The document discusses protecting occupied buildings from process tank rupture and spillage. Computational fluid dynamics (CFD) modeling was used to simulate spillage from a ruptured tank and determine the impact on surrounding buildings. The modeling found that spillage could destroy nearby buildings and identified which would be affected. Barriers were then evaluated to protect existing buildings from the spillage impacts.
1. Protecting Occupied Buildings
from Process Tank Rupture
Spillage
David Ho - Principal Consultant/Manager –
Advanced Analysis
November 2016
2. Tank rupture is rather rare – though
if it occurs the consequence can be
catastrophic:
• The spillage can destroy surrounding
buildings
• It has enough energy to overtop bunds
• And very importantly, lives can be lost
3. Boston molasses tank
rupture (1919)
Fuel oil tank failure –
Ashland Oil (1988)
Fertilizer tank collapse –
Allied Terminals, Virginia
(2008)
These pictures show a few well-known tank
failures that have occurred in the US…
4. Tank collapse spilling
radioactive slurry - Ranger
Uranium Mine (2013)
Water tank rupture –
Sunshine Coast (2015)
Leach tank rupture – Ravensthorpe
nickel mine (2014)
In Australia, recent tank failures have been
reported in the media
6. A minerals processing facility owner required an analysis
of their facility to identify hazards and manage the risks
should one of their on-site tanks rupture.
• The facility has aboveground processing tanks
• If one of the tank ruptures an engulfment hazard will occur
• Need to identify which occupied buildings will be affected
• Want to plan for future building locations on site –
temporary and permanent – without exposing staff to risk
7. Tank Characterisation
and Rupture
The critical parameters that could
give the worst type of spillage were
considered.
The parametric study found that
the tank height and fluid density
would have the greatest impact on
the surrounding buildings.
8. Tank Characterisation and Rupture
How different rupture openings could affect spillage were considered.
The panel failure at the base of the tank was selected because the jet of liquid
can flow further and last longer, affecting buildings further away from the tank.
9. Consequence Modelling
• The spillage was simulated using Computational
Fluid Dynamics (CFD)
• In the modelling, the tank was put on flat and site-
specific terrain
• Other objects were included in the model
• The analysis tracked how the fluid escaped from
the rupture opening and provided the flow
velocity, depth and pressure along the flow path
in space and time
10. This shows what happens about six
seconds after a rupture occurs at the
base of this tank.
The liquid jets across the road hitting
the buildings on the other side.
Some liquid has enough energy to
reach the storage silos further away.
11. This shows another area where there is a
retention pond between the tank farm and an
occupied building which is elevated above
ground. The building is supported on stilts.
The spill flows into the retention pond and out
the other side and towards the building.
12. Impact on Buildings
• It is more desirable to perform a high-level assessment if it
can be done
• The maximum head and flow depth around each tank was
quantified as a panel rupture could occur at any position
around the tank
• From the simulation results, contour plot maps of maximum
head and maximum flow depth can be obtained
• The pressure acting on a building wall can be quantified and
estimated anywhere on site
13. Impact on
Buildings
Top graphs
The maximum pressure
and maximum flow
depth away from the
ruptured tank.
Bottom graphics
Results are plotted
around each tank
ignoring the presence
of the other tanks and
objects on site.
14. Impact on
Buildings Height of wall
Pressure
Maximum
flow depth
2 x
Maximum
flow depth
Maximum
head
As long as the maximum
pressure head and flow
depth are known, the
likely pressure on a
building wall can be
estimated.
The structural integrity
of the building can
then be assessed.
15. Protective Measures
• If building relocation costs are too high, buildings
need to be protected
• A barrier to deflect flow is a method to protect
existing buildings
• CFD modelling can be used to evaluate barrier
concepts
• Further site-specific modelling can be used to
consider other site constraints
16. Protective Measures
A number of barrier profiles were
examined to see which one could
best deflect the flow.
The assessment criterion is that no
liquid can go over the barrier.
The graphics on the right show snap
shots of the flow hitting the barrier.
The flow is deflected up and back
and in this case no overtopping
occurs.
17. Protective Measures
Once the barrier profile was
selected, its effectiveness is
further tested in the site model.
In the snap shot to the right,
you can see it protects the
buildings.
18. • Hydrodynamic behaviour of spillage from a ruptured
tank – captured by CFD modelling
• Impact on existing buildings along flow path
• Likely impact to the wall if a building were in the flow
path
• Evaluate effectiveness of barrier concepts
Conclusions
• Hydrodynamic behaviour of spillage from a
ruptured tank was captured by CFD modelling
• Impact on existing buildings along flow path
was determined
• The likely impact to the building wall was
assessed
• Effectiveness of barrier concepts were
evaluated
