# International Mechanical Code > The 2009 International Mechanical Code, incorporated by reference into the Washington State Building Code (WAC 51-52). Governs the design and installation of mechanical and HVAC systems. - Canonical: https://harth.build/resources/building-codes/us-states/washington/imc-2009/ - Last updated: 2026-06-23 ## Direct answer and reference scope International Mechanical Code is presented here as a reference within the IMC 2009 collection for Washington. The 2009 International Mechanical Code, incorporated by reference into the Washington State Building Code (WAC 51-52). Governs the design and installation of mechanical and HVAC systems. Use the [Washington State Building Code Council](https://sbcc.wa.gov/state-codes-regulations-guidelines) to confirm the code edition currently adopted for the project, and compare the model text with state amendments, local amendments, effective dates and the permit authority's interpretation. The [ICC code library](https://codes.iccsafe.org/codes) is the model-code publication path. This Harth page is a searchable reference transcription, not an official code publication, legal opinion or confirmation that this edition controls a particular address. Record the project jurisdiction, application date, occupancy, construction type and amendment set before relying on a section. Where this page conflicts with an official publication or the authority having jurisdiction, the official source controls. _Authored and prepared by Harth. Review scope: official verification path added; code text and current local applicability have not been independently reviewed._ Washington adopted the 2009 IMC as WAC 51-52, effective July 1, 2010, with state amendments. It covers ventilation, exhaust systems, duct systems, combustion air, chimneys and vents, and heating and cooling equipment. The full text below is reproduced from the 2009 edition as incorporated into law, sourced from public.resource.org. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/?context=%2Fresources%2Fbuilding-codes%2Fus-states%2Fwashington%2Fimc-2009%2F - View this page in a browser: https://harth.build/resources/building-codes/us-states/washington/imc-2009/ - All resources for agents: https://harth.build/llms.txt