Allowances for Deficiencies: Temperature, tolerances of account, and natural wastage
A temperature allowance is only to be made when:
- The quantity of oil is stated in bulk litres ( or a similar bulk quantity ) at despatch or receipt; and
- The temperature of the oil is taken and recorded at despatch and receipt.
The most satisfactory method of allowing for temperature deficiency is by conversion ofall quantities of oil to litres at 15ºC. If the deficiency in litres at 15ºC is lessthan the deficiency in bulk litres, the allowance is equal to the difference. If thedeficiency in litres at 15ºC is greater, no allowance is to be made.
At other installations the following allowances expressed as percentages of the bulkquantity despatched are appropriate:
- For light oil, 0.11% per ºC fall in temperature: and
- For heavy oil, 0.08% per ºC fall in temperature.
Adjustments are not to be made on the basis of indirect evidence, suchas ambient temperature.
Although allowances are made for decreases in temperature of oil in transit, it islong-standing practice that normal small increases in temperature should be ignored.
In exceptional circumstances, however, if large increases in temperature occur for a knownreason and there is no doubt about the accuracy of the recorded figures, they are to betaken into account in considering the deficiency.
Tolerances of account
The allowance for accounting tolerances is the sum of the separate tolerances on theaccounts involved in calculating the total deficiency.
For each despatch and receipt account taken in storage tanks by dipping or automatic tankgauge, the tolerance is the quantity represented by a dip of 2mm for each tank, asappropriate.
For each account taken in a rail tank wagon or craft by reference to a calibration table,the tolerance is the quantity represented by the unit to which it is dipped (e.g.millimetre).
For each account taken by weighing, whether the oil is weighed net or the container isgrossed and tared, the tolerance is the quantity represented by the unit to which it isweighed (e.g. kilogram)
The maximum allowances for natural wastage including normal evaporation and handlinglosses are as follows:
|Means of Transport||Allowance|
where measurement is based on storage; tank dip on despatch and/or receipt
other pipeline movements 1. 0.1% of the quantity despatched for each storage tank dipped
Nil Closed drums Nil Ship or craft, except if both despatch and receipt quantities are based on craft dips 0.5% of the quantity despatched (EGAD Regulation 14.2 ) Other 0.5% of the quantity despatched