3.1 Principle
These test procedures test the effectiveness of a
water-based fire-fighting system against two different
scenarios: a cargo fire in a simulated freight truck,
and a passenger vehicle fire.
3.2 Fire source
3.2.1 The primary fire source for both scenarios consists
of EUR standard wood pallets (ISO 6780:2003), stored
inside with the moisture content of 14 ± 2%. Figure
3.2.1 shows details of a EUR pallet.
3.2.2 Plywood panels made of pine or spruce are used as
targets. The panels should be approximately 12 mm thick.
The ignition time of the panel should not be more than
35 s and the flame spread time at 350 mm position should
not be more than 100 s as measured in accordance with
resolution A.653(16).
3.2.3 For ignition, commercial heptane is to be
applied.
Figure 3.2.1 - Typical dimensions of the
standard EUR pallet
3.3 Apparatus
3.3.1 Test area
The tests should be
conducted in a test hall as specified in paragraph 2.4
above, under a flat, smooth, non-combustible ceiling of
at least 100 m2. There should be at least a 1 m space
between the perimeters of the ceiling and any wall of
the test hall.
3.3.2 Fire scenario 1: cargo fire in a simulated freight
truck (see figures 3.3.2.1 to 3.3.2.3) 3.3.2.1 The
primary fuel package consists of 112 wood pallets
arranged in an array of 2 (wide) x 7 (high) x 8 (long)
and raised up on a level of 2.8 m so that the top level
of the fuel package is at 3.8 to 3.9 m above the floor.
3.3.2.2 The support frame for the wood pallet array of
paragraph 3.3.2.1 should be constructed using open steel
racks. The wood pallet piles should be standing freely
on horizontal steel beams without any solid bottoms.
3.3.2.3 The fuel pallet array should be half-shielded by
a 4.5 m long, 2.6 m wide steel plate (thickness at least
2 mm) at 4 m height. The plate should be properly fixed
so that during a test it does not bend to provide an
unobstructed passage of water onto the fuel package.
3.3.2.4 Plywood panel targets (acting also as
obstructions) of dimensions 3.6 m (wide) x 2.4 m (high)
should be arranged symmetrically on both sides of the
fuel package at 1 m distance so that the top edge is at
the same level as the top level of the wood pallet
array.
3.3.2.5 The fire should be ignited by two steel trays
centrally located under the fuel package as shown in
figures 3.3.2.1 to 3.3.2.3. The square trays are 25 cm
high and 0.1 m2 of free surface area. The trays should
be filled with water and 1 l of heptane so that the free
rim height above the liquid surface is 4 cm. The
distance between the bottom of the wood pallet piles and
liquid surface is 29 cm.
Figure 3.3.2.1 - Side view of the cargo
fuel package in a simulated truck
Figure 3.3.2.2 - End view of the cargo
fuel package in a simulated truck
Figure 3.3.2.3 - Top view of the cargo fuel
package in a simulated truck
3.3.3 Fire scenario 2: passenger vehicle fire (see
figures 3.3.3.1 and 3.3.3.2)
3.3.3.1 The primary fuel package consists of 12 wood
pallets arranged in an array of 1 pallet (wide) x 6
pallets (high) x 2 pallets (long) constructed inside a
passenger vehicle mock-up.
3.3.3.2 The passenger vehicle mock-up is constructed of
nominally 2 mm steel.
3.3.3.3 Plywood panel targets (acting also as
obstructions) of dimensions 1.2 m (wide) x 1.75 m (high)
should be arranged symmetrically on both sides of the
mock-up at 0.6 m distance so that the top edge is at the
same level as the top level of the mock-up car.
3.3.3.4 The fire should be ignited by a steel tray
centrally located under the fuel package as shown in
figures 3.3.3.1 and 3.3.3.2. The square tray is 10 cm
high and 0.1 m2 of free surface area. The tray should be
filled with water and 1 l of heptane so that the free
rim height above the liquid surface is 4 cm.
3.4 Nozzle positioning
Nozzles should be installed in an array at the ceiling
level in accordance with the manufacturer’s design and
installation criteria. Tests should be repeated with
three different relative locations between the nozzle
array and the fuel package, i.e., centre of ignition
under one nozzle, between two nozzles and between four
nozzles, as shown in figure 3.4.1.
Figure 3.3.3.2 - Top view of the
passenger vehicle fuel package
Figure 3.4.1 - Nozzle positioning in the two
scenarios
3.5 Instrumentation
Instrumentation for the continuous measuring and
recording of test conditions should be employed. At
least the following measurements should be made:
- gas temperature at 7.5 cm below the ceiling at
locations shown in figure 3.5.1;
- gas temperature at the targets to indicate ignition
of targets as shown in figure 3.5.2; and
- system water pressure near the centre of the piping
array.
System water flow rate should be defined with suitable
means for the system.
Figure 3.5.1 - Thermocouple locations in the two
scenarios*
* For the truck fuel package the three locations at
both ends are used for acceptance evaluation, the
three locations at and around the centre of ignition
are for safety purposes to define during the test
whether the ceiling is at danger. For the passenger
car fuel package all four locations are used for
acceptance evaluation
Figure 3.5.2 - Thermocouple locations at the
plywood targets for determining ignition of targets*
* A thin (about 1 mm) steel sheet is bent on top of
the plywood panels as shown in the figure. Plain
charring of panels is seen as a sharp edge between
the black charring on the exposed surface and intact
surface under the metal sheet. When ignited in
flames charring is seen also under the sheet and
verified by significant increase in the gas
temperature under the metal sheet.
3.6 Test programme and test procedure
3.6.1 Test programme
Tests should be conducted at the minimum system water
pressure at the minimum distance between the lowest part
of the nozzles and the ceiling, as specified by the
manufacturer.
Three tests should be conducted at ceiling heights 5 m
and/or 2.5 m, with different nozzle grid locations
relative to the fuel package as specified in figure
3.4.1.
3.6.2 Test procedure
Prior to starting the test the moisture content of the
fuel package should be measured at several locations
along the full package with a probe-type moisture meter
and the results should be reported.
The actual test procedure for all tests is as follows:
- the water pressure used at the start of the test
should be set at the minimum value for the system
specified by the manufacturer, flowing six open
nozzles. If more than six nozzles operate during the
test, the water supply pressure should be adjusted
accordingly, to keep the required minimum system
water pressure;
- the tray should be filled with 1 l litre of heptane
on the water base as described in paragraph 3.3.2.5
or 3.3.3.4;
- the measurements are started;
- the flammable liquid pool fire/s should be lit by
means of a torch or a match;
- the fire should be allowed to burn freely for a
period of 2.5 min;*
- the test is continued for 30 min after system
activation;
- any remaining fire should be manually extinguished;
and
- the test is terminated.
* If automatic sprinklers activate already during
the 2.5 min pre-burn period, feeding water to the
system should be delayed till after the 2.5
min.
3.7 Acceptance criteria
The principal acceptance criteria are based on the
following factors:
- gas temperatures measured at locations not directly
affected by impinging flames;
- damage to the fuel package; and/or
- ignition of targets.
Note 1: Damage to the fuel package is
defined by the fraction of charring of the full package.
The damage to each individual wood pallet should be
evaluated separately and the total fraction calculated
based on the detailed results. Totally black, i.e.,
totally charred pallet is denoted as 100% damage of the
pallet (even though the pallet may have maintained its
shape) and totally intact pallet is denoted as 0%
damage. Partially charred pallets should be visually
evaluated. Proper and adequate photographs of the
damaged fuel package should be included in the test
report.
Note 2: Ignition of targets is defined by the method
described in figure 3.5.2, if the visibility during the
test is such that it cannot be visually observed.
3.7.1 Fire scenario 1: cargo fire in a simulated freight
truck (ceiling height 5 m)
The following four criteria should be met:
- after system activation the maximum five minute
average at any of the three measurement locations at
the exposed end of the fuel package should not
exceed 300oC;
- after system activation the maximum five minute
average at any of the three measurement locations at
the concealed end of the fuel package should not
exceed 350oC;
- total damage to the wood pallet array should not
exceed 45% as defined after the test; and
- the plywood targets should not ignite during the
test.
3.7.2 Fire scenario 2: passenger vehicle fire
The following two criteria should be met:
- after system activation the maximum five minute
average at any of the four measurement locations
should not exceed 350o C; and
- the plywood targets should not ignite during the
test.