Inspections

Field Inspection and Testing of Motor Fuel

I. POLICY

Maryland Code Business Regulation Title 10 - Motor Fuel and Lubricants Subtitle 2 - Administration and Enforcement § 10-203, addresses the Comptroller’s duty to analyze motor fuel. MD Bus Reg Code § 10- 203 (a) The Comptroller periodically shall collect or cause to be collected and cause to be analyzed samples of all motor fuel that is: (1) subject to regulation under this title; and (2) stored and offered for sale in the State.

II. ANALYSIS OF MOTOR FUEL

Samples of motor fuel which are obtained during motor fuel inspections are analyzed both in the field and at the Motor Fuel Testing Laboratory. Motor fuel samples are tested to determine that products sold and used in the State of Maryland meet or exceed all state specifications, thereby assuring the quality of products distributed to consumers. The Motor Fuel Testing Lab conducts certain analytical tests, to include the following:

III. GASOLINE

  1. Vapor Pressure - the testing of pressure of a confined vapor in equilibrium with its liquid at a specified temperature, indicating a measure of its volatility. This is useful in predicting seasonal gasoline performance as well as the tendencies of gasoline’s evaporative loss and fire hazard. Higher volatility is needed in cold weather with lower volatility needed in hot weather.
  2. Distillation - a method for determining the full range of volatility of motor fuel by progressively boiling off a sample under controlled heating conditions. A distillation curve is used as an important control for fuel standards, such as volatility (vaporization).
  3. Sulfur Content - sulfur is a common natural substance found in petroleum products. Its desired function is to prevent sliding metal surfaces from seizing under conditions of extreme pressure. This is needed to prevent damage to auto-emission control systems and to reduce emissions related to acid rain concerns.
  4. Lead by X-ray Analysis - lead is and has been used in gasoline as an octane enhancer. Lead is no longer permitted in gasoline (except for special uses) and therefore, lead analyses are conducted on terminal samples and special samples only.
  5. Octane Number - octane is an indication of the ability of gasoline to resist knock, or ability to resist deterioration during combustion. An octane number is the numerical value assigned to the antiknock properties of gasoline. The higher the number, the more resistant to knock.
  6. Vapor-Liquid Ratio - a measurement of the ratio of vapor to liquid at a given temperature used to help determine a gasoline’s tendency to contribute to vapor lock in an automotive fuel system.

IV. DISTILLATE FUELS

  1. Flash Point - the lowest temperature at which the vapor of combustible fluid can be made to ignite (flash). Flash points differ according to the intended use of the product. It is an important indicator of the fire and explosion hazards associated with petroleum products.
  2. Dye Check - all fuel oil, off-road diesel and high sulfur diesel are required to be dyed in accordance with IRS regulations to determine taxability.
  3. API Gravity - a measurement of the density of the product being tested. The API gravity scale and the specific gravity scale are used in making this determination.
  4. Viscosity - the measurement of a fluid’s resistance to flow under specified conditions.
  5. Cloud Point - the established cloud point is an indicator of the tendency of the oil to plug filters or small orifices at low operating temperatures.
  6. Pour Point - the lowest temperature at which an oil or distillate fuel is observed to flow when cooled under prescribed conditions (an indicator of the ability of the product to flow at cold operating temperatures).
  7. Water and Sediment - water and sediment are checked visually while the sample is in the cylinder for API gravity determinations. Distillate fuel should be free of sediment entirely, and the presence of water is limited and can be tested further by specific tests, if needed.
  8. Saybolt Color Test - does not test for the presence of dye in a product but determines a standardized range of colors against which the colors of product uniformity and freedom from contamination.

V. REPORTS OF FUEL FAILURES

When a motor fuel sample fails to meet the required specifications, the lab manager shall notify the Field Enforcement Bureau Inspector In-Charge.

VI. STANDARD OPERATING PROCEDURES

Standard Operating Procedures (SOPs) for motor fuel testing are located on the FEB network drive in the SOP folder.

VII. CANCELLATION:

None.