Instantaneous Rate of Discharge

Instantaneous rate of discharge of oil content means the rate of discharge of oil in litres per hour at any instant divided by the speed of the ship in knots at the same instant

The instantaneous rate of discharge of oil content does not exceed 30 litres per nautical mile. The total quantity of discharge must not exceed 1/30000 of the total quantity of the residue formed cargo. The tanker must have operational and approved ODMCS

The formula for IRD is :

IRD (in litres/Nautical mile)= Oil content(ppm) x Flow rate (m3/hr) / (peed (Knots) x 1000)