Casualty Info 3-03
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Transcript of Casualty Info 3-03
8/9/2019 Casualty Info 3-03
http://slidepdf.com/reader/full/casualty-info-3-03 1/2
INFORMATION FROM DNV TO THE MARITIME INDUSTRY NO. 3 – JUNE 2003
Casua lty In formation
Course of eventsDuring morning attendan ce of engine room,
a water leak from the exhaust gas boiler was
discovered. In order to get to port, the water
circulation was shut off, and the instruction
manual on “emergency dry running” was fol-
lowed.
When a rriving at an chora ge, the exhaust
gas boiler overheated, and the crew found
that a soot fire had occurred.
Extent of damage
Tube stacks at gas out let of exh aust gas boil-
er were found heavily damaged. More than
half of the tube stack sectional area was melt-
ed down an d the tubes of the remaining
area were found sagging.
Probable causeEven though the tubes seemed clean from
soot and oil residues at visible inspection,
soot deposits will always be present to some
extent. Boilers with fi nn ed tube design are
even more exposed to accumulation of soot
than boilers with plain tube design, and the
consequences of a fi re are often more
severe.
In this case, it seems that th e circulating
pump was stopped almost immed iately, while
the main engine was left running. This
action left the tube stack fully uncooled and
the soot deposits on the tu bes eventually
ignited and a fi re occurred.
Seconda ry causes may be:
• Insufficient sootblowing and water washingin gen eral, especially soot blowing prior to
and after manoeuvring and after water
washing of t urbo chargers in service.
SHIP TYPE: Any SIZE (g rt ): Any YEAR OF BUILD: Any
Damage to exhaust gasboilers due to dry
running
Sagged economiser tube nests
after soot fire, finned tubes.
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D e s i g n : D N V E G r a p h i c C o m m u n i c a t i o n s 0 3 0 6 - 0 3 7
P r i n t : G A N
G r a fi s k
• Sootblowing with wet steam, which leaves
the soot in the middle of the boiler.
• Sootblowing with too low pressure, which
leaves the soot in th e middle o f the boiler.
• Poor routines in observing the exhaust gas
pressure differential across the boiler.
Lessons to be learned
Actions to be taken prior to dry running:
• When shutting off the water circulation,
the main engine should also be shut down
so the exhaust gas boiler can cool down
and any smouldering soot deposits on the
boiler tubes can die out.
• The heating surface should be inspected
carefully for soot deposits, an d water wash-
ing performed, both for cleaning and
cooling.
• Make every effort to re-establish the water
circulation to th e boiler and thereby
reduce the dry running period to a mini-
mum.
• Boiler manufacturers allow dry running of
exhaust gas boilers onl y in the case of emer-
gency and with a clean boiler. In addition
they emphasise that every possible precau-
tion m ust be observed to prevent soot fi re.
Actions to be taken duringdry running:
• Increase the frequency of sootblowing con-
siderably, an d perform soot blowing several
times prior to manoeuvring.
• Inspect the boiler frequently, and if any
soot is present, th en water wash th e boiler
and increase the sootblowing frequency.
• The boilers instruction manual must be
read ca refully and its instructions are
always to b e followed.
Cas ual ty In f o r mat ion
is published by
Mari t ime Industr ies,
Mari t ime Technolog y and
Pr oduc t ion Ce ntr e
(Dept. fo r Classi f icat ion & ISM)
Det Norske Veritas
NO-1322 Høvik, Norw a y
Tel: + 47 67 57 99 00
Fa x: + 47 67 57 99 11
The purpose of Ca sual ty Informa tion is
to pr ov ide th e ma r ine indus t r y w i th
‘ lessons to be learned’ f rom incidents of
s h ip da mag e a nd m or e s e rious accide nts .
In this way , DNV hopes to contr ibute to
the prevention of s imilar occurrences in
the f uture . The informa tion included
is not necessar i ly res tr icted to cover ships
classed w ith DNV an d is present ed,
w i thout ob l ig a t ion , f o r in f o r mat ion
purposes o nly.
Quer ies may be directed to
Mari t ime Industr ies , Mar i t ime Technolog y an d
Production Centre (Dept. f or Classi f icat ion & ISM),
NO-1322 Høvik, Norw a y.
Fax + 47 67 57 99 11. E-mail MTPNO860@dn v.com
Copyr ight a nd disclaimer : This publicat ion ma y be
r e pr oduce d f r e e ly on condi t ion tha t De t Nors ke
Veri tas (DNV) is alwa ys sta ted as th e source .
DNV accepts no responsibi li ty for an y errors or
misinterpretat ions .
View inside economiser
with melted tubes.