I. Is Rock Wool a Non-Combustible Material?

Domestic Standard Certification

According to GB 8624 "Classification of Combustion Performance of Building Materials and Products":

Rock Wool → Class A

Class A = Non-combustible Material

This means:

It does not participate in combustion

It does not produce a combustion-supporting effect

It does not release heat to propel the spread of fire in a fire.

II. Why is Rock Wool Naturally Non-Combustible?

Rock wool is classified as a non-combustible material due to its inorganic mineral properties.

Raw Materials Determine its Fire-Resistant Nature

Rock wool is mainly made from the following raw materials:

Basalt

Dolomite

Blast Furnace Slag

These materials themselves:

High melting point (>1000℃)

Do not contain organic combustible components

Do not decompose to produce combustible gases

Stable fiber structure

Rock wool has an inorganic fiber structure:

It does not melt or drip at high temperatures

It does not shrink or collapse

It maintains structural integrity

Even in a fire, it can form a stable insulation layer.

III. Actual Performance of Rock Wool in Fires

Qualified rock wool products typically exhibit the following characteristics in a fire:

Non-combustible

No flame propagation

No melting or dripping

No release of toxic fumes

Effectively slows the spread of fire

Therefore, rock wool not only "doesn't burn itself," but also protects the structure it insulates.

IV. The Essential Difference Between Rock Wool and "Flame-Retardant Materials" (Key Point)

Many customers easily confuse non-combustible with flame-retardant. Here's a professional distinction:

| Comparison Items | Rock Wool | Flame-Retardant Rubber & Plastic |

| ----- | ----- | -------- |

| Material Properties | Inorganic Material | Organic Material |

| Combustible | ❌ Non-combustible | ⚠️ Combustible but inhibited |

| Fire Rating | Class A | Class B1 |

| Performance in a Fire | Does not participate in combustion | Self-extinguishing upon removal of flame |

Rock wool ≠ flame-retardant material, but is a naturally non-combustible material. V. Typical Application Scenarios of Rock Wool as a Non-combustible Material

Due to its Class A fire resistance, rock wool is widely used in:

Exterior wall insulation systems

Fireproof barriers

Smoke and exhaust duct insulation

Insulation for high-temperature industrial equipment

Petrochemical, power, and metallurgical industries

In areas where Class A non-combustibility is mandatory, rock wool is often the preferred material.

VI. Common Engineering Misconceptions

Several professional reminders:

The binder content in rock wool products is extremely low and does not affect the overall Class A rating.

Rock wool with aluminum foil or fiberglass cloth on the surface can still achieve Class A (subject to test reports).

Whether it is "non-combustible" is ultimately determined by a third-party test report.

VII. Summary Section Available on the Official Website

Rock wool is an inorganic non-combustible insulation material. According to GB 8624 standard, its combustion performance rating is Class A. Under fire conditions, rock wool does not participate in combustion or cause flame spread, and can effectively slow down the development of fire. It is a commonly used high-safety thermal insulation material in the construction and industrial fields.