(1)
Vehicle tanks used as measures shall be calibrated as capacity measures.
(2)
lit the case of meter equipped tanks the meter shall be treated as a separate measuring instrument for the purposes of calibration.
(3)
The compartment capacity or capacities shall be taken as including the capacities of the delivery lines leading from the emergency, safety or master valve to the outlet valve or discharge valve except that in the case of vehicle compartment terminating in a single delivery pipeline fitted with an outlet valve, the compartment capacity or capacities shall be taken as excluding the capacity of the delivery pipeline but a notice shall be prominently exhibited on the vehicle tank indicating clearly and indelibly the following-
(a)
marked capacity includes capacity of delivery line; or
(b)
marked capacity excludes capacity of delivery line as the case may be.
(4)
The safety or master valve shall be positioned at the lowest point of the outlet from the compartment.
(5)
The proving measure of bulk meter should be mounted on an overhead gantry or a separate framework in a convenient position above a firm and level platform, preferably of concrete on which the vehicle stands during calibration.
(6)
The vehicle shall be placed in a level position before commencing calibration as the accuracy of calibration depends on the level of the tank; the sequence in which compartments are calibrated should be such as to minimize unequal spring deflection on the axles of the vehicle.
(7)
The front and rear tyres of the vehicle shall be at the correct pressures. The tyres shall be inspected for wear and tear which should be reasonably even and there shall not be excessive difference in the tread between the front set of tyres and the rear set at the time of calibration.
(8)
The interior of the compartment shall be inspected and cleaned where necessary.
(9)
Before starting calibration the pipelines, outlet valves and other connections shall be tested against leakage by partially filling and draining each compartment in turn through the outlet valve.
(10)
During the process sufficient quantity of the testing medium should be introduced inside the compartment to wet the internal surface of the tank and pipelines.
(II)
After taking the precautions mentioned above, the compartment to be calibrated shall be incrementally tilled with appropriate proving measures or bulk meters in steps up to the marked capacity of the compartment with the delivery lines leading to the outlet valve full or empty as provided in subrule (3).
(12)
The ullage mark shall be taken carefully and the line shall be cut on the ullage stick at right angles to the axis with the help of tri-squarc and scriber. If an ullage indicator is used, it shall be correctly set and sealed.
(13)
A mark shall also be on the dipstick to indicate the ''proof level". In the case of ullage stick, the distance from the ullage point to the T-joint shall be marked on the stick.
(14)
The dipstick shall as well be marked to indicate incremental volumes up to full tank/compartment capacity.
(15)
The sequence for calibrating compartments should be in sequence of filling them.
(I 6) The sequence of discharge shall be in the reverse order to that filling.
(17)
Each compartment shall be left full before proceeding to the next in sequence.