Endress+Hauser NXA820 - Page 30

Calculations Tankvision
30 Endress+Hauser
8.1.7 Volume Correction Factor - VCF
The VCF corrects for the temperature expansion of the liquid. Expecially hydrocarbons have
a large expansion factor. The most common VCF corrections were developed by American
Society for Testing and Materials (ASTM), USA and Institute of Petroleum, UK and updated
regularly. There are more authorities issuing VCF corrections. Most of them are derived from
the ASTM/IP tables.
VCF Implementation
• Calculations are based on "representative samples" ("generalized products")
• The "Tables" are based on specific calculation procedures
• Calculation is complex and rounding and truncating unique. There are many small but
significant differences - exact requirements and needs depend on application, country and
company.
L00-NXA82xxx-16-00-00-xx-044
1 Gasolines
2Crudes
3Jets
4 Fuel oils
5 Lube oils
VCF Tables
• The formulas are too complex for direct use - hence the "Tables" were printed
• There are specific tables for:
– Products (crudes, refined products, lube oils, alcohols, palm oil, chemicals, etc.)
– Different measurement units (kg/m³ vs. °API, °C vs. °F, etc.)
– Different "Reference" or standard temperature (60 °F, vs. 15 °C, 25 °C or 30 °C)
– Each table has range limits
– Tables for VCF and for density correction are available
VCF = e
[- t(1.0+0.8t)]aD aD
60 60
a
60
==
++
K +K p +K p
01 2
**2
K
0
K
1
K
2
p
*2
p
*2
p
*
900
800
700
600
500
400
300
a
T
X10 (°F)
5 -1
.81.01.21.4 1.61.82.02.22.4 2.6
(1/p) X 10 [kg/m ]
T
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