ENGINE - Royal Australian Navy

Once activated the section valve
(s) will open and the following
will occur:
a. The associated protected
area's ventilation fans will
stop.
b. The associated protected
area's ventilation shutters will
close.
c. The watermist audible and
visua l alarms will be activated
in the associated protected
zone(s).
d. There will be a 30 second
delay (this is for the system
to detect that the activation
is authentic and not due
to a leak in the system).
This wi ll then automatically
sequentially start al l motors
and pumps at the pump unit
when it detects a water flow or
a water pressure drop of below
17 bar for more than 20 to 30
seconds.
e. The pump unit will then supply
water at a pressure of 140 bar
to all spray heads within the
protected zone(s.)
If any of the pump unit motors
fail to start or if one stops whilst
in operation, then the primary
pump unit will shut down and
the secondary Pump Unit will
automatically start.
System shut down is achieved
from any of the release panels
or starter cabinets by pressing
the reset push button which will
close the section valve(s) and
shut down the pump unit. The
system will then reset itself by
opening a solenoid valve to drain
out the high water pressure which
will be around 140 bar down to
22 bar which in turn wi ll close the
solenoid valve and al low the air
operated booster pump to bring
the system pressure back up to 25
bar which is the standby pressure,
ready for system activation.
Conclusion
In summary watermist provides
a quantum leap in improvements
to crew safety in the event of
a major fire incident. Watermist
is on ly one component of a
complete fire detection, control
and extinguishment system.
The most important element of
wh ich includes the competence
and actions of the crew in any
incident. Watermist can be used
in combination wi th other systems
such as the existing gaseous
systems and initial use will be in
parallel with existing systems. The
introduction of the new system
will require new SOP's, training
and incorporation into existing
doctrine. All personnel posted to
ships fitted with watermist should
make themselves aware of the
capabilities of the new system and
avail them selves of the contents
of AF MEMO 23/08 - Use of Fixed
Fire Fighting Systems. Is summary
the effectiveness of any system is
only as good as the personnel that
operate it and so it is important
to understand the operation and
limitations of th is new system and
crucially to understand completely
what the existing local procedures
are in the event of any incident.
Whilst prevention of an incident
is always better than an effective
response, knowledge and a calm,
considered response may the final
deciding factor in avoiding and
effectively dealing with not just a
fire, but any incident onboard.
References:
1. An independent Guide on
Watermist systems for
residential buildings, V2.0, Dr
C. Wil liams & Dr L. Jackman,
2006, Building research
Establishment, Uk
2. The development of Water Mist
Fire Protection Systems for US
Ships, US NAVAL Engineers
Journal, Nov 2000, pg 49 -57,
Robert , Darwin & Dr Fredrick
W. Williams.
3. Supplementary brief to
Amphibious (LPA) Class
Hydrogen Fluoride (HF) risk
Brief, Oct 2008, B. McNeice.
4. A Review of waterm ist fire
suppression technology: Part II
- Application Studies, Journa l
of fire protection Engineering,
Feb 2001, pp16-42, Uu , Z.G;
Kim,A. K.
5. Watermist of Ship Machinery
Spaces, DSTO (Maritime
Platform Division), Apr 2006,
I. Burch .
6. The effects of water spray
cooling in conjunction with
Halogenated Extingu ishants
on HF generation and decay,
DSTO, Mar 2007, I. Burch.
7. AF Memorandum 23/08 - Use
of fixed fire fighting systems
dated 30 may 2008.
8. Successful shipboard Halon
replacements, US DOD (NAVY)
NAVSEA 05L4, D. Barylski,
M. Hunstad, R. Sheinson, A.
Maranghides.
Biography for LEUT S. Tacon
Leut Tacon is currently the Deputy Engineer
at the Amphibious FEG. Leut Tacon
completed his Bachelor of Eng(Mech) at
the University of Wollongong and worked
as a System Engineer prior to joining the
RAN in 1997. He completed his MEOCC
onboard HMAS Melbourne and has enjoyed
postings to the MCDSPO, Hydro FEG and
FSU (Formerly FIMA) Waterhen before
attaining his charge qualification on HMAS
SUCCESS in 2006.