Hemet Municipal Code Div. 2 Wildland Interface Area Requirements

Southern California, and specifically Riverside County has a critical wildland fire problem. The combination of the adverse fire weather, dry native vegetation and wind patterns creates an explosive situation that promotes the rapid spread of fire through the hillsides and wildland/urban interface areas.

(Ord. No. 1453, § 1, 10-13-92)

As the city grows and development occurs into the hillsides and interface areas, it is incumbent upon government to ensure such development proceeds in a fire safe environment. Hence, the provisions of this division shall apply as follows:

(1) The wildland interface area and severity zones shall be as indicated on "Exhibits A and B" following this division.

(2) New development shall comply with all provisions.

(3) Existing development shall comply with section 14-421, (Landscaping and perimeter protection) immediately. Sections 14-419 (Water supplies) and 14-420 (Structural design and construction) shall be imposed to the extent practical, as determined by the fire chief and building official, and work shall be accomplished concurrent with any improvement and/or alterations to structures and facilities.

Specific plan.

The standards incorporated herein may be modified through the specific plan process where the staff site plan review committee is satisfied that public health and safety is maintained in the design. Recommendations by said staff site plan review committee shall ultimately be approved by the city council through the specific plan process.

(Ord. No. 1453, § 2, 10-13-93; Ord. No. 2059, § 2, 6-24-25)

Editor's note— Exhibits A and B referenced in subsection (1) are not set out herein, but are on file and available for inspection in the offices of the city clerk and the planning department.

Adequate ingress and egress are necessary to allow safe and rapid passage of both fire equipment and private vehicles in opposite directions simultaneously. If inadequate, access becomes critical during a wildfire both from a firefighting standpoint and with regard to life safety.

(1) Provide two or more routes of access to a public road, loop roads with a single entry do not meet this requirement.

(2) Dedicate and improve streets and roads to city standards.

(3) Perimeter streets should be placed on sloped side of the development where possible.

(4) Cul-de-sacs, designed to city standards, shall not exceed 350 feet in length in extreme and high hazard severity zones and 660 feet in moderate zones and shall have a minimum width of 36 feet curb to curb with a 50-foot minimum curbline radius at the turn-around. Dead end streets are prohibited.

(5) Minimum centerline radius of curvature of roads shall be no less than 60 feet.

(6) Road grades shall be based on hazard severity zones, and grades of eight percent or greater shall have a paved surface. Maximum grades shall be eight percent, extreme; ten percent high; and fifteen percent moderate zones. Variance may be granted with approval of the fire chief, but shall not exceed 200 feet in length in two percent above standard.

(7) Road intersections shall be as close to 90 degrees as terrain will permit, for at least 80 feet from intersection centerlines.

(8) Install street name signs of durable, permanent, fire-proof materials at all intersections within any development having private streets.

(Ord. No. 1453, § 3, 10-13-92)

All structural development regardless of type or location shall have a dependable supply of water adequate for both normal daily consumption and emergency fire needs.

(1) The minimum size of water distribution mains on which fire hydrants are located shall be sufficient to provide the required fireflow but, in no case less than eight-inch circulating (loop) mains.

(2) Water source or storage should have a capacity sufficient to provide a minimum fire flow, as determined by the fire chief, for two hours with a residual pressure of 20 psi in addition to maximum daily flow requirements for other consumer uses.

(3) Fire hydrant spacing shall not exceed 300 feet.

(4) Fire hydrants are required on cul-de-sac streets 300 feet or more in length.

(5) The size, type and location of fire hydrant shall meet the approval of the city's fire chief.

(6) Homes with an individual private water supply shall conform to the fire department standard for "Alternate Water Supply Installation" (see Exhibit C).

(Ord. No. 1453, § 4, 10-13-92)

Editor's note— Exhibit C referenced in subsection (6) is not set out at length herein, but is on file and available for inspection in the offices of the city clerk and the planning department.

Because of the behavior of wildfires, particularly during a high wind-driven fire, how a building is designed and constructed is the most important factor in providing fire safety for a home or other structures. Homes apparently well separated from wildland vegetation will be damaged or destroyed if poorly designed and constructed without regard to fire safety.

(1) Roof coverings. The roof is the most vulnerable part of a structure during a fire. Because of its horizontal component, a roof can catch and hold the flying firebrands almost invariably associated with strong winds.

a. Uniform Building Code noncombustible Class A roofing material shall be used in all fire hazard severity zones.

b. Open-ends of tile roofs shall be sealed with a noncombustible building material.

c. Noncombustible material shall be used on all patio coverings.

(2) Vents. The attack of homes by windborne firebrands is a serious problem in unprotected vent systems on the structure.

a. Individual roof and gable vents shall not exceed 144 square inches.

b. Undereave vents shall be located near the fascia rather than near the wall.

(3) Overhang and stilt construction. Structures with large open eaves, balconies, raised decks and built on stilts are always dangerous in the wildland but particularly on hillside sites because the underside traps convected heat and flames.

a. The size of eaves shall be minimal and boxed in with stucco or other fire resistive material.

b. Noncombustible or combustible materials covered with fire-resistant material shall be utilized in the construction of any overhanging member or columns.

c. Stilt constructed underfloor areas shall be encased to the groundline with materials meeting the standards for exterior vertical walls.

(4) Setback and exterior siding. Structure fire ignitions during a wildfire are almost entirely external. Fire-resistance of the exterior walls and adequate setbacks on ridges and against slopes will greatly reduce the loss due to flames, radiated and convected heat directly hitting the home.

a. Exterior walls shall be stucco or other fire-resistive material.

b. The applicable degree of fire-resistance of all exterior walls shall extend from ground level to the roof line.

c. Provide a minimum 30 foot setback from slopes and adjacent property lines to all habitable structures.

(5) Glass. Windows allow entry of radiated heat of such intensity that interior materials (drapery, furniture, etc.) are ignited. They also admit convective heat, firebrands, or flames when they are open or broken. Large picture windows and sliding glass doors are particularly vulnerable. The orientation of the glass surface will determine the degree of hazard it represents. If it is on the uphill and/or windward side and facing toward a concentration of vegetative fuel, the danger is heightened.

a. Provide extra-strength tempered and/or double paned glass for glazed openings on the side of the housing facing:

1. The normal fire-carrying wind;

2. The downhill side;

3. Concentrations of vegetation.

(Ord. No. 1453, § 5, 10-13-92)

The proximity of a structure to native vegetation is a direct measure of the probability of its destruction. Heavy fuel loading of native vegetation must be reduced a sufficient distance from the structure to avoid ignition of the building and to allow firefighters a place in which to work. The obvious alternative is suitable landscaping utilizing specimen native shrubs and low-growing, low-volume fire retardant plants.

(1) Clear and thin all native vegetation in proximity to windows and other openings and to the following distances based on: Fire hazard severity zones:

a. Upslope: moderate, 30 feet; high, 60 feet; extreme, 100 feet.

b. Across slope: moderate, 60 feet; high, 100 feet; extreme, 200 feet.

c. Downslope: moderate, 100 feet; high, 200 feet; extreme, 300 feet.

(2) Provide plants that have been tested and proved to have significant fire retardant qualities (see "Exhibit D").

(Ord. No. 1453, § 6, 10-13-92)

Editor's note— Exhibit D referenced in subsection (2) above is not set out at length herein, but is on file and available for inspection in the offices of the city clerk and the planning department.