Tianjin Explosions – 12 August 2015

Analysis, Thoughts and What it means for you

Nigel CannAssociate Principal | Risk & SecurityFIChemE RPEQ CEng CEnv GAICDProfessional Process Safety Engineer

Tianjin Explosions – 12 August 2015

Pictures from the D van Duren video within The Australian newspaper

https://www.youtube.com/watch?v=cO1q3HwB0y0

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•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

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Before

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After

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Before…

…After

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•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

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•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

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•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

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•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

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•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

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•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

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The Crater

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Crater – 85m diameter estimated

85m

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•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

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•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

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•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

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•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

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SummaryCalculation Method Equivalent

TNT (T)Crater

Diameter (m) CommentsReported value from Richter

scale magnitude 21Calculated value from

satellite images 85Crater 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 limitConwep – 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 quantityConwep – 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 clayConwep – asphalt on wet

clay 180 85 ± 31 Calculated quantity based on crater diameter

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•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

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Reported Impacts

Ref: The Guardian

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•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

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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 destruction30-39kPa - House damaged beyond repair21-26kPa - Reinforced structures distort14-16kPa - Buildings uninhabitable10kPa - Unstrengthened buildings will suffer average damage costing in the range of 10% of the total replacement cost to repair7kPa - Damage to internal partitions and joinery work5.4kPa - Unstrengthened buildings suffer minor damage3.5-3.8kPa - 90% broken windows1.7-1.8kPa - Unstrengthened buildings suffer only superficial damage

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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

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

85m

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Around the crater

Before…

70-170kPa - Unstrengthened buildings suffer complete destruction30-39kPa - House damaged beyond repair

Building – 150m away

Building – 165m away

Building – 65m away

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70-170kPa - Unstrengthened buildings suffer complete destruction30-39kPa - 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

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Demolished building – 165m away

No building here at all! – 65m away

Building – 150m away

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)

Train Station – 460m away

Donghai Road Station – 460m away (21kPa)

460m

21-26kPa - Reinforced structures distort

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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

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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

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Buses behind rail station – 550m away

550m

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Buses behind railway station 550m away – consistent with 16kPa

https://en.wikipedia.org/wiki/2015_Tianjin_explosions#/media/File:Tianjin_explosion_destroyed_buses_(5).jpg

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Lattice tower – 450m away

450m

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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

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Steel frame builders’ sheds – 500m to 650m away destroyed beyond repair

500m

650m21-26kPa - Reinforced structures distort14-16kPa - Buildings uninhabitable

Before

After – 500-650m away, 16-21kPa

Steel frame builders’ sheds – 500m to 650m away destroyed beyond repair

21-26kPa - Reinforced structures distort14-16kPa - Buildings uninhabitable

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Approx. 500m – Structural collapse of unstrengthened buildings – uninhabitable (21 kPa)

http://www.bbc.com/news/world-asia-china-33844084

21-26kPa - Reinforced structures distort14-16kPa - Buildings uninhabitable

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Apartment block – 1.2km away

1.2km

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Apartment block 1.2km away – consistent with 3-5kPa, almost every window broken

5.4kPa - Unstrengthened buildings suffer minor damage3.5-3.8kPa - 90% broken windows

44 http://www.bbc.com/news/world-asia-china-33998655

Most windows damaged – 1km away

1km

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1km standoff approx. – most windows damaged, consistent with 7kPa

http://www.bbc.com/news/world-asia-china-33998655, Dan der Duren video

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Tianjin Stadium – 1.7km away

1.7km

3.5-3.8kPa - 90% broken windows1.7-1.8kPa - Unstrengthened buildings suffer only superficial damage

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Tianjin Stadium – approx. 1.7km away, broken glass consistent with 2 - 3.5kPa range

3.5-3.8kPa - 90% broken windows1.7-1.8kPa - Unstrengthened buildings suffer only superficial damage

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

Detailed Facades Analysis

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Buildings Analysed

Harbour city residence, 33 storey building:600-700m away

Wantong New Town International residence: 17-33 storey building: 2km away

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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 uninhabitable10kPa - Unstrengthened buildings will suffer average damage costing in the range of 10% of the total replacement cost to repair

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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)

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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

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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 91Calculated quantity based on observed damage effects in

a 2km radiusD = 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

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•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

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•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

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What are you going to do this afternoon?

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•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

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•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

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Use of Toughened and/or Laminated Glass instead of Annealed Glass

Toughened glass

Annealed glass

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

Annealed Glass

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

Toughened Glass

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•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

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•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

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Questions?