ISO 8697:1999 pdf free download.Crude petroleum and petroleum products — Transfer accountability — Assessment of on board quantity (OBQ) and quantity remaining on board (ROB).
ISO 8697 is intended to encourage uniformity of measurement, accounting and reporting procedures of “On Board Quantity” (OBQ) and the quantity “Remaining on Board” (ROB).
All safety precautions should be in accordance with the International Safety Guide for Oil Tankers and Terminals (ISGOTT) [4] and regulations specified by the vessel or terminal operator and any statutory authorities who may be concerned.
The inclusion of clingage, hydrocarbon vapours, and the contents of associated pipeline and pumps as part of OBQ and ROB, have been considered. However, methods for the calculation of those quantities are not sufficiently accurate to justify their inclusion in the assessment of OBQ or ROB.
This International Standard specifies a method for assessing small volumes of material in the cargo tanks of marine tanker vessels prior to loading (OBQ) or upon completion of discharge (ROB) by manual gauging.
It is not applicable to the estimation of clingage, hydrocarbon vapours or the contents of associated pipelines or pumps.
3 Principle
The depth of any non-liquid, oil and water layers on the bottom of each tank is determined by manual gauging. Each layer in each tank is assessed to determine whether or not it is in the form of a wedge and the voume of each is calculated. The total volume of each layer in the ship is calculated and reported.
NOTE The configurations of layers (non-liquid, oil and water) that can be found are illustrated in annex A.
4 Procedure for collection of data
4.1 Measurement of OBQ shall be taken on tanks that are ready for loading on arrival of the vessel and/or presented ready for loading after deballasting operations.
If it is an operational requirement to commence loading prior to completion of all deballasting operations from cargo tanks, it is necessary to conduct OBQ measurement on those tanks that contain ballast at the appropriate intermediate stage in the operation.
Measurement of ROB shall be taken on tanks on completion of discharge operations and before ballasting operations.
If it is an operational requirement to commence ballasting some cargo tanks prior to completion of discharge of cargo from other tanks, it is necessary to carry out ROB measurements on tanks at the appropriate intermediate stage in the operation prior to ballasting the affected tank.ISO 8697:1999 pdf download.