Section
1 General
1.1 Frequency of surveys
1.1.1 The requirements of this Chapter are applicable to the Periodical Surveys
set out in Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys.
Except as amended at the discretion of the Classification Committee, the periods
between such surveys are as follows:
- Annual Surveys, as required by Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.1.
- Intermediate Surveys as required by Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.2.
- Bottom Surveys as required by Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.3 and Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.4.
- Special Surveys at five-yearly intervals,
see
Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.7, for alternative
arrangements, see also
Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.9, Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.10 and Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.11.
- Complete Surveys of machinery at
five-yearly intervals, see
Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.16.
1.1.2 When it has been agreed that the complete survey of the hull and
machinery may be carried out on the Continuous Survey basis, all compartments of the
hull and all items of machinery are to be opened for survey in rotation to ensure
that the interval between consecutive examinations of each part will not exceed five
years, see
Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.10 and Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.18. The requirements of Pt 1, Ch 3, 1.1 Frequency of surveys 1.1.1Pt 1, Ch 3, 1.1 Frequency of surveys 1.1.1.(a) to Pt 1, Ch 3, 1.1 Frequency of surveys 1.1.1.(c) are also to be complied with.
1.1.4 For the frequency of surveys of boilers and other pressure vessels,
steam pipes, screwshafts, tube shafts, propellers and thrusters, see Pt 1, Ch 3, 10 Boilers, see also 1.1.5.
1.2 Surveys for damage or alterations
1.2.1 At any time when a unit is undergoing alterations or damage repairs, any
exposed parts of the structure normally difficult to access are to be specially
examined, e.g., if any part of the main or auxiliary machinery, including boilers,
insulation or fittings, is removed for any reason, the steel structure in way is to
be carefully examined by the Surveyor, or when cement in the bottom or covering on
decks is removed, the plating in way is to be examined before the cement or covering
is relaid.
1.3 Unscheduled surveys
1.3.1 In the event that LR has cause to believe that its Rules and Regulations
are not being complied with, LR reserves the right to perform unscheduled surveys of
the hull, machinery, or drilling/process plant and the applicable statutory
requirements, whether or not the appropriate statutory certificate has been issued
by LR.
1.3.2 In the event of significant damage or defect affecting any unit, LR
reserves the right to perform unscheduled surveys of the hull structure or machinery
of other similar units classed by LR and deemed to be vulnerable.
1.4 Surveys for the issue of Convention
Certificates
1.4.1 Surveys are to be held by LR when so appointed, or by the Exclusive
Surveyors to a National Administration or by an IACS Member, when so authorised by
the National Authority, or, in the case of Cargo Ship Safety Radio Certificates or
Safety Management Certificates, by any organisation authorised by the National
Authority. In the case of dual classed units, Convention Certificates may be issued
by the other Society with which the unit is classed, provided this is recognised in
a formal Dual Class Agreement with LR and provided the other Society is also
authorised by the National Authority.
1.5 Definitions
1.5.2
Critical areas are locations vulnerable to substantial corrosion, buckling
and/or fatigue cracking.
1.5.3 A ballast tank is a tank which is used solely for salt-water
ballast. A space which is used for both the storage of liquids and salt-water
ballast will be treated as a salt-water ballast tank when substantial corrosion has
been found in that space.
1.5.4 Preload Tank is a tank within the hull of a self-elevating unit.
These tanks are periodically filled with salt water ballast and used to preload the
footings of the unit prior to commencing drilling operations. Preload Tanks are
considered equivalent to Ballast Tanks.
1.5.5
Spaces are separate compartments such as tanks, pump-rooms, cofferdams and
void spaces bounding cargo holds, decks and outer hull.
1.5.6 An Overall Survey is a survey intended to report on the overall
condition of the hull structure and to determine the extent of additional Close-up
Surveys as necessary.
1.5.7 A Close-up Survey is a survey where the details of structural
components are within the close visual inspection range of the Surveyor, i.e.,
normally within reach of hand.
1.5.8
Representative spaces are those which are expected to reflect the condition
of other spaces of similar type and service and with similar corrosion prevention
systems. When selecting representative spaces, account should be taken of the
service and repair history on board and identifiable Critical Structural Areas.
1.5.9 Enclosed space. An enclosed space is any place of an enclosed
nature where there is a risk of death or serious injury from hazardous substances or
dangerous conditions. Examples include, but are not limited to: boilers, pressure
vessels, cargo spaces (cargo holds or cargo tanks), cargo space stairways, ballast
tanks, double bottoms, double hull spaces, fuel oil tanks, lube oil tanks,
sewage-tanks, pump-rooms, compressor rooms, cofferdams, void spaces, duct keels,
inter-barrier spaces, engine crankcases, excavations and pits.
1.5.10
Substantial corrosion is wastage of individual plates and stiffeners in
excess of 75 per cent of allowable margins, but within acceptable limits.
1.5.11 A protective coating is normally a full hard protective coating.
This is usually to be an epoxy coating or equivalent.
1.5.12 An independent double bottom tank is a double bottom tank which is
separate from topside tanks, side tanks or deep tanks.
1.5.13
NDE is Non-Destructive Examination, consisting of visual examination and
Non-Destructive Testing (NDT).
1.5.14
Coating condition is defined as follows:
GOOD. Condition with only minor spot rusting.
FAIR. Condition with local breakdown of coating at edges
of stiffeners and weld connections and/or light rusting over 20 per cent or more of
areas under consideration, but less than as defined for poor condition.
POOR. Condition with general breakdown of coating over 20
per cent of areas and hard scale at 10 per cent or more of area under
consideration.
1.5.15 A prompt and thorough repair is a permanent repair completed at
the time of survey to the satisfaction of the Surveyor, thereby removing the need
for the imposition of any associated condition of class or recommendation.
1.5.16
Critical structural areas are locations which have been identified from
calculations to require monitoring or from the service history of the subject unit
or from similar units, if applicable, to be sensitive to cracking, buckling or
corrosion which would impair the structural integrity of the unit.
1.5.17 Specially considered (in connection with close-up surveys and
thickness measurements) means sufficient close-up inspection and thickness
measurements are to be taken to confirm the actual average condition of the
structure under the coating.
1.5.18 Excessive Diminution (or excessive corrosion) is an extent of
corrosion beyond allowable limits
1.5.19 Suspect Area are locations showing Substantial Corrosion and/or
are considered by the Surveyor to be prone to rapid wastage.
1.5.20
A natural gas fuel installation comprises the following; fuel bunkering, fuel
storage, fuel processing and fuel delivery to gas fuelled consumers. The scope of
the natural gas fuel installation extends from the bunker manifold to the natural
gas fuelled consumer and includes any re-liquefaction plant and compressors that are
fitted to manage boil off.
1.6 Planned survey programme
1.6.1 A planned survey programme is to be developed by the Owner and submitted
to LR for approval in advance of the first survey, see
Pt 1, Ch 2, 3.5 Existing installations Periodical Surveys 3.5.11 . The programme should include guidance for
control and recording of all relevant aspects of the inspection and replacement
philosophy. In particular, the programme is to include and address the following:
- the overall design configuration;
- field life potential;
- appropriate regulatory requirements;
- main hull structural arrangement plans;
- details of planning, identification and preparation
procedures;
- areas to be surveyed and extent of hull cleaning;
- inspection and testing schedules for all relevant compartments,
equipment and systems;
- inspection methods and procedures;
- extent, frequency and circumstances for application of
NDE;
- locations for non-destructive testing;
- schedule for overall survey, close-up survey and thickness
measurement;
- condition of coatings and corrosion prevention systems;
- methods for reporting and recording of damage or deterioration
found and remedial measures;
- allowable wastage limits (corrosion margins and wear
allowances) for each part of the structure and mooring system.
1.6.2 Particular attention is to be paid to critical areas and also to areas of
suspected damage or deterioration and to repaired areas. Surveys are to take into
account locations highlighted by service experience and the design assessment.
1.6.5 Planned surveys and procedures as agreed by LR will be subject to
revision if found necessary at subsequent surveys or when required by the
Surveyor.
1.6.6 A planned survey programme for installations with riser systems assigned
a PRS notation is to be developed by the Owner and submitted to LR for
approval, see Pt 1, Ch 3, 15 Riser systems.
1.7 Preparation for survey and means of
access
1.7.1 In order to enable the attending Surveyor(s) to carry out the survey,
provision for proper and safe access is to be agreed between the Owner and LR. Tanks
and spaces are to be safe for access, gas free and properly ventilated. Prior to
entering a tank, void or enclosed space, it is to be verified that the atmosphere in
that space is free from hazardous gas and contains sufficient oxygen.
1.7.2 In preparation for survey, thickness measurements and to allow for a
thorough examination, all spaces are to be cleaned, including removal from surfaces
of all loose accumulated corrosion scale. Spaces are to be sufficiently clean and
free from water, scale, dirt, oil residues, etc., to reveal corrosion, deformation,
fractures, damages or other structural deterioration as well as the condition of the
protective coating. However, those areas of structure whose renewal has already been
decided by the Owner need only be cleaned and descaled to the extent necessary to
determine the limits of renewed areas.
1.7.3 Sufficient illumination is to be provided to reveal corrosion,
deformation, fractures, damages or other structural deterioration.
1.7.4 Means are to be provided to enable the Surveyor to examine the structure
in a safe and practical way.
1.7.5 Survey at an offshore location or anchorage may be undertaken when the
Surveyor is fully satisfied with the access, egress and communications arrangements
provided and that the personnel on board are competent in the application and use of
all relevant safety and communications equipment and procedures.
1.7.6 Where soft or semi-hard coatings have been applied, safe access is to be
provided for the Surveyor to verify the effectiveness of the coating and to carry
out an assessment of the conditions of internal structures which may include spot
removal of the coating. When safe access cannot be provided, the soft or semi-hard
coating is to be removed.
1.8 Thickness measurement at survey
1.8.1 This Section is applicable to the thickness measurement of the structure
where required by Pt 1, Ch 3, 2 Annual Surveys Hull and machinery requirements, Pt 1, Ch 3, 3 Intermediate Surveys Hull and machinery requirements, Pt 1, Ch 3, 4 Bottom Surveys In dry dock and In-water Hull and machinery requirements and Pt 1, Ch 3, 5 Special Survey Hull requirements.
1.8.2 Prior to the commencement of the Intermediate Survey and Special Survey,
a meeting is to be held between the attending Surveyor(s), the Owners
representative in attendance, the thickness measurement company representative and
the Master of the unit or an appropriately qualified representative appointed by the
Master or Owner, so as to ensure the safe and efficient conduct of the survey and
thickness measurements to be carried out. See also
Pt 1, Ch 3, 1.6 Planned survey programme 1.6.1.
1.8.3 Thickness measurements are normally to be taken by means of ultrasonic
test equipment and are to be carried out by a firm approved in accordance with LRs
Approval for Thickness Measurement of Hull Structure.
1.8.4 The Surveyor may require to measure the thickness of the material in any
portion of the structure where signs of wastage are evident or wastage is normally
found. Any parts of the structure which are found defective or excessively reduced
in scantlings are to be made good by materials of the approved scantlings and
quality. Attention is to be given to the structure in way of discontinuities.
Surfaces are to be re-coated as necessary.
1.8.5 Thickness measurements are to be taken in the forward and aft areas of
all plates. Where plates cross ballast/cargo tank boundaries, separate measurements
for the area of plating in way of each type of tank are to be reported. In all
cases, the measurements are to represent the average of multiple measurements taken
on each plate and/or stiffener. Where measured plates are renewed, the thickness of
adjacent plates in the same strake is to be reported.
1.8.6 Thickness measurement of units with storage tanks for liquefied gases or
chemicals will be specially considered.
1.8.7 The extent and frequency of thickness measurement on structure with
substantial corrosion will be specially considered. The survey will not be
considered complete until all required thickness measurements have been carried
out.
1.8.8 Thickness measurements are to be witnessed by the Surveyor to the extent
necessary to control the process. This also applies to thickness measurements
carried out while the unit is at an offshore location.
1.8.9 Thickness measurements may be carried out within the 12 months prior to
the due date of the Special Survey.
1.8.10 Where it is required as part of the survey to carry out thickness
measurements for the structural areas subject to Close-up Survey, these measurements
are to be carried out simultaneously with the Close-up Survey.
1.8.11 The Surveyor may extend the scope of thickness measurement if deemed
necessary.
1.8.12 Thickness determination by drilling structural members is not
permitted.
1.8.13 In all cases, the extent of the thickness measurements is to be
sufficient to represent the actual average condition.
1.8.14 A report is to be prepared by the approved firm carrying out the
thickness measurements. The report is to give the location of measurement, the
thickness measured as well as the corresponding original thickness. The report is to
give the date when measurement was carried out, the type of measuring equipment,
names of personnel and their qualifications and is to be signed by the Operator.
1.8.15 The thickness measurement report is to be verified and signed by the
Surveyor and countersigned by an authorising Surveyor.
1.9 Repairs
1.9.1 Any damage in association with wastage over the allowable limit
(including buckling, grooving, detachment or fracture), or extensive areas of
wastage over the allowable limits, which affects or, in the opinion of the Surveyor,
will affect the structural, watertight or weathertight integrity of the unit, is to
be promptly and thoroughly repaired. Areas to be considered include, (where
fitted):
- side shell frames, their end attachments and adjacent shell
plating;
- deck structure and deck plating;
- bottom structure and bottom plating;
- side structure and side plating;
- inner bottom structure and inner bottom plating;
- inner side structure and inner side plating;
- watertight or oiltight bulkheads;
- hatch covers and hatch coamings.
For locations where adequate repair facilities are not available,
consideration may be given to allow the unit to proceed directly to a repair
facility. This may require discharging the cargo and/or temporary repairs for the
intended voyage.
1.9.2 Where it is proposed to defer repairs, a defect criticality assessment is
to be submitted for approval, demonstrating the effectiveness of any mitigation
measures (inter alia monitoring, loading restrictions) and continued
suitability until repaired.
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