SFM 12-7A-3

SFM 12-7A-3 is the California test method for the underside of horizontal projections. That means roof eaves, floor projections, and exposed underfloor areas. The method asks whether an underside assembly resists a direct flame from below. It is not a vent test. OSFM handbook category 8160 is the listing bucket. Un-vented fiber-cement soffit can be an 8160 covering. Perforated soffit is not an ember-rated eave vent.

Why it matters

Wind-blown embers collect on the wall and under the overhang. Flame from below can ignite the same surface. Open rafter tails and cheap soffit vents give fire a place to land and a hole into the attic. This test is about the covering that faces the ground, not the hole that ventilates the attic. See eaves.

The live California construction book is CWUIC, Title 24 Part 7, as of 1 January 2026. People still search Chapter 7A. 12-7A-3 is the test method in the California Referenced Standards Code. It is not the construction chapter.

How it works

The method is published in the California Referenced Standards Code as Horizontal Projection Underside. The specimen is a representative eave or projection. Typical framing, joints in soffit material, and other field features belong in the specimen.

A 12 by 12 inch burner at about 300 kW sits below the assembly. Direct flame exposure lasts 10 minutes. Observation continues so the full run is 40 minutes. Three specimens must meet the conditions of acceptance. If one fails, three more may be run, and all of those must pass.

Conditions of acceptance:

1. No flame penetration of the eaves or horizontal projection assembly at any time.
2. No structural failure of the eaves or horizontal projection subassembly at any time.
3. No sustained combustion of any kind at the conclusion of the 40-minute test.

A pass is a result for that assembly, as built for the test. Thickness, backing, fasteners, and orientation in the listing DESIGN line are part of the result. Absence from an 8160 list is not proof of failure. Presence is not a permit.

The paths

Keep the covering and the opening separate.

1. California performance path (this method). Spec an underside assembly tested to SFM 12-7A-3. Models that OSFM has listed sit in handbook category 8160. Confirm the live GOVmotus record. Listing is the performance path for that model. It is not a statutory mandate for most WUI products. See OSFM BML.

2. California noncombustible covering. Some 8160 rows are listed as noncombustible under-eave material, not as a 12-7A-3 protocol line. On this site that includes HardieSoffit un-vented (8160-2026:0007) and CemSoffit un-vented (8160-2026:0006). Read the DESIGN line. Un-vented is the covering. It is not a vent.

3. Oregon R327 underside (where adopted). Oregon R327 does not name SFM 12-7A-3. When any of the eave framing is under 12 feet, protect it with one of:

1. Noncombustible material.
2. Ignition-resistant material.
3. One layer of 5/8 inch Type X exterior gypsum sheathing behind the exterior covering.
4. The exterior portion of a 1-hour fire-resistance-rated exterior wall assembly.
5. A soffit assembly tested to ASTM E2957 that meets the code’s conditions of acceptance.

Deschutes County counts handbook products when they are shown on the drawings. That is local practice, not a rewrite of Oregon’s named tests. Full overlay: R327 versus CWUIC.

4. The opening (a different method). If the attic still needs air, the hole in the soffit is a vent. That is OSFM 8165 and ASTM E2886, or a prescriptive mesh path where the adopted code still allows it. Where R327 is adopted, vents on the underside of eaves, soffits, or cornices are restricted unless the building official accepts a manufactured ember- and flame-resistant vent, or the opening sits 12 feet or more above grade. See mesh versus listed vents.

What people mix up

• Treating perforated or louvered fiber-cement soffit as an ember-rated eave vent. It is not. See Findings.
• Specifying an 8160 soffit panel and calling it a listed vent. 8160 is the covering. 8165 is the opening.
• Treating every 8160 row as a 12-7A-3 test. Some rows are listed as noncombustible under-eave material.
• Assuming ASTM E2957 and SFM 12-7A-3 are interchangeable without the building official. Oregon names E2957. California publishes 12-7A-3.
• Assuming IBHS Essential already scored enclosed eaves. That is Enhanced. It is not this test.
• Thinking a listing number is a permit. Show the model on the drawing. Confirm GOVmotus.

How to check

Walk the house. Open eave or boxed soffit. Note every hole, including dryer and bath fans that dump at the overhang.

On a listing, read the category first. 8160 is this underside bucket. 8165 is a vent. Then read the model and the DESIGN line. Match thickness, vented versus un-vented, and any required gypsum, OSB, or moisture-barrier backing. Nusku Thermacor eave material (8160-2064:0504) is an 8160 row that names SFM 12-7A-3. Un-vented HardieSoffit names noncombustible. Neither is an 8165 vent.

On the drawing, name the covering path and the vent path. If you enclose the eave, size remaining vents so the attic still meets ventilation code. Read how to read a listing.

Limits

This page does not decide what your building official will stamp. It does not rate attic airflow. It does not test vents. A pass is for the tested assembly, not every board in the same brand catalog. It does not make the house fireproof. SFM 12-7A-1 (siding) and SFM 12-7A-4 (decking) are different methods.

Related records

• Eaves and soffits
• Vented fiber-cement soffit is not an ember-rated vent
• OSFM BML
• ASTM E2886
• CWUIC

Sources

• SFM 12-7A-3, California Referenced Standards Code (ICC / California)
• 2025 OSFM WUI Listed Products Handbook (CAL FIRE OSFM)
• OSFM Building Materials Listing search (CAL FIRE OSFM)
• 2023 ORSC Section R327 amendment (Oregon Building Codes Division)
• Fire Hardening Requirements (R327) (Deschutes County)
• 2025 California Wildland-Urban Interface Code (ICC / California)
• Wildfire Prepared Home (IBHS)