SFM Standard 12-7A-2

SFM Standard 12-7A-2 is the California test method for exterior windows. A 150 kW burner at the sill runs for eight minutes. A pass means that window assembly did not let flame through the frame or pane, and the frame and pane did not fail structurally. It is not dual-pane glass. It is not tempered glass. It is not an OSFM listing. CWUIC 504.8 treats it as one of four glazing paths. See windows and dual-pane versus tempered.

Why it matters

Radiant heat can break glass before flame reaches the wall. Once the pane is gone, embers and hot gas enter the room. CAL FIRE’s home-hardening page tells you to upgrade older single-pane units to dual-pane tempered glass and to keep plants off the glass. That is guidance. It is not this test.

The lab method asks a different question. Can this frame and this glazing hold together when a burner sits under the sill? Combustibles in Zone 0 make a real fire more like that burner. The test does not replace the five-foot zone.

How it works

The method lives in the California Referenced Standards Code, Chapter 12-7A, under Exterior Windows. It is a California State Fire Marshal procedure. It is not ASTM.

You install the window in a wall module. A gas burner under the sill is set to 150 kW. The fixture limits specimen width to 3 feet (900 mm). The flame covers the full width of the sill.

To pass, the window and its assembly must take eight minutes of that flame with no flame penetration through the frame or pane, and with no structural failure of the frame or pane. Flame-through or structural failure at any time is a fail.

A pass is a result for that specimen, in that frame, with that glazing, as built for the test. It is not a rating you print on a dual-pane energy sticker.

The paths

1. Prescriptive path in California. Adopted code CWUIC 504.8 (mapped fire hazard areas; people still search Chapter 7A) requires exterior windows, window walls, glazed doors, windows in exterior doors, and skylights to be one of: multilayered glazed panels with at least one tempered pane complying with California Building Code Section 2406; glass block; glazing with a 20-minute fire-protection rating; or glazing meeting SFM Standard 12-7A-2. Dual-pane annealed energy-code glass is not the first option.

2. Performance path. Test the window assembly to 12-7A-2. Models that took that path appear as listed records on the OSFM Building Materials Listing under category 8120. The listing-body record is for a model, not a brand name. Listing is voluntary for most WUI products. Missing from the handbook is not an automatic ban. Presence is not an automatic permit.

3. Oregon R327, where adopted. R327.3.6 lists tempered glass, multilayered glazed panels, glass block, or a 20-minute fire rating. Those are or options. Dual-pane energy-code windows are multilayered. You do not need 12-7A-2. Confirm with the building official. Read R327 versus CWUIC.

4. Insurance and retrofit checklists. California Safer from Wildfires credits multipane windows. IBHS Wildfire Prepared Enhanced specifies dual-pane glass with tempered panes in both, or 20-minute glass, or glass block. Essential is the ember package (roof, vents, Zone 0). Neither checklist is this test method.

Deschutes County’s R327 page names double-pane windows as a commonly used fire-hardening material. OSFM handbook products count when they are shown on the drawings. That is local practice.

What people mix up

• Treating dual-pane, tempered, and 12-7A-2 as one product. They are three different facts. The dual-pane versus tempered guide is the crosswalk.
• Telling a California client that Oregon energy-code dual-pane satisfies CWUIC because it satisfies R327.
• Importing “Chapter 7A listed windows only” onto an Oregon drawing when the official did not ask for that.
• Calling every vinyl dual-pane unit an OSFM 8120 listed window. Almost none are. The 2025 handbook has a short 8120 list.
• Calling dual-pane a “fire-rated window.” A 20-minute fire-protection rating is a different CWUIC option.
• Treating a 12-7A-2 pass as a 20-minute rating, or the reverse.
• Specifying a brand instead of a path. If you use the listing path, spec the listing ID and the model.
• Using an 8120 listing as a door spec. Exterior door leaves sit in OSFM category 8150 (SFM 12-7A-1). CWUIC still puts glazed doors and windows in doors on the 504.8 glazing list, which can include 12-7A-2. Read the doors page for the leaf.
• Scaling a 3-foot specimen to every lite on the house. The apparatus caps window width at 3 feet. Listing 8120-2120:0500 is a 36 by 42 inch section. Confirm size and model on the listing.
• Using IBHS Essential as a window spec. Enhanced is the dual-tempered line.
• Ignoring skylights. CWUIC 504.8 includes them. Operable skylights also need 1/8 inch noncombustible mesh. That mesh rule is not this test.

How to check

Read the adopted code for the lot. If none, you are in voluntary hardening or an insurer checklist.

On the house, note single-pane versus dual-pane at the edge of the sash. Tempered glass usually has a corner etching. If you cannot see an etching, do not write “tempered” on the drawing.

If the official wants this performance path, open the product record, then the listing URL. Confirm the live GOVmotus record and the exact model. Put that model on the drawings. See how to read a listing.

This site currently records two OSFM 8120 assemblies, both Riviera Bronze: 8120-2120:0100 (laminated annealed glass or an insulating unit with at least one tempered pane) and 8120-2120:0500 (triple-layer laminated section). Confirm both before you specify either. Do not invent a listing ID for a big-box dual-pane unit that is not on the handbook.

On a product page we cite 12-7A-2 only when a listing body or the standard itself is in the source list. Manufacturer “12-7A-2 approved” copy is not enough.

Limits

This page does not decide what your building official will stamp. It does not rate U-factor, hail, wind, or egress. It does not make the house fireproof. Two 8120 records are not a shopping catalog. Most energy-code windows never appear in category 8120, and they do not need to when the prescriptive path is the rule in force.

The method tests a window assembly in a fixture. It does not test every skylight geometry, every sliding-door size, or every aftermarket film. Installation still has to match the listing and the manufacturer’s instructions.

R327, where adopted, is new-construction scope unless the local department says otherwise. FireApproved is not a listing body and not an authority having jurisdiction.

Related records

Sibling SFM methods cover other assemblies: 12-7A-1 siding and door leaves, 12-7A-3 eave undersides, 12-7A-4 decking. Do not swap those numbers.

Sources

1. SFM Standard 12-7A-2, 2022 California Referenced Standards Code Chapter 12-7A. ICC / California. Official source for the 150 kW, eight-minute method and the 3-foot fixture limit.
2. 2025 California Wildland-Urban Interface Code. ICC / California. CWUIC 504.8 glazing paths.
3. 2025 OSFM WUI Listed Products Handbook (2 September 2025). CAL FIRE OSFM. Category 8120.
4. OSFM Building Materials Listing search. CAL FIRE OSFM. Live listing index.
5. 2023 ORSC Section R327 amendment. Oregon Building Codes Division. R327.3.6.
6. Home Hardening. CAL FIRE. Retrofit guidance, not a listing mandate.
7. Fire Hardening Requirements (R327). Deschutes County. Double-pane practice and handbook products on drawings.
8. Wildfire Prepared Home. IBHS. Enhanced window spec is not 12-7A-2.
9. California Safer from Wildfires. California Department of Insurance. Multipane credit.