M81

Safety measures against chemical treatment(Jan2021)(cont)
fluids used for exhaust gas cleaning systems(Rev.1July 2023) and the residues which have hazardous
properties
M81
M81

1.

General

1.1 With regard to regulation 14 of MARPOL Annex VI requiring ships to use fuel oil with asulphur content not exceeding that stipulated in regulations 14.1 or 14.4, regulation 4 allows,with the approval of the Administration, the use of an alternative compliance method at leastas effective in terms of emission reductions as that required by the MARPOL Annex VI,including the standards set forth in regulation 14.
1.2 As some types of exhaust gas cleaning systems to be approved by the Administration
as “alternative compliance method” consume chemicals which are typically carried on board
in bulk quantities, the prescriptive requirements contained in this UR related safety measuresagainst chemical treatment fluids apply to exhaust gas cleaning systems using such fluids. In
this context, the term “chemical treatment fluid” means the aqueous solution of sodiumhydroxide (NaOH) or calcium hydroxide (Ca(OH)2) that has corrosive properties or are
considered to represent a hazard to personnel (See section 2 of this UR).
1.3 For exhaust gas cleaning systems using chemicals other than the above, safetymeasures are to be taken according to the result of a risk assessment to be conducted toanalyze the risks, in order to eliminate or mitigate the hazards to personnel brought by theuse of such exhaust gas cleaning systems, to an extent equivalent to systems complying with
M81 2.1 to M81 2.16.

Note:
1.

This UR is to be uniformly implemented by IACS Societies for EGCS:i) when an application for installation, i.e. submission date of plans, is made on orafter 1 July 2022; orii) which is installed in ships contracted for construction on or after 1 July 2022.

2.

Rev.1 of this UR is to be uniformly implemented by IACS Societies for EGCS:i) when an application for installation, i.e. submission date of plans, is made on orafter 01 July 2024; orii) which is installed in ships contracted for construction on or after 01 July 2024.

32.

The “contracted for construction” date means the date on which the contract to build
the vessel is signed between the prospective owner and the shipbuilder. For furtherdetails regarding the date of “contract for construction”, refer to IACS ProceduralRequirement (PR) No. 29.

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2.
Requirements for exhaust gas cleaning systems using aqueous solution of NaOHor Ca(OH)2 for chemical treatment fluid
2.1 The storage tank for chemical treatment fluids is to be arranged so that any leakage will
be contained and prevented from making contact with heated surfaces. All pipes or other tankpenetrations are to be provided with manual closing valves attached to the tank. In cases
where such valves are provided below top of tank, they are to be arranged with quick acting
shutoff valves which are to be capable of being remotely operated from a position accessible
even in the event of chemical treatment fluid leakages. Tank and piping arrangements are tobe approved.
2.2 The storage tank is to be protected from excessively high or low temperatures
applicable to the particular concentration chemical treatment fluids. Depending on theoperational area of the ship, this may necessitate the fitting of heating and/or coolingsystems.
2.3 If a storage tank for chemical treatment fluids is installed in a closed compartment, thearea is to be served by an effective mechanical ventilation system of extraction type providing
not less than 6 air changes per hour which is independent from the ventilation system of otherspaces accommodation, service spaces, or control stations. The ventilation system is to becapable of being controlled from outside the compartment. A warning notice requiring the useof such ventilation before entering the compartment shall be provided outside thecompartment adjacent to each point of entry.
2.4 The storage tank may be located within the engine room. In this case, the requirementsof 2.3 shall be complied with, except that a separate ventilation system is not required when
the general ventilation system for the space providing not less than 6 air changes per hour isarranged so as to provide an effective movement of air in the vicinity of the storage tank andis maintained in operation continuously except when the storage tank is empty and has beenthoroughly ventilated.
2.5 Each storage tank for chemical treatment fluids is to be provided with level monitoringarrangements and high/low level alarms. In cases where heating and/or cooling systems areprovided, high and/or low temperature alarms or temperature monitoring are also to beprovided accordingly.
2.6 The storage tanks are to have sufficient strength to withstand a pressure corresponding
to the maximum height of a fluid column in the overflow pipe, with a minimum of 2.4 m above
the top plate taking into consideration the specific density of the treatment fluid.
2.7 Where chemical treatment fluid is stored in integral tanks, the following are to beconsidered during the design and construction:.1

These tanks may be designed and constructed as integral part of the hull, (e.g.
double bottom, wing tanks).

.2

These tanks are to be coated with appropriate anti-corrosion coating and are to
be segregated by cofferdams, void spaces, pump rooms, empty tanks or othersimilar spaces so as to not be located adjacent to accommodation, cargo spaces
containing cargoes which react with chemical treatment fluids in a hazardous
manner as well as any food stores, oil tanks and fresh water tanks.

.3

These tanks are to be designed and constructed as per the structuralrequirements applicable to hull and primary support members for a deep tankconstruction.
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2.8

These tanks are to be included in the ship’s stability calculation.

The requirements specified in M81 2.3 also apply to closed compartments normallyentered by persons:.1when they are adjacent to the integral storage tank for chemical treatment fluids
and there are possible leak points (e.g. manhole, fittings) from these tanks; or.2when the treatment fluid piping systems pass through these compartments,
unless the piping system is made of steel or other equivalent material with melting
point above 925 degrees C and with fully welded joints.

2.9 The chemical treatment fluid piping and venting systems are to be independent of othership service piping and/or systems. The chemical treatment fluid piping systems are not to belocated in accommodation, service spaces, or control stations. The vent pipes of the storagetank are to terminate in a safe location on the weather deck and the tank venting system is tobe arranged to prevent entrance of water into the tank for chemical treatment fluids.
2.10 Storage tanks and pipes/piping systems and drip trays for chemical treatment fluids
which transfer undiluted chemical treatment fluids are to be of steel or other equivalentmaterial with a melting point above 925 degrees C.
2.11 Storage tanks and pipes/piping systems for chemical treatment fluids are to be madewith a material compatible with chemical treatment fluids, or coated with appropriate anticorrosion coating.
Footnote:
Several metals are incompatible with the chemical treatment fluids, e.g. NaOH isincompatible with zinc, aluminum, etc.
2.12 Regardless of design pressure and temperature, piping systems containing chemicaltreatment fluids only are to comply with the requirements applicable to Class I pipingsystems. As far as practicable, e.g. except for the flange connections that connect to tankvalves, the piping systems are to be joined by welding.
2.13 The following connections are to be screened and fitted with drip trays to prevent thespread of any spillage where they are installed:.1

Detachable connections between pipes (flanged connections and mechanicaljoints, etc.);.2

Detachable connections between pipes and equipment such as pumps, strainers,heaters, valves; and.3

Detachable connections between equipment mentioned in the above subparagraph.

The drip trays are to be fitted with drain pipes which lead to appropriate tanks, such as
residue tanks, which are fitted with high level alarm. Otherwise, the drip trays are to be fittedwith alarms for leak detection. In cases where such tank is an integral tank, M81 2.7.1 andM81 2.7.2 are to be applied to the tank.
2.14 For the protection of crew members, the ship is to have on board suitable personnel
protective equipment. The number of personnel protective equipment carried onboard is to be
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appropriate for the number of personnel engaged in regular handling operations or that may
be exposed in the event of a failure; but in no case is there to be less than two sets available
onboard.
2.15 Personnel protective equipment is to consist of protective clothing, boots, gloves andtight-fitting goggles.
Eyewash and safety showers are to be provided, the location and number of these eyewash
stations and safety showers are to be derived from the detailed installation arrangements. Asa minimum, the following stations are to be provided:.1

In the vicinity of transfer or treatment pump locations. If there are multiple transfer
or treatment pump locations on the same deck then one eyewash and safety
shower station may be considered for acceptance provided that the station iseasily accessible from all such pump locations on the same deck.

.2

An eyewash station and safety shower is to be provided in the vicinity of achemical bunkering station on-deck. If the bunkering connections are located on
both port and starboard sides, then consideration is to be given to providing two
eyewash stations and safety showers, one for each side.

.3An eyewash station and safety shower is to be provided in the vicinity of any partof the system where a spillage/drainage may occur and in the vicinity of system
connections/components that require periodic maintenance.

2.16 Storage tanks for chemical treatment fluids are to be arranged so that they can besafely emptied of the fluids and ventilated by means of portable or permanent systems.
3.

Requirement for Exhaust Gas Cleaning Systems discharge water pipeline

3.1 Overboard discharges from exhaust gas cleaning system (EGCS) are not to beinterconnected to other systems.
3.2 Due consideration is to be given to the location of overboard discharges with respect tovessel propulsion features, such as thrusters, propellers or to prevent any discharge water onto
survival craft during abandonment.
3.3 The piping material for the EGCS discharge water pipeline system is to be selected basedon the corrosive nature of the liquid media.
3.4 Special attention is to be paid to the corrosion resistivity of EGCS overboard discharge
piping. Where applicable, adequate arrangements are to be provided to prevent galvanic
corrosion due to the use of dissimilar metals.
3.5 In case distance piece is fitted between the outboard discharge valve and the shell
plating, it shall be made of corrosion resistant material steel or be coated with an anti-corrosive
material suitable for the operating environment. The thickness of the distance piece shall be atleast the minimum values specified in .1 and .2 as below; otherwise Sch.160 thickness specified
in piping standards shall, as far as practicable, be used.
.1

12 mm in cases where complete pipe is made of corrosion resistant materialsteel.

.2

15 mm of mild steel in cases where the inside the pipe is treated with an
anticorrosive coating or fitted with a sleeve of corrosion resistant material.
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34.

Miscellaneous

34.1 Tanks for residues generated from the exhaust gas cleaning process are to satisfy thefollowing requirements:.1

The tanks are to be independent from other tanks, except in cases where thesetanks are also used as the overflow tanks for chemical treatment fluids storage
tank.

.2

Tank capacities are to be decided in consideration of the number and kinds of
installed exhaust gas cleaning systems as well as the maximum number of days
between ports where residue can be discharged ashore. In the absence of
precise data, a figure of 30 days is to be used.

.3

Where residue tanks used in closed loop chemical treatment systems are also
used as the overflow tanks for chemical treatment fluids storage tank, therequirements for storage tanks apply.

End ofDocument

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