygen, carbon dioxide (CO2),
carbon monoxide (CO) and smoke density.
The heat release rate is calculated by oxygen
consumption calorimetry and the smoke
production rate is determined from the smoke
density and flow rate in the duct.
Vinyl wallpaper
900
Heat release rate (kW)
Flashover at the end of ISO 9705 test.
Plywood
Plywood & paint
800
Fibre-cement
700
Plastic co-polymer
600
Modified polyester
500
Burner
Polyester
Synthetic rubber
400
300
200
100
Time (secs)
Figure 1: Heat release rates for the eight lining materials. Flashover occurs at 1,000 kW.
88
BUILD October/November 2007
12
00
11
00
10
00
90
0
80
0
70
0
60
0
50
0
40
0
30
0
20
0
10
0
Figure 1 shows the heat release rate for
each of the eight linings tested. When the heat
release rate exceeds 1,000 kW, flashover is
considered to have occurred (see photo) and
the group number is assigned according to
the time that it took to happen.
Table 1: Physical properties and test results of products tested.
Product
Weight
Density
kg/m
kg/m
Thickness BCA Group
mm
No.
Cone
calorimeter
prediction
of BCA
Group No.
Cone calorimeter
Vinyl wallpaper
0.21
452
0.46
The lining materials were also exposed to
50 kW/m2 radiation using a cone calorimeter
(see Figure 2). The data recorded was similar
to the ISO 9705 room, including oxygen,
optical density for smoke, and mass loss.
Again, the results were assessed and a group
number was assigned for each material.
Plywood
4.67
513
9.1
Plywood with one coat of undercoat
4.79
510
9.4
6.47
1378
4.7
Plastic co-polymer wall lining
4.37
929
4.8
100% polyester wall covering
0.38
127
100% modified polyester wall cover-
1.8
150
12
5.04
1938
2.6
Cone calorimeter a low cost option
The results (see Table 1) indicate that the
cone calorimeter test provided the same or
more conservative classifications as the room
test. Since the room test costs about 10 times
that of a set of cone calorimeter tests, the
cone calorimeter provides a low cost option
for getting a group number for a material,
with the small risk of a conservative (higher
group number) result.
The cone calorimeter option may not
be suitable for non-homogenous materials
such as metal skin panel assemblies with
combustible core materials and foil faced
combustible materials. In these cases, the
full-scale room test should be carried out.
and two coats of intumescent paint
Fibre-cement board with a glazed
finish on fire exposed side
ing
Synthetic rubber mass loaded noise
barrier with polypropylene scrim backing
Table 1: Physical properties and results for products tested.
temperature and differential pressure
measurements taken here
exhaust
blower
soot sample tube
exhaust hood
Changes to the Building Code possible
The ISO 9705 test method has been adopted
by the Building Code of Australia as the
primary means of demonstrating acceptable
fire properties for walls and ceilings.
Similarly, the correlation method, based on
the cone calorimeter, has also been adopted
for prediction of the group number, providing
a more convenient and less expensive
alternative. The Department of Building and
Housing will consider these findings in a
future review of the New Zealand Building
Code compliance document for fire safety.
This work was jointly funded by Building
Research Levy, the Department for Building
and Housing and Plastics New Zealand Inc.
For more information see BRANZ Study
Report SR160, downloadable from the
BRANZ website at www.branz.co.nz.
laser photometer
beam including
temperature
measurement
gas samples
taken here
cone heater
controlled
flow rate
spark igniter
specimen
load cell
vertical orientation
Figure 2: Cone calorimeter (adapted from www.doctorfire.com/cone.html).
BUILD October/November 2007 9
