The department of health will use the following criteria for approving the installation of manufactured homes:

(1) New and relocated manufactured homes must be installed according to the manufacturer's written installation instructions;

(2) If the manufacturer's installation instructions are unavailable for manufactured homes, the department of health will accept the following:

(a) American National Standards Institute (ANSI) A225.1, 1994 edition, section 3; or

(b) The installation instructions of an engineer or architect licensed in Washington.

(3) The department of health will inspect the installation to determine if the manufactured home is placed on a properly prepared site and anchored according to the:

(a) Manufacturer's installation instructions;

(b) ANSI A225.1, 1994 edition, section 3; or

(c) Design of an engineer or architect licensed in Washington.

(4) The department of health will require, at a minimum, specific instructions be obtained from a licensed engineer or architect when a manufactured home is to be installed on a site where the specific soil bearing capacity is not addressed in the manufacturer's instructions.

(5) The department of health may review, at a minimum, the following installation requirements:

(a) Heat duct crossovers, except that heat duct crossovers supported above the ground by strapping or blocking to avoid standing water and to prevent compression and sharp bends to minimize stress at the connections are also accepted;

(b) Dryer vents exhausted to the exterior side of the wall or skirting, when installed; and

(c) Hot water tank pressure relief lines. These lines must be exhausted to the exterior side of the exterior wall or skirting and downward.

(6) Water lines, waste lines, gas lines and electrical systems must be installed according to the requirements of this chapter.

(7) When skirting is used the skirting must:

(a) Be made of a material suitable for ground contact including all metal fasteners which must be made of galvanized, stainless steel or other corrosion resistant material;

(b) Be recessed behind the siding or trim and attached in such a manner to prevent water from being trapped between the skirting and siding or trim; and

(c) Have vent openings located close to corners which:

(i) Provide cross-ventilation on at least two opposite sides;

(ii) Are designed to prevent the entrance of rodents by covering the vent openings with corrosion-resistant wire mesh with mesh opening of one-fourth inch in dimension; and

(iii) Have a net area of not less than one square foot for each one hundred fifty square feet of under floor area.

(8) Provide access to the under floor area of the manufactured home so that all areas under the home are available for inspection. The opening must not be less than eighteen inches by twenty-four inches. The cover must be of metal, pressure treated wood or vinyl.