© 2019 Department of Petroleum Resources. All rights reserved Department of Petroleum Resources (DPR) PROCEDURE GUIDE

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2.2.9 Side gauge to show depth of liquid in tank, or any suitable arrangement for both local
and remote reading of tank liquid levels.
2. 3 Procedure for Tank Gauging
2.3.1 Preparation of Tank for Gauging
2.3.1.1 Prior to gauging, the tank should have been allowed to settle for the minimum period
specified for that grade of petroleum or petroleum product which in any case shall not be
less than 6 hours after filling. Lesser duration can be allowed before draining if it is
demonstrated that the tank has settled sufficiently before the officially specified settlement
time. Thereafter, the tank is drained until the segregated free water has been completely
bled out and a composite sample of the content of the tank taken, to spot check on its
BS&W in accordance with the prescribed method for petroleum and petroleum products
quality determination. If the BS&W value obtained falls within the limit allowed for that
production or custody transfer point, then further gauging exercise is embarked upon
preparatory to commencement of loading. Otherwise, the tank is allowed further settling
time until this is achieved, subject to a maximum time extension of 3 hours. However, if the
desired BS&W value is not achieved after the extended settling period, the DPR Officer – In
– Charge should be notified for further directives. The maximum BS&W shall be 0.5% for
export.
2.3.2 Tank Gauging
2.3.2.1 This is the measurement of the level of petroleum or petroleum product in a tank.
This shall be by Manual Gauging or by Automatic Tank Gauging (ATG).
2.3.3 Manual Gauging Using Steel Tape
2.3.3.1 General Specification for Manual Gauging Using Steel Tape
2.3.3.1.1 Shall be made of high-quality steel (preferably mild or stainless steel) and shall be
of a continuous length to cover the total height of the tank.
2.3.3.1.2 Width should be at least 0.5” or 1.27cm.
2.3.3.1.3 Thickness should be about 0.012” (0.03048cm).
2.3.3.1.4 Scale to be graduated in steps of 0.0625” (0.15875cm) and be accurate to 0.125”
(0.3175cm) per 100ft (30meters) at 60oF. Tip of the bob when attached should correspond
to the zero point of the scale.
2.3.3.1.5 Housing of the tape should be a durable reel and crank mounted in a frame or case.
2.3.3.1.6 Tape should be fitted with a spring snap catch or other safe locking device to which
the bob can be securely attached.
2.3.3.1.7 The bob should be made of a corrosion-resistant material, 6 inches (15.24cm) long,
1 inch (2.54cm) diameter and of about 20 oz (0.567 kg) minimum in weight but sufficient to
hold the gauging tape taut at full length in accordance with API MPMS Chapter 3.
2.3.3.1.8 Bob’s end shall be tapered to a point and not flat.
2.3.4 General Specification for Manual Gauging Using Ullage, Temperature and
Interface (UTI)
2.3.4.1 Shall have a valid calibration/recertification certificate which shall be renewed
annually.