Cold storage warehouses, food processing plants and prefabricated buildings all depend on insulated panels to hold a steady temperature. From blast freezers and cold rooms to clean rooms and prefabricated housing, the choice of panel core determines both operating cost and life safety. But not every insulation is equal: many traditional foam cores burn readily and give off thick, toxic smoke. Rock wool — also called stone wool — solves both problems at once, pairing strong thermal performance with genuine A1 fire safety. In this guide we explain why rock wool is the preferred core for cold storage and sandwich panels, how it performs, and what to look for when buying from a factory.
Why Fire Safety Matters in Cold Storage and Sandwich Panels
Cold rooms carry a higher fire risk than many operators expect. Refrigeration equipment, electrical wiring and the stored goods themselves can all act as ignition sources, while combustible cores made of EPS, XPS or polyurethane spread flame quickly and release dense, toxic smoke. Inside a sealed, refrigerated building that combination can be catastrophic.
Rock wool is classified A1 non-combustible — the highest fire rating under the European classification system. It is produced from basalt rock melted at about 1450°C, so the finished board can withstand temperatures above 1000°C without burning, melting or releasing toxic smoke. In a sandwich panel, a rock wool core contains a fire, slows its spread and protects the structural steel behind the panel. For food facilities and insurers alike, an A1 core is frequently a hard requirement.
Thermal Performance That Keeps the Cold In and Costs Down
A cold store is only as efficient as its insulation. Rock wool has a thermal conductivity of ≤ 0.040 W/m·K (lambda), meaning it resists heat flow very effectively. For a refrigerated facility running 24 hours a day, a low and stable lambda translates directly into lower energy bills and a more consistent internal temperature.
Two properties make rock wool especially well suited to cold and humid conditions:
- Low moisture absorption. Rock wool is hydrophobic, so it does not soak up condensation the way some organic foams can. Its insulating performance therefore stays stable through years of freeze–thaw and high-humidity exposure.
- Dimensional stability. Rock wool boards hold their shape and thickness, so panel joints stay tight and thermal bridging remains minimal.
As a rule of thumb, a 100 mm rock wool board provides an R-value of about 2.5 m²·K/W, which is why panel manufacturers can meet demanding U-value targets with a comparatively thin core — saving space inside the building while keeping energy use low. Pair a rock wool core with a proper vapour barrier and the panel system keeps performing for decades.
Rock Wool Sandwich Panels: A Factory-Built, Fire-Safe System
Most cold storage and prefabricated buildings are assembled from sandwich panels: two metal faces bonded to an insulating core. Rock wool is an ideal core material because it delivers fire safety, thermal insulation and sound absorption in a single layer.
| Property | Typical Value |
|---|---|
| Standard board size | 1200 × 600 mm |
| Thickness range | 30 – 200 mm |
| Facade series density | 50 – 120 kg/m³ |
| Fire rating | A1 non-combustible |
| Thermal conductivity (λ) | ≤ 0.040 W/m·K |
A rock wool core also adds meaningful sound reduction between rooms and from outside, a welcome benefit in busy food plants and urban prefabricated sites. Because the mineral fibres are inert and non-hygroscopic, the core will not rot, support mould growth or attract pests — qualities that matter in food-grade environments.
Taishi Rock Wool is one of China’s largest rock wool producers, with an annual capacity of 800,000 tonnes across 7 production bases. The company holds the China Famous Trademark designation and manufactures its boards from basalt melted at 1450°C, fiberized through the pendulum (spinner) process to produce a uniform, high-quality fiber mat with consistent density and thermal performance. Browse the full product range to see board sizes, densities and thicknesses.
Standards and Certifications: What to Ask For
When sourcing rock wool for cold storage or sandwich panels, insist on test reports. A credible supplier should be able to provide:
- GB/T 25975-2018 — the Chinese national standard for rock wool board, covering thermal conductivity, density, water repellency and fire performance.
- EN 13162 — the European harmonised standard for factory-made mineral wool thermal insulation products.
- ASTM C612 — the American standard for mineral fibre blanket and board insulation.
Taishi Rock Wool can supply EN 13162 and ASTM C612 reports on request, alongside full GB/T 25975-2018 documentation. Request copies before you place an order, and confirm that each certificate matches the exact density and thickness you are buying. If you are new to the material, our overview guide explains what rock wool board is and how it is made in more detail.
Get a Factory-Direct Quote for Your Cold Storage Project
Ready to specify rock wool for a cold room, freezer or sandwich panel line? Taishi Rock Wool exports worldwide through Geyuan Insulation (Shandong) Co., Ltd. Tell us the density, thickness and quantity you need, and our team will reply with a factory-direct quotation within 24 hours. Contact our team to get started.
Related reading
- What Is Rock Wool Board? Manufacturing, Properties and Applications
- Rock Wool Thermal Conductivity and R-Value Explained
- How to Import Rock Wool from China: A Complete 7-Step Guide
Buyer questions we get most
What density of rock wool is used in cold-storage panels?
Cold rooms and refrigerated panels are normally specified at 100–120 kg/m³ so the core holds its shape and compressive strength at temperature.
Which format suits a sandwich-panel core?
Strips (lamella) with the fibre oriented across the thickness, because the core has to carry load. Rigid boards are used for site-built cold rooms and plant rooms.
Does rock wool work with foil facings?
Yes — foil facings are common on cold-store work for vapour control, and they are applied on our lamination line before the material is packed.
About this guide
Who maintains it
This guide is maintained by the Taishi Rock Wool export team in Shandong, China — factory-direct rock wool and glass wool from seven production bases with a combined capacity of 800,000 tonnes a year. Technical questions go straight to the factory rather than to a trading desk: WhatsApp +86 175 6050 1246 or email cliu32626@gmail.com.
Standards and sources referenced
- GB/T 25975-2018 — Chinese national standard for rock wool and its products; our production and test reports follow it.
- EN 13162 — European product standard for mineral wool, including how thermal conductivity (λ) is declared.
- EN 13501-1 — fire classification of construction products; class A1 means non-combustible.
- ISO 8301 / ASTM C518 — steady-state thermal conductivity test methods behind any quoted λ figure.
- ASHRAE Handbook—Fundamentals — definitions of thermal conductivity and R-value used here.
- EURIMA — European Mineral Wool Manufacturers Association, technical guidance on mineral wool performance.
- Insulation Institute (NAIMA) — industry technical resources on insulation performance and specification.
Last updated: September 23, 2026