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

GCSNO861@dnv.com

MSC.1/Circ.1324

MSC.1/Circ.1325

MEPC.2/Circ.17

IBC Code Chapter 17

IBC Code Chapter 18

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