8.9.1.1 To Calculate the Correction for Sediment and Water (CSW) The CSW is a correction factor that determines the net standard volume as a percentage of the gross standard volume. To calculate this correction, the percentage of sediment and water (S&W) must be known. This sediment and water percentage value is deducted from 100, then the result is divided by 100. CSW = (100 - S&W%) / 100
It can also be calculated on a grade or parcel basis if the S&W was analyzed on an appropriate representative sample.
8.9 To Calculate Net Standard Volume (NSV) 12 This is obtained by multiplying the Gross Standard Volume (GSV) by the Correction for Sediment and Water (CSW). NSV = GSV x CSW which can be expanded to: NSV = GSV x [(100 - S&W%) / 100] 8.9.1 Sediment and Water (S&W) Crude oil and some liquid petroleum products contain sediment and water suspended or entrained throughout that fluid. The quantity of sediment and water is determined by laboratory analysis of a representative sample and is expressed as a percentage, usually volume percent. Sediment and Water is usually only deducted from crude oil cargoes. Petroleum products are not normally corrected for S&W unless required as a commercial condition or other specific requirement. Products are normally reported to Gross Standard Volume and the subsequent weight is also based upon the GSV quantity.
8.10 To Calculate Apparent Mass or Weight in Air W This is usually calculated by multiplying the gross or net standard volume by the appropriate weight correction factor (WCF). NET STANDARD WEIGHT (IN AIR) = NSV x WCF Or GROSS STANDARD WEIGHT (IN AIR) = GSV x WCF
8.9.1.2 To Calculate the Volume of Sediment and Water
It is frequently necessary to calculate the actual volumetric value of the sediment and water. This can be achieved by subtracting the Net Standard Volume (NSV) from the Gross Standard Volume (GSV). S&W vol = GSV - NSV or S&W vol = GSV - {GSV x [(100 - S&W%) / 100]} On multiple tank shipments, net standard volume can be calculated on a tank-by-tank basis if the individual S&W values are known.
69
Made with FlippingBook Digital Publishing Software