BS 8489-7:2016 pdf download – Fixed fire protection systems – Industrial and commercial watermist systems Part 7: Fire performance tests and requirements for watermist systems for the protection of low hazard occupancies
5 Test conditions
5.1 The maximum nozzle spacing (as specified by the manufacturer) shall be used for all tests except the small compartment test with bunk beds (see 7.2). This includes utilizing the maximum ceiling spacing of nozzles from walls.
5.2 Corridor nozzles for the small compartment test with bunk beds (see 7.2) shall be installed at the maximum spacing as specified by the manufacturer, at an equal distance from the centreline of the small compartment doorway.
5.3 A target, automatic closed nozzle, with a thermosensitive component rating equal to the four nozzles installed in the enclosure, shall be located in the two exit doorways (see A.2), to determine potential operation of these nozzles. For upright and pendent nozzles, the target nozzles shall be installed 102 mm inside the doorway, in the pendent position, such that the centre of the heat responsive element is 51 mm below the ceiling.
5.4 The heat responsive element and temperature rating of the nozzles used in all fire tests shall be identical.
5.5 For all fire tests, the system shall be either:
a) pressurized to the minimum operating pressure specified by the manufacturer. Following activation of the first nozzle, the flowing water pressure shall be maintained at the minimum system operating pressure; or
b) pressurized to the minimum stand-by pressure specified by the manufacturer. Following activation of the first nozzle, the flowing water pressure shall be gradually increased to the minimum system operating pressure specified by the manufacturer. The delay time until the minimum system operating pressure is reached shall correspond to the delay time expected in an actual installation. The delay time recorded during the tests shall be documented and included in the system specifications.
5.6 The air in the test enclosure shall be conditioned to an ambient temperature of (15 ±10) °C, measured with the thermocouple located 76 mm below the ceiling.
5.7 The fuel load materials for the category III test shall be conditioned at normal room temperature (20 ±10) °C for a period of seven days prior to testing commencing.
The wood crib sticks shall have a moisture content between 9% and 13%. 6 Principle The low hazard occupancy tests comprise small, large and open compartments, plus open plan office simulations. The watermist system needs to pass all the tests for the category(ies) for which it is to be used.
7.1.1 The following individual tests shall be conducted: a) for category I systems: 1) small compartment with bunk beds (7.2); b) for category II systems: 1) large compartment with corner crib and simulated furniture up to maximum coverage of four nozzles (7.3); 2) open space with sofas under one nozzle (7.4); 3) open space with sofas between two nozzles (7.5); 4) open space with sofas between four nozzles (7.6); c) for category III systems: 1) open space with simulated work station under one nozzle (7.7); 2) open space with simulated work station between two nozzles (7.8); 3) open space with simulated work station between four nozzles (7.9).
7.1.2 System components, component locations, operating conditions and test enclosure details shall remain unaltered throughout all of the fire tests for a given application. During each test, all systems shall operate without manual intervention. All tests shall be conducted using the specifications from the manufacturer’s design and installation manual with regard to nozzle placement, spray flux, and spray duration.
7.1.3 Prior to the start of each test: a) the igniter (4.11) shall be soaked in 120 mL of heptane (see 4.12) for the category I and II tests (see 7.2 to 7.6) and 120 mL of white spirit (see 4.13) for the category III test (see 7.7 to 7.9); b) the room shall be dried and all water from previous testing shall be removed; c) there shall be no visible water on the floor, ceiling or walls.
7.1.4 The category I and II tests (see 7.2 to 7.6) shall be conducted for 10 min after the activation of the first nozzle. The category III tests (see 7.7 to 7.9) shall be conducted for 30 min after the activation of the first nozzle. After this period, any remaining fire shall be extinguished manually.BS 8489-7 pdf download.