8/3/2019 DNV Technical eNewsletter PV Valve Jan2012
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Depending on their physical properties
and thereof assigned carriage requirements
(apparatus group in this case), flammable
chemicals (FP60C) subject to the IBC
Code will require the cargo tank to be
fitted with flame preventing devices
approved for the products MESG value.
These amendments take effect as follows:
Newbuildings: ships keel-laid on or after
1 January 2013 Existing ships: first scheduled dry
docking after 1 January 2013
New requiremeNt
In order to carry chemicals that require
electrical equipment apparatus group
IIB or IIC once the new amendments
become applicable to a ship, the MESG
value for which devices such as P/V valves,
gas-freeing covers and flame arresters
protecting a cargo tank are approved has
to be documented according to the revised
standard.The required apparatus group for a
product is given in column (i) in chapter
17 of the IBC code or in MEPC.2/circ.17
Annex 1 and Annex 3*.
impact for owNers aNd yards
As a consequence of the MESG testing
requirements, ships keel-laid before
1 January 2013 which are currently
certified for the carriage of chemicals
assigned apparatus group IIB or IIC will
need to document the MESG value of their
flame preventing devices no later than at
the first dry docking which occurs after
1 January 2013. Alternatively, a revised
Certificate of Fitness product list may be
issued, excluding those products that
require apparatus group IIB and IIC. The
documentation will be reviewed and the
devices verified as part of the periodical
Chemical Code survey.
Existing ships with an NLS Certificate
(Certificate for the Carriage of Noxious
Liquid Substances in Bulk) for the carriage
of chapter 18 products only** and ships
that have a Certificate of Fitness but arenot certified to carry products requiring
apparatus group IIB or IIC will not be
affected and no further action is required.
New ships keel-laid on or after 1 January
2013 must have the appropriate flame
preventing devices which meet the
requirements of the cargoes intended for
carriage fitted before delivery.
steps to take
To assist customers, DNV will issue an
RR (Retroactive Requirement) to ships
certified for the carriage of productsrequiring apparatus group IIB or IIC if
DNV has issued the Certificate of Fitness.
However, as some ships may be omitted,
ship owners are urged to check whether or
not their ships are affected, and to take the
appropriate action. This can be done by
simply checking whether any IIB products
are listed on the current Certificate of
Fitness.
Acceptable documentation can be
the type approval certificate, laboratory
report (which should be included in the
manufacturers instruction manual) or MEDcertification. The MESG value may also be
printed on the nameplate of the device itself
or specified in P/V-valve flow curves.
For a tank fitted with devices that have
different MESG values, e.g. pressure-
vacuum valve combinations or gas-freeing
covers, the highest MESG value is the
governing one.
We strongly recommend examining
the documentation in time and assessing
whether further steps need to be taken. If
it is unclear whether or not a device meets
a required standard, you are advised tocontact the maker of the device.
* The correct information has now beenassigned to most of the approximately 140products for which the electrical equipmentinformation was previously missing (MSC.1/Circ.1325). These corrections are shown in
Annex 1 of MEPC.2/Circ.17 and will take effectwith the next amendment to the IBC code,which is expected to enter into force on 1 July2014.
** Offshore support vessels may have chapter 17products listed on their NLS certificate. Thoseproducts will be subject as well if the apparatus
group is IIB or IIC.
The amendments to the revised standards for the design, testing and location of devices to prevent thepassage of flame into cargo tanks in tankers (MSC.1/Circ.1324) define the test media to be used whendetermining the appropriate Maximum Experimental Safe Gap (MESG) value for the flame preventing device.
Technical eNewslettermesG n v vn h g l n g n(al h h c fn h cg dng chl n Bl)
11 January 2012
DNV disclaimer of liability
For more information, please contact
DNV GCSNO861, Safety Systems
MSC.1/Circ.1324
MSC.1/Circ.1325
MEPC.2/Circ.17
IBC Code Chapter 17
IBC Code Chapter 18
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