Does aluminum melt in a fire? Wildfire and house fire heat

Yes, aluminum can melt in a fire: it melts at about 660 C (1220 F), while USGS says wildfires can reach 2,200 F in extreme conditions and NIST puts a room in flashover at about 1,000 C (1,832 F). As of 10 November 2026, melting does not disqualify aluminum under California’s proposed Zone 0 rule, which tests whether a material burns, and that rule is adopted but not in effect.

Melting and burning are different things. A melted aluminum fence section loses its shape but adds no fuel to the fire, and fuel at the house wall is what the Zone 0 rule targets. For whether aluminum counts as noncombustible in the first place, see is aluminum noncombustible.

What temperature does aluminum melt at?

The Aluminum Association’s paper “Fire Safety of Aluminum and Its Alloys” (undated; accessed 10 November 2026) gives these figures:

• Unalloyed aluminum melts at about 660 C (1220 F).
• Most alloys “begin to lose strength at temperatures above 150°C, or 300°F.”

The second number matters more for a fence. An aluminum post or rail can bend under its own weight or a gate’s weight long before anything melts.

How hot do wildfires and house fires get?

Here are the published figures next to the aluminum numbers, lowest first:

NIST defines flashover as the point in a contained fire where surfaces exposed to radiation “from fire gases in excess of 600° C” reach ignition temperature “more or less simultaneously.” The flashover and extreme wildfire figures both sit above aluminum’s melting point. Whether a particular fence melts depends on how long it stays in that heat.

How long does the heat last at a fence?

A passing flame front is short. Jack Cohen of the USDA Forest Service said in a 2000 lecture that crown fire experiments in forests and shrublands show “the burning duration of these large flames is on the order of one minute at a specific location,” because those fires burn through fine vegetation fast.

Fuel at the fence base burns longer. NIST’s 2022 fence study found that placing mulch under a fence panel “resulted in steady progression of the fire along the fence, reaching the end of the panel in minutes.” NIST tested combustible fences there, but the same report warns that “combustible materials at the base of even noncombustible fences can transport fire.” Leaves, needles and mulch piled against a metal fence keep flame on the metal for as long as they burn.

A burning house burns longest. A fence section bolted to a house that is fully involved sits next to window flames and wall fires for as long as the house burns. In our reading, this is the case where aluminum at the wall end is most likely to sag or melt.

The Aluminum Association argues that three properties slow heating: the specific heat of aluminum alloys is about twice that of steel, their thermal conductivity is 3 to 6 times higher than ordinary steel, and a bare surface reflects 80 to 90 percent of radiant heat. These are trade group figures for the metal and do not come from a fire test of any fence. The 80 to 90 percent figure is for a bare surface; the paper gives none for a coated one, and a powder coated fence is not bare.

Will aluminum melt in a house fire?

It can. A room in flashover runs at about 1,000 C by NIST’s figure, roughly 340 C above aluminum’s melting point. Wildfires have done the same outdoors. CBS News reported on 12 November 2018 that in the Camp Fire “the blaze was so hot that aluminum wheels on vehicles melted,” and the same story carries an AP photo of molten aluminum flowing from a burned car on Windermere Drive in Malibu on 10 November 2018.

The Aluminum Association’s account of vehicle fires matches this. People inspecting burned wrecks sometimes assumed the missing aluminum had burned away, but the paper says “in reality it had merely melted off of the wreck and pooled on the ground below.”

Why is melting different from burning?

Burning releases heat and flame. Melting is a change of state, and aluminum puddles do not add fuel to a fire. The Aluminum Association makes this point through the cases that gave aluminum a reputation for burning:

• Composite cladding fires in the UK and Australia. The panels had a polyethylene core that burned; the aluminum “would eventually melt” but “did not combust or add to the fire in any way.”
• Navy ship fires in the 1970s, where aluminum ladders and superstructure “melted in the extreme temperatures but did not combust or otherwise contribute to the fires.”

The one exception the paper names is finely divided powder mixed with an oxidizer, as in thermite. It says even aluminum foil “will simply melt like solid bulk aluminum.”

The Board of Forestry’s guidance says “Combustible fences attached to the structure create a direct path for a fire to touch the structure.” A burning wood fence carries flame to the siding. A metal section that softens or melts does not feed that path. NIST’s report classes noncombustible fences as low fire hazard: “They do not burn on their own and have been shown to provide protection against radiant heat.”

Does melting matter under the Zone 0 noncombustible definition?

No, as the rule is written. The Board’s rule, adopted 19 August 2026, defines noncombustible as materials that pass ASTM E136, meeting the standard in Section 501.4.1 of the California Wildland-Urban Interface Code (14 CCR 1298.02(f); 1299.02(g)); our guide to what counts as noncombustible covers the definition in full. E136 holds samples at 750 C for up to 30 minutes. That is above aluminum’s melting point. The pass criteria the Aluminum Association lists cover weight loss, furnace temperature rise and flaming; none of them asks whether the sample keeps its shape. The Aluminum Association reports that all nine alloys and the commercially pure aluminum it had tested passed.

The WUI Code’s other route, ASTM E2652, does not suit aluminum. The Aluminum Association quotes its scope as “not suitable or satisfactory for materials that soften, flow, melt, intumesce or otherwise separate from the measuring thermocouple.” Section 501.4 also bars materials whose combustibility increases with “age, moisture or other atmospheric conditions,” which deals with weathering.

The rule is adopted but not in force. The Board filed it with the Office of Administrative Law on 28 August 2026 (file 2026-0828-03E) and withdrew it on 8 September 2026. On 10 November 2026 OAL’s under-review list had no Board of Forestry entry. If it takes effect as adopted, attached fences and gates would need a 5 foot noncombustible span from the house; details are in Zone 0 fence requirements.

How do I keep an aluminum fence from getting that hot?

Keep fuel away from it. NIST found that “Noncombustible fences free of leaf litter and other combustible debris will not spread fire,” and the Board’s guidance says to “Remove vegetation and combustible materials in contact with the fence.” In practice that means no wood mulch under the fence line in Zone 0, clearing leaves and needles that collect at the base, and moving firewood, bins and cushions away from it.

If the melting point is the deciding factor for you, aluminum vs steel for wildfire compares the two metals. If your fence is coated, is powder-coated aluminum noncombustible covers the coating rules. Either way, ask the seller for an ASTM E136 report on the alloy in the product you are buying. A general paper about alloys does not cover a specific fence.