LPS 1230 Test Protocol
Following the success of tests carried out at Boreham Wood prior to the LPC being taken over, a second, more exhaustive series of fire tests on Scotch Mist® was commissioned. Fire testing was conducted against selected approval fires for gaseous extinguishing systems, including some of the baffled fires used within the test standard LPS 1230. Local application and total flood tests were carried out on each of the test fire scenarios, each test lasting for only ten minutes.
The enclosure used for the evaluation of extinguishing systems is a purpose built structure having internal dimensions of 8.1 metres long by 4.1 metres wide and 3.6 metres high. The internal volume is approximately 120 cubic metres.
Forced ventilation is available to ensure that test fires are fully ventilated and burn with an upright plume, whilst there is a high level controllable extraction capable of extracting volumetric flows of up to 9 cubic metres per second, for the removal and treatment of smoke and hot gases. An over-pressure device is fitted in a panel adjacent to the door of the test enclosure and an over-pressure protection vent, weighted to open at 600 Pascals, located in the ceiling.
The large wood crib fire (see Fire Tests at Boreham Wood) is particularly difficult to extinguish due to its capacity for deep seated burning but for each of the total flood tests, the fire was controlled for the period of the test and for local application system designs, all wood crib fires were successfully extinguished, with no reignition occurring when the Scotch Mist® was turned off after the ten minute test period.
The PVC crib fire (see Fire Tests at Boreham Wood) has been re-designed since the first series of tests and is now an even more stringent test for gaseous extinguishing agents. Some baffled fire tests were carried out in order to test the ability of Scotch Mist® to tackle shielded fires, such as may be found within an EDP environment, but none of the baffled test fires were extinguished, although there was evidence of fire control during system operation. All unbaffled test fires were successfully extinguished within the 10 minutes of water mist operation, whether local application or total flood design.
Two sizes of pan fires are used for the heptane test fires, a small 300mm diameter pan, used for the original approval fires for gaseous extinguishing systems (see Fire Tests at Boreham Wood), and a large 600mm square pan, used for approval fires for gaseous extinguishing systems when tested to ISO 14520 under the standard LPS 1230.
All heptane pan fires were successfully extinguished by Scotch Mist® with the local application design and were controlled with the total flood design.
But of most significance was the heptane spray fire, carried out under a number of varying conditions. The heptane spray fire was tested using large metallic obstructions that became a source of reignition when hot, and various tests were carried out under ventilated and non-ventilated conditions. With the exception of a single test carried out at low pressure, all spray fires were extinguished.