The Washington State Department of Labor & Industries (L&I) adopts rules for design plans for factory assembled structures

April 19, 2023

The Washington State Department of Labor & Industries (L&I) has adopted rules for review and approval of design plans for factory assembled structures. The rules allow agency-approved, licensed engineers, architects, or firms, to review plans for the following:

  • Recreational park trailers (also known as park model recreational vehicles and park trailers);
  • Recreational vehicles;
  • Food trucks and trailers (conversion vendor units).

The changes also update and clarify existing rules for plan reviews. These affect commercial coaches and factory-built housing and commercial structures.

L&I formally filed the rules (CR-103 Rulemaking Order) on April 11.

You can find the adopted rules here.

Or by going online to the program’s “Laws & Rules” page here.

Why this is happening now

Since 2021, L&I filed a series of emergency rules to address a backlog of design plans in the Factory Assembled Structures Program (FAS). The rule incorporated the use of licensed professionals. It also clarified what a design plan submission must include and how to submit design plans for approval for commercial coaches, factory-built housing, and commercial structures. This rulemaking adopts permanent rules.

The changes affect rules under:

The new rules took effect April 11, 2023. For technical assistance about the new rules, please contact us at or call 1-800-705-1411, Option 3. If you need additional information or have questions about the rulemaking process, please contact Alicia Curry, at 360-902-6244 or

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