(1) Plans and specifications of each model or production prototype of a mobile home, commercial coach, conversion vending units as specified in subsection (2) of this section, medical units, recreational vehicle, and/or park trailer showing body and frame design, construction, plumbing, heating and electrical specifications and data shall be submitted to the department of labor and industries for approval and recommendations with respect to compliance with the rules and standards of each of such agencies. When plans have been submitted and approved as required, no changes or alterations shall be made to body and frame design, construction, plumbing, heating or electrical installations or specifications shown thereon in any mobile home, commercial coach, conversion vending units, medical units, recreational vehicle, or park trailer without prior written approval of the department of labor and industries.

(2)(a) Conversion vending units with any of the following components are subject to the requirements of subsection (1) of this section unless exempted by the department by rule after consultation with the advisory committee created in section 4, chapter 167, Laws of 2016:

(i) Have concentrated loads exceeding five hundred pounds;

(ii) Contain fuel gas piping systems and equipment;

(iii) Contain solid fuel burning equipment;

(iv) Contain fire suppression systems;

(v) Contain commercial hoods;

(vi) Contain electrical systems and equipment in excess of 30A/120V;

(vii) Contain electrical systems with more than five circuits;

(viii) Contain electrical systems incorporating photovoltaic energy, fuel cell energy, or other alternative energy systems; or

(ix) Contain plumbing drainage systems conveying solid or bodily waste.

(b) Professional engineer or architect approval is only required for conversion vending units that have concentrated loads exceeding five hundred pounds.

(c) Plan review is not required for those systems and other items listed in (a) of this subsection, or as modified by rule, that are already inspected and approved by another jurisdiction either to a common recognized standard or to standards substantially equivalent to Washington state. An insignia or certified inspection record from the inspecting jurisdiction will suffice as evidence of prior plan review approval.

(3) The director may adopt rules that provide for approval of a plan that is certified as meeting state requirements or the equivalent by a professional who is licensed or certified in a state whose licensure or certification requirements meet or exceed Washington requirements.