CHAPTER 8 :
SPECIALISED SHIPS,
TANKERS, CHEMICAL CARRIERS, LIQUEFIED GAS CARRIERS, DANGEROUS GOODS AND OFFSHORE INSTALLATIONS
8.1 Fire safety measures
for tankers
8.1.1 Application
8.1.1.1 This section concerns details, relevant to fire protection on
tankers and tanker safety as a whole, which
are not specifically dealt with elsewhere in these Instructions or in the regulations. It may
also be applicable to ships which
are not normally operated as tankers but which may be engaged in the carriage of flammable liquids
in bulk.
8.1.1.2 SOLAS I Reg 2 defines a tanker as
“a cargo ship constructed or adapted for the carriage in bulk of liquid cargoes of an inflammable1 nature”. SOLAS II-2
Reg 1.6.1 clarifies the meaning of ‘inflammable/flammable’ by stating
“Requirements for tankers in this
chapter shall apply to tankers carrying crude oil or petroleum products having
a flashpoint not exceeding 60°C
(closed cup test), as determined by an
approved flashpoint apparatus, and a Reid vapour pressure
which is below the atmospheric
pressure or other liquid products
having a similar fire hazard” (the MS
(Large Ships..) Regulations call
these category A tankers) The same definitions can be assumed
for non SOLAS ships.
8.1.1.3 In
matters of tanker safety reference should be made to the 'International Safety Guide for Oil Tankers and Terminals' (ISGOTT Guide)
published by the International Chamber of Shipping, Oil Companies International
Marine Forum and the International Association of Ports and Harbours.
CHEMICAL
TANKERS
8.1.1.4 These
Instructions apply in general to
chemical tankers although provisions of
the 'Code for the Construction and
Equipment of Ships carrying Dangerous Chemicals in Bulk'
or the 'International Code for the
Construction and Equipment of Ships
Dangerous Chemicals in Bulk'
as appropriate should
be taken into account,
see the Instructions
to Surveyors on
Chemical Tankers. Should any difficulty arise in complying
with both the regulations and the above
Codes the matter should be referred to the appropriate Headquarters Branch
LIQUEFIED GAS CARRIERS
8.1.1.5 Liquefied gas carriers which have a
valid Certificate of Fitness need not be provided with a fixed deck foam
system or an inert gas system other than as required in accordance with the
provisions of the 'Code for the Construction
and Equipment of Ships
carrying Liquefied Gases in Bulk' or the 'International Code for the Construction and Equipment of Ships carrying
Liquefied Gases in Bulk' as appropriate, see the Instructions to Surveyors on Gas Carriers.
8.1.2 Location and separation of spaces
(ships constructed on or after 1 February 1992)
8.1.2.1 The regulations place restrictions on the types of
spaces which can be located near to cargo and slop tanks and requires separation from possible sources of flammable
gases by a cofferdam, cargo pump room, oil fuel bunker or
ballast tank. Interpretations of
these requirements follow:
8.1.2.2 Construction of ‘cofferdams’ and prohibition of containment of cargo,
wastes and goods (SOLAS II-2 Reg. 4.5.1):
The expression ‘cofferdam’
is meant, for the purposes
of the regulations, an isolating
space between two adjacent steel bulkheads or decks. The minimum distance between two bulkheads or decks, should be sufficient for safe access and inspection.
In order to meet the single failure principle, in the particular case when a
corner-to-corner situation occurs, this principle may be met by welding a diagonal plate across the corner (see figure below). No cargo,
wastes or other goods should be
contained in cofferdams.
(Unified Interpretation - MSC/Circ. 1120)
CORNER-TO-CORNER
SITUATION IN A COFFERDAM
8.1.2.3 Safety aspects of double bottoms and duct
keels under cargo oil tanks
(SOLAS II-2 Reg.
4.5.2.4):
Pipe ducts in the double bottom shall comply with the following
requirements:
(i) They should not communicate with the
engine room.
(ii) Provision shall be made for at least two
exits to the open deck arranged at a maximum distance from each other. One of
these exits fitted with a watertight closure may lead to the cargo pumproom.
(iii) In the
duct, provision shall be
made for adequate
mechanical ventilation.
(IACS Unified Rule F 26)
8.1.2.4 Separation of cargo oil tanks (SOLAS II-2 Reg. 4.5.1):
Pump-rooms intended
solely for ballast transfer need not comply with the requirements of regulation
4.5.10. The requirements of regulation 4.5.10 are only applicable to the
pumprooms where pumps for cargo, such as cargo pumps, stripping pumps, pumps
for slop tanks, pumps for COW or similar pumps are provided.
(Unified Interpretation
- MSC/Circ. 1120)
8.1.2.5 Restriction on boundary openings (SOLAS II-2
Reg 4.5.2, IBC Code
3.2.3, IGC Code
3.2.4)
Access to forecastle
spaces containing sources of ignition may be permitted through doors facing
cargo area provided the doors are located outside hazardous areas as defined in
IEC Publication 60092-502.
(IACS Unified
Interpretation SC 120)
8.1.2.6 Cargo
areas (SOLAS II-2 Reg 3.6 and 4.5.1.1)
For ships constructed on or after 5 October 2007:
1 A
void space or
ballast water tank
protecting a fuel
oil tank, in accordance with MARPOL, as shown in figure
1, need not be considered as a “cargo area” as defined in SOLAS regulation
II-2/3.6 even though they have a cruciform contact with the cargo oil tank or
slop tank.2
2 The void space
protecting a fuel oil tank, in accordance with MARPOL, is not considered as a
cofferdam as specified in SOLAS regulation II-
2/4.5.1.1. Therefore,
location of the void space shown in figure 1 should be considered acceptable
even though they have a cruciform contact with the slop tank.
2 As defined by MARPOL
73/78.
BALLAST WATER TANK (BWT) FUEL OIL TANK (FOT) CARGO OIL TANK (COT)
(Unified Interpretation - MSC/Circ. 1239)
8.1.2.7 Cargo
openings in the
bottoms of topside
tanks of ships
carrying alternatively oil and grain on ships carrying alternatively oil
having a flash point not exceeding 60°C (closed cup test) or other cargoes.
When ships are
designed to transport alternatively oil or dry cargoes, openings which may be
used for cargo operations are not permitted in bulkheads and decks separating
oil cargo spaces from other spaces not designed and equipped for the carriage
of oil cargoes unless alternative approved means are provided to ensure
equivalent integrity.
(IACS Unified Rule F
27)
8.1.2.8 Bow and stern loading and unloading arrangements on oil tankers
Where a cargo hose
connection is arranged outside the cargo tank area, the pipe leading to such
connections is to be provided with means of segregation such as a spectacle
flange, removable spool piece or equivalent3
located within the cargo area. The space within 3 m of the manifold is
to be considered as a dangerous area with regard to electrical or incendive
equipment.
(IACS Unified rule F
16)
8.1.2.9 Fore peak ballast system on oil tankers
3 See MSC/Circ. 474.
The fore peak can be ballasted with the system serving ballast
tanks within the cargo area, provided :
• The tank is considered as hazardous;
• The vent pipe openings are located on open deck 3 m away from sources of ignition;
• Means
are provided, on the open deck, to allow measurement of
flammable gas concentrations within the tank by a suitable
portable instrument;
• The access to
the fore peak and sounding arrangements are direct from open deck. In case the fore peak tank is separated by cofferdams from the cargo tanks, an access through a gas tight bolted manhole located in an enclosed
space may be accepted. In
that case, a warning sign
is to be provided at the manhole stating that the tank may only be opened after it
has been proven to be gas free
or the electrical equipment
which is not electrically safe in the enclosed space is isolated.
(IACS Unified rule F 44)
8.1.2.10 Location of paint lockers within the cargo
block (SOLAS II-2 Reg 4.5.1.2 and .3)
Paint lockers,
regardless of their use, should not be located above the tanks and spaces
defined in SOLAS regulation II-2/4.5.1.2 for oil tankers.
(Unified
Interpretation - MSC/Circ. 1239)
8.1.2.11 An access to a deck foam system room (including the foam tank and
the control station) can
be permitted within the limits,
provided the regulations are complied with and the door
is located flush with the bulkhead.
8.1.2.12 The navigation bridge external doors and windows which are located within the limits should be tested
for gas tightness. If a
water hose test is applied the following may be taken as a guide:
(a) nozzle
diameter; minimum 12mm;
(b) water
pressure just before the
nozzle; not less than 2 bar; and
(c) distance between the nozzle and the doors or windows; maximum
1.5 m.
8.1.3 Venting, purging, gas-freeing and ventilation
8.1.3.1 High velocity
devices to prevent the passage of flame into cargo tanks in oil tankers are now
approved under the MED. Other types should take into account MSC/Circ. 677, as
amended by MSC/Circ.1009, and MSC/Circ. 731
8.1.3.2 Secondary means of venting cargo tanks (SOLAS
II-2 Reg 4.5.3.2.2 and
11.6.3.2)
1. A P/V breaker
fitted on the IG main may be utilised as the required secondary means of
venting.
2. The
height requirements of
Reg. II-2/4.5.3.4.1 and
11.6.2 and the requirements for
devices to prevent
the passage of
flame of Reg.
II-
2/4.5.3.3 are not
applicable to the P/V breaker provided the settings are above those of the
venting arrangements required by Reg. II-2/11.6.1.
3. Where the venting
arrangements are of the free flow type and the masthead isolation valve is
closed for the unloading condition, the IG systems will serve as the primary
underpressure protection with the P/V breaker serving as the secondary means.
4. Inadvertent
closure or mechanical failure of the isolation valves required by SOLAS Reg.
II- 2/4.5.3.2.2 and the FSS Code, Ch. 15, 2.3.2.2 need not be considered in
establishing the secondary means since:
a) The valves are
operated under the control of the responsible ships officer and a clear visual
indication of the operational status of the valves is required by SOLAS Reg.
II-2/4.5.3.2.2, as amended, and
b) The possibility of
mechanical failure of the valves is remote due to their simplicity.
(IACS Unified
Interpretation SC 140)
8.1.3.3 Safety
devices in venting
systems (SOLAS II-2 Reg 4.5.3.3)
1 Ullage openings do
not include cargo tank openings that are fitted with standpipe arrangements
with their own manually operated shutoff valves.
2 Examples include
the common 2.54 cm (1") and 5.08 cm (2") diameter standpipe
arrangements that are used for sampling, monitoring or measuring of ullage/
temperature/ interface, oxygen, liquid and hand dipping in the cargo tank.
(Unified
Interpretation - MSC/Circ. 1169)
Ullage plugs,
sighting ports and tank cleaning openings are not to be arranged in enclosed
spaces.
(IACS Unified Rule
F3)
8.1.3.4 Due to the practical difficulties of protecting openings into cargo tanks when using portable tank
washing machines, such openings are
not required to be fitted with devices to prevent the passage of flame provided all tank cleaning
operations are performed in accordance
with accepted industry practices outlined in
the ISGOTT Guide.
8.1.3.5 The following gas-freeing arrangements may be accepted on tankers
which are not fitted with inert gas
systems:
(a) when using centrifugal portable or fixed gas-freeing fans, gas freeing may be done through outlets having
a height of at least 2 m above the cargo tank
deck which are protected by devices to prevent the passage of flame, which have not undergone the
endurance burning test, provided a minimum discharge velocity of 20m/sec is maintained;
(b) when
using portable axial flow gas-freeing fans, gas freeing may be done through
outlets having a height of at least 2
m above the cargo tank deck without any device to prevent the passage of flame provided a minimum discharge velocity
of 30m/sec is maintained at all times;
(c) the
arrangements stated in sub-paragraphs
(a) and (b) of this paragraph
apply only whilst gas-freeing, during
which time due regard should be given
to the
required operational
procedures to
ensure an acceptable
level of safety;
(d) portable gas-freeing fans need not be fitted with a device to prevent
the passage of flame at the
inlet of the fan provided that when, in
the event of loading and ballasting operations taking place concurrently with gas-freeing
operations, gas monitoring at cargo
tank deck level is carried out and
where concentrations exceeding 30 per
cent of the lower explosive limits are detected near the gas freeing inlet the
gas freeing operation is stopped; and
(e) all operational procedures associated with gas-freeing should be stated in
the ship's Standing Orders/ISM procedures.
8.1.4 Ignition sources
8.1.4.1 Anchor windlass and chain locker openings
constitute ignition hazards. They are to be located at the
distance required by the regulations.
Electrical equipment fitted in
compliance with IEC Publication 60092- Electrical installations in ships - Part
502: Tankers - Special features is not considered a source of ignition or
ignition hazard.
IACS Unified Interpretation SC 57)
8.1.4.2 Openings for pressure release,
permitted electrical equipment (SOLAS II-2 Reg. 11.6.2.2):
1 Areas
on open deck, or semi-enclosed spaces on open deck, within 3 m of cargo tank
ventilation outlets which permit the flow of small volumes of vapour, air or
inert gas mixtures caused by thermal variation are defined as Zone 1. Permitted
electrical equipment:
• Certified safe type equipment
for Zone 1.
2 Areas within 2 m beyond the zone
specified in 1 above are defined as
Zone 2. Permitted
electrical equipment:
• Certified safe type equipment for Zone
1,
• Equipment of a type, which ensures the
absence of sparks, "hot spots" during its normal operation,
• Equipment having an enclosure filled
with a liquid dielectric, the application, or encapsulated,
• Pressurised equipment,
• Equipment specifically designed for Zone
2 (for example type "n" protection in accordance with IEC Publication
60079-15).
Note:
Zones 1 and 2 are
those defined in IEC Publication IEC 60092 Electrical installations in ships -
Part 502: Tankers - Special features.
(Unified
Interpretation - MSC/Circ. 1120)
8.1.4.3 Vent outlets for cargo
loading, discharging and ballast,
permitted
electrical equipment:
1 Areas
on open deck, or semi-enclosed spaces on open deck, within a vertical cylinder
of unlimited height and 6m radius centred upon the center of the outlet, and
within a hemisphere of 6m radius below the outlet which permit the flow of
large volumes of vapour, air or inert gas mixtures during
loading/discharging/ballasting are defined as Zone 1.
Permitted electrical equipment:
• Certified
safe type equipment for Zone 1.
2 Areas
within 4 m beyond the zone specified in 1 above are defined as
Zone 2.
Permitted electrical equipment:
• Certified
safe type equipment for Zone 1;
• Equipment
of a type, which ensures the absence of sparks, “hot spots”, during its normal
operation;
• Equipment
having an enclosure filled with a liquid dielectric, the application, or
encapsulated;
• Pressurized
equipment; and
• Equipment
specifically designed for Zone 2 (for example type “n”
protection in accordance with IEC
60079-15).
Note:
Zones 1 and
2 are those
defined in IEC
Publication IEC 60092
Electrical installations in ships -
Part 502: Tankers - Special features. IACS Unified Interpretation SC 70)
8.1.4.4 Where there is a possibility that cargo flow
will generate static electrical charges IACS Unified Rule E 9 should be
complied with.
8.1.4.5 Cathodic protection on oil tankers
F1.1 Impressed
current systems are
not permitted in oil cargo tanks.
F1.2 Magnesium or
magnesium alloy anodes are not permitted in oil cargo tanks and tanks adjacent
to cargo tanks.
F1.3 Aluminium anodes
are only permitted in cargo tanks and tanks adjacent to cargo tanks in
locations where the potential energy does not exceed 28 kg m (200 ft lb). The
height of the anode is to be measured from the bottom of the tank to the centre
of the anode, and its weight is to be taken as the weight of the anode as
fitted, including the fitting devices and inserts. However, where aluminium
anodes are located on horizontal surfaces such as bulkhead girders and
stringers not less than 1 m wide and fitted with an upstanding flange or face
flat projecting not less than 75 mm above the horizontal surface, the height of
the anode may be measured from this surface.
Aluminium anodes are not to be located under tank hatches or Butterworth
openings (in order to avoid any metal parts falling on the fitted anodes),
unless protected by adjacent structure.
F1.4 There is no restriction on the positioning of zinc anodes.
F1.5 The anodes
should have steel cores and these should be sufficiently rigid to avoid
resonance in the anode support and be designed so that they retain the anode
even when it is wasted.
F1.6 The steel
inserts are to be attached to the structure by means of a continuous weld of
adequate section. Alternatively they may be attached to separate supports by
bolting, provided a minimum of two bolts with locknuts are used. However,
approved mechanical means of clamping will be accepted.
F1.7 The supports at
each end of an anode should not be attached to separate items which are likely
to move independently.
F1.8 When anode
inserts or supports are welded to the structure, they should be arranged so
that the welds are clear of stress raisers.
(IACS Unified Rule
F1)
8.1.4.6 Temperature of steam and heating media within the cargo area
On oil tankers, the
steam and heating media temperature within the cargo area is not to exceed
220°C.
On gas carriers and
chemical tankers, the maximum temperature is to be adjusted to take into
account the temperature class of the cargoes.
(IACS Unified Rule
F24)
8.1.4.7 Aluminium coatings
on board oil tankers and chemical tankers
The use of aluminium
coatings is prohibited in cargo tanks, cargo tank deck area,
pump rooms, cofferdams
or any other
area where cargo vapour may accumulate.
Aluminised pipes may
be permitted in ballast tanks, in inerted cargo tanks and, provided
the pipes are
protected from accidental
impact, in hazardous areas on
open deck.
(IACS Unified Rule
F2)
8.1.5 Fixed
deck foam system
Refer to chapter
7.
8.1.6 Fixed
dry powder system
8.1.6.1 The specification
for fixed dry
powder systems are
contained in the International Code
for the Construction
and Equipment of
Ships Carrying Liquefied Gases in
Bulk (IGC Code), as amplified by MSC Circular 1315, and are not currently
covered by the MED.
8.1.6.2 Testing of
new installations should comply with part 4 of MSC Circular
1315. A short test
discharge may be considered necessary to verify monitor throw/positioning or
the ability of the crew to control hose applicators.
8.1.6.3 At resurvey
surveyors should ensure that the maintenance specified in
MGN 355 has been
carried out and that visual examination shows no defects
8.1.7 Protection of cargo pump rooms
8.1.7.1 Designation as “pump rooms”
SOLAS Reg. II-2/4.5.1.1 states:
"Pump-rooms, containing
pumps and their
accessories for ballasting
those spaces situated adjacent to cargo tanks and slop tanks and pumps
for oil fuel
transfer shall be
considered as equivalent to a cargo pump room within the context of this
regulation provided that such pump-rooms have the same safety standard as that
required for cargo pump rooms.” However relaxations can be made in certain
circumstances whilst maintaining "the same safety standard as that
required for cargo pump rooms":-
Pump rooms intended
solely for ballast transfer need not comply with the requirements of regulation
II-2/4.5.10. The requirements of regulation II -
2/4.5.10 are only
applicable to the pump rooms where pumps for cargo, such as cargo pumps,
stripping pumps, pumps for slop tanks, pumps for COW or similar pumps are
provided.
(Unified
Interpretation - MSC/Circ. 1120)
Pump-rooms intended
for fuel oil
transfer need not
comply with the requirements of regulation II-2/4.5.10.
(IACS Unified
Interpretation SC 188)
8.1.7.2 Pump room ventilation
With the following
arrangement of exhaust trunking there should be 20 air changes per hour on the
total volume of the pump room:
(i) In the pump room
bilges just above the transverse floor plates on bottom longitudinals, so that
air can flow over the top from adjacent spaces.
(ii) An emergency
intake located about 2 m above the pump room lower grating. This emergency
intake would be used when the lower intakes are sealed off due to flooding in
the bilges. The emergency intake should have a damper fitted which is capable
of being opened or closed from the exposed main deck and lower grating level.
(iii) The foregoing
exhaust system is in association with open grating floor plates to allow the
free flow of air.
(iv) Arrangements
involving a specific ratio of areas of upper emergency and lower main
ventilator openings, which can be shown to result in at least the required 20
air changes per hour through the lower inlets, can be adopted without the use
of dampers. When the lower access inlets are closed then at least 15 air
changes per hour should be obtained through the upper inlets.
(IACS Unified Rule F
21)
8.1.7.3 Emergency lighting (SOLAS
II-2 Reg. 4.5.10.1.2):
Where the lighting in cargo pump-rooms
can be commonly used as the emergency lighting, this lighting should be
interlocked with the ventilation systems. However, this interlock should not
prevent operation of the emergency lighting in case of the loss of the main
source of electrical power.
(Unified Interpretation - MSC/Circ.
1120)
8.1.7.4 Monitoring the concentration
of hydrocarbon gases in cargo pump-rooms on oil tankers (SOLAS II-2 Reg.
4.5.10.1.3):
1 Sequential
sampling is acceptable as long as it is dedicated for the pump room only,
including exhaust ducts, and the sampling time is reasonably short.
2 Detection
positions are the zones where air circulation is reduced (e.g. recessed
corners).
(Unified Interpretation - MSC/Circ.
1120)
8.1.7.5 Bilge level monitoring devices
(SOLAS II-2 Reg. 4.5.10.1.4):
Bilge high-level alarms
are acceptable as an alternative means for the level monitoring devices.
(Unified
Interpretation - MSC/Circ. 1120)
8.1.7.6 Pump room alarms
Where audible alarms
are fitted to warn of the release of fire extinguishing medium into pump rooms,
they may be of the pneumatic type or electric type.
(a) Pneumatically
operated alarms
In cases where the
periodic testing of such alarms is required,CO2 operated alarms should not be
used owing to the possibility of the generation of static electricity in the
CO2 cloud. Air operated alarms may be
used provided the air supply is clean and dry.
(b) Electrically
operated alarms
When electrically
operated alarms are used, the arrangements are to be such that the electric
actuating mechanism is located outside the pump room except where the alarms
are certified intrinsically safe.
(IACS Unified Rule
F5)
8.1.8 Instruments for measuring oxygen and
flammable vapour concentrations
8.1.8.1 Fixed gas detection
systems:
This
UR applies to
gas analysing units
of the sampling
type located outside gas
dangerous zones and fitted on board gas carriers or on board oil/chemical
tankers.
Gas analysing units with non-explosion
proof measuring equipment may be located
in areas outside cargo areas, e.g. in cargo control room, navigation bridge or
engine room when mounted on the forward bulkhead provided the following
requirements are observed:
1. Sampling lines shall not run
through gas safe spaces, except where permitted under 5.
2. The gas sampling pipes shall be
equipped with flame arresters. Sample gas is to be led to the atmosphere with
outlets arranged in a safe location.
3. Bulkhead penetrations of sample pipes between safe and dangerous areas
shall be of
approved type and
have same fire integrity as the division penetrated. A
manual isolating valve shall be fitted in each of the sampling lines at the
bulkhead on the gas safe side.
4. The
gas detection equipment
including sample piping,
sample pumps, solenoids, analysing units etc. shall be located in a
reasonably gas tight enclosure (e.g. a fully enclosed steel cabinet with a
gasketed door) which is to be monitored by its own sampling point. At gas
concentrations above 30% LFL inside the enclosure the entire gas analysing unit
is to be automatically shut down.
5. Where the enclosure cannot be
arranged directly on the bulkhead, sample pipes shall be of steel or other
equivalent material and without detachable connections, except for the
connection points for isolating valves at the bulkhead and analysing units, and
are to be routed on their shortest ways.
(IACS Unified Rule F43)
8.1.8.2 Portable gas detection (SOLAS II-2 Reg 4.5.7.1)
To meet the requirement for “sufficient set of spares”:
Every oil tanker is
to be provided with at least two portable gas detectors capable of measuring
flammable vapour concentrations in air and at least two portable O2 analysers.
(IACS Unified Rule
F7)
In addition, for
tankers fitted with inert gas systems, it is recommended that at least two
portable gas detectors are to be capable of measuring concentrations of
flammable vapours in inerted atmosphere
8.2 Inert gas Installations
Inert gas system
components are now covered by the Marine Equipment Directive. IACS Unified Rule
F20 contains more detailed requirements than those in the FSS Code for boiler
flue, oil fired gas generator and nitrogen generator systems.
8.2.1 Oil and petroleum tankers
8.2.1.1 L.S.
Regulation 30(1) and
SOLAS Ch II-2 Regulation 4.5.5
require tankers of 20,000 tons or over carrying flammable
bulk liquid cargoes,
ie. crude oil and petroleum
products
having
a
flashpoint
not
exceeding
60oC, to be provided with an inert gas system complying with the requirements contained in Schedule 9 of MSN 1666(M) or the FSS Code, dependent on date of build.
8.2.1.2 Reference
is made to MSC/Cir.731 - Revised factors to be taken into consideration
when designing cargo tank venting and gas freeing arrangements
MSC/Cir.485 -
Clarification of inert gas system requirements under SOLAS 1974, as amended
(for tankers between 20,000 and 40,000 tonnes deadweight constructed before 1
September 1984), and MSC/Cir.387 - Revised guidelines for inert gas systems. The
term cargo tank includes slop tanks.
8.2.2 Chemical
tankers and gas carriers
8.2.2.1 It should be remembered that the International Codes for the
Construction and Equipment of Ships carrying
Dangerous Chemicals in Bulk and Liquefied Gases in Bulk are applicable
to such ships regardless of size including
those of less than 500 GT. They in turn apply most of SOLAS Ch II-2 to chemical tankers and gas carriers regardless of size.
8.2.2.2 Chemical tankers
having valid Certificates of Fitness for the Carriage of Dangerous Chemicals in Bulk or gas carriers having valid Certificates of Fitness for the Carriage of Liquefied Gases in
Bulk should comply with the following:
8.2.2.3 Chemical
tankers, when carrying
crude
oil
or
flammable petroleum products should comply with the alternative requirements for inert gas systems
contained in A 567(14) (Schedule 10 of MSN
1666(M)) unless they comply with the FSS Code (or Schedule 9 of MSN 1666 for pre 2002 ships). Inert gas may be
nitrogen gas from nitrogen generators subject to
the application of IMO Resolution A 567(14).
8.2.2.4 Gas
carriers when carrying
flammable cargoes described in
8.2.1.1 should be provided with cargo tank inerting arrangements equivalent to those specified in Schedules 9 or
10 of MSN 1666(M); or
8.2.2.5 Chemical tankers
and gas carriers, if constructed before 1 July 1986, when carrying flammable cargoes
other than crude
oil or petroleum products
such as cargoes listed in Chapter VII
of the Code for the Construction and Equipment
of Ships Carrying
Dangerous Chemicals in Bulk or Chapters 17 and
18 of the International
Code
for
the
Construction
and
Equipment
of
Ships
Carrying Dangerous
Chemicals In Bulk are
not required to be inerted;
or
8.2.2.6 Chemical tankers and gas carriers, if
constructed on or after 1 July 1986,
when carrying flammable cargoes other than crude
oil or petroleum products
such as cargoes listed in Chapter VI
and VII
of the Code for the Construction and Equipment
of Ships Carrying
Dangerous Chemicals in Bulk or Chapters 17 and
18 of
the International Code
for the Construction and
Equipment of Ships Carrying Dangerous Chemicals in Bulk, are
not required to be provided with an
inert gas system if the capacity of
tanks, used for the carriage of these cargoes, does not exceed 3,000 m3, the individual nozzle
capacities of tank washing
machines do not exceed 17.5 m3 per hour and the total combined
throughput from the number of machines
in use in a cargo tank at any
one time does not exceed 110 cubic metres per hour.
8.2.3 Isolation arrangements in inert gas main
The following satisfies
FSS Code Chapter
15, paragraph 2.3.2.7:
(Unified Interpretation - MSC/Circ. 1120)
8.2.4 Testing
8.2.4.1 The surveyor should witness such tests as are necessary
to ensure gas of
the right quality
and, so far
as is practicable, the
appropriate quantity is produced. Although oxygen content of less than 1 per cent by volume can be achieved 5 per cent may be regarded as
acceptable. Special attention should be paid to the automatic regulating and
sensing valves, to the oxygen or
carbon dioxide recorder, to alarms and to
the necessary water supplies.
8.2.4.2 At initial survey a full scale test should be carried out to demonstrate the following:
(a) a positive pressure can be maintained
on all cargo and slop tanks during
the maximum discharge rate attainable;
(b) the oxygen content in the cargo tanks is acceptable during the maximum discharge and also during the topping up phase
when no cargo is being discharged;
(c) all alarms operate at the stipulated pressures, temperature levels and flow
rates;
(d) all required shut down facilities are activated
at the stipulated pressures,
temperatures, levels and flow rates; and
(e) the effectiveness
of
the
instrumentation, including
recorders
for
the
oxygen content and pressure in the cargo tanks.
8.2.4.3 During
renewal survey it may be impractical to inspect
the scrubber, deck water seal and the pressure vacuum release arrangements. Furthermore
it is not usually possible to test the ‘back flow prevention’ function of the deck water seal during the
time the cargo tanks need to be kept
inerted. The integrity of the deck water seal can only be established by
a thorough internal examination for corrosion and erosion, particularly
those dimensions in the structure
necessary to form the required levels
in the seal. Thus the survey of the deck seal can
only be undertaken when the ship is gas free or when it can be established with some degree of confidence that
the deck isolating and non-return valve or valves are sufficiently gas tight to enable such examination
to be undertaken in safety. Where it is impracticable to
inspect such items at the time of survey, it is in order for the
surveyor to accept a report by the ship’s Chief Engineer, provided the inspection, maintenance, repair and operation of the inert gas system is fully
documented. Surveyors should
ensure however that all major
items are seen within any 5 year period.
8.3 Special requirements for
ships carrying dangerous
goods
8.3.1 Statutory requirements
8.3.1.1 L.S. Regulation 103, S.S. Regulation 45 and
SOLAS II-2 Regulation 19 applies the statutory requirements to ships which carry dangerous goods. Dangerous goods are those defined as such by the Merchant Shipping (Dangerous Goods and Marine Pollutants) Regulations 1997. The
effect of these requirements is to
require certain additional precautions when certain classes of dangerous goods
are carried. Any requests for reduced
protective requirements, allowed for cargo ships under 500 gt., should be referred to HQ.
8.3.1.2 Chapter
7 of the International
Maritime Dangerous Goods Code (IMDG
Code) contains operational measures which must be taken in
addition to the ship requirements. Refer to chapter 3 of the
International Maritime Dangerous Goods Code (IMDG Code) for a description of the term “limited
quantities”.
8.3.2.3 Surveyors
should note that the voluntary Code of Safe Practice for Solid Bulk Cargoes (BC
Code) is being replaced by the International Maritime Solid Bulk Cargoes
(IMSBC) Code on a voluntary basis from July 2009 however this is due to become
mandatory by 1 January 2011.
8.3.2 Interpretations
8.3.2.1 Interpretation of Table 1 of MSN 1669(M):
A “purpose built container space” is a cargo space fitted with cell guides for stowage securing of containers.
(Unified Interpretation - MSC/Circ.
1120)
“Ro-Ro spaces”
include special category
and vehicle deck spaces.
(Unified Interpretation - MSC/Circ. 1120)
Weather decks (SOLAS II-2 Reg 19, Table 19.1)
For the purposes of
Reg. II-2/19 a ro-ro space fully open above and with full openings in both ends
may be treated as a weather deck.
(IACS Unified
Interpretation SC 86)
8.3.3 Fire extinguishing
8.3.3.1 Water supplies,
for open top container ships:
The
water spray system
required by items
9.2, 9.3 and 9.4 of MSC/Circ
608/Rev 1 “Interim Guidelines for Open Top Container Ships” will also satisfy
the requirements for dangerous
goods.
The amount of water required for fire fighting purposes in the largest hold
is to
satisfy simultaneous use from the water spray system
plus four jets of water from nozzles.
(Unified Interpretation - MSC/Circ. 1120)
8.3.3.2 Equivalent protection (SOLAS
II-2 Reg 10.7.2)
Water supplies
defined in regulation
19.3.1.2 are considered
as an acceptable protection for
cargoes listed in table 2 of MSC/Circ.671.
(MSC Circular 671 has
been replaced by MSC Circular 1146 which should be used instead.)
Ships carrying
dangerous goods on deck only:-
Any cargo space in a
ship engaged in the carriage of dangerous goods on deck or in cargo spaces
should be provided with a fixed gas fire- extinguishing system complying with
the provisions of the FSS Code or with a fire-extinguishing system which, in
the opinion of the Administration, gives equivalent protection for the cargoes
carried.
(Unified
Interpretation - MSC/Circ. 1120)
8.3.3.3 Cargo space
water spray systems are covered
in chapter 7.
8.3.3.4 Hydrants for dangerous goods (SOLAS II-2 Reg 19.3.1.2)
The number and
position of hydrants should be such that at least two of the required four jets
of water, when supplied by single lengths of hose, may reach any part of the
cargo space when empty; and all four jets of water, each supplied by single
lengths of hose may reach any part of ro-ro cargo spaces.
(Unified
Interpretation - MSC/Circ. 1120)
Note that SOLAS Reg
10.2.3.1.1 specifies maximum hose lengths for ships >July
2002. UK
regulations for older
SOLAS and for
all non SOLAS
ships have different maximum
lengths.
8.3.3.5 Replacement of water with foam:
A high expansion foam
system complying with the FSS Code, chapter 6, section 2.2, is acceptable as an
alternative to the water application system required by SOLAS II-2 Reg 19.3.1.3
and .4 except if cargoes dangerously react with water (see IMDG Code).
(Unified Interpretation - MSC/Circ. 1120)
8.3.4 Sources of ignition
8.3.4.1 Sources of ignition (SOLAS II-2 Reg 19.3.2)
1. Reference should be made to IEC 60092-506
standard, Special features - Ships carrying specific dangerous goods and
materials hazardous only in bulk.
2. For pipes having open ends (e.g.,
ventilation and bilge pipes, etc.) in a hazardous area, the pipe itself should
be classified as a hazardous area. See IEC 60092-506 table B1, item B.
3. Enclosed
spaces (e.g., pipe
tunnels, bilge pump-rooms,
etc.) containing such pipes with equipment such as flanges, valves,
pumps, etc., should be regarded as an extended hazardous area, unless provided
with overpressure in accordance with IEC 60092-506 clause 7.
(Unified
Interpretation - MSC/Circ. 1203)
8.3.4.2 Bilge pumping
for open top container ships:
Bilge
systems for cargo
holds should be independent of the machinery space bilge system and be located
outside of the machinery space.
(IACS Unified Interpretation SC 111)
8.3.4.3 Arrangements
for enclosed spaces containing bilge pumps serving cargo spaces (SOLAS II-2 Reg
19.3.5.4)
Electrical
equipment in the
space should comply
with IEC Publication
60092- 506 standard.-
Electrical installations in ships. (Unified Interpretation - MSC/Circ. 1120)
8.3.4.4 Exhaust fans:
1 Exhaust fans should be of non-sparking
type in accordance with IACS Requirement F 29, as revised.
2 The purpose of suitable wire mesh guards
is to prevent foreign objects from entering into the fan casing. The standard wire mesh guard should
have a size of 13mm x 13mm.
(Unified
Interpretation - MSC/Circ. 1120)
8.3.5 Ventilation
8.3.5.1 Ventilation requirements for
individual cargoes and open-top container cargo holds (SOLAS II-2 Reg 19.3.4)
1 General
If
adjacent spaces are not separated from cargo spaces by gastight bulkheads or
decks, ventilation requirements should apply as for the cargo space itself,
required under regulation 19.3.4.2 and its interpretations.
2 Requirements for individual cargoes:
.1
Cargoes liable to give off vapours or gases which can form an explosive mixture
with air (See the BC Code, Appendix B, e.g. IMO Class 4.3 materials):
Two
separate fans should be permanently fitted or being of a portable type adapted
for being permanently fitted prior to loading and during voyage. The fans
should be either explosion proof or arranged
such that the
escaping gas flow
is separated from electrical cables and components. The
total ventilation should be at least six air changes per hour, based upon the
empty space. Ventilation should be such that any escaping gases cannot reach
living spaces on or under deck.
.2
Cargoes liable to spontaneous combustion (only applicable to seed cake (b) and
(c)):
Two
separate fans should be permanently fitted or being of a portable type adapted
for being permanently fitted prior to loading and during voyage. The fans
should be either explosion proof or arranged
such that the escaping gas
flow is separated
from electrical cables and components. The total ventilation should be
at least six air changes per hour, based upon the empty space. Ventilation
should be such that any escaping gases cannot reach living spaces on or under
deck.
(Unified Interpretation - MSC/Circ. 1120)
least
six air changes per hour, based upon
the empty space. Ventilation should be such that any escaping gases cannot
reach living spaces on or under deck.
(Unified Interpretation - MSC/Circ. 1120)
Note 8.3.2.3, above, on the replacement of the BC Code by the IMSBC Code.
3 For open-top containerships
Power ventilation
should be required only for the lower part of the cargo hold for which purpose
ducting is required. The ventilation capacity should be at least two air changes
per hour, based on the empty hold volume below weather deck.
(Unified
Interpretation - MSC/Circ. 1120)
8.3.6 Insulation of machinery space boundaries
(SOLAS II-2 Reg
19.3.8)
In the case that a
closed or semi-closed cargo space is located partly above a machinery space and
the deck above the machinery space is not insulated, dangerous
goods are prohibited
in the whole
of that cargo space. If the uninsulated deck above
the machinery space is a weather deck, dangerous goods are prohibited only for
the portion of the deck located above the machinery space.
(IACS Unified
Interpretation SC 103)
8.3.7 Personnel protection
8.3.7.1 Type and suitability of protective clothing:
1 When selecting the protective clothing the danger of the chemicals according to the class and
liquid or gaseous state should be taken into
account.
2 The required protective clothing is for emergency
purposes. For solid
bulk cargoes the protective clothing is to satisfy the equipment
requirements specified in Appendix E of the BC Code for the individual
substances. For packaged goods the protective clothing is to
satisfy the equipment requirements specified in emergency procedures (EmS) of the Supplement to IMDG Code for the individual substances.
(Unified Interpretation - MSC/Circ. 1120)
8.3.7.2 Self-Contained Breathing Apparatus
(SCBA) (SOLAS II-2 Reg
19.3.6.1)
Where dangerous goods
are carried the self-contained breathing apparatus should be
of positive pressure
type, according to
the MED, and
should be suitable for use
together with the chemical protection clothing on board. For each item of breathing apparatus, two complete sets of air
bottles are required. These spare bottles are to be in addition to the spare
bottles required for the fireman’s outfit.
8.3.7.3 Application of the requirements to different classes of dangerous goods:
Certification for
carriage of solid dangerous bulk
cargoes covers only those cargoes
listed in Appendix
B of the BC Code except
cargoes of MHB. Other
solid dangerous bulk cargoes may only be permitted subject to acceptance by the Administrations involved.
(Unified Interpretation - MSC/Circ. 1120)
8.4 Ships carrying explosives
8.4.1 L.S. Regulation 102(1) contains
the requirements for ships which
carry explosives of such nature and such quantity as are not permitted to be carried in passenger ships by Regulation 16(1)
of the Merchant
Shipping (Dangerous Goods and
Marine Pollutants) Regulations 1997.
8.4.2 In all cases
reference should be made to MSN 1706 'The Carriage of Military and Commercial Explosives' and the 'International
Maritime Dangerous Goods Code' (IMDG Code).
8.5 Vehicle, special category and ro-ro spaces
8.5.1 Fire
extinguishing
8.5.1.1 Fire
protection of weather
decks (SOLAS II-2 Reg 20.4 and 20.6)
The requirements for
a fixed fire extinguishing system, fire detection, foam applicators and
portable extinguishers need not apply to weather decks used for the carriage of
vehicle with fuel in their tanks.
(IACS Unified
Interpretation SC 73)
8.5.1.2 Portable fire extinguishers on weather decks
used as ro-ro cargo space
(SOLAS II-2 Reg
20.2.6.1)
The requirements set
out in this regulation need not to be applied to weather decks used as ro-ro
cargo spaces.
(Unified
Interpretation - MSC/Circ. 1120)
8.5.1.3 Portable fire-fighting appliances in cargo
holds loaded with vehicles with fuel in their tanks (SOLAS II-2 Reg 20.6.2)
Cargo holds, loaded
with vehicles with fuel in their tanks and stowed in open or closed containers
need not to be provided with the portable fire extinguishers, waterfog
applicators and foam applicator unit.
(IACS Unified
Interpretation SC 205)
8.5.2 Sources of ignition
8.5.2.1 To
prevent ignition of flammable
vapours, the electrical equipment less than 450 mm from the deck
should be of certified safe type and wiring, if fitted,
should be suitable for use in zone 1 areas (gas group II(A) and temperature class
T3), as defined by the IEC.Refer to IEC Publication 60079 Part 14 for types of protection suitable for use in Zone 1 areas.
8.5.2.2 Electrical equipment fitted above a height of 450mm from the deck:
For equipment above a
height of 450 mm above deck the degree of protection of electrical equipment
required by this regulation will be realized:
.1 by an enclosure of
at least IP 55 as defined in IEC Publication
600529 -
Classification of Degree
of Protection Provided
by
Enclosures; or
.2 by apparatus for
use in zone 2 areas as defined in Publication
60079 -
Electrical Apparatus for
Explosive Gas Atmospheres
(Temperature class
T3). (Unified Interpretation - MSC/Circ. 1120)
8.5.2.3 Electrical equipment and wiring in exhaust
ventilation ducts:
1 The electrical equipment referred to in
these regulations should be of certified safe type and wiring, if fitted, and
should be suitable for use in zone 1 areas as defined in IEC Publication 60079
- Electrical Apparatus for Explosive Gas Atmospheres (Gas group II A and
temperature class T3).
2 Exhaust fans should be of non-sparking
type in accordance with
IACS Requirement F
29, as revised. (Unified Interpretation - MSC/Circ. 1120)
8.5.3 Ventilation
8.5.3.1 Capacity of ventilation systems (SOLAS II-2 Reg 20.3.1.1)
Reference is made to
MSC/Circ.729 - Design guidelines and operational recommendations for
ventilation systems in ro-ro cargo spaces.
(Unified
Interpretation - MSC/Circ. 1120)
8.5.3.2 Alarm in case of loss of ventilation capacity (SOLAS II-2 Reg
20.3.1.3)
The requirement to
indicate any loss of ventilating capacity is considered complied with by an
alarm on the bridge, initiated by fall-out of starter relay of fan motor.
(Unified
Interpretation - MSC/Circ. 1120)
8.5.4 Horizontal fire zone concept
(SOLAS II-2 Reg
20.2.2.1)
The "total
overall clear height" is the sum of distances between deck and web frames
of the decks forming one horizontal zone.
(Unified
Interpretation - MSC/Circ. 1120)
8.6 Offshore support
vessels
8.6.1 Carriage of flammable liquids
These may be engaged in oil recovery, well stimulation, offshore supply work or similar operations. When it is intended
to construct or convert such vessels for the carriage of flammable liquids in
bulk a submission should be made to
Headquarters at an early stage. The requirements
for oil recovery vessels
are set out in a code of
practice entitled - “Code of Practice For Vessels Engaged in Oil Recovery
Operations”, MSN 1663 refers. Other
vessels used intermittently for the carriage
of flammable liquids in
bulk will be treated in a similar
manner.
8.6.2 Carriage of dangerous goods and noxious
liquids
The special nature of
offshore support vessels has been recognised and MGN
282 contains
permissible variations to the normal requirements for carriage of packaged
dangerous goods. In addition MSN 1458 contains a general exemption from the UK
regulations for noxious liquid substances, dangerous goods and marine
pollutants if Resolution A673(16) “Guidelines for the Transport and Handling of
Limited Amounts of Hazardous and Noxious Liquid Substances in Bulk on Offshore
Support Vessels” is complied with. These guidelines have been amended by MEPC.
158(55), MSC.184(79) and MSC.236(82).
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