A Brief Comparison of Insulation Core Materials

The thermal insulation performance and fire safety of steel-structure factories and cold-chain warehouses depend primarily on the insulation core material within the sandwich panels. Currently, the five mainstream types on the market are: rock wool, polyurethane (PU/PIR), expanded polystyrene (EPS), slag wool, and glass wool. These materials differ significantly in terms of fire resistance, temperature tolerance, thermal conductivity, and smoke safety.

☆High-Quality Rock Wool (Class A Non-combustible)

Does not release toxic smoke when exposed to open flames, ensuring safety during evacuation

Temperature tolerance up to 600°C; fire resistance duration of 30–240 minutes

Thermal conductivity of 0.036–0.043; stable thermal insulation performance

Best overall performance and highest versatility; suitable for the vast majority of permanent industrial buildings; high pass rate for inspections

☆Expanded Polystyrene/EPS (Class B Combustible)

Produces large amounts of toxic black smoke when burning; poses significant safety risks

Maximum service temperature of only 85°C; prone to softening and deformation

Thermal conductivity of 0.039–0.041; adequate thermal insulation capability

Limited to short-term, temporary structures; strictly prohibited for permanent buildings; highly likely to fail fire safety inspections

☆Polyurethane/PU/PIR (Class B Combustible)

Combustion accompanied by black smoke; maximum temperature tolerance of only 170°C

Thermal conductivity of 0.022–0.024; best thermal insulation and cold retention capabilities among the five types

Suitable for low-temperature cold-chain buildings, though rock wool partitions must be used for firewalls and evacuation routes

☆Slag Wool (Class A Non-combustible)

No toxic smoke during combustion, but overall performance is inferior to rock wool

Maximum temperature tolerance of only 3... ...00°C; fire resistance rating of less than 60 minutes.

Thermal conductivity of 0.038–0.048; relatively low thermal insulation efficiency.

Prone to pulverization and settling over long-term use; suitable only for low-end, simple factory buildings; not recommended for high-standard projects.

☆Glass wool (Class A non-combustible)

Smokeless and non-toxic; maximum temperature resistance of 200°C; fire resistance duration of 30–120 minutes.

Thermal conductivity of 0.033–0.043; however, the fibers are brittle and have poor moisture resistance.

Thermal insulation performance drops significantly when exposed to moisture; primarily used for insulating ventilation ducts; rarely used for walls or roofs.

Material Selection Recommendations

Low-temperature cold chain storage: Use polyurethane for the main building envelope; use rock wool for fire separation zones.

Standard industrial plants, large-scale warehouses, and buildings with critical fire safety requirements: High-quality rock wool is the preferred choice.

Short-term temporary facilities: Polystyrene (EPS) boards may be used; avoid them entirely for permanent structures.

Ventilation duct insulation: Glass wool is a suitable option.

Small, simple buildings with limited budgets and no high-temperature exposure: Slag wool may be used for short-term applications.

Polyurethane offers superior thermal insulation but has significant fire safety limitations; polystyrene boards are low-cost but pose the highest fire safety risks; slag wool and glass wool each have their own limitations regarding durability and application scenarios. High-quality rock wool balances fire safety, high-temperature stability, and long-term thermal insulation performance, making it the most versatile option. When selecting materials for a project, one should not focus solely on insulation performance or low cost; instead, a comprehensive assessment considering fire safety regulations, ambient temperatures, and the intended service life is necessary to avoid inspection failures and long-term safety hazards.

For more information needed or any inquiry,please feel free to contact Yumisteel team.