October 2018

Remote Inspection Technique Systems (RITS) Assessment Standard for use on LR Class Surveys of Steel Structure

Document HistoryDate: Notes:

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© Lloyd’s Register, 2018 .

Contents Section 1 Introduction/application ..................................................................................................................................... 1

1.1 General ................................................................................................................................................................... 1

1.2 Scope ...................................................................................................................................................................... 1

1.3 RITS types .............................................................................................................................................................. 1

1.4 Terms and definitions ............................................................................................................................................. 2

Section 2 Specification ...................................................................................................................................................... 4

2.1 General ................................................................................................................................................................... 4

2.2 Performance criteria ............................................................................................................................................... 4

Section 3 Performance requirements for RITS ................................................................................................................. 7

3.1 Navigation and access ............................................................................................................................................ 7

3.2 Defect detection ...................................................................................................................................................... 7

3.3 Data ...................................................................................................................................................................... 12

Section 4 RITS performance tests .................................................................................................................................. 13

4.1 Introduction ........................................................................................................................................................... 13

4.2 Navigation and access .......................................................................................................................................... 13

4.3 Defects .................................................................................................................................................................. 13

4.4 Tank testing .......................................................................................................................................................... 15

4.5 Data ...................................................................................................................................................................... 15

Section 5 RITS certification ............................................................................................................................................. 16

5.1 Statement of Capability ......................................................................................................................................... 16

Appendix 1 – Statement of Capability of a remote inspection technique system (RITS) for use on Classification Periodic Surveys ................................................................................................................................................................ i

1

Section 1 Introduction/application

1.1 General

1.1.1 This standard specifies testing and acceptance criteria for assessing and quantifying the capabilities of a remote inspection technique system (RITS) in performing inspections of steel structure on ships and floating offshore assets in service, when those inspections are being used toward the credit of Periodic Surveys as required by Lloyd’s Register (LR).

1.1.2 On completion of testing of the RITS in accordance with this standard and to the attending Surveyor’s satisfaction, a Statement of Capability may be issued by LR.

1.2 Scope

1.2.1 This standard sets down assessment criteria relating to the use of a RITS to perform inspection of steel structure for the purpose of identifying and quantifying defects within that structure. This standard does not deal with the assessment of quality aspects or safety aspects of RITS and their operation, nor does this standard deal with the approval of service suppliers.

Figure 1.1.1 Typical structure of a bulk carrier cargo hold and an oil tanker cargo oil tank

1.3 RITS types

1.3.1 For the purposes of this standard, RITS delivery platform types can be categorised as below: • UAV – unmanned aircraft/aerial vehicle• ROV – remotely operated vehicle used underwater• Crawler – robotic platform able to move around structure by remaining attached to the structure• Fixed – sensor deployed in a fixed location• Other.

1.3.2 These may be tethered or untethered. For the purposes of undertaking inspections RITS may use a variety of sensors to examine the structure and discern defects. Typical sensors deployed by RITS are:

• Normal visual light range cameras• Infrared/thermal cameras• Stereoscopic (3D) cameras• LIDAR• UT TM probes• SONAR.

1.3.3 As a system, a RITS includes associated support equipment (e.g. for a UAV platform this will include ground control station, data links, telemetry, communications and navigation equipment), sensors and any data analytics capability.

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1.4 Terms and definitions 1.4.1 Edge corrosion – local corrosion at the free edges of plates, stiffeners, primary support members and around openings.

Figure 1.1.2 Diagram of typical edge corrosion

1.4.2 Geolocation – attribution of data to a specific structural element and location within the vessel. 1.4.3 Grooving corrosion – typically local material loss adjacent to weld joints along abutting stiffeners and at stiffener or plate butts or seams.

Figure 1.1.3 Diagram of typical grooving corrosion

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1.4.4 Inspection – the examination of structure against a specified standard and the identification of results falling outside of specified limits. 1.4.5 LIDAR – light detection and ranging, a remote sensing method that uses light in the form of a pulsed laser to measure ranges, i.e. laser scanning and modelling 1.4.6 Pitting corrosion – scattered corrosion spots/areas with local material reductions which are greater than the general corrosion in the surrounding area.

Figure 1.1.4 Diagram of typical pitting percentages 1.4.7 RITS – remote inspection technique system including sensors, associated support equipment, ground control station, data links, telemetry, communications and navigation equipment. 1.4.8 SRB – sulphur-reducing bacteria. 1.4.9 Survey – the examination of structure, with the results being compared against a specified standard. Results falling outside the specified limits are considered and decisions are made on the repairs required, deferment of repairs and the continued use of that structure. 1.4.10 UT TM – ultrasonic testing thickness measurement, gauging the thickness of material using an ultrasonic probe.

20% scattered

30% scattered

40% scattered

50% scattered

4

Section 2 Specification 2.1 General 2.1.1 For the purposes of testing and certification against this standard, prior to testing the following performance criteria are to be specified by the manufacturer/vendor:

• The inspection types for which the RITS has been designed to perform; • Any areas of the specified inspections that the RITS has not been designed to examine; • The defect types for which the RITS has been designed to find/identify; • The defect types for which the RITS has been designed to quantify/size; • The lighting requirements; • The required structural condition for performing the specified inspections; • The level of automation for navigation; • The level of automation for data collection/analytics.

2.2 Performance criteria 2.2.1 The performance criteria can be further detailed as below:

a. RITS inspection types for Classification Surveys: • General external surveys (in air); • Overall survey of cargo holds – hatch covers open; • Overall survey of enclosed spaces; • Close-up survey of cargo holds – hatch covers open; • Close-up survey of enclosed spaces; • Thickness measurement of enclosed spaces; • Thickness measurement of non-enclosed spaces; • In-water mooring chain visual inspection up to a depth (to be stated); • Mooring chain thickness measurement up to a depth (to be stated); • Tank testing.

b. Lighting: • Daylight, e.g. external or in a cargo hold with hatch covers open; • Well-lit by artificial light separate to the RITS; • Using only RITS mounted lighting.

c. Condition of structure:

• Clean; • Coated/uncoated; • Dirty, such as corrosion scale debris or mud; • Adhered scale corrosion; • Corrosion deposits, such as SRB deposits covering pits; • Cargo residue; • Water/liquid; • Coverings, such as linings or ceilings.

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Figure 1.2.1 Typical condition of a double bottom ballast tank prior to cleaning

Figure 1.2.2 Typical cargo residue in a bulk carrier cargo hold

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d. Types of defect found in steel structures: • Cracking; • Deformation; • Coating breakdown; • Corrosion.

e. Levels of automation:

• Navigation:

o Manual control; Control of the sensor delivery platform is manual;

o Semi-autonomous control; Sensor delivery platforms with some automatic control capability assisting manual input, e.g. on a UAV or ROV with altitude hold, position hold and collision avoidance/mitigation

o Fully autonomous; Sensor delivery platforms with fully automatic control able to navigate independently without human intervention.

• Sensor operation: o Sensor operation manual; o Sensor operation semi-autonomous; o Sensor operation fully autonomous.

• Data analytics:

o Manual review of data post inspection; o Manual live review of data during inspection; o Automated data analytics post inspection.

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Section 3 Performance requirements for RITS 3.1 Navigation and access 3.1.1 For each specified inspection type a RITS is to be able to access for inspection the specified structural areas. The inspection types are given in Ch 1, 2.2 Performance criteria. If there are any areas the RITS is unable to access for the specified inspection then these areas will be listed as exclusions on the Statement of Capability issued by LR on completion of testing. 3.1.2 For a full examination of structure, a RITS is to be able to access for examination all of the structural areas required for each inspection type specified. For each structural element this means the capability to examine from all required sides. 3.1.3 For a full inspection of a tank this will include: • Overhead structure (e.g. deck transverse, underside of a stringer, underside of a horizontal bracket); • Tank bottom plate and associated structure (e.g. bottom shell, transverse web frames, longitudinals); • Behind structure (e.g. behind the face plate of a stinger or longitudinal); • Sounding pipe and its striking plate; • Under suction foot; • Cross connection tunnels/ducts; • Outfitting (e.g. any extended spindles, valves, sea connections, penetrations, piping, ladders).

Figure 1.3.1 Example of tank suction foot 3.1.4 The areas that a RITS is capable of accessing will depend on its design navigation capability. For a RITS that is designed to only support an attending Surveyor during surveys then the RITS will only be required to access areas inaccessible to the Surveyor. For a RITS that is designed to be fully autonomous, with no Surveyor intervention, the RITS is to be capable of accessing all areas required for a given Classification Survey.

3.2 Defect detection 3.2.1 For the specified structural conditions and lighting conditions a RITS is to be capable of finding/identifying the specified defects in the steel structure of ships and floating offshore installations and in addition, if specified, is to be capable of quantifying/measuring those identified defects. 3.2.2 Cracking Cracking can occur in structure as a result of fatigue at structural connections, as a result of structural overload and impact or from latent defects in parent material or welds.

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When specified, a RITS is to be able to identify cracks in any part of the structure being examined and in addition, if specified, is to be capable of quantifying/measuring those identified cracks. Identification and measuring can either be performed manually or by autonomous means.

Figure 1.3.2 Example of crack in a bottom shell longitudinal 3.2.3 Deformation Deformation may be present in the structure from new build. Permanent structural deformation can be caused on ships in service by buckling from impact, or from overload by compressive forces or shear forces. Structural deformation can also be caused by tank testing. When specified, a RITS is to be able to identify deformation in any part of the structure being examined and in addition, if specified, is to be capable of quantifying/measuring the deformation. Identification and measuring can either be performed manually or by autonomous means.

Figure 1.3.3 Typical structural deformation

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3.2.4 Coating breakdown The coating condition in tanks is required to be assessed. For class, coating condition is defined as: GOOD: Condition with spot rusting on less than 3 per cent of the area under consideration without visible failure

of the coating. Rusting at edges or welds should be on less than 20 per cent of edges or weld lines in the area under consideration.

FAIR: Condition with breakdown of coating or rust penetration on less than 20 per cent of the area under consideration. Hard rust scale should be less than 10 per cent of the area under consideration. Rusting at edges or welds should be on less than 50 per cent of edges or weld lines in the area under consideration.

POOR: Condition with breakdown of coating or rust penetration on more than 20 per cent or hard rust scale on more than 10 per cent of the area under consideration or local breakdown concentrated at edges or welds on more than 50 per cent of edges or weld lines in the area under consideration.

Figure 1.3.4 Example of good coating

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Figure 1.3.5 Example of fair coating

Figure 1.3.6 Example of poor coating

When specified, a RITS is to be able to identify coating breakdown on any part of the structure being examined and to assess its condition against the class defined criteria. Coating condition assessment can either be performed manually or by autonomous means.

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3.2.5 Corrosion Corrosion can manifest in steel structure in the form of general wastage, edge wastage (knife-edging), grooving and pitting. When specified, a RITS is to be able to identify corrosion in any part of the structure being examined and in addition, if specified, is to be capable of measuring the thickness of each structural element at any point/location. Identification and thickness measuring can either be performed manually or by autonomous means.

Figure 1.3.7 Example of corrosion in ballast tank

Figure 1.3.8 Example of corrosion in ballast tank

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3.3 Data 3.3.1 Sensor calibration The sensors deployed by the RITS are to be:

• Capable of calibration for the finding/identification of the specified defects. • When specified, capable of calibration for the quantification/measuring of defects.

3.3.2 Collection/analytics: On a RITS where data is stored for review post inspection:

• It is to be geolocated. • It is to be presented in a format acceptable to the Surveyor. • It is to be of a quality that enables the Surveyor to discern any defects present.

The design requirements for data geolocation and data formatting will depend on the level of automation for data collection and data analytics.

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Section 4 RITS performance tests 4.1 Introduction 4.1.1 Testing is to be carried out against the specification. Tests are to be performed in order to demonstrate that the RITS is capable of performing the specified inspection types and is capable of being used to find/identify the specified defects, and if applicable, is capable of quantifying/measuring those identified defects. 4.1.2 The testing is to be carried out in an environment that replicates the environment of the specified survey type(s) for which the RITS is to be certified to conduct inspections; this includes the lighting conditions and the condition of the space/structure. Alternatively the testing may be carried out on site/on location. The test environment, whether actual or replicated, is to contain the specified defects. 4.1.3 Testing is to fully demonstrate the autonomous capabilities of the RITS. 4.1.4 Prior to testing, a test plan is to be submitted to LR for review and acceptance. The test plan is to include the location at which the tests are to be held (i.e. a test facility or ship’s name), a test programme, details of the prepared defects and it is to specify the performance criteria against which the RITS is to be assessed. 4.1.5 The tests are to be witnessed by an attending LR Surveyor and are to be conducted to the satisfaction of the attending Surveyor. 4.1.6 For certification in accordance with this standard, as a minimum the following capabilities of the RITS are to be assessed by testing: 4.2 Navigation and access 4.2.1 The manufacturer/vendor is to specify:

• The types of inspections that the RITS is designed to perform. • The lighting conditions in which the RITS is designed to conduct inspections. • The design manual/autonomous navigational capabilities of the RITS.

4.2.2 The testing is to demonstrate that the RITS is able to access and illuminate the specified areas/structure in order that adequate and meaningful examination may be performed. 4.3 Defects 4.3.1 The manufacturer/vendor is to specify:

• The condition of the steel structure on which the RITS is designed to perform inspections; • The lighting conditions in which the RITS is designed to conduct inspections; • The defect types for which the RITS has been designed to find/identify; • The defect types for which the RITS has been designed to quantify/measure; • The design manual/autonomous data collection capabilities of the RITS; • The design manual/autonomous data analytics capabilities of the RITS.

4.3.2 The RITS is to be tested to demonstrate that it can be used to find/identify the specified defects. 4.3.3 When specified, the RITS is to be tested to demonstrate that it can be used to quantify/measure those defects.

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4.3.4 Defect test criteria

a. Cracking

i. Identification of cracks: Testing is to demonstrate that the RITS can be used to find/identify a longitudinal crack in the fillet weld of a bracket toe connection.

ii. Quantification/measuring of cracks:

Testing is to demonstrate that the RITS can measure the length of a longitudinal crack in the fillet weld of a bracket toe connection, with crack dimensions of 0,5 mm gape (tolerance −0,25 mm to +0,75 mm) and 50 mm length (tolerance 25 mm to 100 mm). Note some limited variation in these values is permitted at the discretion of LR.

Figure 1.4.1 Diagram of crack in fillet weld of bracket toe

b. Structural deformation

i. Identification of deformation: Testing is to demonstrate that the RITS can be used to find/identify deformation of structural members and deformation of plating.

ii. Quantification/measuring of deformation:

Testing is to demonstrate that the RITS can be used to measure deflection of plating of 100 mm over a 4000 mm span and a 50 mm offset of a longitudinal stiffener edge over a 2000 mm length. Note these measurements are approximate and some limited variation is permitted at the discretion of LR.

c. Coating breakdown

i. Identification of coating breakdown:

Testing is to demonstrate that the RITS can be used to find/identify coating breakdown on plating and structural members.

ii. Quantification/measuring of coating breakdown:

Testing is to demonstrate that the RITS can be used to quantify coating breakdown on plating and structural members in accordance with the following criteria:

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Good Fair Poor Breakdown of coating or area rusted (see Note 1) <3% (see Note 3) 3–20% >20% Local breakdown of coating or rust on edges (see Note 2) <20% 20–50% >50% Local breakdown of coating or rust on weld lines (see Note 2) <20% 20–50% >50% Note 1. % is the percentage calculated on basis of the area under consideration Note 2. % is the percentage calculated on basis of edges or weld lines in the area under consideration Note 3. Spot rusting, i.e. rusting in spot without visible failure of coating.

d. Corrosion

i. Identification of corrosion: Testing is to demonstrate that the RITS can be used to find/identify the following types of corrosion:

• General wastage • Edge wastage (knife-edging) • Grooving • Pitting

ii. Quantification/measuring of corrosion:

Testing is to demonstrate that the RITS can be used to quantify/measure corrosion on plating and structural members in accordance with the following criteria:

• General wastage – material thickness to be gauged to 0.1 mm accuracy • Edge wastage (knife-edging) – material thickness to be gauged to 0.1 mm accuracy • Grooving – depth and width of grooving to be measured to 1.0 mm accuracy • Pitting – pitting intensity is to be ascertained and quantified as a percentage of the area under

consideration. Depth of pitting to be gauged to 0.1 mm accuracy Notes

• Measurement of steel thickness is to be of sound material only and is not to include the thickness of any coatings, dirt or corrosion deposits (e.g. scale).

• Measurement of grooving depth and pitting depth is to be taken through to sound material, thus the depth

measurement is not to be reduced by dirt or corrosion deposits. 4.4 Tank testing 4.4.1 The manufacturer/vendor is to specify:

• The RITS is designed to perform tank testing inspections. 4.4.2 Testing is to demonstrate that the RITS can be used to:

• Find and identify leaks in the watertight boundaries being tested; • Measure deflection in watertight boundaries to an accuracy of 10 mm.

4.5 Data 4.5.1 Sensor calibration Testing is to demonstrate that the sensors deployed by the RITS are:

• Capable of calibration for the finding/identification of defects; • When specified, capable of calibration for the quantification/measuring of defects; • Capable of calibration prior to each inspection.

4.5.2 Collection/analytics On a RITS where a Surveyor views data in a live format, the tests carried out are to demonstrate that the presentation of data is of a quality that enables the attending Surveyor to discern any defects present. On a RITS where data is stored, tests are to be carried out to demonstrate that the data collected by the RITS is correctly geolocated, is presented in a format acceptable to the Surveyor and is of a quality that enables the attending Surveyor to discern any defects present and their location.

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Section 5 RITS certification 5.1 Statement of Capability 5.1.1 On completion of testing of the RITS in accordance with this standard and to the attending Surveyor’s satisfaction, a Statement of Capability (see Appendix 1) may be issued by LR to state the performance criteria against which the RITS has been satisfactorily tested. 5.1.2 The Statement will be for a named RITS, it will include the RITS type, the sensors deployed and their specification. 5.1.3 The Statement will list:

• Inspection types for Classification Surveys; • Any areas unable to access on those inspections – exclusions; • Data capture/collection associated with the sensors; • Data review/analytics methods associated with the RITS; • Lighting type; • Condition of structure/space; • Defect type finding/identification capability; • Defect type quantification/measuring capability; • Automation capabilities relating to

o Navigation; o Data collection; o Data analytics.

5.1.4 An annex is to be added to the Statement of Capability detailing the sensor calibration methods. 5.1.5 Any change in the design and capability of the RITS, which impacts on the performance criteria against which the RITS has been tested, may invalidate the Statement of Capability and mean retesting is required. Such changes are to be notified to LR for review and for a decision on whether or not retesting of the RITS is required.

Appendix 1 – Statement of Capability of a remote inspection technique system (RITS) for use on Classification Periodic Surveys Note: The light grey text in the defined fields on the 'Statement of Capability' is provided for example purposes only and should not be reproduced.

DRAFT STATEMENT OF CAPABILITY

Statement no: Page 1 of 2

STATEMENT OF CAPABILITY OF A REMOTE INSPECTION TECHNIQUE SYSTEM (RITS) FOR USE ON CLASSIFICATION PERIODIC SURVEYS

Office: Date: Test Dates First: Final:

RITS Manufacturer: e.g. Aerodrone Marine Services RITS Type : e.g. Nimbus 2000 Tethered UAV

Sensors Deployed Type Name Cracking Visual light range stills and video

camera Kodak Instamatic

Structural Deformation

Light Detection and Ranging (LIDAR) Laser Imaging

Coating Breakdown Visual light range stills and video camera

Kodak Instamatic

Corrosion Visual light range stills and video camera

Kodak Instamatic

This statement is issued to <INSERT NAME OF COMPANY> to certify that the undersigned Surveyor to Lloyd’s <ENTITY> did, at their request, attend <PLACE> on the above date(s) for the witness of testing on the aforementioned RITS in accordance with Lloyd’s Register’s ‘Remote Inspection Technique Systems (RITS) - Assessment Standard for use on LR Class Periodic Surveys of Steel Structure’.

The testing was completed satisfactorily and found acceptable for the performance of the below indicated inspections of steel structure on ships and floating offshore assets in service in accordance with the criteria specified on page two of this statement, when those inspections are being used toward the credit of periodic surveys as required by LR: INSPECTION TYPE APPLICABLE EXCLUSIONS* General external surveys (in air) Yes N/A Overall survey of cargo holds – hatch covers open Yes Yes Overall survey of enclosed spaces Yes Yes Close-up survey of cargo holds – hatch covers open Yes Yes Close-up survey of enclosed spaces Yes Yes Thickness measurement of enclosed spaces Yes No Thickness measurement of non-enclosed spaces Yes No In-water mooring chain visual inspection up to a depth (to be stated) No N/A Mooring chain thickness measurement up to a depth (to be stated) No N/A Tank testing Yes No

Surveyor to Lloyd’s Register EMEA a member of Lloyd’s Register Group

*Exclusions (areas the RITS is unable to access for inspection): Free Text Field – e.g. Under Elephants Foot, underside and behind stiffener flanges, etc.

Statement no. RITS COMPLIANCE CRITERIA Page 2 of 2

DEFECT TYPE – CRACKING

LIGHTING CONDITION OF STRUCTURE NAVIGATION SENSOR

OPERATION MEASURE / QUANTIFY DATA ANALYTICS

Daylight Clean X Manual X Manual Y / N Y Manual review of data post inspection X

Artificial light

Coated X Semi-autonomous

Semi-autonomous X Manual live review of

data during inspection

RITS mounted X Dirty Fully

autonomous Fully

autonomous Automated data

analytics

No lighting Adhered scale Corrosion deposits Cargo residue Water/liquid Coverings DEFECT TYPE – STRUCTURAL DEFORMATION

LIGHTING CONDITION OF STRUCTURE NAVIGATION SENSOR

OPERATION MEASURE / QUANTIFY DATA ANALYTICS

Daylight Clean Manual Manual Y / N Y Manual review of data post inspection

Artificial light

Dirty X Semi-autonomous

Semi-autonomous X Manual live review of

data during inspection X

RITS mounted

Adhered scale X Fully autonomous X Fully

autonomous X Automated data analytics

No lighting X Corrosion deposits X Cargo residue X Water/liquid Coverings DEFECT TYPE – COATING BREAKDOWN

LIGHTING CONDITION OF STRUCTURE NAVIGATION SENSOR

OPERATION MEASURE / QUANTIFY DATA ANALYTICS

Daylight Clean X Manual Manual Y / N Y Manual review of data post inspection

Artificial light X Dirty Semi-

autonomous Semi-

autonomous X Manual live review of data during inspection X

RITS mounted

Adhered scale Fully autonomous X Fully

autonomous X Automated data analytics

No lighting Corrosion deposits Cargo residue Water/liquid Coverings DEFECT TYPE – CORROSION LIGHTING CONDITION OF

STRUCTURE NAVIGATION SENSOR OPERATION

CORROSION TYPE

MEASURE DATA ANALYTICS

Daylight Clean X Manual Manual General Wastage X Y / N Y Manual review of

data post inspection

Artificial light X

Dirty

Semi-autonomous

Semi-autonomous

Edge Wastage X Y / N Y

Manual live review of data during inspection

RITS mounted Coated X

Fully autonomous

X Fully autonomous

X Grooving Y / N Y

Automated data analytics X

No lighting

Able to measure through adhered scale

Pitting X Y / N Y

Able to measure through corrosion deposits

Cargo residue Water/liquid Coverings

iv

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