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CAN CGSB 3.18-2010 (2016): Automotive Unleaded Gasoline — Technical Requirements and Compliance Guide
Understanding the Canadian National Standard for Unleaded Automotive Gasoline
Scope and Purpose
CAN CGSB 3.18-2010 (2016) is the national standard of Canada for automotive unleaded gasoline, published by the Canadian General Standards Board (CGSB). It defines the physical, chemical, and performance requirements for gasoline intended for use in spark-ignition engines designed to operate on unleaded fuel. The standard applies to all commercially supplied unleaded gasoline in Canada, including grades for seasonal volatility variations and oxygenate blends such as ethanol. It does not cover leaded racing fuel, aviation gasoline, or gasoline for use in off-road applications unless explicitly referenced in provincial regulations. The purpose of this standard is to ensure consistent fuel quality, engine compatibility, and environmental compliance across the Canadian supply chain.
Technical Requirements
CAN CGSB 3.18-2010 (2016) specifies mandatory limits for a wide range of fuel properties. Key parameters include octane quality, volatility, sulfur content, corrosion tendencies, and oxygenate concentration. These requirements are designed to protect modern engine systems, reduce emissions, and maintain drivability under Canada’s diverse climatic conditions.
| Property | Limit / Requirement | Test Method (ASTM) |
|---|---|---|
| Research Octane Number (RON) | ≥ 91.0 for premium; ≥ 87.0 for regular* | D2699 |
| Motor Octane Number (MON) | ≥ 82.5 for premium; ≥ 80.0 for regular* | D2700 |
| Anti-Knock Index (AKI) = (RON+MON)/2 | ≥ 87.0 for regular; ≥ 91.0 for premium* | D4814 |
| Copper Strip Corrosion (3 h at 50 °C) | No. 1 max | D130 |
| Existent Gum (washed, mg/100 mL) | 5 max | D381 |
| Sulfur (mg/kg) | ≤ 80 (summer); ≤ 100 (winter)** | D2622 / D7039 |
| Lead (mg/L, unleaded) | No addition; ≤ 5 naturally present | D3237 |
| Benzene (vol-%) | ≤ 1.0 | D5580 |
| Total Aromatics (vol-%) | ≤ 35.0 | D5580 |
| Olefins (vol-%) | ≤ 10.0 | D1319 |
| Oxygenates | Ethanol ≤ 10 vol-%; MTBE ≤ 2 vol-%; other ethers ≤ 2.7 vol-% | D4815 / D5599 |
| Vapor Pressure (kPa, at 37.8 °C) | Class AA: 45–62; Class A: 48–72; Class B: 55–79; Class C: 62–85; Class D: 69–93; Class E: 79–103 | D5191 |
| Distillation – 50% evaporated (°C) | Class AA: 70–115; Class A: 70–115; Class B: 66–115; Class C: 60–115; Class D: 55–110; Class E: 50–105 | D86 |
| Distillation – 90% evaporated (°C) | 160–188 for all classes | D86 |
*Minimum octane grades are typically declared by the supplier; premium grade (91 AKI) and regular (87 AKI) are the most common. The standard allows for intermediate grades with the same minimum RON and MON, provided AKI matches the declared grade. Vapor pressure and distillation limits are set per volatility class, chosen to match seasonal and regional conditions. The sulfur limit was harmonized with federal regulations under the Canadian Environmental Protection Act, 1999 (CEPA) for the control of vehicular emissions.
Implementation Highlights
Implementation Tip: When formulating gasoline to CGSB 3.18-2010 (2016), blenders and refineries should use a volatility class selection based on month of sale and geographic zone. The CGSB standard provides a table of recommended classes for five zones across Canada (Coastal, Central, Prairie, Northern, and Mountain) for summer (May–September) and winter (October–April) periods. Overlapping grade designations are allowed only if both the seasonal limits and the supplier’s declared grade are honored.
The standard permits the addition of deposit control additives (detergents) to maintain intake system cleanliness. While no specific test is mandated in the standard, most major suppliers in Canada follow the Top Tier Detergent Gasoline performance guidelines. CGSB 3.18-2010 (2016) also allows up to 10 vol-% ethanol, provided the ethanol meets the requirements of CAN/CGSB-3.511 for denatured fuel ethanol. Denaturant requirements and blending practices must also comply with provincial and federal biofuel mandates.
Important Consideration: The standard classifies gasoline into six vapor pressure/distillation classes (AA through E). A fuel designated for winter use in a cold region (Class E) must not be sold in a summer low‑volatility region (Class AA) because it can cause hot‑weather driveability problems. Suppliers must maintain rigorous seasonal transitions, often requiring different blending recipes at terminals.
Testing intervals and frequency are not prescribed by the standard itself; however, most suppliers adopt a quality control plan that aligns with the CGSB sampling frequency guidelines (e.g., one sample per batch or per 200,000 liters). The referee test methods are all ASTM International standards, as listed in the table. Any disagreement in test results between parties is resolved by using the referee method specified for each property.
Compliance Notes
Compliance with CAN CGSB 3.18-2010 (2016) is mandatory under the Canadian Environmental Protection Act (CEPA) for unleaded gasoline sold or imported for use in motor vehicles in Canada. The standard is referenced in the Gasoline Regulations (SOR/90-247) as amended. Enforcement is carried out by Environment and Climate Change Canada (ECCC), which conducts market surveys and inspects fuel samples from retail stations, terminals, and refineries.
Compliance Milestone: As of 2026, amendments to the Gasoline Regulations have not been published to supersede the 2010 version. The 2016 reaffirmation confirms that the technical content remains current. For up‑to‑date regulatory references, always consult the CGSB store and the ECCC website. The next planned review is for the 2023‑2024 cycle, but as of early 2026 the 2010 edition (with 2016 reaffirmation) is still the active standard.
Non‑compliance can result in penalties including warnings, product recalls, and fines. Specific non‑conformities commonly observed in the market include:
- Excess benzene content (above 1.0 vol‑%) due to high‑aromatic blending components.
- Sulfur exceedances during winter months when heavier streams are used.
- Incorrect vapor pressure class for the season/region (e.g., supplying Class C summer fuel in a region that requires Class AA).
- Oxygenate overdosing beyond the 10 vol‑% ethanol limit, leading to corrosion and drivability issues.
Critical Risk: Supplying leaded or lead‑contaminated gasoline as “unleaded” is a direct violation of CGSB 3.18-2010 (2016) and CEPA. Even trace levels above 5 mg/L can damage catalytic converters and oxygen sensors. Suppliers must maintain strict segregation of leaded and unleaded product streams.
Provincial regulations may impose additional requirements. For example, British Columbia and Quebec have their own sulfur limits that are more stringent than the federal limits referenced in CGSB 3.18. Fuel marketers should confirm that their product meets the most restrictive of the federal, provincial, and CGSB requirements.
Frequently Asked Questions
Q: Is CAN CGSB 3.18-2010 (2016) still in force, or has it been replaced?
A: As of 2026, the 2010 edition with its 2016 reaffirmation remains the current published standard. A newer edition was drafted in 2020 but has not been formally adopted by CGSB as the mandatory version. Always check the CGSB Online Store for the latest status.
A: As of 2026, the 2010 edition with its 2016 reaffirmation remains the current published standard. A newer edition was drafted in 2020 but has not been formally adopted by CGSB as the mandatory version. Always check the CGSB Online Store for the latest status.
Q: Can ethanol blends up to E15 or E85 be certified under CGSB 3.18?
A: No. The standard only permits up to 10 vol-% ethanol. For ethanol concentrations between 10 % and 15 % (E15), suppliers should refer to ASTM D5798 or the under‑development CGSB 3.19 standard for high‑ethanol blends, where applicable provincial regulations allow it. E85 is governed by separate standards (e.g., ASTM D5798).
A: No. The standard only permits up to 10 vol-% ethanol. For ethanol concentrations between 10 % and 15 % (E15), suppliers should refer to ASTM D5798 or the under‑development CGSB 3.19 standard for high‑ethanol blends, where applicable provincial regulations allow it. E85 is governed by separate standards (e.g., ASTM D5798).
Q: What is the difference between “regular” and “premium” grades under this standard?
A: The standard does not mandate grade designations; it provides minimum RON, MON, and AKI values. “Regular” typically refers to an AKI of 87, and “premium” to AKI of 91, but the supplier must declare the grade and ensure the fuel meets the octane requirements for that grade. Some suppliers offer “mid‑grade” (AKI 89) gasoline, which must still satisfy the relevant RON and MON minima.
A: The standard does not mandate grade designations; it provides minimum RON, MON, and AKI values. “Regular” typically refers to an AKI of 87, and “premium” to AKI of 91, but the supplier must declare the grade and ensure the fuel meets the octane requirements for that grade. Some suppliers offer “mid‑grade” (AKI 89) gasoline, which must still satisfy the relevant RON and MON minima.
Q: Does CGSB 3.18 require the use of specific detergent additives?
A: No, but deposit control is strongly recommended. The standard only limits existent gum (≤ 5 mg/100 mL). For modern engines, using a gasoline meeting a qualified detergent gasoline standard (e.g., Top Tier, or the recommended practices of the Automobile Manufacturers Association) can help maintain intake valve and fuel injector cleanliness beyond what CGSB 3.18 mandates.
A: No, but deposit control is strongly recommended. The standard only limits existent gum (≤ 5 mg/100 mL). For modern engines, using a gasoline meeting a qualified detergent gasoline standard (e.g., Top Tier, or the recommended practices of the Automobile Manufacturers Association) can help maintain intake valve and fuel injector cleanliness beyond what CGSB 3.18 mandates.
© 2026 – Technical overview of CAN CGSB 3.18-2010 (2016). This article is for informational use only; always refer to the official CGSB document and applicable regulations for complete requirements.