FOCUS Fire service measures
Figures 17 and 18 (top two) and Figures 19 and 20
therefore between the different grades and types of plastic was not as significant as earlier research would have suggested, and would appear to be a function of the fluid dynamic regime that the orientation of the fuel bed has on the fire behaviour. Typically, the surface temperatures of the burning stacks are likely to be in the region of 1,100°C to 1,200°C or more. The impact of the heat flux on fire crews and surroundings cannot be underestimated, and it is suggested appliances and equipment should be a minimum of 40m away from a plastic bale fire (see Figure 17 above).
Extinguishing methods
Water tests Two 70mm jets were applied. The jets were applied to the base of one of the gaps to use the fluid dynamic flows, driving the system to transmit the steam through the fire as postulated following work package 1, 2 and 3 of the WISH fire test programme. One jet remains in the original position to prevent the fire burning back, while the second jet is worked around the base of the stack to extinguish the fire. This system worked well and supports the theoretical model. Water usage was 19,000 litres (2x70 mm jets at 7 bar delivering 475 l/min for 20 mins).
CAFS The attack used in test one was emulated using CAFS. A Class A wet solution was used and this was markedly more effective.
30 NOVEMBER 2018
www.frmjournal.com
Water usage was 1,800 litres of water (7 mins, 2x128 l/min).
Wetting agent The wetting agent resulted in the quickest knock down of all the media used, and produced the least run off. (2x45mm jets at 7 bar using 0.3% induction of agent [5 litres]). Time to extinction: 2 minutes (see Figures 18, 19 and 20 above).
Case study
On 4 August 2014, a fire was reported at the Shanks MBT plant at Rainham in East London. London Fire Brigade attended, and made the following observation regarding large piles of RDF: ‘It should be noted if the waste is a large stack of RDF and the sprinklers are located high up in the roof space, by the time they are activated, then due to the make-up of the RDF, a crust forms and any water runs off the crust and does not penetrate to extinguish the fire.’4 The fire became deep seated and, despite
all the fire suppression systems, it then burned for more than 48 hours. Interestingly, this is consistent with the above test, demonstrating both anecdotally from real fire experiences and from test data that piled waste materials are surprisingly water resistant. In such cases, the fire was not dealt with within the four hour target. This individual site was heavily fire
engineered with a substantial emphasis on fire suppression. However, it is clear to see fire
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
