3 Method of Test

3.1 Principle

This test procedure is intended for the determination of the effectiveness of different aerosol agent extinguishing systems against spray fires, pool fires and class A fires. It also establishes the minimum safe distances from condensed aerosol generators to personnel and combustible materials.

3.2 Apparatus

3.2.1 Test room

The tests should be performed in 100 m² room, with no horizontal dimension less than 8 m, with a ceiling height of 5 m. The test room should be provided with a closable access door measuring approximately 4 m² in area. In addition, closable ventilation hatches measuring at least 6 m² in total area should be located in the ceiling. A larger room may be employed if approvals are sought for larger volumes.

3.2.2 Integrity of test enclosure

The test enclosure should be nominally leaktight when doors and hatches are closed. The integrity of seals on doors, hatches and other penetrations (e.g., instrumentation access ports) should be verified before each test.

3.2.3 Engine mock-up

3.2.3.1 An engine mock-up of size (width x length x height) 1 m x 3 m x 3 m should be constructed of sheet steel with a nominal thickness of 5 mm. The mock-up should be fitted with two steel tubes diameter 0.3 m and 3 m length that simulate exhaust manifolds and a solid steel plate. At the top of the mock-up, a 3 m²tray should be arranged (see figures 1, 2 and 3).

3.2.3.2 A floor plate system 4 m x 6 m x 0.75 m high should surround the mock-up. Provision should be made for placement of the fuel trays, as described in table 1, and located as described in table 2.

3.2.4 Instrumentation

Instrumentation for the continuous measurement and recording of test conditions should be employed. The following measurements should be made:

.1 temperature of the generator casing;
.2 temperature of the generator discharge stream measured at 0.5 m, 1.0 m and 2.0 m away from the discharge ports;
.3 temperature at three vertical positions (e.g., 1 m, 2.5 m and 4.5 m);
.4 enclosure pressure;
.5 gas sampling and analysis, at mid-room height, for oxygen, carbon dioxide, carbon monoxide and other relevant products;
.6 means of determining flame-out indicators;
.7 fuel nozzle pressure in the case of spray fires;
.8 fuel flow rate in the case of spray fires;
.9 discharge nozzle pressure; and
.10 means of determining generator discharge duration.

3.2.5 Generators/nozzles

3.2.5.1 For test purposes, generators/nozzles should be located as recommended by the manufacturer.

3.2.5.2 If more than one generator/nozzle is used, they should be symmetrically located.

3.2.6 Enclosure temperature

The ambient temperature of the test enclosure at the start of the test should be noted and serve as the basis for calculating the concentration that the agent would be expected to achieve at that temperature and with that agent weight applied in the test volume.

3.3 Test fires and programme

3.3.1 Fire types

The test programme, as described in table 3, should employ test fires as described in table 1 below.

Parameters of test fibres

Fire

Type

Fyeahuel

Fire size, MW

Remarks

76 − 100 mm ID can

Heptane

0.0012 to 0.002

Tell tale

0.25 m² tray

Heptane

0.35

(See Note 1)

2 m² tray

Diesel/fuel oil

(See Note 1)

4 m² tray

Diesel/fuel oil

Low pressure,
low flow spray

Heptane
0.03 ± 0.005 kg/s

1.1

Wood crib

Spruce or fir

0.3

(See Note 2)

0.10 m²tray

Heptane

0.14

Polymeric sheets

PMMA, Polypropylene, ABS

(See Note 3)

Notes to table 1:

Diesel/Fuel oil means light diesel or commercial fuel oil.

The wood crib should be substantially the same as described in standard ISO 14520-1:2006 (Gaseous fire extinguishing systems, Physical properties and system design, Part 1: General Requirements). The crib should consist of six members of trade size 50 mm x 50 mm x 450 mm, kiln dried spruce or fir lumber having a moisture content between 9 and 13%. The members should be placed in 4 alternate layers at right angles to one another. Members should be evenly spaced forming a square structure. Ignition of the crib should be achieved by burning commercial grade heptane in a square steel tray 0.25 m² in area. During the pre-burn period the crib should be placed centrally above the top of the tray a distance of 300 to 600 mm.

The polymeric sheet test should be substantially the same as described in standard ISO 14520-1:2006 (Gaseous fire extinguishing systems, Physical properties and system design, Part 1: General Requirements).

Spray fire test parameters

Fire type	Low pressure, low flow (E)
Spray nozzle	Wide spray angle (80°) full cone type
Nominal fuel pressure	8.5 Bar
Fuel flow	0.03 + 0.005 kg/s
Fuel temperature	20 + 5°C
Nominal heat release rate	1.1 + 0.1 MW

3.3.2 Test programme

3.3.2.1 The fire test programme should employ test fires singly or in combination, as outlined in table 3 below.

Test programme

Test No.

Fire combinations (see table 1)

Tell tales, 8 corners. (see note)

B:	=	0.25 m² heptane tray under mock-up
G:	=	0.10 m² heptane tray on deck plate located below solid steel obstruction plate
	=	Total fire load: 0.49 MW

C:	=	2 m2 diesel/fuel oil tray on deck plate located below solid steel obstruction plate
F:	=	Wood crib positioned as in figure 1
E:	=	Low pressure, low flow horizontal spray − concealed − with impingement on inside of engine mock-up wall.
H	=	Polymeric sheets positioned as in figure 1
	=	Total fire load: 4.4 MW

D:	=	4 m² diesel tray under engine mock-up
	=	Total fire load: 6 MW

Note to table 3:

1	=	Tell-tale fire cans should be located as follows:
.1	=	in upper corners of enclosure 150 mm below ceiling and 50 mm from each wall; and
.2	=	in corners on floors 50 mm from walls.

3.3.2.2 All applicable tests of table 3 should be conducted for every new fire-extinguishing media.

3.3.2.3 Only test 1 is required to evaluate new nozzles and related distribution system equipment (hardware) for systems employing fire-extinguishing media that have successfully completed the requirements of paragraph 3.3.2.2 above. Test 1 should be conducted to establish and verify the manufacturer’s minimum nozzle design pressure.

3.4 Extinguishing system

3.4.1 System installation

The extinguishing system should be installed according to the manufacturer’s design and installation instructions. The maximum vertical distance should be limited to 5 m.

3.4.2 Agent

3.4.2.1 Design application density

The agent design application density is the net mass of agent per unit volume (g/m³) required by the system designer for the fire protection application.

3.4.2.2 Test density

The test density of agent to be used in the fire-extinguishing tests should be the design application density specified by the manufacturer, except for test 1, which should be conducted at not more than 77% of the manufacturer’s recommended design application density.

3.4.2.3 Quantity of aerosol agent

The quantity of aerosol agent to be used should be determined as follows:

where:

W	=	agent mass (g);
V	=	volume of test enclosure (m³);
q	=	design application density (g/m³); and
f	=	efficiency coefficient of the manufacturer’s generator (%)

3.5 Procedure

3.5.1 Fuel levels in trays

The trays used in the test should be filled with at least 30 mm fuel on a water base. Freeboard should be 150 ± 10 mm.

3.5.2 Fuel flow and pressure measurements

For spray fires, the fuel flow and pressure should be measured before and during each test.

3.5.3 Ventilation

3.5.3.1 Pre-burn period

During the pre-burn period the test enclosure should be well ventilated. The oxygen concentration, as measured at mid-room height, should not be less than 20% volume at the time of system discharge.

3.5.3.2 End of pre-burn period

Doors, ceiling hatches and other ventilation openings should be closed at the end of the pre-burn period.

3.5.4 Duration of test

3.5.4.1 Pre-burn time

Fires should be ignited such that the following burning times occur before the start of agent discharge:

.1 sprays − 5 to 15 s;
.2 trays − 2 min;
.3 crib – 3 separate tests, one of 2 min, one of 4 min and one of 6 min; and
.4 polymeric sheets – 210 s.

3.5.4.2 Discharge time

Aerosol agents should be discharged at a rate sufficient to achieve 100% of the minimum design density in 120 s or less.

3.5.4.3 Hold time

After the end of agent discharge the test enclosure should be kept closed for 15 min.

3.5.5 Measurements and observations

3.5.5.1 Before test:

.1 temperature of test enclosure, fuel and engine mock-up;
.2 initial weights of agent containers;
.3 verification of integrity agent distribution system and nozzles; and
.4 initial weight of wood crib.

3.5.5.2 During test:

.1 start of the ignition procedure;
.2 start of the test (ignition);
.3 time when ventilating openings are closed;
.4 time when the extinguishing system is activated;
.5 time from end of agent discharge;
.6 time when the fuel flow for the spray fire is shut off;
.7 time when all fires are extinguished;
.8 time of re-ignition, if any, during hold time;
.9 time at end of hold time;
.10 at the start of test initiate continuous monitoring as per paragraph 3.2.4 above; and
.11 for condensed aerosol generators:
- .1 temperature of the casing during the fire test and hold time period; and
- .2 temperature profile of the generator discharge stream versus distance away from the discharge ports.

3.5.6 Tolerances

Unless otherwise stated, the following tolerances should apply:

.1	length	± 2% of value;
.2	volume	± 5% of value;
.3	pressure	± 3% of value;
.4	temperature	± 5% of value; and
.5	concentration	± 5% of value.

These tolerances are in accordance with standard ISO 6182-1:2004.