3 Fire Tests

  3.2.1.1 These tests are intended to evaluate the nozzle’s fire-suppression capabilities against external fires on open cabin balconies. The tests may be conducted inside a well ventilated test hall having a specified area of at least 100 m², a specified height of at least 5 m and adequate natural or forced ventilation to ensure that there is no restriction in air supply to the test fires. The fire test hall should have an ambient temperature of 20 ± 5°C at the start of each test.

  3.2.2.1 The fire tests should be conducted in a test apparatus consisting of a balcony mock-up in accordance with figure 1. The balcony ceiling should be smooth to allow an unobstructed flow of gases.

  3.2.2.2 The mock-up should be constructed of nominally 12 mm thick non-combustible wallboard panels. Plywood panels should be attached to the wall below the ventilation channel opening, and on the back wall, covering at least 2 m horizontally, starting from the fan side corner. The panels should be 2 m high and 3 to 4 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 the FTP Code. Prior to the test, the plywood panels should be conditioned at 21 ± 2.8º C and 50 ± 10% relative humidity for at least 72 h.

  3.2.2.3 The dimensions of the balconies should be in accordance with figure 1, or may be increased up to the maximum coverage area (length and width) to be protected by one nozzle.

  3.2.2.4 A fan should be attached to the balcony mock-up, as indicated in figure 1. The fan should provide an average air velocity of 5 ± 0.2 m/s measured as an average over several locations. Typically, sufficient dimensions of the fan are 0.8 m in diameter with a power of 5.5 kW.

  3.2.2.5 For ceiling nozzles, the velocity measurements should be done at nine locations; at the nozzle and around it on a circle of 0.5 m radius (figure 3(a)). For sidewall nozzles, the measurement should be done in six locations, at the nozzle and around it on a half-circle of 0.5 m radius (figure 3(b)). In vertical direction, the measurement should be done in the middle of the wind channel (25 cm from the ceiling). The intention is to distribute measurement locations over the region where the wind affects the suppression medium flow.

  3.2.3.1 The fire source should consist of a wood crib, two simulated chairs and a table mock-up.

  3.2.3.2 Each chair should be fitted with two 0.5 m by 0.8 m by 0.1 m polyether cushions. The cushions should be made of non-fire retardant polyether and they should have a density of approximately 33 kg/m³. When tested according to standard ISO 5660-1 (ASTM E-1354), the polyether foam should give results as given in the table below. Prior to the test, the cushions should be conditioned at 21 ± 2.8ºC and 50 ± 10% relative humidity for at least 72 h.

 The frame of the chairs should be of steel nominally 2 mm thick consisting of rectangular bottom and backrest frames constructed of steel angles, channels or rectangular stock of at least 3 mm thickness. The frame dimensions should be 0.5 m x 0.8 m (figure 2). The seat and backrest cushions should be supported on each frame by steel bars 20-30 mm wide x 0.80 m long located in the centre of the frames and welded to the edges. Steel plates should not be used to support the cushions. The assembled frames should be supported by four legs 500 mm in height constructed of similar steel stock. The frames should be equipped with a metal wire net to support the cushions, and the backrest should be tied in place, to keep from falling over during the test. The backrest should be placed on top of the seat cushion.

  3.2.3.3 A table should be constructed of a similar steel stock as the chairs. The table should have a 0.5 m by 0.5 m metal frame, supported by four legs, 520 mm in height. A 0.5 m by 0.5 m table plate should be fitted into the frame, made of 2 mm thick steel.

  3.2.3.4 The two chairs should be placed in the fan side corner of the balcony, in such a way that the polyether foam is 0.1 m from the plywood panel, according to figures 3 and 4, corners of the cushions touching. The table should be placed in the corner, edges aligned with the ends of the chairs.

  3.2.3.5 The wood crib should be dimensioned 0.3 m x 0.3 m x 0.15 m (high). The crib should consist of four alternate layers of four trade size nominal 38 mm x 38 mm kiln-dried spruce or fir lumber 0.3 m long. The alternate layers of the lumber should be placed at right angles to the adjacent layers. The individual wood members in each layer should be evenly spaced along the length of the previous layer of wood members and stapled together. After the wood crib is assembled, it should be conditioned at a temperature of 50 ± 5ºC for not less than 16 h. Following the conditioning, the moisture content of the crib should be measured at various locations with a probe-type moisture meter. The moisture content of the crib should not exceed 5% prior to the fire test.

  3.2.3.6 A square steel tray of area 0.1 m² and height 0.1 m should be located under the table, so that its corner is next to the point where chairs touch. The wood crib should be supported directly over the tray, edges aligned with the chair ends. The top of the wood crib should be 0.27 m above the floor level (figure 4).

  3.2.3.7 For ignition, the tray should be filled with 1 l of water and 250 ml of commercial heptane.

  3.2.4.1 The tests with the given balcony dimensions are intended for a single nozzle protection. The single nozzle has to be located symmetrically in the balcony, at the centreline in the position recommended by the manufacturer’s installation instructions, vertically at least 0.4 m above the lower edge of the wind channel. The two most conceivable locations are shown in figure 3.

  3.2.4.2 If the nozzle is located closer to the fan side wall than at the centreline, the protection width of the nozzle will be less than 3 m, i.e. twice the tested distance between the nozzle and wall. If a larger than 3 m protection width is aimed at, a wider balcony should be constructed for the test.

  3.2.4.3 The nozzle should be connected to a suitable water supply and arranged to operate at the minimum pressure specified by the manufacturer.

  3.2.4.4 The tests should be repeated using two nozzle orientations, where applicable. At first, the lowest discharge density should be directed towards the cabin wall, and then, towards the fan side wall.

  3.2.5.1 Thermocouples should be installed at four locations; two on the front edge of the balcony ceiling, one 1 m and the other 2 m from the fan side wall, one of the back edge of the ceiling, 2 m from the fan side wall and one in the centre of the side wall opposite the fan. Thermocouples should be installed 30 mm from the ceiling.

  3.2.5.2 System water pressure should be measured near the nozzle, and the system water flow rate should be defined with suitable means for the system.