Fire & Gas Dampers
Introduction
Fire Ratings and Approvals
Fire & Gas Dampers are used in ventilation systems
Offshore and marine fire divisions are normally clas-
to prevent the spread of flame and/or smoke
sified as `A' or `B' that relate to temperature limits
between divisions.
to be adhered to on the non-fire side of the division.
The divisions are insulated to reduce the tempera-
Wozair manufacture three types of Fire & Gas
ture rise to pre-defined limits. Where a fire damper
Damper depending on the application and specifi-
is fitted these temperature limits must be main-
cation. All dampers have been independently tested
tained. However as the fire damper is a metal struc-
and have third party certification.
ture the temperature rise cannot be limited without
the provision of insulation, which must be applied in
Each type of Fire & Gas Damper can be supplied in
the same manner as that of the surrounding duct-
either stainless or carbon steel and can be provid-
work system. The temperature rise is measured
ed with numerous control systems including manu-
over the exterior surface of the insulation.
al latch, pneumatic and electric operation.
Installations:
All dampers can be supplied to suit rectangular or
circular ducts.
Class B For a damper to pass a class B approval,
it must maintain its integrity and resist the passage
of flame for a period of greater than 30 minutes, the
Authority/Cer tification
temperature rise on the external surface of the
damper must not rise higher than 139 deg C above
FGD
ambient during the time period nor should the tem-
perature at any point on the insulation rise more
The damper has been subject to a 2 hour Hydrocarbon
than 225 deg C during the same time period.
fire test and is certified by DNV & Lloyd's Register of
Shipping for bulkhead & deck applications. The damper
Class A Classification is common for Offshore
is suitable for use in `A-0' `A-60' & `H-0' `H-120'
applications:
Divisions with the ducting suitably insulated. Control
enclosures can be supplied pre-insulated for ease of
Fire Dampers rated for A0 class divisions are
installation.
required to pass a 1 hour fire test.
MFD
Fire Dampers for A60 divisions must maintain
The damper has been subject to a 4 hour fire test
integrity and resist the passage of flame for a peri-
in accordance with the IMO Resolution A.754 (18)
od of greater than 60 minutes, the temperature rise
and BS476 Pt20 and is certified by Lloyd's Register
on the external surface of the damper must not rise
of Shipping for bulkhead & deck applications. The
higher than 139 deg C above ambient during the
damper is suitable for use in `A-0'-`A-60' Divisions
time period nor should the temperature at any point
with the ducting suitably insulated. Control enclo-
on the insulation rise more than 180 deg C during
sures can be supplied pre-insulated for ease of
the same time period.
installation.
For smoke clearance the damper is certified at
When suitably insulated Wozair Fire Dampers fulfil
300 deg C for 1 hour high temperature operation.
these requirements.
The damper is also Type Approved by DNV, BV, ABS,
RINA and GL.
Class H0 H120 Fire Divisions Wozair FGD Fire
Dampers have been tested and approved to meet
LFD
this standard which involves a 2 hour fire test to the
The damper has been subject to a 4 hour fire test in
hydrocarbon temperature curve.
accordance with the IMO Resolution A.754 (18) and
BS476 Pt20 and is certified by Lloyd's Register of
It must be clearly understood that a Fire Damper
Shipping for bulkhead & deck applications. The damper
can only carry an A0 classification by itself and on
is suitable for use in `A-0'-`A-60' Divisions with the duct-
installation with suitable insulation (by others) the
ing suitably insulated. Control mounting plates or enclo-
higher classification will be achieved.
sures can be supplied pre-insulated for ease of installation.
Enclosures will be pre-insulated where required.
The damper is also Type Approved by DNV, BV,
Approval for installation must be gained from the
ABS, RINA and GL.
appropriate certifying authority.