ASTM Fire Ratings
Explained

Southern California properties often need perimeter materials selected with wildfire exposure, maintenance, and local defensible-space expectations in mind. Fire-performance documentation can be one part of a broader fire-aware perimeter plan, alongside site cleanup, spacing, access, and AHJ review.

Aluminum fencing is commonly used as a non-combustible material option in fire-aware perimeter planning. Product documentation, assembly details, and local AHJ review determine suitability for a specific parcel.

Steel fencing is commonly used as a non-combustible material option in fire-aware perimeter planning. Project acceptance depends on the specific product documentation, assembly details, and local AHJ review.

Composite fencing may have ASTM E84 documentation depending on the product line. Because composite assemblies are product-specific, product documentation, assembly details, and local AHJ review determine suitability before installation near structures.

Wood and standard vinyl fencing are combustible materials that need careful review near structures. Cedar and pine typically fall into Class C or remain unrated entirely, and standard vinyl can melt or deform under heat. For properties in high-risk areas, pairing a documented non-combustible fence with landscape rock as non-combustible ground cover can support defensible-space planning when local requirements and AHJ review align.

Yes — the City of San Diego has already adopted Zone 0, ahead of the state. The city's requirement lives in San Diego Municipal Code (SDMC) §512.0604, part of the San Diego Wildland Urban Interface (SDWUI) Code. It defines Zone 0 and applies to new structures applying for a building permit on or after February 28, 2026, and to existing structures one year later, February 28, 2027. Its text does not use the word “fence”: the fence and gate rules come from Fire-Rescue Standard D-2 (new structures in a Very High Fire Hazard Severity Zone: new fences and gates in Zone 0 must be steel, aluminum, fiber cement board or masonry, with a 5-foot noncombustible transitional span where a fence attaches) and the Zone 0 Guidelines for Existing Structures. Our Zone 0 address checker shows whether an address point falls in a mapped Fire Hazard Severity Zone.

The statewide Zone 0 rule is separate: the California Board of Forestry adopted it as emergency regulations on August 19, 2026 and submitted it to the Office of Administrative Law; as of September 2026 it is not yet in effect. The December 31, 2025 deadline set by Executive Order N-18-25 passed without adoption. The rule traces to AB 3074 (2020) and PRC §4291; the package adds 14 CCR §§1298.01–1298.04 for local-responsibility areas, where it covers occupied structures in Very High Fire Hazard Severity Zones, and amends §§1299.01–1299.03 for the State Responsibility Area, where it covers all structures. Once in effect, it bars combustible fences and gates attached to an occupied structure and new combustible fences and gates in Zone 0; existing structures get 3 years for the fence and gate rules, or up to 5 on a local fire agency’s timeline.

San Diego's Zone 0 Guidelines for Existing Structures include specific exceptions. Existing vinyl fencing (or fencing without combustible reinforcement) may stay within 5 feet if it runs parallel to the wall, sits no less than 4 feet from the structure, is in good condition and clear of debris, and has no vegetation between the fence and the structure. New parallel wood fencing is permitted only if it is Fire Retardant Treated Wood (FRTW), meets the vinyl conditions, and is listed in the California OSFM Wildland Urban Interface (WUI) Products Handbook. An existing fence attached perpendicular to the house needs a 5-foot noncombustible transitional span, and homeowners should attempt full compliance, including replacing noncompliant fences and gates, by February 28, 2029. The guidelines note that your insurer or the IBHS may not accept vinyl or FRTW within 5 feet.

Sources: City of San Diego Zone 0 Guidelines for Existing Structures (rev. 4/22/2026); San Diego Fire-Rescue Standard D-2; SDMC §512.0604; California Board of Forestry Zone 0 emergency action notice (Aug. 20, 2026). Confirm current status with your AHJ before final design decisions.

Matching a fence material to a fire-rating requirement? Ask for the product’s ASTM documentation and confirm acceptance with your local jurisdiction (AHJ) before you commit to a design.