Information about Family Naming Conventions for Vehicles and Engines
- Consolidation of EPA Standardized Naming Conventions (PDF)
(8 pp, 114 K, June 26, 2017,
On this page:
- Step 1. Find the applicable model year code
- Step 2: Determine your manufacturer code
- Step 3: Find your industry sector
A family is the basic unit that EPA uses to identify a group of vehicles or engines for certification and compliance purposes.
- Engine family;
- Test group;
- Vehicle family;
- Durability group; and
- Evaporative and/or permeation and/or refueling family.
A manufacturer should apply for new certificates and pay the appropriate certification fees for each family name that it intends to produce for sale in the United States.
A family name is a 12 character code that identifies all parts of that particular engine.
The typical naming convention is shown below, although some sectors have a slight variation.
* For dual or variable displacement families, enter the maximum displacement. If the displacement is given in liters, the decimal point count as a digit. In all cases, the displacement will be read in liters if a decimal point is included and it will be read in cubic inches or cubic centimeters if there is no decimal point.
Follow these steps to create your family name:
From the table below, find the code for Position 1 of your family name.
This code is the 3-character, alpha-numeric code that EPA assigns to each company. Use this code for Positions 2-4 of your family name.
Click on your industry sector to view specific instructions for determining Positions 5-12 of your family name.
* This also includes heavy-duty highway vehicles at or below 14,000 pounds GVWR that are not tested on a chassis-dynamometer for certification under 40 CFR Part 1037 (i.e., certified to the requirements and standards of §1037.105, per §1037.104(f)).