Due to the tight configuration layout of the tank farm, access was limited for firefighters to
effectively provide cooling by directing water and foam to affected areas . The layout also
advanced heat radiation from one tank to cause fire to multiple tanks. Below is the
INGENIEUR
recommended bund specification to be put in place:
Figure
2: Proposed individual bund configuration for flammable liquid storage tanks. Tanks lined
Figure 2: Proposed individual bund configuration for flammable liquid storage tanks. Tanks
straight is a better layout as this minimises heat exposure to multiple tanks and allows for better
lined straight is a better layout as this minimises heat exposure to multiple tanks and allows
emergency
response coverage as opposed to configuration in Photo 1.
for better emergency response coverage as opposed to configuration in Photo 1.
deluge
system for a period of at least 20 minutes, necessitating interim bund integrity assessments.
Material: Bund floor and walls shall be built of materials impervious to the contents of any
or to 133% of the capacity of the largest tank, One of the signs of bund failure is when there
tank within the bund. It shall be of sufficient strength and structural integrity to ensure that
whichever is greater (2). Generally, bund walls is no water collected after heavy rainfall. It
it is unlikely to burst or leak within ordinary use (0). In the particular case of bulk storage of
is recommended to have an inspection every
should
not exceed 1.5 m in height (6) so that:
● ●
flammable
liquids,
bunds shall
have
fire resistant
integrity.
The
objective
is to
three structural
years (6), or
whenever
there
is an accident
Fire-fighting
operations
are not
hindered.
● ●
Egress from a bunded area in event of an impacting the structure of the bund.
retain the integrity of a bunded area as long as possible in the event of a fire. Concrete and
There is no hard and fast rule over the method
emergency is relatively easy
clay
are inherently fire resistant, but the risk of a loss of integrity exists due to joints and
● ●
Natural ventilation of the bunded area is statement for bund integrity assessment. Visual
penetrations to the bund walls and floors, and the way these features are sealed (0).
inspection looks into signs of damage at the inner
encouraged
For the purpose of bulk storage of flammable and outer wall, including bund base and joints.
liquids, it is recommended for each tank to have Hydrostatic testing is filling and holding the bund
individual bunds separate from other tanks as any 4 with water up to a level that corresponds with the
design capacity of the bund.
potential
leak may result in pool fire.
Note that hydrostatic testing may not be
Pipeworks: All pipework shall go over the bund
walls, as far as reasonably practicable, otherwise appropriate for reasons such as:
● ●
it shall be with adequate sealing and support
Tank stability compromised (Tanks may try
such that the penetrations are liquid tight and fire
to float and may become unstable)
●
●
resistant (3). All valves, filters, sight gauges, vent
Corrosion of tank base.
● ●
pipes and other ancillary equipment should be
Flooding of electrical equipment within
situated within the bund area and arranged such
bund
● ●
that leaks and discharges are contained within the
Excessive amount of water usage
bund area (2).
Distance: A good design must take into
consideration the distance between tanks. A Active Fire Protection
safe distance is when radiant heat from adjacent
tank fire is low enough that the adjacent tank In any fire tank incident, a deluge system is
can withstand the radiance for certain amount of essential because the application of water
time. This will give a time window for emergency spray/deluge onto storage tanks & vessels and
response reaction to the incident and minimise structural steel provides effective cooling of
damage.
exposed surfaces, minimising collateral damage.
The distance between tanks is also important Water requirement shall be calculated to cater for
to include access for emergency response teams simultaneous deluge activation of the tank on fire
because otherwise it would be a futile exercise and additional tanks adjacent to it, as adjacent
to extinguish the fire due to the limited range of tanks also require cooling during a fire incident.
fire water/foam. Width of access must allow a fire
Specific attention must be given to the rim seal
truck to easily manoeuvre around the storage tank fires on floating roof tanks scenario (open top and
and propel fire water/foam to the exact location covered floating roof). This is mentioned in typical
and minimise consequences.
design standards and codes used in industry
Integrity: Bunds may deteriorate or suffer such as National Fire Protection Association
damage during the lifetime of its operation, (NFPA 11)(5). However, incidents have occurred
6
66
VOL
2018
VOL 76
55 OCTOBER-DECEMBER
JUNE 2013