If you’ve ever walked past a fire escape in an urban building, leaned against a security fence at a construction site, or stood in front of a ventilation grille in a commercial kitchen, chances are you’ve interacted with standard expanded metal—one of the most underrated, versatile building materials on the market. As a supplier of standard expanded metal, I get asked a lot of questions about its properties, but few are as critical (and as often misunderstood) as its fire resistance. Fire safety isn’t just a buzzword for architects, facility managers, or contractors; it’s non-negotiable for code compliance, building occupancy, and, most importantly, keeping people safe when an emergency strikes. So today, I want to break down exactly what standard expanded metal’s fire resistance is, how it performs in real-world conditions, and why it’s a reliable choice for projects that need to hold their own when temperatures spike. Standard Expanded Metal
First, let’s start with a quick refresher on what standard expanded metal actually is, because this is the foundation of understanding its fire performance. Unlike welded wire mesh (which is made by welding individual wires together) or perforated metal (which has holes punched out of a solid sheet), standard expanded metal is created by slitting and stretching a single sheet of metal in one continuous operation. The result is a uniform, interconnected grid of diamond-shaped openings, with no loose wires, no weak weld points, and a structure that’s part solid metal, part open space. Most standard expanded metal we supply is made from carbon steel, aluminum, or stainless steel—each has its own unique properties, and fire resistance depends heavily on the base metal you choose, as well as the gauge (thickness) and mesh size of the sheet.
Now, let’s get to the core question: How does standard expanded metal hold up in fire? The short answer is that its fire resistance is almost entirely determined by the melting point of its base metal, and how that metal behaves when exposed to extreme heat. For context, common building materials have vastly different melting points: wood catches fire and burns at around 572°F (300°C), plastics melt at between 320°F and 500°F (160°C to 260°C), and even most common steels start to lose structural integrity long before they melt. Carbon steel, the most common material for standard expanded metal used in construction, has a melting point of roughly 2750°F (1510°C)—that’s way higher than the temperatures generated by most standard structural fires, which typically peak between 1200°F and 2000°F (650°C to 1090°C) in enclosed spaces.
But here’s the catch: While steel doesn’t melt easily, it does lose its strength at elevated temperatures. At 1000°F (538°C), carbon steel loses about half of its room-temperature yield strength, and at 1200°F (649°C), it can drop to just 10% of its original strength, which is why structural steel in buildings is almost always coated with fire-resistant materials like intumescent paint or gypsum board. This is a key point that many people miss: standard expanded metal isn’t fireproof (no building material is), but it does have a much higher fire resistance rating than many alternative materials it’s often compared to. For example, perforated carbon steel of the same gauge has nearly identical fire performance, but welded wire mesh, with its welded joints, can fail at lower temperatures if the welds soften or break before the solid metal structure does. Standard expanded metal’s integrated, slit-and-stretch structure means there are no weak points at the connections, so it maintains more structural integrity longer under heat.
If you’re specifying standard expanded metal for high-heat applications, the base metal choice is non-negotiable, and I’ve seen this play out on dozens of projects I’ve supported over the years. Let’s break down the common materials we supply and their fire-related performance:
Carbon steel standard expanded metal is the workhorse for most general construction, architectural, and industrial applications. Its melting point is high, as we noted, but it’s prone to rust if not treated, so we typically supply it hot-dip galvanized after expansion, which adds a layer of zinc that also boosts its heat resistance slightly. Galvanized carbon steel expands at a consistent rate when heated, and while it will soften at fire temperatures, it won’t fail catastrophically at the lower end of standard fire curves—this makes it ideal for fire escape treads, safety grilles, and temporary construction barriers that need to resist minor exposure to sparks or small, localized fires. That said, for applications where it will be exposed to prolonged, intense heat (like near commercial furnaces or in areas designated as fire-separation zones), carbon steel will need additional fireproof coatings to extend its performance.
Aluminum standard expanded metal is lighter than steel, which makes it popular for cladding, window screens, and architectural facades, but it has a much lower melting point: around 1220°F (660°C). That’s right around the upper end of a typical structural fire, so aluminum expanded metal will soften and melt faster than carbon steel when exposed to sustained high heat. That doesn’t make it a bad choice—it just means it’s not suitable for primary structural applications that need to hold up during a full building fire. We regularly specify aluminum for exterior screens, light fixtures, and interior decorative grilles where it will only be exposed to occasional, low-level heat from sunlight or small kitchen fires, and it performs reliably there. The tradeoff is its light weight and corrosion resistance, which make it perfect for non-structural interior and exterior uses.
Stainless steel standard expanded metal is the top tier for fire resistance, hands down. The most common type, 304 stainless steel, has a melting point of around 2600°F (1427°C), nearly identical to carbon steel, but it has a key advantage: it forms a thin, stable chromium oxide layer when heated, which prevents oxidation and slows down structural degradation even at very high temperatures. 316 stainless steel, the marine-grade variant, adds molybdenum for extra corrosion resistance, and it also performs exceptionally well in fire conditions. For applications like commercial kitchen exhaust hoods, furnace guards, or fire-rated ductwork, stainless steel standard expanded metal is often the only material that meets local building codes for continuous high-heat exposure. I remember a project a few years ago for a large hotel chain that needed custom expanded metal grilles for their commercial kitchen vents—they initially quoted carbon steel, but their fire marshal required 316 stainless because the grilles would be within 10 feet of fryers that regularly hit 400°F (204°C), and a fire there could spike to well over 2000°F. The stainless steel held up perfectly during a test burn, and it’s still in place three years later with zero signs of distortion.
Beyond base metal, two other factors affect standard expanded metal’s fire performance: gauge and mesh size. Thicker-gauge metal (think 1/4-inch or heavier) has more mass, so it takes longer to heat up and lose strength than a thin 16-gauge sheet. That’s why we always advise contractors and architects to specify the thickest gauge possible for applications near heat sources. Mesh size also matters: smaller, tighter diamond openings mean more solid metal per square foot, so there’s more material to resist heat and maintain structure, while larger, open mesh sizes are lighter but can heat up faster. For example, a heavy-gauge, small-mesh expanded metal fence will hold up to a welding spark or a small brush fire far better than a thin, large-mesh version of the same material.
Now, let’s talk about real-world testing and code compliance, because that’s what matters most when specifying materials for a building. Standard expanded metal isn’t routinely tested for fire resistance in the same way that structural steel beams or fire doors are, but that doesn’t mean its performance isn’t standardized. Many of our clients use it in applications that require a fire rating, and we work with them to match it to the appropriate testing standards. For example, if you need expanded metal for a fire-rated wall assembly, you can pair standard expanded metal lath with fire-resistant gypsum board, and the combined assembly will meet ASTM E119 (the standard test for fire resistance of building materials) for 1-hour, 2-hour, or even 3-hour ratings. I’ve seen this work flawlessly in office buildings, where expanded metal lath is used to hold plaster on fire-rated interior walls, and the assembly has passed all code requirements for years.
Another common use case where fire performance is critical is security fencing, especially around industrial facilities or storage yards. A few months ago, a manufacturing client came to me asking about expanded metal fencing that could resist arson attempts—their yard had been targeted by vandals who lit small fires under the fence to cut through it with torches. We recommended 1/2-inch gauge 304 stainless steel standard expanded metal, and we ran a test for them: we lit a controlled fire under a 4-foot section of the fence that burned for 20 minutes, reaching temperatures over 1800°F. The fence didn’t bend, break, or distort enough to be cut, and once the fire was out, it cooled down quickly and remained structurally sound. That’s exactly the kind of real-world fire resistance we design our products to provide.
Of course, no material is perfect, and standard expanded metal does have limitations when it comes to fire. It’s not a replacement for full fire-rated structural steel in load-bearing applications that need to remain intact during a major building fire, and thin-gauge aluminum expanded metal will melt if exposed to prolonged high heat. But for the vast majority of applications—fire escapes, safety grilles, vent covers, lath for fire-rated walls, security fencing, and kitchen components—standard expanded metal’s fire resistance is more than sufficient, and it’s often more cost-effective and easier to install than alternative materials.
As a supplier, I’ve spent years working with architects, contractors, facility managers, and DIY builders to match the right standard expanded metal product to their needs, and fire resistance is always a key consideration. I always tell my clients to ask themselves three questions first: 1) What is the maximum temperature this material will be exposed to? 2) Is it for load-bearing or non-load-bearing use? 3) What local fire codes apply to this application? Those three questions will narrow down the best base metal, gauge, and mesh size every time.
If you’re working on a project and need help figuring out which standard expanded metal will perform reliably in fire conditions, or if you have specific needs for high-heat applications, I’d encourage you to reach out to discuss your requirements in detail. We work closely with fire marshals and code officials across the country to ensure our products meet all necessary standards, and we can provide samples, test data, and custom sizing to fit any project, large or small.
Perforated Metal References
ASTM International. (2022). Standard Test Methods for Fire Tests of Building Construction and Materials (ASTM E119).
American Iron and Steel Institute. (2021). Steel Design Guide Series: Fire Resistance of Structural Steel.
National Fire Protection Association. (2020). NFPA 70: National Electrical Code (Chapter 5: Special Occupancies).
International Code Council. (2022). International Building Code (Chapter 7: Fire and Smoke Protection Features).
Anping Yilida Metal Wire Mesh Co., Ltd.
Anping Yilida Metal Wire Mesh Co., Ltd. is one of the most reliable standard expanded metal manufacturers and suppliers in China, also supports customized service. Please feel free to buy bulk high quality standard expanded metal made in China here from our factory.
Address: Wire Mesh Development Zone, Anping, Hebei Province, China
E-mail: sales@wiremesh-yg.cn
WebSite: https://www.yilidametal.com/
