On this page

Why it matters
How it works
How the documents split
The paths
What people mix up
How to check
Limits
Related records

Home / Guides / How it works / ASTM E119 versus a WUI wall test

ASTM E119 versus a WUI wall test

Last verified 2026-08-27.

ASTM E119 is a furnace fire-resistance method for building elements. Intertek’s public scope page says it measures how long an assembly contains a fire, keeps load, and limits heat, often followed by a hose stream. SFM 12-7A-1 is a 10-minute 150 kW flame on a siding and sheathing assembly. A 20-minute fire door is a different object. Do not swap them on a WUI wall.

You are looking at a wall section that says “1-hr Type X.” The sider thinks that is the wildfire path. The examiner wants the covering path in R327 or 12-7A-1. The furnace rating is still a party-wall or occupancy separation object.

No g3-passed exhibit matches this split. MECH-002 is the Steiner tunnel. MECH-003 is gypsum calcination. Do not reuse them as an E119 furnace.

Why it matters

People paste an interior fire-resistance hour onto an exterior WUI wall and call it done. Embers and a 10-minute flame against siding are not a furnace that heats the whole assembly from one side for an hour. The Type X path is a covering exception. It is not a shortcut to skip 12-7A-1 in California or to invent an hourly rating in Oregon.

How it works

E119, as labs describe it in public, puts a specimen on a furnace that follows a time-temperature curve. Failure is temperature rise, flames through, or load loss. Time is reported as 1/2-h, 1-h, 2-h. A hose stream may follow. That is structure fire from the inside of the building out, or occupancy separation.

WUI wall tests face flame or embers from outside. 12-7A-1 is ten minutes at 150 kW on the cladding and sheathing. ASTM E2707 is another exterior-wall flame method the site already carries. Neither is E119.

How the documents split

Object	What it measures	What it is not
ASTM E119 (lab public scope)	Furnace duration, load, heat, hose stream	A WUI siding listing
SFM 12-7A-1	10 min, 150 kW, siding and sheathing	An hourly fire-resistance rating
Oregon Type X path	5/8 in Type X behind the covering	“1 hour E119” on the elevation
20-minute fire door	Interior-rated leaf	The exterior wall
Char rate	AWC βn from E119 furnace exposure	A deck or siding listing
Steiner tunnel	Surface flame spread	Fire-resistance hours

The paths

1. Name the exposure. Interior fire-resistance is E119. Exterior wildfire flame on a wall is 12-7A-1 or E2707, or a deemed-to-comply covering path.

2. Do not relabel Type X as an hourly rating. Why Type X works is water in the core. The permit path is the covering exception. Hold the gypsum open until inspected.

3. Do not use a 20-minute door as the wall. WUI doors versus 20-minute fire doors.

4. California listing is still a model. 12-7A-1 is the test. The BML row is the listing. Listed is voluntary until the AHJ says otherwise.

5. Timber char is not siding. Char rate cites AWC’s E119-derived βn. Different object.

What people mix up

E119 hours as a WUI wall pass.
Type X chemistry as a 1-hour stamp on the elevation.
12-7A-1 as E84.
A 20-minute fire door as the exterior wall.
Hose-stream E119 as a wildfire hose attack.

How to check

Read the test name on the drawing. E119, 12-7A-1, E2707, or Type X.
Open the matching hub on this site. Confirm what it covers.
If someone wrote “1-hr” on siding, ask which method. Furnace or wildfire flame.
If the lot is Oregon R327, open the Type X path, not an E119 catalog.
Do not download a paywalled E119 body from this page. Intertek is a lab description.

Limits

This page does not reprint the ASTM E119 time-temperature curve. The standard body was not opened. FireApproved is not ASTM and not OSFM. Use the method the adopted code names.

Where this differs

Find what applies near you

Enter a ZIP before browsing the complete evidence. Matching, inherited, and place-neutral records will move first; other places and unmapped application rows will fold into expandable groups. Nothing is removed. All 7 cited place claims remain available.

Standards and listing systems (1)

Intertek public ASTM E119 method page. E119 test methods evaluate the duration for which building elements contain a fire, retain structural integrity, or both, during a predetermined furnace exposure. The specimen is exposed to a standard fire controlled to specified temperatures over time. When required, usually for wall assemblies, the fire exposure is followed by a standard hose-stream exposure. Performance is the period before the first critical point, which may include temperature rise, flames or hot gases, or failure to maintain load. Results are expressed as 2-h, 6-h, 1/2-h, and similar. This is a laboratory’s public description of the method. The ASTM body is paywalled.

As of 2026-08-23 · ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials — Intertek

California CWUIC mapped fire hazard areas

CWUIC 504.5 keeps separate one-hour exterior-side, noncombustible, SFM 12-7A-1, ASTM E2707, Type X, and other exterior-wall paths. A product tested to SFM 12-7A-1 is evidence for that alternative; it does not become an ASTM E119 one-hour wall, and an OSFM listing is not itself the statutory requirement.

As of 2026-08-27 · 2025 California Wildland-Urban Interface Code construction notes, Section 504.5 — Town of Truckee public record

Colorado Wildfire Resiliency Code 2025

CWRC 404.3 Class 2 exterior walls include assemblies with a minimum 1-hour fire-resistance rating, rated for exposure on the exterior side, among other methods. That is not SFM 12-7A-1 and not Oregon's Type X-behind-covering path. Class 1 does not add this wall rule. Confirm the local ordinance.

As of 2026-08-25 · 2025 Colorado Wildfire Resiliency Code — Colorado Division of Fire Prevention and Control

Oregon R327 where adopted

One layer of 5/8-inch Type X exterior gypsum sheathing behind the covering is a deemed-to-comply wall path. That is not an E119 hourly rating written on the siding.

As of 2026-08-23 · 2023 ORSC Section R327 amendment — Oregon Building Codes Division

Pennsylvania 2021 IWUIC Class 1 and 2 exterior walls

Pennsylvania incorporates the unmodified 2021 IWUIC effective 1 January 2026. Sections 504.5 and 505.5 include approved noncombustible material as one Class 1 and Class 2 exterior-wall path. That material attribute does not establish a one-hour assembly, wall extent, another alternative, or the complete wall. Official map, assigned class, project, assembly, local amendment, and building-official confirmation remain checks.

As of 2026-08-27 · 2021 ICC Code Adoption Final Report — Pennsylvania Department of Labor & Industry

Salt Lake City 2006 UWUI exterior walls

Current Salt Lake City Code 18.44.010.B applies the Utah Wildland Urban Interface Code on property shown on the City WUI map. In the 2006 book, Sections 504.5 and 505.5 give IR1 and IR2 walls separate one-hour exterior-side and approved noncombustible-material paths. A Table 503.1 N.C. result instead requires both a one-hour wall and a noncombustible exterior surface. A product attribute does not establish the complete wall or the table result.

As of 2026-08-27 · Salt Lake City Code 18.44.010 International Fire Code and Standards Adopted — Salt Lake City / American Legal Publishing

Taylorsville 2006 UWUI exterior walls

Ordinance 25-15 adopts the Utah Wildland Urban Interface Code with FFSL-approved alternatives or amendments on the attached map. In the 2006 book, Sections 504.5 and 505.5 give IR1 and IR2 walls separate one-hour exterior-side and approved noncombustible-material paths. A Table 503.1 N.C. result instead requires both a one-hour wall and a noncombustible exterior surface. A product attribute does not establish the complete wall or the table result.

As of 2026-08-27 · Taylorsville Ordinance 25-15 Utah Wildland Urban Interface Code — City of Taylorsville

Questions

Is a 1-hour E119 wall a WUI wall?

Not by itself. E119 is a furnace method for how long an element contains fire and holds load. California’s SFM 12-7A-1 is a 10-minute 150 kW direct-flame exposure on a siding and sheathing assembly. Oregon’s Type X path is one layer of 5/8-inch Type X behind the covering. Those are different books.

Is the 20-minute fire door an E119 wall?

No. A 20-minute fire door is an interior-rated leaf. See WUI doors versus 20-minute fire doors. Do not specify a 20-minute door as the exterior wall assembly.

Does Type X chemistry equal an E119 rating?

No. Why Type X works is calcination. An E119 rating is an assembly in a furnace for a stated time. R327’s Type X path does not ask you to write “1 hour E119” on the siding.

Is char rate an E119 number?

AWC’s Fire Design Specification uses a nominal char rate from ASTM E119 furnace exposure. That is timber design, not a WUI siding listing. See char rate.

Sources

2025 California Wildland-Urban Interface Code construction notes, Section 504.5 — Town of Truckee public record (official). Accessed 2026-08-27.
2006 Utah Wildland-Urban Interface Code — International Code Council (hosted by Sanpete County) (official). Accessed 2026-08-27.
Salt Lake City Code 18.44.010 International Fire Code and Standards Adopted — Salt Lake City / American Legal Publishing (official). Accessed 2026-08-27.
Taylorsville Ordinance 25-15 Utah Wildland Urban Interface Code — City of Taylorsville (official). Accessed 2026-08-27.
ASTM E119 Standard Test Methods for Fire Tests of Building Construction and Materials — Intertek (secondary). Accessed 2026-08-23.
SFM 12-7A-1 — California Office of the State Fire Marshal (official). Accessed 2026-08-23.
2023 ORSC Section R327 amendment — Oregon Building Codes Division (official). Accessed 2026-08-23.
2025 Colorado Wildfire Resiliency Code — Colorado Division of Fire Prevention and Control (official). Accessed 2026-08-25.