1. Tianjin Explosions – 12 August 2015
Analysis, Thoughts and What it means for you
Nigel Cann
Associate Principal | Risk & Security
FIChemE RPEQ CEng CEnv GAICD
Professional Process Safety Engineer

2. Tianjin Explosions – 12 August 2015
Pictures from the D van Duren video within The Australian newspaper
https://www.youtube.com/watch?v=cO1q3HwB0y0

3. 3
• The events of the night
• Use the crater size to estimate the explosion
• Look at the impacts to fine tune estimate
• Discuss the lessons learned
• What are you going to do this afternoon?
Agenda

4. 4
Before

5. 5
After

6. 6
6
Before…
…After

7. 7
• Ruihai Logistics stores and distributes hazardous chemical in the
Port of Tianjin
• Chemicals include:
- Calcium carbide (reacts with water to form acetylene –
explosive vapour cloud)
- Ammonium nitrate, potassium nitrate, sodium nitrate
(explosives)
- Sodium cyanide (reacts with water to produce toxic gas)
Facility Details – Tianjin Dongjiang Port Ruihai
International Logistics

8. 8
• A fire followed by explosions occurred on 12 August 2015.
• The fire started to get “out-of-control” around 22:50 hours local
time.
• The two major explosions occurred within 30 seconds of each
other.
• Multiple additional explosions occurred over the next few days.
• The largest explosion (the second one) occurred at 23:30 local
time.
Explosions Details

9. 9
• The US Geological Survey located in Beijing reported the first
large explosion to be 2.3 moment magnitude. This initially was
estimated as a blast equivalent to 3T TNT (or NEQ).
• The second large explosion had a Richter magnitude of 2.9,
which was reported as equivalent to 21T TNT.
• However, the Richter scale does not accurately portray the mass
involved in the explosion, as it only measures the ground
vibrations. Much of an on or above ground blast’s energy also
travels through the air.
• The mass involved in the largest explosion was therefore thought
to be greater than 21T NEQ.
Explosive Mass

10. 10
• The report explosion of 21T NEQ appeared to be a low estimate
based on the reported damage.
• Observation of photos of the crater in particular suggested that
the 21T NEQ was a “low” estimate.
• Observation of photos during clean-up suggested the smaller
explosions occurred in the warehouse obliterating it, and a large
Ammonium Nitrate explosion occurred in the container storage
area producing the large crater.
• The explosion occurred approximately 30-40 minutes after the
fire, which is consistent with similar explosions involving AN (e.g.
West Texas) and Charleville.
Reason for Analysis

11. 11
• AN is a strong oxidant, and is commonly
processed and then used as an explosive in
mining, or as a component in fertilizers
• There is a lot of guidance on the safe storage, handling and
transport of AN. AN should not be stored near combustible
materials.
• AN has been the cause of multiple large scale explosions in the
past:
- Truck carrying AN rolled and exploded in rural Queensland
(2014)
- West Texas fertilizer plant fire and explosion, USA (2013)
- AZF fertilizer plant explosion in Toulouse, France (2001)
Ammonium Nitrate

12. 12
• Pure, compact AN is stable and very
difficult to ignite.
• AN readily dissolves in water. Hence, water
is an effective suppression medium for fires involving AN.
• When heated, AN first melts and then begins decomposing when
heated beyond its melting point. Prolonged heating can lead to an
explosive decomposition.
• However under certain conditions and when combustible
materials are present (the AN continues to heat up), the reactions
change and far more gas is produced.
• When a fire is spread to AN and it is also confined (e.g. in
shipping containers), an explosion can occur.
• https://www.youtube.com/watch?v=GxKXAbS7WAo
Ammonium Nitrate Explosions

13. 13
The Crater

14. 14

15. 15
Crater – 85m diameter estimated
85m

16. 16
• D = 0.51 * Q1/3
(where D = radius of crater, Q = NEQ)
• Q = (D / 0.51)3
Q = (85/2 / 0.51)3
Q = 580T NEQ
• Calculation estimates approximately 580T NEQ
(27x more than the reported quantity of 21T NEQ)
• For 21T, using the equation gives a crater diameter of 28m
• However it does not take into account the geology of the land
Explosive Force Calculation – Equations
Ref: Ambrosini D, Luccioni B " Craters produced by large scale explosions",
Mecanica Computational Vol XXV11, pp1801-1821, 2008

17. 17
• Man-made, dredged materials
• Mostly wet, silty clay -> this is more likely to have similar
properties to wet clay than wet sandy clay
• Probably a layer of asphalt on top
Tianjin Port Geology

18. 18
• Data from the US army for the calculation of blast effects, based
on experimental data
• Using crater size of 85m and on wet clay:
- Explosive quantity: 130T
(6x more than the reported quantity of 21T NEQ)
• For 21T on wet clay, gives a crater diameter of 50m
• What about the asphalt?
Explosive Force Calculation – Conwep 1

19. 19
• Data from the US army for the calculation of blast effects, based
on experimental data
• On wet clay with asphalt:
Explosive Force Calculation – Conwep 2
Equivalent TNT (T) Crater Diameter (m) Comments
130 76 ± 28
Calculated quantity on
wet clay only
180 85 ± 31 Wet clay under asphalt

20. 20
Summary
Calculation Method
Equivalent
TNT (T)
Crater
Diameter (m)
Comments
Reported value from Richter
scale magnitude
21
Calculated value from
satellite images
85
Crater diameter / NEQ
equation
580 85 Calculated quantity based on crater diameter
Crater diameter / NEQ
equation
21 28
Calculated crater diameter based on
reported quantity
Conwep – wet clay 130 85 Calculated quantity based on crater diameter
Conwep – wet clay 21 50
Calculated crater diameter based on
reported quantity
Conwep – asphalt on wet clay 72 63 ± 23
Calculated quantity based on crater diameter
– lower limit
Conwep – asphalt on wet clay 720 135 ± 50
Calculated quantity based on crater diameter
– upper limit
Conwep – asphalt on wet clay 21 42 ± 15
Calculated crater diameter based on
reported quantity
Conwep – asphalt on wet clay 580 126 ± 46
Calculated crater diameter based on quantity
calculated using equations
Conwep – asphalt on wet clay 130 76 ± 28
Calculated crater diameter based on quantity
calculated on wet clay
Conwep – asphalt on wet clay 180 85 ± 31 Calculated quantity based on crater diameter

21. 21
• This means that if we assume a crater diameter of 85m, and the
ground materials are asphalt over wet clay, the explosive quantity
could be between 72T and 720T -> a very wide range!
• The report explosion of 21T NEQ is a very low estimate.
• It is likely the explosive quantity is of the order of 180T NEQ.
Explosives Quantity Summary

22. 22
Reported Impacts
Ref: The Guardian

23. 23
• The following references were used to determine effect distances
and interpretation of impacts:
- OPSMAN 3 – Department of Defence, Australia, EO safety
principals (now DEOP 101)
- Lees, Loss prevention in the process industries – 2nd edition
2001
- New South Wales Hazardous Industry Planning Advisory Paper
(HIPAP) No 6 (2011)
- Queensland Explosives Inspectorate, Information Bulletin 53,
2008
- AS2187.1 1998 – Explosives – storage, transport and use,
Part1:storage
References for Effect Distances

24. 24
Impact distances for 180T NEQ
Note: 180T NEQ of AN equates to between 360T and 720T of
actual AN depending on explosive efficiency.
70-170kPa -
Unstrengthened buildings
suffer complete destruction
30-39kPa - House damaged
beyond repair
21-26kPa - Reinforced
structures distort
14-16kPa - Buildings
uninhabitable
10kPa - Unstrengthened
buildings will suffer average
damage costing in the range
of 10% of the total
replacement cost to repair
7kPa - Damage to internal
partitions and joinery work
5.4kPa - Unstrengthened
buildings suffer minor
damage
3.5-3.8kPa - 90% broken
windows
1.7-1.8kPa -
Unstrengthened buildings
suffer only superficial
damage

25. 25
Review of published images confirms the analysis
http://www.dailymail.co.uk/news/article-3199058/China-orders-evacuation-residents-two-
mile-radius-Tianjin-blast-site-police-confirm-area-contaminated-deadly-CYANIDE.html

26. 26
An explosion of 180T NEQ
on asphalt on wet clay
produces 85m diameter crater
85m

27. 27
Around the crater
Before…
70-170kPa -
Unstrengthened
buildings suffer
complete
destruction
30-39kPa -
House damaged
beyond repair
Building –
150m away
Building –
165m away
Building –
65m away

28. 28
70-170kPa -
Unstrengthened
buildings suffer
complete
destruction
30-39kPa -
House damaged
beyond repair
Around the crater
After…
Brick
Building –
150m away,
gutted, barely
standing
Steel framed
building –
165m away,
totally
destroyed
Building
eliminated! –
65m away

29. 29
Demolished building
– 165m away
No building
here at all! –
65m away
Building –
150m away

30. 30
http://www.smh.com.au/world/tianjin-blast-shock-turns-to-anger-and-distrust-
after-massive-explosions-20150821-gj4eoz.html
Unstrengthened buildings suffer severe damage –
150m away (100kPa)

31. Train Station – 460m away
Donghai Road
Station – 460m
away (21kPa)
460m
21-26kPa -
Reinforced
structures
distort

32. 32
Donghai Road train damage – 460m away (21kPa)
(inside station) blast side
http://www.gettyimages.com.au/detail/news-photo/subway-train-is-damaged-at-
donghai-road-subway-station-news-photo/485074894

33. 33
460m away (21kPa) – blast located on the right of
image
http://www.gettyimages.com.au/detail/news-photo/subway-train-is-damaged-at-
donghai-road-subway-station-news-photo/485074894

34. 34
Buses behind
rail station –
550m away
550m

35. 35
Buses behind railway station 550m away –
consistent with 16kPa
https://en.wikipedia.org/wiki/2015_Tianjin_explosions#/media/File:Tianjin_explo
sion_destroyed_buses_(5).jpg

36. 36
Lattice tower
– 450m away
450m

37. 37
450m from centre
of explosion
(“50m away” from
site boundary) –
major container
distortion on truck
under the bridge
450m from centre
of explosion
(“50m away” from
site boundary) –
lattice tower still
standing

38. 38
Steel frame
builders’ sheds –
500m to 650m
away destroyed
beyond repair
500m
650m
21-26kPa -
Reinforced
structures
distort
14-16kPa -
Buildings
uninhabitable

39. Before

40. After – 500-650m away, 16-21kPa
Steel frame
builders’ sheds –
500m to 650m
away destroyed
beyond repair
21-26kPa -
Reinforced
structures
distort
14-16kPa -
Buildings
uninhabitable

41. 41
Approx. 500m – Structural collapse of
unstrengthened buildings – uninhabitable (21 kPa)
http://www.bbc.com/news/world-asia-china-33844084
21-26kPa -
Reinforced
structures
distort
14-16kPa -
Buildings
uninhabitable

42. 42
Apartment block
– 1.2km away
1.2km

43. 43
Apartment block 1.2km away – consistent with
3-5kPa, almost every window broken
5.4kPa -
Unstrengthen
ed buildings
suffer minor
damage
3.5-3.8kPa -
90% broken
windows

44. 44 http://www.bbc.com/news/world-asia-china-33998655
Most windows
damaged – 1km away
1km

45. 45
1km standoff approx. – most windows damaged,
consistent with 7kPa
http://www.bbc.com/news/world-asia-china-33998655, Dan der Duren video

46. 46
Tianjin Stadium –
1.7km away
1.7km
3.5-3.8kPa - 90%
broken windows
1.7-1.8kPa -
Unstrengthened
buildings suffer only
superficial damage

47. 47
Tianjin Stadium – approx. 1.7km away, broken
glass consistent with 2 - 3.5kPa range
3.5-3.8kPa - 90%
broken windows
1.7-1.8kPa -
Unstrengthened
buildings suffer only
superficial damage

48. 48
• Arup’s UK team also investigated the explosion and performed
analysis on the facades damage to determine the explosive
quantities
Detailed Facades Analysis

49. 49
Buildings Analysed
Harbour city
residence, 33 storey
building:
600-700m away
Wantong New Town
International residence:
17-33 storey building:
2km away

50. 50
Harbour City – 600-700m away
• On some buildings, glazing in the
entire façade has broken in a high-
hazard manner.
• Other buildings had glazing failure at
all levels of hazard: no-break, low
hazard, and high hazard.
14-16kPa - Buildings uninhabitable
10kPa - Unstrengthened buildings will suffer
average damage costing in the range of 10% of
the total replacement cost to repair

51. 51
Wantong New Town – 2km away
• Glazing appeared to be on the break / no break threshold – some
larger panes broken, smaller panes unbroken.
3.5-3.8kPa - 90% broken windows (1650m)
1.7-1.8kPa - Unstrengthened buildings suffer
only superficial damage (2500m)

52. 52
Explosive Mass Estimates
• Assumptions:
- Glass is assumed to be 4mm annealed
- Blast load is assumed to be a hemispherical, reflected blast
wave. Effects such as confinement or shielding are not
considered
• Blast charge weight in the order of 30-50T TNT, with an upper
mass of 100T TNT
• However, as there are many uncertainties in the analysis, the
charge weight upper bound could be in the order of 800-1000T
TNT

53. 53
Summary of Calculated NEQ
Calculation Method
Equivalent
TNT (T)
Crater
Diameter (m)
Comments
Crater diameter / NEQ equation 21 28 Calculated crater diameter based on reported quantity
Conwep – wet clay 21 50 Calculated crater diameter based on reported quantity
Conwep – asphalt on wet clay 21 42 ± 15 Calculated crater diameter based on reported quantity
Facades analysis 30-50 Calculated quantity based on observed facades damage
Conwep – asphalt on wet clay 72 63 ± 23
Calculated quantity based on crater diameter – lower
limit
OPSMAN 3 / NEQ equation 91
Calculated quantity based on observed damage effects in
a 2km radius
D = 44.4*Q1/3
Facades analysis – upper limit 100 Calculated quantity based on observed facades damage
Conwep – wet clay 130 85 Calculated quantity based on crater diameter
Conwep – asphalt on wet clay 130 76 ± 28
Calculated crater diameter based on quantity calculated
on wet clay
Conwep – asphalt on wet clay 180 85 ± 31 Calculated quantity based on crater diameter
Crater diameter / NEQ equation 580 85 Calculated quantity based on crater diameter
Conwep – asphalt on wet clay 580 126 ± 46
Calculated crater diameter based on quantity calculated
using equations
Conwep – asphalt on wet clay 720 135 ± 50
Calculated quantity based on crater diameter – upper
limit
Facades analysis – upper limit
given uncertainties
800-1000 Calculated quantity based on observed facades damage
CRATER TOO SMALL
Likely ground conditions have more clay
Likely Range 130-180 T NEQ based on crater and effects

54. 54
• BHP Billiton lost 3 days unloading iron ore shipments even though bulk terminals some way from
the
• John Deere lost 5 days of production at their facility in Tianjin. Several workers were injured and
needed medical treatment.
• Toyota lost 2 weeks of production their local affiliate’s two plants in the Tianjin Economic
Technological Development Area. The explosions injured 67 FAW Toyota workers living in the
vicinity and about 4,700 Toyota and Lexus vehicles were damaged. The value of the production
halted is estimated at $103m a week with a total of over $200m in production losses.
• Chinese insurance companies are expecting to face an estimated initial insured loss of about
$1bn-$1.5bn. A significant amount of those losses are to be covered by reinsurance.
Commercial Implications

55. 55
• The large explosion occurred approximately 30-40 minutes after the fire,
which is consistent with similar explosions involving AN (e.g. West Texas).
• It is likely based on the pictures during the clean-up that there was a fire in the
warehouse which produced a number of smaller explosions close enough to a
large store of Ammonium Nitrate (AN) in the container yard.
• The large explosion would appear to be of the order of 130 to 180T TNT
equivalent based on the crater size and the photographed damage area, and the
assumptions that the ground is asphalt on wet clay.
• This would equate to 260 to 720T of AN involved in the explosion (depending
on the explosive efficiency assumed).
• It was reported that 800T of AN was stored on site.
Explosion Conclusions

56. 56
What are you going to do this afternoon?

57. 57
• How well do we understand the impacts of the Dangerous Goods
we store?
• Are they stored appropriately?
• Do we store dangerous goods incompatible with water (Class
4.3)?
• Do they have the right separation distances from incompatible
goods?
• Is our fire fighting response and capability appropriate for the
goods we handle?
• How do we let the fire brigade know where our dangerous goods
storages are?
Immediate Lessons to Learn (Questions to Answer)
STORAGE of Dangerous Goods

58. 58
• Do we know the full consequences of incidents from the
hazardous goods on our sites?
• Do we know the impact our neighbours can have on us
(consequences)?
• Have we informed our surrounding communities?
• Do we have emergency response plans and strategies?
• When was the last time we tested our emergency response plan?
• Was the fire brigade involved?
• If you have a building in a 3kPa contour of a potential explosion,
think toughened and/or laminated glass !
• Does your Senior Management and Board understand the true
picture?
Immediate Lessons to Learn (Questions to Answer)
All facilities

59. 59
Use of Toughened and/or Laminated Glass instead
of Annealed Glass
Toughened glass
Annealed glass

60. 60
• Breaks into large,
jagged shards
• More likely to cause
injury (and fatality)
Annealed Glass

61. 61
• Annealed glass that has been treated to increase its strength
• Breaks into small, granular pieces
• Less likely to cause injury (and fatality)
Toughened Glass

62. 62
• Glass can break but laminate stops it flying out and potentially
causing injury
• Laminate will move in blast and absorb energy and keep blast
outside of building (assuming frame suitable designed also)
Laminated Glass

63. 63
• Arup is an employee trust that runs a project
management, built environment and infrastructure
engineering design business around the globe.
• In the context of this presentation we help industry, building
owners and developers that have dangerous goods storages and
operations make appropriate design and operational decisions.
• We also help those that may be subject to the consequences (from
natural causes, hazardous goods or terrorism activities) design and
construct the appropriate resilience into their buildings and
structures.
ARUP
We shape a better world

64. 64
Questions?