Oil & gas industry business practices distinguish between quantity values for weight in vacuum (mass) and weight in air. When product is weighed in the real world, the weighing process may neglect the fact that the product displaces surrounding air and thus a reduced weight value (weight in air) is obtained and recorded; for calculations based on mass, such results require correction.
On the other hand, the laboratories that determine crude oil and product densities, usually provide the density in vacuum, which can be utilized to calculate the weight in vacuum (mass).
The SAP QCI calculates the weight in vacuum(mass) for oil products, using a mass-related density value and product volume.
Back in the real world, contractual agreements between sellers and buyers and in some countries, governmental authorities, require the reporting of quantities based upon the “weight in air”.
One way of performing the necessary calculation is to reduce the density in vacuum before the calculation process however, this is not usually a standard procedure and will not work for the varying product density and temperature factors used around the world.
As part of the standard ASTM D 1250-80, tables 8, 26 and 56 were released to convert mass = “weight in vacuum” to “weight in air”; according to ASTM rules, these tables are the current valid standard.
QuantityWare delivers an equation-based solution which provides exactly the same results as the printed ASTM tables 8, 26 and 56. The function-based solution is supplied as standard functionality within the BCP package. Furthermore, QuantityWare offers a quantity conversion solution that includes the calculation of values for weight in air AND weight in vacuum (mass) in parallel.