ROCKWOOL mineral wool insulation for Fire Partition, ThermalRock S model

ThermalRock

ThermalRock S mineral wool insulation is a high-density rigid board (120 – 150 kg/m3) used for building partition walls or Fire Partition to prevent fire spread between buildings

To reduce losses from fire, fire escape walls or corridors and building partition walls or Fire Partitions must have fire resistance capability

Thermal Conductivity

Before we explain what thermal conductivity is, we’d like to briefly explain the concept of heat transfer first

If we imagine we have a metal cup with hot water inside, and we touch that metal cup, we’ll feel that it’s hot. But if it’s a ceramic cup (pottery, coffee mug), we might feel it’s warm, but certainly not as hot as the metal cup

Now let’s return to thermal conductivity or K-Value. The metal cup feels cold because it has “high thermal conductivity”, allowing heat from the hot water to easily transfer through the metal to our hand. Conversely, the ceramic cup has “low thermal conductivity”, making it harder for heat from the hot water inside to reach our hand. Or as we say, the ceramic cup is a good thermal insulator because it transfers less heat

Therefore, for thermal insulation, a lower thermal conductivity value is better

Thermal conductivity testing for insulation can be conducted. For ROCKWOOL’s ThermalRock S mineral wool insulation, it is tested according to ASTM C518 standard, and the test results are shown in this table

Table of thermal conductivity values for ThermalRock S mineral wool insulation

Product	ThermalRock S120	ThermalRock S140	ThermalRock S150
Thermal Conductivity (W/m.K)	0.034	0.034	0.034

Sound absorption value

For wall systems and ceiling work, the main goal may be only sound insulation or heat insulation. But mineral wool insulation with an open cell structure can provide both heat insulation and significant protection against external noise

The sound absorption value or NRC (Noise Reduction Coefficient) tells us how much sound is absorbed when it hits this material. For example, NRC = 0.8 means if sound hits this material, 80% will be absorbed and only 20% will be reflected

So when there’s external noise like car horns during heavy traffic at night, when the sound hits our wall with ThermalRock S insulation installed, the insulation will absorb the sound inside and not release it, effectively blocking the sound from passing through. Thus, the loud noise will be significantly reduced

Non-combustible material EN13501-1

In fire resistance or fire protection work, the first important point is that the material must be “non-combustible” and must not cause the fire to spread further. ThermalRock S mineral wool insulation has been tested according to EN13501-1 standard to classify materials from A – F based on fire severity

Table classifying materials by fire severity

Definition	Classification according to European Standard EN 13501-1
Non-Combustible materials	A1
	A2 – s1d0	A2 – s1d1	A2 – s1d2
	A2 – s2d0	A2 – s2d1	A2 – s2d2
	A2 – s3d0	A2 – s3d1	A2 – s3d2
Combustible materials – very limited contribution to fire	B – s1d0	B – s1d1	B – s1d2
	B – s2d0	B – s2d1	B – s2d2
	B – s3d0	B – s3d1	B – s3d2
Combustible materials – limited contribution to fire	C – s1d0	C – s1d1	C – s1d2
	C- s2d0	C – s2d1	C – s2d2
	C – s3d0	C – s3d1	C – s3d2
Combustible materials – medium contribution to fire	D – s1d0	D – s1d1	D – s1d2
	D – s2d0	D – s2d1	D – s2d2
	D – s3d0	D – s3d1	D- s3d2
Combustible materials – highly contribution to fire	E	E – d2
Combustible materials – easily flammable	F

“s” Smoke emission level: ranges from 1 (low-no smoke) to 3 (high smoke emission)

“d” Flaming droplets: ranges from 0 (no droplets) to 1 (many droplets)

Table showing levels of smoke production and flaming droplets

Additional class			Level Definition
Smoke emission during combustion	S	1	Quantity/speed emission of absent or weak
		2	Quantity/speed emission of average intensity
		3	Quantity/speed emission of high intensity
Production of flaming droplets/particles during combustion	D	0	No dripping
		1	Slow dripping
		2	High dripping

From the material classification table, we can see that ThermalRock S mineral wool insulation is an A1 class material, which is non-combustible, does not produce smoke, and does not produce flaming droplets. Therefore, it can be confidently used as a material for fire protection

Moisture absorption/Water absorption

In wall systems, moisture is a significant problem. Damp walls can cause paint to blister, mold to grow on ceilings and walls, and water stains on walls, reducing the building’s lifespan

This issue has led insulation manufacturers to develop their products further by making mineral wool insulation less water-absorbent. This means the insulation won’t retain water. When water drops onto ROCKWOOL mineral wool insulation, it forms droplets and doesn’t penetrate the insulation, instead remaining as water droplets on the surface

This method allows the insulation to dry quickly when air passes through, causing the water droplets to evaporate completely. ROCKWOOL mineral wool insulation has also passed moisture absorption tests according to ASTM C1104 and ASTM C1104M standards, with a water vapor absorption value of only 0.04%, which is practically no water vapor absorption at all

Mineral wool insulation and cancer risk

Only in Thailand is there concern about “mineral wool” causing “cancer”. This is a misunderstanding due to translation issues. Mineral wool insulation (ROCKWOOL) and asbestos are confused due to similar terminology. We will explain the difference.

Asbestos is a naturally occurring group of minerals with white fibers smaller than 0.1 micron, derived from silicate minerals. It can become airborne and break into smaller, sharp fibers. It is a known carcinogen.

ROCKWOOL mineral wool insulation is produced through a controlled manufacturing process that melts basalt and dolomite rocks to spin fibers 4-6 microns in size. These fibers can break but have large, rounded ends too big to enter the lungs. It does not cause cancer.

Table of differences between ROCKWOOL mineral wool insulation and asbestos

Difference	ROCKWOOL mineral wool insulation	Asbestos
Raw material	Basalt rock, dolomite	Silicate mineral group
Source	Standardized machinery	Accumulation of silicate minerals
Fiber characteristics	4-6 microns, rounded fiber ends	Smaller than 1 micron, sharp fiber ends
Health impact	Does not cause cancer in humans	Causes cancer in humans
Classification by International Agency for Research on Cancer	Group 3: Not classifiable as to its carcinogenicity to humans	Group 1: Carcinogenic to humans

We can find information about various carcinogenic substances from the International Agency for Research on Cancer (IARC). The IARC divides products into 3 groups

Table classifying carcinogenic substances

Group 1	Carcinogenic to humans
Group 2A	Probably carcinogenic to humans
Group 2B	Possibly carcinogenic to humans
Group 3	Not classifiable as to its carcinogenicity to humans