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CAN CGSB 3.0 No. 60.32-2013: Standard Test Method for Water and Sediment in Crude Oil and Heavy Fuel Oils by Centrifuge
Technical Overview of the Canadian General Standards Board Method for Measuring BS&W in High-Viscosity Petroleum Products
The Canadian General Standards Board (CGSB) standard CAN CGSB 3.0 No. 60.32-2013 — titled “Method of Test for Water and Sediment in Crude Oils and Heavy Fuel Oils by Centrifuge” — establishes a laboratory procedure for determining the volume of water and sediment (commonly referred to as BS&W) present in crude oils and heavy fuel oils. This method is essential for quality control in the upstream and downstream petroleum industry, particularly for custody transfer measurement, refining process optimization, and compliance with Canadian transport regulations.
1. Scope and Application
The standard is applicable to crude oils and heavy fuel oils that are sufficiently viscous to require heating or dilution with a solvent to achieve homogeneity and adequate settling of water and sediment. It covers the determination of total water and sediment (conjoined) expressed as a volume percent. The method is not recommended for light distillates or products containing visible free water, where alternative procedures such as ASTM D1796 (CAN/CGSB 3.0 No. 60.31) or Karl Fischer titration (ASTM D6304) are more appropriate.
Within Canada, CAN CGSB 3.0 No. 60.32-2013 is recognized by federal and provincial regulatory bodies for the official determination of BS&W in crude oil shipments, custody transfer, and pipeline acceptance. It is technically equivalent to ASTM D4007-11 and IP 359, although it includes specific provisions for Canadian heavy oil types (e.g., Western Canadian Select, Cold Lake blend).
2. Technical Requirements and Test Procedure
2.1 Principle of the Method
A measured volume of sample is mixed with a solvent (typically toluene or xylene) and subjected to centrifugation at a defined relative centrifugal force (RCF) and temperature. The water and sediment are forced to the bottom of a conical centrifuge tube, where the combined volume is read to the nearest 0.01 mL.
2.2 Key Test Conditions
| Parameter | Specification |
|---|---|
| Sample volume | 50 mL or 100 mL (depending on tube type) |
| Solvent (diluent) | Toluene or xylene, typically 1:1 volume ratio with sample (pre-warmed if needed) |
| Solvent blank | Run a separate solvent blank to correct for any sediment in the solvent |
| Centrifuge RCF | 600–700 g (e.g., 1500–1800 rpm depending on rotor radius) |
| Temperature | 60 °C for heavy crude oils; ambient (20–25 °C) may be used for lighter grades |
| Centrifugation cycles | Two cycles of 5 minutes each with intermediate mixing; total 10 minutes |
| Reading device | Conical centrifuge tube graduated at 0.01 mL intervals, with a tapered tip |
2.3 Test Procedure Summary
- Pre-warm the sample to 60 °C if necessary and mix thoroughly to ensure homogeneity.
- Transfer the required volume of sample into a clean, dry centrifuge tube.
- Add an equal volume of solvent (or as specified) and mix by shaking.
- Place the tube in the centrifuge, ensuring proper balance.
- Centrifuge for 5 minutes at the specified RCF.
- Remove the tube, stir the interface with a rod, and repeat centrifugation for another 5 minutes.
- Read the combined volume of water and sediment at the bottom of the tube. Subtract the solvent blank reading if used.
- Report the result as volume percent of water and sediment.
TIP: For accurate readings, ensure the centrifuge tube is free of scratches and calibration marks are verified against a reference standard. Always allow the tube to cool to room temperature (if heated) before reading to avoid thermal expansion errors.
WARNING: Solvents such as toluene and xylene are toxic, flammable, and suspected carcinogens. All handling must be performed inside a certified fume hood. Use explosion-proof centrifuge equipment when working with flammable solvents.
3. Implementation Highlights
Successful implementation of CAN CGSB 3.0 No. 60.32-2013 in a petroleum laboratory requires careful attention to equipment calibration, operator training, and quality assurance. The following points are critical for obtaining reliable and reproducible results:
- Centrifuge qualification: The centrifuge must be capable of maintaining the specified RCF and temperature. National and international standards require periodic verification of speed, temperature, and timer accuracy.
- Solvent selection: While toluene is the preferred solvent, the standard permits the use of xylene or perchloroethylene provided the solvent blank does not exceed 0.01 mL. Users should verify solvent compatibility with the sample matrix, especially for heavy fuel oils containing diluents.
- Interference from emulsions: Stable emulsions may not break under centrifugation. If a persistent emulsion layer is observed, the test must be reported as “emulsion not broken” and an alternative method (e.g., Karl Fischer titration) should be used.
- Precision and bias: The standard provides repeatability (r) and reproducibility (R) limits based on round-robin testing. For crude oils, typical repeatability is 0.1 mL or less, while reproducibility may extend to 0.25 mL for heavy oils.
SUCCESS: When performed correctly, this method delivers a rapid and cost-effective BS&W measurement (typically under 30 minutes) that aligns with international trade requirements for crude oil quality.
DANGER: Never exceed the maximum fill volume indicated on the centrifuge tube. Imbalance during high-speed rotation can cause tube failure, rotor damage, or personal injury. Always use matching tubes and balance loads to within 0.1 g.
4. Compliance and Quality Assurance
Organizations adopting CAN CGSB 3.0 No. 60.32-2013 for regulatory or contractual purposes should incorporate the following compliance measures:
- Accreditation: Laboratories performing the test for custody transfer must be accredited to ISO/IEC 17025 and include this method in their scope of accreditation.
- Reference materials: Use CRM (certified reference materials) for BS&W to validate method performance periodically. If CRMs are unavailable, inter-laboratory comparison programs provide a reliable alternative.
- Documentation: Maintain records of centrifuge calibration, solvent blank data, and operator training certificates. The standard revision should be clearly identified on the test report (e.g., CAN CGSB 3.0 No. 60.32-2013).
- Updates: Check the CGSB website for amendments, corrigenda, or withdrawal. As of 2026, the 2013 edition remains current; confirm with the issuing body for the most recent status.
It is also advisable to compare results obtained with CAN CGSB 3.0 No. 60.32-2013 against alternative methods (e.g., ASTM D4007, IP 359) when cross-border transactions are involved, to ensure contractual consistency.
Frequently Asked Questions
Q: What is the difference between CAN CGSB 3.0 No. 60.32-2013 and ASTM D4007?
A: CAN CGSB 3.0 No. 60.32-2013 is the Canadian adoption of ASTM D4007. The two standards are technically identical in apparatus, reagents, and procedure. The CGSB edition, however, includes additional notes on testing highly viscous Canadian heavy oils and references Canadian regulatory requirements.
A: CAN CGSB 3.0 No. 60.32-2013 is the Canadian adoption of ASTM D4007. The two standards are technically identical in apparatus, reagents, and procedure. The CGSB edition, however, includes additional notes on testing highly viscous Canadian heavy oils and references Canadian regulatory requirements.
Q: Which petroleum products can be tested with this method?
A: The method is intended for crude oils and heavy fuel oils that are viscous enough to require heating or solvent dilution. It is not suitable for light distillates (gasoline, kerosene) or products with significant free water. For those, other CGSB test methods (e.g., No. 60.31 for light fuels or No. 60.26 for Karl Fischer) should be applied.
A: The method is intended for crude oils and heavy fuel oils that are viscous enough to require heating or solvent dilution. It is not suitable for light distillates (gasoline, kerosene) or products with significant free water. For those, other CGSB test methods (e.g., No. 60.31 for light fuels or No. 60.26 for Karl Fischer) should be applied.
Q: How is the result reported if an emulsion layer is present after centrifugation?
A: If an emulsion interface persists and prevents clear reading, the test is considered inconclusive. The standard instructs the operator to report “emulsion not broken” and recommend an alternative water determination method such as Karl Fischer titration (CGSB 3.0 No. 60.26) or distillation (ASTM D4006).
A: If an emulsion interface persists and prevents clear reading, the test is considered inconclusive. The standard instructs the operator to report “emulsion not broken” and recommend an alternative water determination method such as Karl Fischer titration (CGSB 3.0 No. 60.26) or distillation (ASTM D4006).
Q: Why is the solvent blank necessary?
A: The solvent blank ensures that any sediment present in the solvent (e.g., from aging or storage) does not bias the result. A blank reading greater than 0.01 mL indicates contaminated solvent, which must be replaced before re-running the test.
A: The solvent blank ensures that any sediment present in the solvent (e.g., from aging or storage) does not bias the result. A blank reading greater than 0.01 mL indicates contaminated solvent, which must be replaced before re-running the test.
Document based on CAN CGSB 3.0 No. 60.32-2013 — Method of Test for Water and Sediment in Crude Oils and Heavy Fuel Oils by Centrifuge. Published by the Canadian General Standards Board, 2013. This article reflects technical interpretations applicable as of 2026.