Comparison of Core Material Types for Sandwich Panels

Core Material Type	Key Features	Primary Applications	Fire Rating	Thermal Performance
Rock Wool	Class A Non-combustible, High-temperature resistance, Sound absorption	High fire safety requirements: Industrial plants, Public buildings	Class A (Non-combustible)	Good
Fiberglass Wool	Lightweight, Cost-effective, Installation-friendly	General insulation and soundproofing: Offices, Shopping malls	Class A (Non-combustible)	Good
Polyurethane (PU/PIR)	Excellent thermal insulation, Lightweight with high strength	High insulation requirements: Cold storage, Logistics	Class B (Flame-retardant – B1)	Excellent
Polystyrene (EPS/XPS)	Low cost, Lightweight, Moisture-resistant	Budget projects with moderate insulation needs: Temporary structures, Warehouses	Class B (Combustible – B2)	Good

Description: Inorganic fibers made from natural basalt and mineral slag, melted at high temperatures.
Greatest Advantage: Absolute fire safety (Class A non-combustible material).
Advantages:
- Excellent fire resistance (melting point >1000°C)
- Outstanding sound absorption and noise reduction
- High durability, no aging
Disadvantages:
- Relatively heavy weight
- Thermal performance declines when wet
- Higher cost compared to some alternatives
Typical Applications: Industrial plants, hospitals, schools with strict fire safety requirements.

Description: Polymer material formed by foaming isocyanate and polyol mixtures, including PUR (Polyurethane) and superior PIR (Polyisocyanurate).
Greatest Advantage: Best thermal insulation performance among all core materials.
Advantages:
- Extremely low thermal conductivity (0.022-0.024 W/m·K)
- Lightweight with high strength, strong adhesion
- Excellent moisture resistance
Disadvantages:
- Moderate fire performance (Class B1), decomposes at high temperatures
- Higher cost
Typical Applications: Cold storage facilities, constant temperature and humidity workshops requiring maximum insulation.

Description: Includes EPS (Expanded Polystyrene) and XPS (Extruded Polystyrene).
Greatest Advantage: Best cost-effectiveness.
Advantages:
- Lowest cost, economical
- Lightweight, easy to cut and install
- Good moisture resistance, low water absorption
Disadvantages:
- Poor fire performance (Class B2/B3), shrinks and releases toxic gases when exposed to fire
- Low strength, prone to compression deformation
Typical Applications: Budget-conscious temporary structures, warehouses, market sheds.

Description: Cotton-like material formed by fiberizing molten glass.
Greatest Advantage: Cost-effective thermal and acoustic insulation.
Advantages:
- Good fire performance (Class A non-combustible)
- Effective thermal and sound insulation
- Flexible, suitable for complex shapes
Disadvantages:
- Fibers can become airborne, requiring careful handling
- Prone to collapse and performance degradation when wet
Typical Applications: Office partitions, commercial buildings where extreme conditions aren’t expected.

The choice of core material depends on your project’s primary requirements:

Maximum Fire Safety: Choose Rock Wool
Best Thermal Performance (e.g., cold storage): Prefer Polyurethane, especially PIR
Budget Constraints with Moderate Fire Requirements: Consider Polystyrene
Balancing Fire Safety, Insulation and Cost: Fiberglass Wool provides a good compromise

Always consider local building codes, fire regulations, and specific application requirements when making your final decision.