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

Page 92 of 114
 
91 | P a g e 
 
 
4 
Dimensions  
Length: 
 
Upstream diameter: 
Downstream diameter: 
First pipe connection: 
Second pipe connection: 
Upstream pressure tap: 
Downstream pressure tap: 
D 
PRESSURE TAPS 
 
 
1 
Orientation 
 
 
2 
Location 
of 
static 
pressure 
transducer 
(upstream/downstream) 
 
 
3 
No. of pressure taps 
 
 
4 
Pressure tap size  
 
 
5 
Condition of tap hole 
edge 
 
 
6 
Temperature probe type 
 
 
E 
METER PARAMETERS 
 
 
1 
Minimum flow rate 
 
 
2 
Maximum flow rate 
 
 
3 
Meter factor 
 
 
 
 
1.16 LNG OPERATIONS 
The LNG loaded at the loading points shall be measured in cubic meters by gauging LNG 
loaded in tanks of the LNG tanker vessel in accordance with ISO 10976:2015. 
1. Each tanker should be equipped with level measuring device of different types 
capable of determining the LNG level to within accuracy equal to or better than 
±7.5mm. The level of the liquid in the tank shall be determined by main primary 
capacitance measuring devices which give automatic readouts in the cargo control 
room, but if there is a failure, the level of liquid shall be determined by using the 
Auxiliary liquid level gauging device for the relevant cargo tank(s). For volume 
calculations, the gauging table shall convert the level of the liquid in tanks to the 
volume of that cargo tank using one (1) millimeter as the smallest unit of dimension. 
  
1.16.1 QUALITY OF LNG FOR TRUCKING IN NIGERIA 
Quality of LNG loaded should: 
i. 
have a Gross calorific value (Volumetric) between 39.90 and 42.70 MJ/SCF on 
a dry basis 
ii. 
Not contain more than 1 (one) mol% of nitrogen 
Hydrogen Sulphide                                      5.0 mg/SCF 
Mercaptan sulphur                                      2.3 mg per standard cubic feet 
Mercury                                                          50 mg per standard cubic feet 
Carbon Dioxide                                              0.1 mol per cent 
Carbonyl Sulphide plus Hydrogen               15.0 mg per standard cubic metre