oil definition

1

4

= ( 1 -

( 2

-

3 )

+

Figure 1 Shore - Shore Loss

2 ) +

Outturn Loss

( 3 -

4 )

3

2

1

DISCHARGE

Tanker before discharghing

OVERALL ANALYSES OF OUTTURN LOSS

IN TRANSIT

3

Tanker after Loading

LOADING

2

Supplier (B/Lading)

(BILL OF LADING)

CRUDE OIL LOADING TERMINAL

1

TOTAL PHYSICAL AND APPARENT LOSSES (incl. MEASUREMENT ERROR)

4

Receiver (Outtun)

RECEIVERS T ERMINAL (SHORE OUT TURN)

4

DEFINITIONS A glossary of terms used in these procedures is provided in this Chapter. It incorporates terms, which have been approved by ISO/TC 28 for use in connection with crude oil measurements. Clingage: Oil residues which adhere to the surface of tank walk and structures on completion of discharge. Critical zone: The volume close to the bottom of a floating roof tank in which there are complex interactions and buoyancy effects as the floating roof comes to rest on its legs. The zone is usually clearly marked on tank calibration tables and measurements for custody transfer should not be made within it. Density: The ratio of the mass of a substance to its volume. Since density is dependent on temperature and pressure these should be stated. In-transit loss: The difference between the Total Calculated Volume on board a vessel after loading and the Total Calculated Volume on board before discharge. Load on top (LOT): The procedure of commingling the recovered oil slops with the next cargo by loading the cargo on top of the slops. Meter factor: The ratio of the actual volume of liquid passed through a meter to the volume indicated by the meter. Meter K-factor: The number of pulses emitted by a meter whilst unit volume is delivered (usually expressed in pulses/m3). On board quantity (OBQ): All the oil, water, sludge and sediment in the cargo tanks and associated lines and pumps on a ship before loading a cargo commences. Outturn: The quantity of cargo discharged from a vessel, measured by a shore terminal. Outturn certificate: A statement issued by a receiving terminal certifying the outturn. Outturn loss: The difference in Net Standard Volume of oil between the quantity shown on the Bill of Lading and the quantity shown on the Outturn Certificate. The adjusted loss is the Outturn Loss plus the difference between the OBQ and the ROB. Quantity remaining on board (ROB): All the oil, water, sludge and sediment in the cargo tanks and associated lines and pumps on a ship after discharging a cargo has been completed, excluding vapour but including clingage Sediment: Suspended Sediment: Non-hydrocarbon solids present within the oil but not in solution. Bottom Sediment: Non-hydrocarbon solids present in a tank as a separate layer at the bottom. Total Sediment: The sum of the suspended and bottom sediment. Slops: Material collected after such operations as stripping, tank washing or dirty ballast separation It may include oil, water, sediment and emulsions and is usually contained in a tank or tanks permanently assigned to hold such material. Vessel experience factor-loading (VEFL): The adjusted mean value of the VLRs obtained after several voyages (see Appendix C for more details) Vessel experience factor-discharge (VEFD): The adjusted mean value of the VDRs obtained after several voyages (see Appendix C for more details) Vessel load ratio (VLR): The ratio of the quantity (TCV) of oil measured on board a vessel immediately after

loading less the On Board Quantity (OBQ) to the quantity (TCV) measured by the loading terminal, i.e. VLR = Vessel's TCV after loading - OBQ Shore TCV loaded Vessel discharge ratio (VDR): The ratio of the quantity (TCV) of oil measured on board a vessel immediately before discharge less the Quantity remaining on Board (ROB) to the quantity (TCV) measured by the receiving terminal, i.e. VDR = Vessel's TCV before discharge - ROB Shore TCV received

Volume correction factor: A factor dependent upon the oil density and temperature which corrects oil volumes to the standard reference temperature. For crude oil such factors shall be obtained from the API-ASTM-IP Petroleum Measurement Tables. Volumes for dynamic measurement calculations Indicated Volume: The change in meter reading that occurs during transfer through a meter. Gross Volume: The indicated volume multiplied by the appropriate meter factor for the liquid and flow rate concerned, without correction for temperature and pressure. Note.' This includes all water and sediment transferred through the meter. Gross Standard Volume: The gross volume corrected to standard conditions, i.e. 150C and 1 01325 bar. Net Volume. The gross volume minus the volume of water and sediment transferred through the meter. Net Standard Volume: The net volume corrected to standard conditions, i.e. 15~C and 1,01325 bar. Volumes for static measurement calculationsTotal Observed Volume (TOV): The volume of oil including total water and total sediment, measured at the oil temperature and pressure prevailing. This may be either the volume in a tank or the difference between the volumes before and after a transfer. Gross Observed Volume (GOV): The volume of oil including dissolved water, suspended water and suspended sediment but excluding free water and bottom sediment, measured at the oil temperature and pressure prevailing. This may be either the volume in a tank or the difference between the volumes before and after a transfer. Gross Standard Volume (GSV): The volume of oil including dissolved water, suspended' water and suspended sediment but excluding free water and bottom sediment, calculated at standard conditions, i.e., 150C and 1.01325 bar. This may be either the volume in a tank or the, difference between the volumes before and after a transfer. Net Observed Volume (NOV): The volume of oil excluding total water and total sediment, measured at the oil temperature and pressure prevailing This maybe either the volume in a tank or the difference between the volumes before and after a transfer. Net Standard Volume (NSV): The volume of oil excluding total water and total sediment, calculated at standard conditions, i.e. 15°C and 1.01325 bar. This may be either the volume in a tank or the difference between the volumes before and after a transfer. Total calculated Volume (TCV): The gross standard volume plus the free water measured at the temperature and pressure prevailing Water-Dissolved Water: the water contained within the oil forming a solution at the prevailing temperature. Suspended Water: The water within the oil, which is finely, dispersed as small droplets. It may, over a period of time, either collect as free water or become dissolved water, depending on the conditions of temperature and

pressure prevailing. Free Water: The water that exists in a separate layer. It typically lies beneath the oil. Total Water: The sum of all the dissolved, suspended and free water in a cargo or parcel or oil. Water cut or dip: The measured depth of free water lying on the bottom of the tank. Wedge formula: An equation relating the volume of liquid material in a ship's tank to the dip, ship's trim, dipping point location and the tank's dimensions when the ship's calibration tables cannot be applied. To derive the equation, assumption have to be made The major assumption in the derivation is that the material is free flowing and will accumulate in the after end of a tank when the ship is trimmed by the stern. An example is given in Appendix F. Weight conversion factor: A factor, dependent on the density, for converting volume to weight-in-air Such factors shall be obtained from the API-ASTM-IP Petroleum Measurement Tables. Weight-Gross Weight-in-Air: The weight of oil including dissolved water, suspended water and suspended sediment but excluding free water and bottom sediment. •

Net Weight-in-Air: The weight of oil excluding total water and total sediment.

GENERAL PRINCIPLES 3.1

THE PURPOSE OF A CARGO SURVEY

The main purpose of a cargo survey is to provide a certified statement of the quantity and quality of oil loaded or discharged and to draw attention to matters which may be relevant to the protection of the client's interests. The surveyor should advise and assist in minimizing the extent to which procedural and/or measurement errors before, during and after the loading or discharge could affect the quantity and quality of oil recorded on documents issued at a port of loading or discharge. In addition to the above the survey should also serve to assist in minimizing the quantity of oil remaining onboard the vessel after completion of discharge.

3.2 GENERAL RESPONSIBILITIES To achieve the purpose described above, the cargo surveyor must discharge a number of responsibilities, some of a general nature and others of a highly specialized and clearly defined nature. The general responsibilities are described immediately below and the specialized responsibilities form the subject matter of subsequent chapters. 3.2.1 The surveyor shall make himself available in time to carry out (or witness) each stage in the oil transfer which he has been appointed to attend. To carry out the survey properly, more than one surveyor may be required to be in attendance at certain times. 3.2.2 Details of the measurement, sampling, analytical methods and certification referred to in these procedures may be specified separately by interested parties. In the absence of such instructions, equivalent recognized standards and procedures shall be followed. 3.2.3 A formal protest in writing shall be submitted to the terminal operator and/or the master of the vessel whenever: (i) operational or other restrictions make it impossible for the cargo surveyor to follow the procedures in this document, (ii) any conditions of the contract(s) governing the transfer of the cargo are not met. Such protests in writing should be issued when the occasion for protest is first observed and before the vessel sails from the port of loading or discharge. Any observed and unresolved measurement differences between quantities determined by the cargo surveyor and other parties concerned shall be advised in writing to such parties. Any additional comments on any of the events reported under this clause shall be included in the cargo surveyor’s report. 3.2.4 Before any cargo operations commence, the cargo surveyor shall meet all key personnel concerned with such operations to discuss operational plans and procedures relating to the measurement of the cargo. 3.2.5 Any procedure to be performed on board a vessel shall be accomplished with the Master's explicit approval and in the presence of his nominee. For safety reasons, only equipment approved by the Master or terminal operator shall be used. 3.2.6 The cargo surveyor shall comply with all applicable governmental, local port authority and terminal regulations in force at the port of loading or discharge. 3.2.7 With regard to the tank measurements, permission shall be sought from the Master and the terminal's representative to open the vessel's tanks arid the shore tanks respectively for manual measurement. In the event

that permission for the specified operations to be performed is refused or there are other reasons why manual measurements cannot be made written protests shall he made to the Master and/or Terminal representative and the facts recorded in the cargo surveyor's report. On vessels fitted with inert gas systems, prior agreement to permit the surveyor appropriate access shall he obtained from all the responsible parties. 3.2.8 The surveyor's report shall be issued on completion of measurement operations and in accordance with the instructions given in the survey contract 3.2.9 Cargo surveyors should record each occasion when they are required to take measurements tinder conditions which are not conducive to custody transfer accuracy. The following conditions are given as examples of good practice. a) When measurements are made in a vertical cylindrical shore tank liquid depths should never be less than 2 meters. This will ensure that there is sufficient head of liquid to minimize the effect of tank bottom movement where only one dip is employed. b) Where only one tank is involved in the loading or discharge, accurate measurement can be achieved only by ensuring that the change in liquid level between start and completion of the operation is not less than 7 meters. c) A floating roof should never be grounded and a minimum liquid level of 3 meters above any sediment layer shall be maintained at all times to ensure that the roof is not in the critical zone. d) When oil is being metered from a shore tank it is essential to ensure that there is a minimum liquid level of 2 meters so that no air will be entrained in the metering system. e) Where ballasting is taking place at the same time as cargo loading or discharge. It is essential to ensure that proper separation is achieved both on the vessel and on shore All valves should be leak free and twin valve separation or spading between the two operations should be maintained.

3.2.10 Measurement equipment shall be frequently recalibrated (Appendix A refers) and the calibration documents shall be available for inspection.

SAFETY REQUIREMENTS 4.1 GENERAL 4.1.1 The safety precautions given below apply generally and constitute good practice but the list is not necessarily comprehensive. The list shall be read in conjunction with the appropriate national safety regulations, the Institute of Petroleum Model Code of Safe Practice in the Petroleum Industry, or any recognized code in the petroleum industry. The precautions given below shall be taken whenever they do not conflict with local or national regulations which must, in any case, always be followed. Careful consideration shall be given to the nature and known hazards of the material being sampled which will affect the detailed nature of the precautions to be observed. 4.1.2 Personnel shall be made aware of the potential hazards and be given instruction in safety precautions to be observed. 4.1.3 All regulations covering entry into hazardous areas shall be rigorously observed. 4.1.4 Care shall be taken to avoid breathing hydrocarbon vapour during the sampling operations. Protective gloves of hydrocarbon-insoluble materials shall be worn Eye shields or face shields shall be worn where there is a danger of splashing. Additional precautions may be necessary when handling sour crude.

4.2 SAFETY ASPECTS OF EQUIPMENT 4.2.1 The surveyor shall only use equipment which com plies with all safety codes, especially electrical codes. Whenever regulations stipulate that certain equipment, e.g. electronic tapes, shall be earthed while in use, such equipment shall be earthed before and during tank entry and until withdrawn from the tank. 4.2.2 Sample receivers and container shall be designed in accordance with the appropriate national or international standards. Inspection and any pressure testing required shall be performed according to the local regulations by a competent person and such tests shall be recorded Cleaning and leak testing operations shall be performed at regular intervals. 4.2.3 Ropes used for lowering sampling equipment shall bc electrically conductive and shall not be made solely from man-made fibers. Vegetable fibers such as manila or sisal are preferred for this purpose. 4.2.4 Portable metal sampling equipment used in flammable atmospheres shall be of non-sparking metal but not aluminium or aluminium alloys. 4.2.5 Sampling personnel shall be provided with carriers for their equipment so that at least one hand is free. 4.2.6 Lamps and torches shall be of an approved type suitable for the electrical classification of the area. 4.2.7 Suitable clothing and equipment to provide protection against all known hazards associated with the operations being carried out should be worn.

4.2.8 Clothing should be of cotton, linen or wool and the wearing of man-made fibers should be avoided. 4.2.9 Footwear capable of causing sparks shall not be worn in areas where flammable vapours are likely to be present. Rubber footwear is not recommended in dry zones. 4.2.10 It is recommended that in the case of crudes with a high Reid Vapour Pressure, sample bottles be protected with a metal case until the sample is discarded. Such a metal case shall not be fabricated from aluminium.

SAFETY AT SAMPLING POINTS 4.3.1 Sampling points shall be provided which enable samples to be taken in a safe manner. Any potential hazards associated with sampling shall be clearly marked and it is recommended that a pressure gauge should be provided at any point at which pressures above atmospheric might be encountered. 4.3.2 The sampling point and equipment shall be adequately maintained and regularly inspected and records of such maintenance and inspection shall be kept. 4.3.3 Safe access to sampling points, with adequate lighting, shall be provided. Access ladders, stairways, platforms and handrails shall be maintained in a structurally safe and clean condition (i.e. free of oil to prevent slipping hazards) and be regularly inspected by a competent person. 4.3.4 Adequate and safe drainage for all draining and flushing requirements shall be provided. 4.3.5 Any spillages or defects in equipment shall be reported immediately to a competent person. 4.3.6 Care shall be taken to avoid breathing petroleum vapours during sampling operations. 4.3.7 Floating-roof tanks shall be sampled from the top platform whenever practicable, as under certain conditions toxic and flammable vapours may accumulate above the roof. If, exceptionally, permission is granted for anyone to stand on the roof to take samples, the following precautions shall be taken: • Anyone descending onto the roof shall wear a self-contained breathing apparatus; • At least two persons shall remain at the head of the stairway to the roof where they can clearly observe persons on the roof; • The persons descending to the roof shall take the required samples and return to the head of the stairway in the minimum possible time; • If facilities are available, radio communication shall be maintained with the terminal control room. The following are some of the conditions which may render the atmosphere above the roof hazardous: (a) the product contains hydrogen sulphide and/or volatile mercaptans; (b) the roof is not fully floating; (c) the roof-seal is faulty. 4.3.8 All equipment and material used by the cargo surveyor, especially waste or rags, must be removed on completion of the operation.

4. 4 STATIC ELECTRICITY

4.4.1 The following precautions shall be taken to avoid danger from static electricity when sampling tanks containing flammable hydrocarbons stored at temperatures above their flash points or in which a flammable atmosphere of hydrocarbon vapour or mist has been produced. 4.4.2 The contents of storage or vessels' tanks shall not he sampled during filling 4.4.3 When sampling, the sampling line shall be kept earthed at all times to prevent sparking, either by earth connection or by firm contact with the dip hatch. 4.4.4 Each tank shall be earthed and a relaxation time of 30 minutes after completion of transfer or loading into each tank or container must be allowed before introducing any conductive sampling equipment into the tank or container. However, if one or more of the following apply, sampling may take place before the elapse of the 30-minute relaxation time: (a) For a floating-roof tank, the sampling is carried out from a slotted dip pipe. (b) For a fixed-roof tank, the tank is fitted with an earthed floating cover. 4.4.5 Measurement and sampling shall not be carried out during periods of atmospheric electric disturbance or hail storms. 4.4.6 In order to earth any static charges on his person, a surveyor shall touch some part of the tank structure at least 1 m from any tank entry point immediately before carrying out any measurement or sampling operation.

4.5 ENTRY INTO ENCLOSED SPACES . Because of the possibility of oxygen deficiency as well as the presence of hydrocarbon or toxic gas in a cargo tank, cofferdam, double bottom tank or any enclosed space, it is the Master's responsibility to identify such spaces and to establish procedures for safe entry. Surveyors must consult the responsible officer to determine whether entry into such enclosed spaces is permitted. It is the duty of the responsible officer to check the atmosphere in the compartment, ventilate the space, ensure the appropriate procedures are followed, ensure the safety of the personnel concerned, and issue an entry permit. 4.5.1 Suitable notices should be prominently displayed to inform personnel of the precautions to be taken when entering tanks or other enclosed spaces and of any restrictions placed upon the work permitted therein. 4.5.2 No one should enter cargo tanks unless an entry permit has been issued by a responsible officer who has ascertained immediately before entry that the tank atmosphere is in all respects safe for entry Before issuing an entry permit the responsible officer should ensure that: • the appropriate atmosphere checks have been carried out; • effective ventilation will be maintained continuously while men are in the tank; • lifelines and harnesses are ready for immediate use; • approved breathing apparatus and resuscitation equipment are ready for use at the entrance to the tank; • proper clothing and particularly safety helmets are being worn; • where possible, a separate means of access is available for use as an alternative means of escape in an emergency; • a responsible member of the crew is in constant attendance outside the tank in the immediate vicinity of the entrance and in immediate contact with a responsible officer.

The above conditions must be observed fully at all times and upon all occasions In the event of an emergency, under no circumstances should the attending crew member enter the tank before help has arrived. The lines of communication for dealing with emergencies should be clearly established and understood by all concerned 4.5.3 Before entry is allowed into cofferdams, double bottoms or other enclosed spaces, they should be thoroughly ventilated to ensure an adequate oxygen level, and tests should be carried out with an oxygen analyser. An entry permit signed by a responsible officer should be issued. The presence of toxic or flammable gases should always be suspected in cofferdams and double bottoms into which volatile petroleum may have leaked. The same precautions as for entry into cargo tanks should therefore be observed. 4.5.4 Pumprooms, by virtue of their location, design and operation, constitute a particular hazard and therefore necessitate special precautions. No one should enter a pumproom at any time without first obtaining the permission of a responsible officer. It is the duty of the responsible officer in charge of cargo operations to ensure that adequate ventilation of the pumproom has been accomplished, that the atmosphere within the compartment is suitable for entry, and that adequate communication procedures are established and maintained. Notices should be displayed at the pumproom entrance prohibiting entry without prior permission The pumproom life lines and harness should be rigged ready for immediate use. Where possible an unobstructed direct lift should be provided. Approved breathing apparatus and resuscitation apparatus should be available in an accessible location. At no time should a cargo surveyor enter a pump-room unless accompanied by a responsible member of the ship's staff. 4.5.5 It is stressed that entry into tanks which are known to be non-gas free or oxygen deficient can only be permitted in exceptional circumstances and when there is no practicable alternative. In this highly hazardous situation, the personnel involved must be well trained in the use of breathing apparatus and aware of the dangers of removing their breathing apparatus while in the hostile atmosphere. It is recommended that cargo surveyors should never enter into a compartment where such conditions prevail.

MEASUREMENT AND SAMPLING PROCEDURES A number of measurement and sampling procedures may be applied several times during the cargo loadingtransportation-discharge cycle. Accordingly, to avoid repetition in the guidelines these procedures are described in this chapter only. A brief reference to them is then made, as necessary, in the subsequent chapters which detail the sequence of procedures to be applied at loading and discharge. 5.1

AUTOMATIC MEASUREMENT SYSTEMS

By mutual agreement between the parties concerned, automatic tank level gauging and temperature measurement System may be used for custody transfer If automatic systems are used, reference to the terminal's gauge proving records should be made and the completeness or otherwise of these records indicated in the general comments section Whenever possible, the surveyor should take his own measurements and compare these with those recorded by the automatic gauge system. Some terminals do not allow surveyors to take their own measurements. Where this is the case, the surveyor must satisfy himself from the terminal's gauge proving records that the gauges are satisfactory, making an appropriate note in the general comments of his report. Provided that the gauges satisfy the following criteria, gauge readings may be used as the basis for calculating oil quantities. a) The difference between the change in tank level during the transfer measured by automatic level gauge and by manual gauge shall be less than 7 mm; Example:

Level before level after Change in tank level

Automatic level gauge (metres) 20.385 5.425 14.960

Manual metres) 20.405 5.440 14.985

The difference between the change in tank level measured by automatic gauge and by manual gauge is 5 mm: accordingly, the use of the automatic level gauge is acceptable. Note that level comparisons become unreliable in high wind conditions and realistic comparisons can only be made in light wind conditions i.e. up to approximately Beaufort Force 4. Automatic level gauge readings should be recorded: (i) after ensuring that the gauge is floating freely; (ii) at the mean of the highest and lowest readings, if the gauge is oscillating because of tank roof movement. (a) The difference in tank temperature measured by automatic temperature gauge and a manual electronic thermometer shall be less than 0.5°C.

5. 2 GAUGING PROCEDURES 5.2.1 Shore Prior to gauging, determine the nature and quantities of material in the shore lines and the total capacity of the lines, from the vessel's flange to the shore tank(s) to be used. Record what steps were taken to determine that the shore pipeline was full of liquid. Where pipeline quantities represent a significant proportion of the total quantity of oil to be loaded sample should be taken from the pipeline to provide a temperature and density, this being preferable to accepting the records of the previous operation. The terminal should arrange for lines and valves to be set so as to minimize the possibility of cargo being contaminated or lost through other lines and tanks e g as a result of ballasting or deballasting operations or from other loading and discharge activities occurring at the same time. The terminal shall be requested to confirm in writing that all relevant lines and valves are set correctly. Attempt to ascertain the last time valves were

properly and thoroughly tested and the method used for such testing. As a preliminary, check and record whether or not the tank roof is free of excessive quantities of water and debris When appropriate, i.e. after loading and before discharge, confirm that the roof is not grounded or in the critical zone and has undergone no significant change in condition since operations began, e.g. due to heavy rain. Report the reference heights of the shore tanks recorded in the tank calibration tables. Check that the reference height stamped on the tank hatch, i.e. the observed reference height, is the same as that recorded in the tank calibration tables. Ullage measurements, recommended when sludge or debris is lying in a tank, should always be related to the measurement reference mark on that tank. If the tank has been in service or mixed recently, wait for at least half an hour for the liquid level to become constant before commencing gauging. All levels should be recorded only after securing two measurements that agree within 3 millimeters. On tanks having floating roofs, note in the inspection report whether the roof legs are in the high or low position. Water cuts shall be obtained using water finding paste or a portable sonic ullage interface tape. Confirm the reference height by direct measurement and establish also whether the gauging pipe is slotted or not. Ascertain the last time the tank was strapped or calibrated, when the tank was last cleaned or inspected and when any repairs were made to the tank. 5.2.2 On Board Ship If possible, observe the vessel's draft and then record the draft, trim and list. Apply trim and list quantity corrections where applicable, as determined from the vessel's trim and list tables. Record the location of the gauging point of each tank and indicate whether the measurements to be used in the calculations are derived from manual or automatic methods. Record the reference heights of the relevant vessel's tanks quoted in the tank calibration tables. If automatic level gauges are to be used, record the actual stored position readings. Note any difference between these readings and the heights recorded in the tank calibration tables. Request and record an explanation from the Chief Officer for such differences. If there are no differences in stored automatic level gauge readings, then automatic gauges may be used for ullages. Where an automatic gauge malfunctions or shows an incorrect stored reading then the ullage should be determined manually, from the official gauge point. A portable sonic ullage/interface tape should be used for all manual ullage measurements If a steel tape and brass bob are used then the oil cut shall be on the tape and not on the bob. Whatever method is used the ullages are to be recorded to the nearest 5 mm. Water cuts shall be taken while gauging each compartment. Record the type of paste or device used to establish the position of the oil/water interface.

5.3 TEMPERATURE MEASUREMENT It is recommended that a portable electronic thermometer be used for all oil temperature measurements and that it be checked against a reference thermometer before use. For oil depths of 3.5 meters or greater, readings shall be taken at five levels. These shall be at oil depths of one-tenth, three-tenths, five-tenths, seven-tenths and ninetenths. When oil depths are less than 3.5 meters, readings shall be taken at three levels. These shall be at oil depths of one-sixth, three-sixths and five-sixths. All temperature readings should be recorded to the nearest 0.1°C and averaged. If the cargo surveyor is of the opinion that temperature layering is present, then a temperature profile should be obtained by taking temperatures at intervals of 1 meter or less through the depth of oil and averaging them.

5.4 SAMPLING The cargo surveyor is responsible for ensuring that representative samples are drawn at all appropriate stages. Such samples may be retained at the terminal or despatched, often via the vessel, to the receiver. They must be clearly labelled and sealed in such a way that in order to gain access to the sample the first action will be to break the seal. 5.4.1 Shore Tanks Each shore tank to be used in the transfer should be sampled in such a manner as to meet the requirements of interested parties and regulatory agencies. In the absence of specific instructions, the most recent standards on sampling must be followed. (IP Petroleum Measurement Manual, Part VI, Sections 1 and 2 refer.) Tank samples should be analysed individually since this provides a better insight into the condition of the tank

and the reliability of the samples. Compositing of tank samples is not recommended. When it is necessary to homogenize samples in the laboratory for blending and sub-sampling purposes, an appropriate commercially available mechanical mixing device shall be used. Manual shaking for the purpose of homogenization of crude samples is not an acceptable method. The samples shall be tested for quality as specified by interested parties Report analytical methods used for testing, i.e. IP, ISO, ASTM or other industry approved test methods.

5.4.2 Automatic Sampling If it has been agreed that samples shall be obtained from an automatic sampler, then: Before transferring cargo: • Record make of sampler. • Record type of sampler, e.g. whether fast loop, grab, flow or time proportional. • Record siting of sampler and whether there are devices for mixing the crude oil prior to its being sampled. • Record sample frequency, e.g. grabs per unit of volume or per unit of time. Record also the size of the grabs. • Check that the controls for sample size versus cargo size are set correctly. Record the sampler control setting. • Record number, type and size of sample receivers. Check that receivers are clean and dry. • Review the maintenance records. Record the dates of the last two occasions when the sampler was proved and tested. If possible, record the results of those tests • Ascertain who is in charge of the sampler, who holds the key and how frequently it is checked. During cargo transfer: • Sampling should begin immediately the transfer starts and be stopped only when it is completed • Check that the automatic sampler is working correctly by weighing the sample containers at regular ntervals. • Compare these weights with theoretical weights for the time interval involved. Check that the ancillary equipment (e.g. insertion turbine meters) is working. After cargo transfer: • Record the time the sampler was taken off line. • Make certain that the sampler performed correctly by (a) weighing the sample containers and (b) recording the number of grabs, taken during the loading, from the grab counter Compare both results against theoretical results for the volume loaded. • If the sampler is taken off line before the transfer is completed and/or if the sample volume received is less than the expected volume, a written protest should be issued to the terminal if the analytical results pertaining to the sample are to be used in the calculation of quantities transferred. • In the laboratory ensure that the sample container contents are properly mixed before sub-sampling Report any difficulties encountered with the automatic sampling procedures. • All analytical results from the automatic sampler shall, where possible, be compared with the analytical results obtained from the representative samples taken from the shore tanks. Record the analytical test methods employed.

5.4.3 On Board Ship At the commencement of a loading take a spot sample from a convenient sample point at the vessel's manifold to verify the content of the line After the time necessary to displace the line con-tent completely, take another sample to verify that the density of the cargo being loaded is within ±0.0020 kg/I at 150C of that of the weighted average density of the samples from the shore tank(s) from which the crude oil is scheduled to be loaded. If the difference exceeds the above figure the loading shall be stopped and an investigation carried out. Confirm that the temperature difference between the storage tanks and the manifold is acceptable for the prevailing conditions, parcel temperature and length and diameter of line. Water cuts shall be taken from each compartment while gauging. Record the type of water finding paste or device used to determine the oil/water interface. Record the interface level and any oil emulsions detected. If free water is present then a free water sample should be obtained using a bottom sampler. This sample shall be retained for two months. Sufficient samples should be obtained to meet the requirements of interested parties and regulatory agencies. Sampling and testing requirements are generally specified by interested parties. In the absence of specific instructions the most recent standards on sampling must be followed (IP Petroleum Measurement Manual, Part

VI Sections 1 and 2 refer.) Take representative samples from each of the vessel's tanks so that a composite sample representative of the total cargo may be prepared in the laboratory for appropriate testing. The composite sample will be made by combining the individual vessel's tank samples in proportion to the volumes contained in the respective tanks. Test samples of slops separately. The length of time samples are to be retained should be established consistent with the circumstances, experience and the policies of the parties involved in the custody transfer.

5.5 CALCULATION OF QUANTITIES Calculate the quantities in each shore tank according to IP Petroleum Measurement Manual, Part 1-Calculation of Oil Quantities. 5.6 USE OF VESSEL EXPERIENCE FACTORS The usual function of Vessel Experience factors(VEF) (see also Appendix C) is as an aid in checking the validity of quantities stated to have been loaded or discharged. exceptionally, they may be used as factors to modify the actual recorded quantities. For example, in the case of off-shore loadings, the VEF may be applied to a ship's measurement of the quantity loaded to establish the quantity to be entered in the Bill of Lading. The surveyor should be advised by his principals whether any particular contract provides that cargo reconciliation between ship and shore, either at loading or discharge, or the overall cargo reconciliation, shall include any measurements modified by application of a VEF. The criteria quoted in the contract for accepting or rejecting a particular reconciliation will depend on whether or not VEFs have been applied.

5.7 BUNKER CHECK The ullage spaces in the vessel's bunker tanks shall be tested for hydrocarbon gas using a combustible gas indicator. Gas samples shall be taken from each bunker tank vent pipe or through a tank hatch. In the event that this is not practicable then gas samples may be obtained through sounding pipes If the presence of hydrocarbon gas in excess of 15% Lower Flammable Limit is detected then: (a) (b) (c) (d)

Take a sample from each bunker tank. Inform the terminal representative. Carry out a flashpoint test of the samples. If the flashpoint of any sample is below 60 °C then make a formal protest in writing to the Master and inform the terminal representative.

PROCEDURES AT LOADING The purpose of this chapter is to specify in general terms the measurements, calculations and records required to be made by cargo surveyors in connection with the loading of oil cargoes. More detailed comments on the measurement and sampling procedures referred to in this chapter have been given in Chapter 5. NOTE Whenever simultaneous deballasting must be performed during loading operations, determine the reason from the vessel's representative and record this on the inspection report.

6.1 BEFORE LOAD1NG- SHORE Cargo will generally be delivered to a vessel from standing tankage, either directly or via a meter bank.. 6.1.1 When the quantity of cargo to be loaded is to be established from standing tankage (static measurement) proceed according to Chapter 5 to: • determine the quantity and quality of material in the shore lines, • determine the level of liquid in each shore tank and its average temperature; • take such manual samples as may be appropriate; • calculate and record the quantity in each shore tank to be used in the loading.

6.1.2 When the quantity of cargo to be loaded is to be established by metering (dynamic measurement) record the type of meter, its size and the maximum rated flow rate; record the position of the temperature probe in the line, i.e. centre, bottom, top, etc.; record the average flow rate, temperature, viscosity and grade of oil to be loaded; if a temperature probe in the shore line is to be used to determine the temperature for correcting the metered quantity loaded, record in the inspection report the last two occasions the probe was checked for accuracy; determine the quantity and quality of material in the shore lines; establish the maximum and minimum flow rate at which the prescribed meter accuracy can be maintained (see Appendix B). NOTE: If the cargo is being delivered from standard tankage, the shore tank measurement procedures detailed in this chapter should also be followed, as these will provide a check on the quantity determined by metering 6.1.3 If an automatic sampler is to be used, follow the procedure in 5.4.2

6.2

BEFORE LOAD1NG-ON BOARD SHIP

6.2.1 Record the grade of cargo which is going into each tank. Record the information specified in 5.2.2.

6.2.2 Request vessel's personnel to drain the ship's lines into the aft-most centre tank if possible. Measure the amount of cargo or ballast water dropped into the tank and sample if sufficient quantity remains Also record the capacity of the lines drained Report transfer of any engine slops into the cargo or slop tanks.

6.2.3 Check the tank reference heights and compare with the corresponding values quoted in the tank calibration tables. Investigate and report any differences.

6.2.4 Determine the amount and nature of any material on board (OBQ) prior to loading. For the previous 3 cargoes, obtain tank washing details and cargo history for each tank to be loaded. Describe material found in bottom of tanks as liquid, non-liquid, free water or sediment. If sufficient quantity is available, then a sample should be obtained and retained. A temperature measurement shall be obtained when there is sufficient liquid available. The temperature should be taken from the mid-point of the oil or oily layer. Solids and small quantities of liquid for which a temperature cannot be obtained may be assumed to be at standard temperature.

6.2.5 Measure the oil level and the oil/water interface level in the slops tank(s), preferably using a sonic interface detector, to determine the separate quantities of free water and slop oil. Take the temperature of and sample the oily layer in the sl6ps tank(s). Determine and record the density, sediment and water content. If any slops are to be commingled with the subsequent cargo, they are to be treated and recorded as OBQ.

6.2.6 Measure and record the quantity of any ballast left on board immediately prior to loading. Also record the presence of any measurable hydrocarbon in any ballast tanks. Issue a written protest to the appropriate party if the requirements of 3.2.9(e) are, not met. 6.2.7 Draw a sample of water from each ballast tank and retain them for a period of two months or longer as advised. Note: these samples should not be composited. 6.2.8 Confirm, in the presence of the vessel's personnel, that sea valves and overboard discharge valves are in the closed position and lashed before loading begins. Seal valves and record the seal numbers. 6.2.9 The quantities and types of material in all non-designated cargo spaces and the forepeak, cofferdams, pump rooms, void spaces, duct keel and segregated ballast tanks shall be determined and recorded. 6.2.10 The volume of bunker oil on board the vessel shall be measured and recorded. Record whether or not the vessel is to be bunkered during the cargo transfer and indicate the quantity of bunkers expected to be supplied An estimate shall be obtained from the Master or Chief Engineer of the approximate quantity of bunkers to be used during the vessel's stay in port. Carry out a bunker check per 5.7. 6.2.11 Record the information required for the wedge calculation (see Appendix F). 6.2.12 The OBQ should be calculated and recorded prior to the commencement of loading. Determine the OBQ for liquids (oil and water) as follows: (a) Use special dip tables or the wedge formula (see Appendix F) if liquid does not cover the bottom of compartment. (b) Use trim/list corrections if liquid covers the entire bottom of any tank. (c) When there is sufficient material available, take temperatures. (d) Calculate and record corrected volumes. Transfer any corrected oil volumes from the slops report to the OBQ/ROB report if cargo is to be loaded on top. Record on the OBQ/ROB report the nature of the material and the method used to determine the volume in each compartment. Material in compartments not receiving cargo should also be measured and reported on an OBQ/ROB report form. This report should be signed by the interested parties. If the vessel’s officer signed under protest, a note shall be made as to whether the vessel chose to have a survey made by another company on its behalf. It is strongly recommended that Dry Tank Certificates are not signed by shore representatives or surveyors. Refer to specific instructions issued by interested parties concerning Dry Tank Certificates.

6.2.13 Determine the VEF loading using the vessel's historic data and the methodology of Appendix C. 6.2.14 Request that the cargo is loaded into one compartment only for at least 15 minutes so that water in the ship/shore line will be more readily detected after the loading.

6.3

DURING LOADING-SHORE

6.3.1 When metering the cargo: • Whenever possible, examine meter records, prove meter performance and establish throughput. A recommended procedure is given in Appendix B. If access is not possible, establish previous performance from available documentation. If neither alternative is possible, issue protest in writing to the Terminal. • Record hourly for each meter: (a) Flow rate (b) Pressure (c) Temperature • • •

Establish hourly: (a) Cumulative volume at line conditions (b) Cumulative volume at standard conditions Establish Gross Standard Volume. Check the temperature of the oil from a point near the meter. Compare this temperature with the temperature readout at the meter bank or in the control room. Record any discrepancy.

6.3.2 Carry Out the procedures relating to automatic sampling (5.4.2) and verify the cargo being loaded (5.4.3). When an automatic sampler is not available or is malfunctioning, draw spot line samples of one litre at hourly intervals from sample points where the line contents are likely to be well-mixed. Issue a protest stating that a sample cannot be drawn through an automatic line sampler and that the samples obtained may not be representative of the total cargo.

6.4 DURING LOADING-ON BOARD SHIP 6.4.1 When deballasting is concurrent with loading: • The ballast tanks shall be checked for oil when deballasting has been completed. • Whenever possible a comparison should be made between the quantity of ballast discharged by the ship and the quantity received by the shore. • If the loading of one parcel is to be followed by the discharge of ballast or the loading of another parcel, then every cargo tank shall be measured, whether empty or containing cargo or ballast, after the first parcel has been loaded. After completing ballast discharge and before recommencing loading, recheck ullages of all tanks loaded. 6.4.2 Take such manual samples as may be appropriate.

6.5

AFTER LOADING~HORE

6.5.1 When the quantity of cargo loaded is being established directly from standing tankage, i.e. by static measurement: • determine the level of liquid in each shore tank and its average temperature (5.2.1 and 5.3); • take such manual samples as may be appropriate (5.4.1);

•

calculate and record the quantity of oil remaining in each tank and hence the quantity of oil loaded (5.5).

6.5.2 Verify the quantity of material in the shorelines. 6.5.3 • When the cargo has been metered, record the closing meter readings and the meter factor used Obtain a complete copy of all meter proving forms and meter tickets. Attach them to the completed meter quantity reports and include in the inspection report. If the meter(s) was not proved during loading, indicate the frequency of meter proving and attach a copy of all current meter proving reports. • The Gross Standard Volume delivered from the shore tanks shall be compared with the Gross Standard Volume obtained from meter reading. • Report the time and date of the main loading events, and also the time and a description of any unusual events.

6.6

AFTER LOADING-ON BOARD SHIP

6.6.1 Before measuring, request that the vessel's lines be vented and drained into the cargo tanks, Record their capacity and into which tank the lines were drained In all instances where the vessel has completed loading, the surveyor must ensure that all internal transfer of cargo has ceased and tank valves are secured prior to gauging. 6.6.2 Proceed according to Chapter 5 to: • Measure and record ullages, water cuts and temperatures in all cargo compartments. Inspect for presence 6f oil in all non-designated cargo spaces. If oil is found, measure in the same manner as in cargo compartments and record the measurements. Note if measurements were manual or automatic and if vessel tanks were inerted during ullaging. 6.6.3 Samples drawn at the loading port shall be sealed and placed on board against a signed receipt from the Master of his confirmation that they will be available for collection at the discharge port. 6.6.4 Confirm in the presence of vessel l's personnel that sea valves and overboard discharge valves are closed and that the seals are still intact. If previously sealed valves are not intact, attempt to ascertain the reasons why the seals were broken. Issue protest to the Master and record the findings in the survey report. 6.6.5 Inspect ballast tank and record the quantity of ballast aboard. Report the presence of any gaugeable hydrocarbons in any ballast tanks and sample if possible. Report any suspected seepage to and from cargo and ballast tanks. The quantities and types of material in the fore peak, cofferdams and segregated ballast tanks shall be determined and recorded. 6.6.6 The volume of bunker oil on board shall be measured and recorded. When applicable, the volume of bunker oil supplied shall be established. Any quantity of bunker oil supplied to the vessel and the advised quantity used during its stay in port shall be reconciled with the quantities of bunker oil in the tanks before and after the cargo transfer. Carry out a bunker check per 5.7. 6.6.7 Record both the actual ullage as measured and the trim-list corrected ullage. 6.6.8 Report the time and date of the main loading events. Include the time and description of any unusual events. 6.6.9 Record weather conditions during loading.

6.7 AFTER LOADING-CALCULATIONS AND REPORT 6.7.1 Calculate the Gross Standard Volume in each ship's tank using the average temperature of each tank Do not use a single average temperature for the entire vessel. Calculate the Total Calculated Volume on board the vessel. 6.7.2 Determine the Vessel Load Ratio (VLR) by comparing the shore Total Calculated Volume or metered quantities (including free and suspended water and sediment) with the vessel Total Calculated Volume loaded. When available, the surveyor’s results shall be used for these calculations. 6.7.3 Test the validity of the VLR by comparing it with the VEFL established under 6.2.13 and applying one of the following criteria: (a) The VLR shall not exceed or be less than the VEFL by more than 0.3%; (b) The VLR shall not exceed or be less than the VEFL by more than two (2) standard deviations. If the criteria are not met, then recheck all measurements and calculations in an attempt to identify the cause of the discrepancy. If the difference cannot be reconciled, a protest shall be made in writing to the parties concerned and the principals shall be advised forthwith. 6.7.4 Comparisons shall be made, in terms of TCV, GSV and NSV, of the cargo surveyor's shore measurement of the quantity loaded and the corresponding quantities, entered by the shore terminal on the Bill of Lading. If the percentage difference in any instance exceeds 0.05% volume, a full investigation shall be initiated to determine the reason for the discrepancy. If an unreconciled difference in excess of 0.05% volume still exists, the cargo surveyor shall protest in writing to the terminal representative and the protest shall be noted in the report. 6.7.5 A telex shall be despatched to the surveyor's principals giving a resumè of his findings and drawing attention to any unresolved problems which may have arisen during the loading The details to be provided are usually agreed between the surveying company and its principals in advance of the survey. 6.7.6 The surveyor shall prepare his report on the loading: this shall include the information listed in Appendix D, Section A, together with details of written protests issued, general observations, and a clear statement as to whether, in the surveyor's opinion, the quantity of cargo loaded conformed to the contract.

PROCEDURES AT DISCHARGE The purpose of this chapter is to specify in general terms the measurements, calculations and records required to be made by cargo surveyors in connection with discharge of oil cargoes. More detailed comments on the measurement and sampling procedures referred to in this chapter have been given in Chapter 5.

7.1 BEFORE DISCHRGE-SHORE 7.1.1 Where the quantity of oil in the shore pipeline prior to discharge represents a significant proportion of the total quantity of oil to be discharged, the surveyor should recommend that the line contents be displaced into a separate shore tank where they can be measured separately. 7.1.2 Record whether the shore line is to be filled or flushed on completion of the operation 7.1.3 Proceed according to Chapter 5 to: • determine the quantity and quality of material in the shore lines; • determine the level of liquid in each shore tank and its average temperature; • take such manual samples as may be appropriate; • calculate and record the quantity in each shore tank to be used in the discharge. 7.1.4 If an automatic sampler is to be used, follow the procedure in 5.4.2.

7.2

BEFORE DISCHARGE- ON BOARD SHIP

7.2.1 Record: • a resumè of weather conditions on the voyage, noting especially number of days of gales and heavy seas; • the grade of cargo in each tank; • the information specified in 5 2.2. 7.2.2 Request that the vessel lines be drained into the aft-most centre tank, and measured. Also, record the capacity of the lines drained. 7.2.3 Note that measurements are to be made in all compartments, including those not scheduled to be discharged. 7.2.4 Samples placed on board at the loading port shall be collected. If such samples are not available for collection, a protest in writing shall be issued to the Master who shall be invited to confirm in writing that samples were not placed on board at the loading port 7.2.5 Confirm in the presence of vessel's personnel that sea valves and overboard discharge valves are closed and that the seals are still intact. If previously sealed valves are not intact, attempt to ascertain why the seals were broken. Compare and note if valve numbers differ from those recorded at load port. Record findings in the inspection report. 7.2.6 Inspect ballast tanks and record the quantity of ballast aboard. Report the presence of any gaugeable hydro carbons in any ballast tanks and sample if possible. Report any suspected seepage to and from cargo and ballast tanks. The quantities and types of material in the forepeak, cofferdams and segregated ballast tanks shall be

determined and recorded. 7.2.7 The volume of bunker oil on board shall be measured and recorded. The quantity of bunkers received and consumed during the voyage should be ascertained from the Master in writing and, if possible, his signature obtained. Record whether the vessel is to be bunkered during the cargo transfer and indicate the quantity of bunkers to be supplied. An estimate shall be obtained from the Master or Chief Engineer of the approximate quantity of bunkers consumed during the vessel's stay in port. Carry out a bunker check per 5.7. 7.2.8 Proceed according to Chapter 5 to measure and record ullages, water cuts and temperatures in all cargo compartments. Inspect for presence of oil in all non-designated cargo spaces and the forepeak, cofferdams, pumprooms, void spaces, duct keel and segregated ballast tanks If oil is found, measure in the same manner as in cargo compartments and record the measurements. Note if measurements were manual or automatic and if vessel tanks were inerted during ullaging. 7.2.9 Record both the actual ullage as measured and the trim-list corrected ullage. Calculate the Gross Standard Volume for each tank using the average temperature for each tank. Do not use an average temperature for the entire vessel. Calculate the Total Calculated Volume on board the vessel. 7.2.10 Compare the Total Calculated Volume and Gross Standard Volume at load port prior to sailing with the Total Calculated Volume and Gross Standard Volume at discharge port prior to discharge. If the difference, in any instance, is greater than 0.2%, recheck the vessel's measurements and calculations. If, after re-checking, the discrepancy remains, issue a written protest to the vessel's representative. 7.2.11 Report the time and date of the main discharge events on a Time Log form. Include the time and a description of any unusual events. 7.2.12 If so instructed, determine the VEFD using the vessel's historic data and the methodology of Appendix C. 7.2.13 Record the dimensions required for the wedge calculation. 7.2.14 Record which tanks are to be crude oil washed.

7.3 DURING DISCHARGE-SHORE When possible carry out the procedures relating to automatic sampling (5 4.2) 7.4 DURING DISCHARGE-ON BOARD SHIP 7.4.1 If ballasting operations are to be carried out simultaneously with discharging, the tanks to be ballasted shall be dipped before ballasting commences to ascertain the quantity and quality of oil and sediment remaining. Before ballasting commences, request that the lines to be used for ballasting are stripped. 7.4.2 Record hourly the discharge pressure and flow rate. Indicate where the vessel's line discharge pressure was measured.

7.5 AFTER DISCHARGE-SHORE 7.5.1 Determine from shore personnel the nature and quantities of material in the shore discharge lines before ullaging. Report finding and include line volume in quantity calculations if necessary. 7.5.2 Proceed according to Chapter 5 to: determine the level of liquid in each shore tank and its average temperature (5.2.1 and 5.3); take such manual samples as may be appropriate (5.4.1); establish the quantity of oil in each tank and hence the quantity of oil discharged (5.5).

7.6 AFTER DISCHARGE-ON BOARD SHIP 7.6.1 Before measuring, request that the vessel's lines be vented and drained into the cargo tanks. Record their capacity and into which tank the lines were drained. The surveyor must ensure that all internal transfer of cargo has ceased and tank valves are secured prior to gauging. 7.6.2 After discharge lines and deck lines have been drained, the surveyor shall determine the nature of any material remaining on board in designated tankage, distinguishing between cargo which is pump-able and reachable by the ship's pumps and cargo which is not. Further attempts should be made to pump the remaining quantities ashore. If this is not done, report the reasons. This is particularly important in the event that a cargo retention clause is included in the Charter Party Agreement. If applicable, a formal protest in writing should be made to the parties concerned. Check the tank reference heights and record the observed heights in the field workbook. 7.6.3 Take a sample of the free water remaining in any of the tanks which should have been discharged. Take samples of any significant quantities of oil remaining in the cargo compartments, particularly if agreement cannot be reached as to its identity. When slops are present, both the oil and water phases should be sampled. 7.6.4 The quantities and types of material in all non designated cargo spaces which include the forepeak, cofferdams, pump rooms, void spaces, duct keel and segregated ballast tanks shall be determined and recorded. 7.6.5 All ballast tanks shall be checked for any traces of hydrocarbon liquids. If oil is found on top of. the ballast, then this oil shall be measured and the quantity of oil included in the ROB report. 7.6.6 Indicate on the time log when the vessel started and stopped the Crude Oil Wash (COW) procedure. Indicate in the survey report which tanks were crude oil washed. 7.6.7 The volume of bunker oil on board shall be measured and recorded. When applicable the volume of bunker oil supplied shall be established. Any quantity of bunker oil supplied to the vessel and the advised quantity used during its stay in port shall be reconciled with the quantities of bunker oil in the tanks before and after the cargo transfer. Carry out a bunker check per 5.7. 7.6.8 If the vessel has not ballasted concurrently with discharge, a check shall be made that the sea and overboard valves are still sealed shut.

7.7 AFTER DISCHARGE CALCULATIONS AND REPORT 7.7.1 Determine the quantity remaining on board (ROB) as follows: (a) Use special dip tables or the wedge formula if the liquid does not cover the bottom of a compartment. (b) ) Use trim/list corrections if the liquid covers the entire bottom of a compartment. (c) When there is sufficient material available, take temperatures and samples. Calculate and record corrected volumes. (d) Transfer corrected volumes to an ROB Report for totalizing. Note on an ROB Report the nature of the material and the method used to determine the volume in each compartment. Material in non-designated cargo compartments should be reported on an ROB Report although not included in the totals unless volumes have changed, intentionally or unintentionally, from those at the load port. This report should be signed by the interested parties. If the vessel's officer signed under protest, a note should be made as to whether the vessel chose to have a survey made by another company on its behalf If there is an irreconcilable dispute between the vessel’s personnel and the surveyor(s) or other interested parties as to the quantity and character (liquid or non-liquid) of the ROB, this shall be reported immediately by telephone or telex to all the parties concerned and noted on the OBQ/ROB Report. 7.7.2 If so instructed, determine the VDR by comparing the shore Total Calculated Volume with the vessel Total Calculated Volume discharged. When available, the surveyor's results shall be used for these calculations. 7.7.3 If the VDR has been determined, test its validity by comparing it with the VEFD established under 7.2.12 and applying one of the following criteria: (a) The VDR shall not exceed or be less than the VEFD by more than 0.3%; (b) The VDR shall not exceed or be less than the VEFD by more than two (2) standard deviations If the criterion is not met, then recheck all measurements and calculations in an attempt to identify the cause of the discrepancy. If the difference cannot be reconciled, a protest shall be made in writing to the parties concerned and the principals shall be advised forthwith. 7.7.4 Comparisons shall be made, in terms of TCV, GSV and NSV, of the surveyor's shore measurement of the quantity discharged and the corresponding quantities entered by the shore terminal on the outturn certificate. If the percentage difference in any instance exceeds 0.05% volume, a full investigation shall be initiated to determine the reason for the discrepancy. If an un-reconciled difference in excess of 0.05% volume still exists, then the cargo surveyor shall protest in writing to the terminal representative and the protest shall be noted in the report. 7.7.5 The surveyor shall certify the Gross and Net Standard Volumes of cargo which, in his opinion, have been received by the shore. 7.7.6 A telex shall be despatched to the surveyor's principals giving a resumè of his findings and drawing attention to any unresolved problems which may have arisen during the discharge. The essential information to be provided is usually agreed between the surveying company and its principals in advance of the survey.

FINAL REPORT 8.1 OUTTURN LOSS Comparisons shall be made, in terms of TCV, GSV and NSV, of the quantity of oil received by the shore terminal and the corresponding quantity entered on the Bill of Lading. If the shore volumes are less than the corresponding Bill of Lading volumes by an amount greater than that set by the parties to the contract, that fact shall be reported without delay in writing. to all parties. If practicable this should: be done before the vessel leaves the discharge port.

8.2 IN-TRANSIT LOSS Check the comparison under 7.2.10 of Total Calculated Volumes after loading and before discharge and record the difference as the In-Transit Loss. 8.3 ADJUSTED OUTTURN LOSS An Adjusted Outturn Loss in terms of Net Standard Volume of Oil shall be calculated and recorded represents the difference between the oil on t vessel after loading and the oil which can accounted for subsequently, either as off-loaded oil or as oil retained on board after discharge, and is therefore a measure of oil which remains unaccounted for. 8.4 FINAL REPORT A Final Report shall be issued and shall include: • all matters pertaining to the loading reported under Chapter 6; • data in accordance with Appendix D, Section A, • all matters pertaining to the discharge reported under Chapter 7; • data in accordance with Appendix D, Section B, • details of written protests issued; • general observations; • the Outturn Loss per 8.1; • the In-Transit Loss per 8.2; • the Adjusted Outturn Loss per 8.3; • final conclusions regarding all the operations surveyed.

REFERENCES TO TEST AND CALCULATION METHODS This chapter provides references to calculation and test methods currently applied in the determination of crude oil quantities.

9.1 The following are documents published by the IP to which it may be useful to refer. However, the latest IP Standard should always be used unless the contract provides otherwise. The reference number and date of the Standard used shall be recorded. 9.1.1 IP Petroleum Measurement Manual Part I Part II

Part IV Part V Part VI

Part VII

Part X

Calculation of Oil Quantities. Tank Calibration Section 1-Vertical Cylindrical Tanks-Measurement Methods Section 3 - Liquid Calibration Methods. Temperature Measurement Methods excluding Averaging Thermometers. Automatic Tank Gauging Sampling for Quantitative Purposes Section 1-Manual Methods Section 2-Automatic Sampling of Liquids from Pipelines. Density Measurement Section 1-Manual Methods Section 2~ontinuous Density Measurement Meter Proving Section 1-Field Guide to Proving Meters with a Pipe Prover.

9.1.2 IP Standard Methods for Analysis and Testing of Petroleum and Related Products IP 356/87 IP 358/82 IP 359/82 IP 53/82 IP 160/87

Water in crude oil by Karl Fischer volumetric titration Water in crude oil by distillation Water and sediment in crude oil by the centrifuge method Sediment in crude and fuel oils by extraction. Density, relative density or API gravity of crude petroleum and liquid petroleum productshydrometer method

9.2 Reference may also be made to the following documents published by other bodies concerned with the measurement and testing of crude oil: 9.2.1 The Manual of Petroleum Measurement Standards published by the API. 9.2.2 Automatic sampling of petroleum and petroleum products (ASTM D 4177-82). 9.3 The API-ASTM-IP Petroleum Measurement Tables, Volumes I, IV, VII and X

Appendix A

RECOMMENDED FREQUENCY OF CALIBRATION AND CHECKING OF INSTRUMENTS A. l MERCURY THERMOMETER (a) Laboratory inspection: Before initial use and at least once a year thereafter, each thermometer shall be checked in the laboratory against a standardized thermometer at three or more temperatures. (b) Field inspection: Before using a thermometer, compare it at one or more temperatures near mid-scale against a recently standardized thermometer. A.2 PORTABLE ELECTRONIC THERMOMETER The accuracy of the portable electronic thermometer shall be checked over the normal working, range at least once a year. The checks shall be carried in a laboratory using constant temperature baths. A permanent record of these checks shall be maintained. When using an electronic thermometer, before and after use check it against a mercury-in-glass 1thermometer or suitable electronic device, at one or more temperatures near to the expected temperature range.

A.3 MANUAL GAUGING TAPES Before using a dip tape the cargo surveyor shall ensure that it is of a type conforming to Part 2 Section 1of the IP Petroleum Measurement Manual, or similar national specifications. Tapes shall be examined periodically for kinks and damage. Kinked or damaged tapes shall be replaced. A.4 PORTABLE SONIC ULLAGE TAPES At six-monthly intervals, the accuracy of the portable sonic ullage tape shall be checked in accordance with the manufacturer's instructions. A.5 HYDROMETERS Before using a hydrometer it shall be checked against another hydrometer that has been calibrated to ± 0.0001 kg/l by a recognized national standards laboratory. Each hydrometer is manufactured with a thin line etched about the top of its stem corresponding exactly to a line on the paper scale inside the stem The coincidence of these two lines shall be checked before every measurement to ensure that the paper scale has not moved.

Appendix B

MONITORING METERING SYSTEM PERFORMANCE AT LOADING B. 1 INTRODUCTION To maintain the highest level of accuracy at all flow rates during the loading of crude oil, it is essential to monitor both the performance of the meter and proving systems and the correct functioning of the equipment and associated instrumentation. It must be recognized that monitoring the functioning of the equipment and instrumentation is a complex task which will need to be carried out by a specialist. There are, nevertheless, some checks which a cargo surveyor should carry out in order to satisfy himself that the measurements taken and quantity shown on the Bill of Lading are correct. These checks are described in this appendix, there being no IP standard which expressly covers the monitoring of ship loading by meter. For details of proving procedures and corrections for the effect of temperature and pressure, reference should be made to the IP Petroleum Measurement Manual Part X 'Field Guide to Proving Meters with a Pipe Prover’.

B.2 DESCRIPTION OF METER LOADING MEASUREMENT SYSTEMS B.2.I Meter Factor The turbine or p.d. meter employed in ship loading normally generates pulses during the transfer of liquid and these pulses are converted to Indicated Volume by dividing by a nominal Meter K-Factor (pulsesim3) which is a constant value set into the electronic totalizer or flow computer. The Indicated Volume calculated using the nominal Meter K-Factor must be corrected to obtain the Gross Volume at line conditions by multiplying by a Meter Factor (F), obtained by calibrating the meter under the actual conditions of loading Each meter should be proved as soon as constant loading conditions have been established.

The Meter Factor (F) is computed from the following equations: F = Vb x Cts x C ps x C’tl x C’pl Vm x C”tl x C” pl where Vb

is the prover base volume at 15°C and 1.01325 bar Vm is the Indicated Volume = pulses nominal Meter K-Factor Cts is the correction for temperature on steel of pipe prover. Cps is the correction for pressure on steel of pipe prover C’tl is the correction for temperature on liquid at pipe prover C"tl is the correction for temperature oil liquid at meter C’pl is the correction for pressure on liquid at pipe prover C”pl is the correction for pressure on liquid at meter

B.2.2 Meter Throughput (Vr) The Indicated Volume displayed by the meter totalizer or printed by the flow computer is multiplied by the Meter Factor at the completion of loading so that the: Gross Volume = Indicated Volume x Meter Factor The Gross Standard Volume ( Vr) is calculated from the equation: Vr = Vg x C”tl x C”pl

Where Vr is the Gross Standard Volume Vg is the Gross Volume Ctl is the Volume Correction Factor for temperature on liquid where the temperature is the flow weighted average for the throughput C “pl is the Compressibility Factor i.e. the correction for pressure on liquid where the pressure is the flow weighted average for the throughput

B.2.3 Meter K-Factor Note that some modern flow computers based on microprocessors are programmed to carry out Gross Volume calculations using actual Meter K-Factors entered immediately after a successful proving sequence, performed as soon as constant loading conditions are established: i.e.

Vg=

pulses actual Meter K-Factor

With such flow computers, retrospective correction of the Indicated Volume using a Meter Factor is unnecessary.

B.2.4 Temperature and Pressure Compensated Systems Some modern metering systems continually compensate for the effect of temperature and pressure during the transfer. At completion of loading it is only necessary to multiply the Indicated Volume by the Meter Factor to obtain the Gross Standard Volume. B.3

MONITORING PROCEDURES

The following procedures are recommended for monitoring the measurement data obtained during the transfer. (i) Verify the value of the nominal Meter K-Factor from records and check that it has been correctly entered or set into the electronic totalizer or flow computer. (ii) Witness proving of each meter during loading and check that: (a) The Meter Factor (or actual Meter K-Factor in the case of flow computers described in B.2.3) was obtained at approximately the average throughput under stable operating conditions. (b) The range of consecutive Meter Factors (or pulse Counts) is within 0.05% in' a sequence of 5 proving runs. (c) The temperature difference between meter and prover for each proving run is less than 0.20C. (d) The prover base volume used in the computation is valid (i.e. not more than 2 years have elapsed since the prover was calibrated). (e) The Meter Factor is within ± O.2% of the previous Meter Factor at equivalent operating conditions. Note:Changes in Meter Factor are often due to significant differences in flow rate and temperature between provings. If there are any discrepancies then the cargo surveyor should advise all parties concerned in writing immediately. (iii) As an additional check, establish that the aver-age throughput temperature at the meter is within 0.30C of the temperature of the vessel's tanks after loading. (iv) Where there is a temperature and/or pressure compensated system, verify the correct functioning of the compensation This is done by recording the temperature and pressure at frequent intervals over a test period during the loading so as to obtain average temperature and pressure. These shall be flowweighted. Apply the appropriate Volume Correction Factors and Compressibility Factors to the Gross Volume and check that the result is within 0.02% of the Gross Standard Volume.

Appendix C

PROCEDURE FOR CALCULATING VESSEL EXPERIENCE FACTORS C.1 INTRODUCTION For a given vessel, an approximately constant ratio can be established between the volume of a cargo measured on board the vessel and the corresponding volume measurement by a shore terminal Such ratios, termed Vessel Experience Factors, find their most frequent application at loading ports where they are used by vessel's personnel and independent surveyors to provide approximate checks on quantities of cargo loaded. They are also used at discharge ports, but much less frequently. This appendix provides two alternative methods for calculating Vessel Experience Factors. Method 1 relies on an arbitrary criterion for accepting/rejecting the individual load (or discharge) ratios which are the constituents of the vessel Experience Factor. Method 2 differs from the first in relying on a statistically more rigorous data acceptance/rejection procedure. Because they give rise to non-typical ratios or because essential information is missing, data relating to the following categories of voyages are excluded from the calculation of Vessel Experience Factors in both methods: • Voyages after dry-dock, • lightenings, • voyages where the Bills of Lading have been based solely on shipboard measurements, • voyages prior to any structural modifications which have affected the vessel's cargo capacity. Although Vessel Experience Factors may be calculated using data relating to a minimum of three admissible voyages, the greater the number of sets of data the greater will be the confidence in the Vessel experience Factor established.

C.2

CALCULATION OF VESSEL EXPERIENCE FACTOR-LOADING

Note: The calculation of the Vessel Experience Factor~Discharge proceeds in like manner

Method 1 In this method, only vessel load ratios within to ± 0.3% of the mean value of the ratios are included in the calculation of the Vessel Experience Factor. The calculation routine is as follows: Step (a) List the admissible VLRs Step (b) Calculate the mean (r) of the listed VLRs Step (c) Calculate 0.3% of the mean Step (d) Delete VLRs lying outside the range given by r ± value determined in (c). Step (e) Recalculate the new mean value (r’) Step (f) Recalculate 0.3% of the new mean Step (g) Report: (i) The Vessel Experience Factor = r ‘established in Step (e). (ii) The range of accuracy of the vessel Experience Factor = ± value determined in Step (f)

Example of Calculation by method 1 Step (a) List admissible data: Voyage

Vessel Load

Number

Ratio (VLR)

1

0.9998

2

1.0120

3

1.0010

4

1.0027

5

1.0022

6

1.0054

7

1.0008

8

0.9990

9

0.9975

10

0.9985

Step (b) Calculate mean of above 10 numbers = 1.0019. Step (c) Calculate 0.3% of 1.0019= 0.0093 Step (d) Delete VLRs lying outside range 1.0019 ± 0.003, i.e. 0.9989 to 1 0049. Thus the VLRs for voyages nos. 2, 6, 9, 10 are deleted. Step (e) Recalculate mean (r') of remaining six VLRs = 1.0009 Step (f) Recalculate 0.3% of 1.0009 = 0.003 Step (g) Report: (i) the Vessel Experience Factor the mean r' calculated in Step(e)= 1.0009. (ii) the range of accuracy of the Vessel Experience Factor = ±0.003

NOTE: VLF.XLS file for experience factor is saved in My Documents.