Angellala Creek ammonium nitrate explosion 5 September H Zuidersma, Principal DG Officer 25 August 2017

Transcription

1 Angellala Creek ammonium nitrate explosion 5 September 2014 H Zuidersma, Principal DG Officer 25 August

2 Angellala Creek ammonium nitrate (AN) explosion On 5 Sept 2014 a huge explosion occurred at Angellala Creek, QLD 30 km south of Charleville and approximately 700 km west of Brisbane B-double road-train carrying 44 X 1.2 T bulka bags of AN Single vehicle accident Ran off the road when approaching a bridge Vehicle caught alight Later a huge explosion Estimated to be T equivalent of TNT 2

3 Road bridge completely destroyed 3

4 Rail bridge 120 m away severely buckled 4

5 Transport vehicle completely destroyed 5

6 Fire truck completely destroyed 6

7 Summary of incident 7

8 Further detail of incident Fortunately no deaths 8 people present People crouched down Some received severe injuries Vehicle came to rest in dry creek bed Pools of water in creek bed Fire started soon after accident 1 hour 15 mins small pyrotechnic effect 2 minutes later huge explosion 8

9 Transport of AN in WA CSBP Kwinana manufactures 810,000 T pa Yara Pilbara now manufactures AN AN imported from overseas T transported in WA p/a double road trains p/a Kwinana to Goldfields 600 km Kwinana to Pilbara 1500 km Fortunately no explosions in WA Had several close calls Chances relatively high that it can occur in WA Large quantities transported over long distances Need to be prepared (emergencies) 9

10 Properties of AN Class 5.1 DG UN no or 2067 Oxidising agent Not combustible Will support combustion Salt Very stable chemical Very insensitive to initiation Not an explosive Low melting point (169 ºC) Low decomposition point (270 ºC) 10

11 Why did the AN explode? Load caught alight Vehicle on its side pointing downwards Candle Effect AN has low melting pointing (169 ºC) Fire temperature > ºC Large fire engulfing P/M and lead trailer Fire burned for 1 hr 20 mins Reduced to small fire just before explosion Large pools of molten AN forming 11

12 Significant temperature events 1200 Temperature curve Temperature (C)

13 Why did the AN explode? At 200 ºC bubbles form Density decreases, sensitivity increases Similar to sensitising bulk explosives on mine sites At 230 ºC sensitivity of molten AN significantly increases At 260 ºC molten AN No 6 det sensitive Above 270 ºC product decomposes Prolonged fire, molten AN contaminated Diesel, rubber, plastic, aluminium, copper Product is further sensitised 13

14 Why did the AN explode? Brink of detonation Possible triggers (shock explosion): Tyre explosion Fuel tank rupture Mechanical explosion Hot product quenched in water Other possible causes: Thermal explosion (cook off) Deflagration under pressure (chemical reaction with heat) Concerted void collapse Cause unknown 14

15 Recapping Solid AN is very safe AN has low melting point Molten AN is shock sensitive Heat is an enemy of AN Fires cause heat Fire is biggest enemy of AN 15

16 Tangible ways to reduce fire Minimise combustibles Firescreens Fire extinguishers Sources of ignition Well maintained vehicles Temperature monitoring equipment Running gear in good condition Tyres in good condition Vehicle suitably modified for load 16

17 Operational ways to reduce fire Driver alert (not fatigued) Driver competent Driver trained for emergencies Good evacuation plan Good communications to base Can call for immediate help Driver periodically checks temperature of running gear Infrared temperature measuring devices 17

18 AN vehicle fire near Tom Price 23 March 2015 B double carrying 44 X 1.2 T bags AN Rear axle fire Tried extinguishing but unsuccessful Decoupled prime mover Good evacuation plan Set up exclusion zone Let it burn out overnight No explosion 18

19 Comparisons Can t really compare but these are positive contributions: Minimal combustibles Effective firescreen Molten AN could flow and did not pool Good emergency plan 19

20 Port of Tianjin, China - AN explosion 12 Aug

21 Blast overpressure warning - slightly confronting 21

22 Nationally addressing the issue competent authorities panel (CAP) CAP has appointed a working group Brief to make recommendations on vehicle design For vehicles transporting AN in Australia WG has met several times Some items being considered are: Types of fire extinguishers Firescreens and heat shields Location of battery Communications systems Safety design features for vehicles Reduce quantity of combustibles Review hazard information on vehicles 22

23 Take away lessons Every effort must be made to avoid fires Where a fire occurs try and extinguish Dry chemical powder extinguishers alone are insufficient Molten AN is unstable and unpredictable It took an hour and 15 mins before the explosion occurred If fire gets out of control then need to evacuate Evacuate to at least 1500 m Fire is your biggest enemy when transporting AN 23

24 Summary Large explosion occurred 5/9/2014 Occurred at Angellala Creek, QLD Solid AN is very stable AN has low melting point Molten AN is shock sensitive Molten AN becomes unpredictable Need to evacuate if AN involved in fire Every effort is to be made to avoid fires Remember: Fires biggest enemy of AN No fires happy days 24

25 Any burning questions? 25

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